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If it does not autorun then please do the following: • Click on my computer • Click the CD/DVD drive and after opening the drive, kindly double click the file Jaypee Jaypee Gold Standard Mini Atlas Series® Optical Coherence Tomography in Retinal Diseases Sandeep Saxena MS MAMS Member, National Academy of Medical Sciences, India DAAD Visiting Professor, University of Bonn, Bonn, Germany Visiting Professor, UNC-Chapel Hill, Chapel Hill, USA Fellow, Barnes Retina Institute and Anheuser-Busch Eye Institute, St. Louis, USA Fellow, New York-Presbyterian Hospital, New York, USA Professor Department of Ophthalmology CSM Medical University (Erstwhile, King George’s Medical University) Lucknow, India ® JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD St Louis (USA) • Panama City (Panama) • New Delhi • Ahmedabad • Bengaluru Chennai • Hyderabad • Kochi • Kolkata • Lucknow • Mumbai • Nagpur Published by Jitendar P Vij Jaypee Brothers Medical Publishers (P) Ltd Corporate Office 4838/24, Ansari Road, Daryaganj, New Delhi 110 002, India, Phone: +91-11-43574357, Fax: +91-11-43574314 Registered Office B-3, EMCA House, 23/23B Ansari Road, Daryaganj, New Delhi 110 002, India Phones: +91-11-23272143, +91-11-23272703, +91-11-23282021, +91-11-23245672 Rel: +91-11-32558559, Fax: +91-11-23276490, +91-11-23245683 e-mail: jaypee@jaypeebrothers.com, Website: www.jaypeebrothers.com Branches 2/B, Akruti Society, Jodhpur Gam Road Satellite, Ahmedabad 380 015 Phones: +91-79-26926233, Rel: +91-79-32988717, Fax: +91-79-26927094, e-mail: ahmedabad@jaypeebrother.com 202 Batavia Chambers, 8 Kumara Krupa Road, Kumara Park East, Bengaluru 560 001 Phones: +91-80-22285971, +91-80-22382956, Rel: +91-80-32714073 Fax: +91-80-22281761, e-mail: bangalore@jaypeebrothers.com 282 IIIrd Floor, Khaleel Shirazi Estate, Fountain Plaza, Pantheon Road, Chennai 600 008 Phones: +91-44-28193265, +91-44-28194897, Rel: +91-44-32972089, Fax: +91-44-28193231 e-mail: chennai@jaypeebrothers.com 4-2-1067/1-3, 1st Floor, Balaji Building, Ramkote Cross Road, Hyderabad 500 095 Phones: +91-40-66610020, +91-40-24758498, Rel:+91-40-32940929 Fax:+91-40-24758499, e-mail: hyderabad@jaypeebrother.com No. 41/3098, B & B1, Kuruvi Building, St. Vincent Road, Kochi 682 018, Kerala Phones: +91-484-4036109, +91-484-2395739, +91-484-,2395740 e-mail: kochi@jaypeebrothers.com 1-A Indian Mirror Street, Wellington Square, Kolkata 700 013 Phones: +91-33-22651926, +91-33-22276404, +91-33-22276415 Fax: +91-33-22656075, e-mail: kolkata@jaypeebrothers.com Lekhraj Market III, B-2, Sector-4, Faizabad Road, Indira Nagar, Lucknow 226 016 Phones: +91-522-3040553, +91-522-3040554, e-mail: lucknow@jaypeebrothers.com 106 Amit Industrial Estate, 61 Dr SS Rao Road, Near MGM Hospital, Parel, Mumbai 400 012 Phones: +91-22-24124863, +91-22-24104532, Rel: +91-22-32926896 Fax: +91-22-24160828, e-mail: mumbai@jaypeebrothers.com “KAMALPUSHPA” 38, Reshimbag, Opp. Mohota Science College, Umred Road, Nagpur 440 009 (MS) Phones: Rel: +91-712-3245220, Fax: +91-712-2704275, e-mail: nagpur@jaypeebrothers.com North America Office 1745, Pheasant Run Drive, Maryland Heights (Missouri), MO 63043, USA Ph: 001-636-6279734 e-mail: jaypee@jaypeebrothers.com, anjulav@jaypeebrothers.com Central America Office Jaypee-Highlights Medical Publishers Inc., City of Knowledge, Bld. 237, Clayton, Panama City, Panama Ph: 507-317-0160 Jaypee Gold Standard Mini Atlas Series Optical Coherence Tomography in Retinal Diseases © 2010, Jaypee Brothers Medical Publishers All rights reserved. No part of this publication and photo CD ROM should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the author and the publisher. This book has been published in good faith that the material provided by author is original. Every effort is made to ensure accuracy of material, but the publisher, printer and author will not be held responsible for any inadvertent error (s). In case of any dispute, all legal matters are to be settled under Delhi jurisdiction only. First Edition: 2010 ISBN 978-81-8448-800-5 Typeset at JPBMP typesetting unit Printed at Preface Ophthalmology is one of the most technology driven disciplines of medicine. Rapid technological advances in the diagnosis and management of vitreoretinal disorders have had dramatic impacts. Evidence-based medicine is a reality today. Spectral-domain optical coherence tomography has begun a new era in ocular imaging. The spectral-domain optical coherence tomography device can produce cross-sectional B-scans, like time-domain optical coherence tomography but with significantly higher resolution, and it can also create 3D area scans by combining B-scans. With 3D image reconstruction, the 3D area scans can be manipulated and viewed from multiple angles. The unprecedented visualization provided by this technology enables determination of specific alterations in retinal anatomy characteristics. Peeling and layer separation in 3D imaging are becoming elegant options. Visualization of separate layers in 3D imaging may be utilized to give a novel perspective. OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES This book Optical Coherence Tomography in Retinal Diseases aims at updating knowledge of the reader on the current status of optical coherence tomography. Medical and surgical diseases of the retina have been included. The aim of this book is to provide a better ‘in vivo’ understanding of retinal disease. I am confident that this mini atlas will be useful to all postgraduate students, vitreoretinal specialists and practicing ophthalmologists. Sandeep Saxena –vi– Contents 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. Optical Coherence Tomography .............................. 1 Three-Dimensional Retinal Imaging .................... 25 Diabetic Macular Edema ......................................... 41 Retinal Vein Occlusion ............................................ 77 Retinal Artery Occlusion ....................................... 101 Age-Related Macular Degeneration .................... 117 Central Serous Chorioretinopathy ....................... 153 Myopia ...................................................................... 171 Epiretinal Membranes ........................................... 179 Vitreomacular Traction Syndrome ...................... 199 Idiopathic Macular Hole ........................................ 215 Cone-Rod Dystrophy .............................................. 243 Optic Disk Pit Maculopathy .................................. 255 Intraocular Tumors ................................................. 265 Intermediate and Posterior Uveitis ...................... 281 Index .......................................................................... 297 1 Optical Coherence Tomography OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION Optical coherence tomography (OCT) is a new technique for high-resolution cross-sectional visualization of retinal structure. Optical coherence tomography achieves 2- or 3-dimensional cross-sectional imaging of retina. Optical coherence tomography is based on the principle of Michelson interferometry. Imaging with OCT is analogous to ultrasound B-scan in that distance information is extracted from the time delays of reflected signals. However, the use of optical rather than acoustic waves in OCT provides a much higher (5-10 micron) longitudinal resolution in the retina versus the 100-micron scale for ultrasound. This is due to the fact that the speed of light is nearly a million times faster than the speed of sound. Use of optical waves also allows a noncontact and noninvasive measurement. The ability to evaluate tissue, in vivo, can have a significant impact on the diagnosis and management of a wide range of retinal diseases. –2– OPTICAL COHERENCE TOMOGRAPHY Time-domain detection technique measures the echo time delay of backscattered or back reflected light via an interferometer with a mechanically scanning optically referenced path. Fourier-domain, spectral-domain or frequency-domain detection technique echo time delays of light are measured by Fourier transforming the interference spectrum of the light signal, which requires no mechanical axial scanning and results in an acquisition speed much higher than that of time-domain OCT. Also, this new technology has a higher sensitivity. –3– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES STRATUS OCT (CARL ZEISS MEDITEC INC., USA) This is an advanced imaging device. This instrument is an interferometer that resolves retinal structures by measuring the echo delay time of light (broad bandwidth near-infrared light beam; 820 nm) that is reflected and back scattered from different microstructural features in the retina. The instrument electronically detects, collects, processes and stores the echo delay patterns from the retina. With each scan pass, the instrument captures from 128 to 768 longitudinal (axial) range samples, i.e. A-scans. Each Ascan consists of 1024 data points over 2 mm of depth. Thus the instrument integrates from 131,072 to 786,432 data points to construct a cross-sectional image (tomogram) of retinal anatomy. It displays the tomograms in real time using a false color scale that represents the degree of light backscattering from tissues at different depths in the retina. The system stores the scans, which can be selected for later analysis. The OCT image can be displayed on a gray scale where more highly reflected light is brighter than less highly reflected light. Alternatively, it can be displayed in color whereby different colors correspond to different degrees of reflectivity. –4– OPTICAL COHERENCE TOMOGRAPHY Stratus optical coherence tomography –5– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES CIRRUS HIGH-DEFINITION OCT (CARL ZEISS MEDITEC INC., USA) This instrument is based on spectral-domain technology. It provides high definition cross-sectional images and 3D layer segmentation maps of internal limiting membrane (ILM) and retinal pigment epithelium (RPE). Scanning laser ophthalmoscope with fundus image with overlay of retinal thickness map, 3D retinal thickness map, 3D segmentation of retinal pigment epithelium and internal limiting membrane layers and 3D segmentation of retinal pigment epithelium layer is available. Axial resolution of this instrument is 5 µm with a transverse resolution of 20 µm. Scan speed is 27000 A-scans per second. Fundus imaging is live during scanning. –6– OPTICAL COHERENCE TOMOGRAPHY Cirrus high-definition optical coherence tomography –7– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES COPERNICUS SPECTRAL-DOMAIN HIGH-RESOLUTION OCT (OPTOPOL, POLAND) This is a 3D retina imaging (zooming, rotating, sectioning, surface reconstruction) system. It is based on spectraldomain technology which is 50 times faster than conventional OCT. It has 6 µm axial resolution with 25000 A-scans per second scanning speed, 1050 A-scans per mm and 8200 lines measurement in 0.4 seconds. It creates AVI animations of retina cross-sections. RTVUE-100 FOURIER-DOMAIN OCT (OPTOVUE INC., ITALY) This instrument is a Fourier domain/spectral domain 3D scan. It has 5 µm axial resolution, transverse resolution of 15 µm with 26000 A-scans per second scanning speed, 2564096 A-scans per frame. Inner and outer retinal thickness map and internal limiting membrane/retinal pigment epithelium elevation map are available. –8– OPTICAL COHERENCE TOMOGRAPHY Copernicus spectral-domain high-resolution optical coherence tomography –9– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRALIS HRA+OCT (HEIDELBERG ENGINEERING, GERMANY) Optical coherence tomography images and simultaneous recording of fluorescein and ICG angiography, digital infrared and blue (“red-free”) reflectance images are obtained with a novel cSLO/OCT imaging system. The optical and technical principles of confocal scanning laser ophthalmoscopy (HRA2, Heidelberg Engineering, Heidelberg, Germany) uses an optically pumped solid state laser (OPSL) source to generate the blue light excitation wavelength of 488 nm for fluorescein angiography, red free and autofluorescence images. Diode laser sources of 790 and 815 nm wavelength are used for ICG and infrared reflectance recordings, respectively. Full emission spectra are recorded via a polarization filter to obtain blue and infrared reflectance images. With regard to the OCT, 40,000 A-scans are acquired per second with a 7 µm optical depth resolution and a 14 µm lateral optical resolution. The new operation software (ART - “Automatic Real Time” - Module, Heidelberg Engineering, Germany) is able to track eye movements in real-time based on the cSLO images. The software then computes and compensates for movements between the B-scan images, caused by position changes of the eye. –10– OPTICAL COHERENCE TOMOGRAPHY Spectralis spectral-domain high-resolution cSLO/OCT (Carsten H. Meyer, MD, Germany). –11– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES ULTRA-HIGH RESOLUTION OPTICAL COHERENCE TOMOGRAPHY Ultra-high resolution optical coherence tomography (UHR OCT) is a recently developed improvement of the wellestablished OCT technology enabling unprecedented in vivo subcellular as well as intraretinal visualization. Ophthalmic UHR OCT exceeds standard resolution OCT by obtaining superior axial image resolution of 3 µm and therefore enables enhanced visualization of intraretinal layers and has the potential to perform noninvasive optical biopsy of the human retina, i.e. visualization of intraretinal morphology in retinal pathologies approaching the level of that achieved with histopathology. This quantum leap in imaging and visualization performance is achieved by employing state-of-the-art ultrabroad bandwidth light source instead of superluminescent diodes. The ultimate availability of this UHR OCT technology strongly depends on the availability of such ultrabroad bandwidth light sources that are suitable for OCT applications. Recently reported, cost-effective approaches for broad bandwidth light sources mainly take advantage of the lower power demand with ultra-high resolution OCT imaging. Limiting factors of these systems are relative small bandwidths for ultralow-pump-threshold KLM Titanium: sapphire lasers and strongly modulated spectra of Cr3+-ion lasers, thus not perfectly suitable for OCT applications. –12– OPTICAL COHERENCE TOMOGRAPHY Ultra-high Resolution Optical Coherence Tomography Horizontal image of a normal human macula (bottom) with two-fold magnification (top). ILM: internal limiting membrane; NFL: nerve fiber layer; GCL: ganglion cell layer; IPL, OPL: inner and outer plexiform layer; INL, ONL: inner and outer nuclear layer; HF: Henle’s fiber layer; ELM: external limiting membrane; IS, OS PR: inner and outer segment of photoreceptor layer; RPE: retinal pigment epithe-lium. Arrows indicate location of total PR (red PR), IS PR (black IS) and OS PR (black OS) layer thickness measurement (Wolfgang Drexler, PhD., Austria). –13– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES ANATOMIC ARCHITECTURE OF THE RETINA The spectral-domain OCT (SD-OCT) scan of the retina shows the anatomic architecture of the retina correlating with distinct bands. There is still some controversy as to the accurate terminology of these bands with histological correlation in the outer retina. To present morphological alterations, the following assumptions have been made: as a plausible morphological substrate of the 1st hyperreflective band (1) is the external limiting membrane, the 2nd band (2) appears to reflect the interface of the inner and outer segments of the photoreceptor layer, the 3rd band (3) is assumed to represent the outer segment—retinal pigment epithelium (RPE) inter digitation and the 4th band (4) may reflect the RPE/Bruch’s membrane complex. It has been speculated that the separation of the 3rd and the 4th hyperreflective band, which is not always visible, is due to multiple scattering on large nonspherical particles (e.g. melanosomes) within the retinal pigment epithelium. –14– OPTICAL COHERENCE TOMOGRAPHY Spectral-domain optical coherence tomography –15– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES OPTICAL COHERENCE TOMOGRAPHY IMAGES OF THE INDIVIDUAL INTRARETINAL LAYERS Optical coherence tomography images of the individual intraretinal layers can also be generated. Quantitative mapping of retinal layers may be documented in the form of various maps. Peeling and layer separation in 3D imaging are becoming elegant options. Visualization of separate layers of 3D images may be utilized to give a novel perspective. False color coding is used to highlight thickness of various layers. Retinal thickness map, retinal nerve fiber layer thickness map, retinal pigment epithelium deformation map and inner segment (IS)/outer segment (OS)-RPE deformation map can be documented very well. –16– OPTICAL COHERENCE TOMOGRAPHY Stratus Optical Coherence Tomography –17– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Retinal thickness map on spectral-domain optical coherence tomography –18– OPTICAL COHERENCE TOMOGRAPHY Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography –19– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Inner segment/outer segment to retinal pigment epithelium thickness map on spectral-domain optical coherence tomography –20– OPTICAL COHERENCE TOMOGRAPHY Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography –21– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES A –22– OPTICAL COHERENCE TOMOGRAPHY B Spectral-Domain Optical Coherence Tomography. Variations in retinal pigment epithelium deformation, retinal nerve fiber layer thickness and retinal thickness are depicted in the form of graphs. –23– 2 ThreeDimensional Retinal Imaging OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY AND 3D IMAGING Spectral-domain optical coherence tomography (SD-OCT) has begun a new era in ocular imaging. The spectral-domain OCT device can produce cross-sectional B-scans, like timedomain OCT but with better resolution, and it can also create 3D area scans by combining B-scans. Its scanning technology takes 20,000 to 26,000 A-scan measurements per second, produces a linear B-scan in less than 0.03 second, and combines them to create a 3D area scan. Since it is possible to acquire high density volumetric data of the macula, the OCT data can be processed to provide comprehensive structural information. With 3D image reconstruction, the 3D area scans can be manipulated and viewed from multiple angles. The unprecedented visualization provided by this technology enables determination of specific alterations in retinal anatomy characteristics. Orthogonal slices or an orthoplane rendering of the 3D OCT data can be obtained. The OCT images can be generated with arbitrary orientations from the 3D OCT data but will have varying transverse resolutions depending on the direction of the scan and the density of the initial 3D OCT data. –26– THREE-DIMENSIONAL RETINAL IMAGING The relationship among the x, y and z plane may be observed exquisitely. The x, y and z planes for slicing are defined as follows: x plane is the horizontal B-scan as it is acquired. The anatomical features as shown in the x plane are real since the eye movement is negligible. y plane is the vertical reconstructed B-scan. The eye movement in the reconstructed B-scan is quite noticeable. z plane is a reconstructed en face image. –27– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Serous Chorioretinopathy. Three-dimensional image showing serous retinal detachment, retinal pigment epithelium detachment and the altered retinal contour. –28– THREE-DIMENSIONAL RETINAL IMAGING Central Serous Chorioretinopathy. Three-dimensional image showing the x, y and z planes. –29– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES A B (A and B) Central Serous Chorioretinopathy. Sequential 3D imaging in x plane showing serous retinal detachment. –30– THREE-DIMENSIONAL RETINAL IMAGING C D Central Serous Chorioretinopathy. Sequential 3D imaging in x plane showing serous retinal detachment (C) and associated retinal pigment epithelium detachment (D). –31– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES A B (A and B) Central Serous Chorioretinopathy. Sequential 3D imaging in y plane showing serous retinal detachment. –32– THREE-DIMENSIONAL RETINAL IMAGING C D (C and D) Central Serous Chorioretinopathy. Sequential 3D imaging in y plane showing serous retinal detachment. –33– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES A B Central Serous Chorioretinopathy. Sequential 3D imaging in z plane showing elevated retinal contour (A), and serous retinal detachment (B). –34– THREE-DIMENSIONAL RETINAL IMAGING C D Central Serous Chorioretinopathy. Sequential 3D imaging in z plane showing serous retinal detachment (C) and retinal pigment epithelium alterations (D). –35– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES PEELING AND LAYER SEPARATION IN THREEDIMENSIONAL IMAGING Peeling and layer separation in 3D imaging are becoming elegant options. False color coding is used to highlight thickness of various layers. Visualization of separate layers in3D imaging may be utilized to give a novel perspective. –36– THREE-DIMENSIONAL RETINAL IMAGING Retinal nerve fiber layer thickness map on 3D imaging. –37– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Retinal nerve fiber layer-retinal pigment epithelium thickness map on 3D imaging. –38– THREE-DIMENSIONAL RETINAL IMAGING Retinal pigment epithelium deformation map on 3D imaging. –39– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES CLINICAL APPLICATIONS OF 3 DIMENSIONAL IMAGING Although currently there is no clinical application for selective visualization of macular layers, the ability to visualize 3D morphology may be helpful in fundamental research applications for elucidating structural changes in retinal diseases or for future clinical applications, such as planning vitreoretinal surgery. Three-dimensional OCT is an effective tool for understanding the 3D structure of the proliferative membrane in diabetic retinopathy and is useful for training and planning of the surgical procedures in vitrectomy. The use of 3D OCT may improve the monitoring of clinically significant macular edema and cystoid macular edema progression and its response to treatment. –40– 3 Diabetic Macular Edema OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES DIABETIC RETINOPATHY Findings of Diabetic Retinopathy Study (DRS), the Early Treatment Diabetic Retinopathy Study (ETDRS), the Diabetic Retinopathy Vitrectomy Study and the Diabetes Control and Complications Trial (DCCT) have provided insights into the understanding and management of diabetic retinopathy. LEVELS OF DIABETIC RETINOPATHY Nonproliferative Diabetic Retinopathy (NPDR) • Mild NPDR: At least one retinal microaneurysm and one or more of the following: Retinal hemorrhage, hard exudate, soft exudate, etc. • Moderate NPDR: Hemorrhages or microaneurysms or both in at least one quadrant and one or more of the following: Soft exudates, venous beading, and intraretinal microvascular abnormalities (IRMA). • Severe NPDR: Hemorrhages or microaneurysms or both in all four quadrants. Venous beading in two or more quadrants. IRMA’s in at least one quadrant. Proliferative Diabetic Retinopathy (PDR) • Early PDR (proliferative retinopathy without DRS highrisk characteristics). One or more of the following: • Neovascularization at the disk (NVE) • Neovascularization elsewhere (NVD) Vitreous or preretinal hemorrhage and NVE <1/2 disk area. –42– DIABETIC MACULAR EDEMA • High-risk PDR (proliferative retinopathy with DRS highrisk characteristics). One or more of the following: • NVD > 1/4-1/3 disk area • NVD; vitreous or preretinal hemorrhage • NVE > 1/2 disk area; preretinal or vitreous hemorrhage. • Advanced PDR High-risk PDR; traction retinal detachment involving macula or vitreous hemorrhage obscuring ability to grade NVD/NVE. DIABETIC MACULAR EDEMA Clinically significant macular edema, as defined by ETDRS, includes any one of the following lesions: 1. Retinal thickening at or within 500 microns from the center of the macula. 2. Hard exudates at or within 500 microns from the center of the macula, if there is thickening of the adjacent retina. 3. An area or areas of retinal thickening at least 1 disk area in size, at least part of which is within 1 disk diameter of the center of the macula. –43– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Nonproliferative Diabetic Retinopathy: Color fundus photograph shows nonproliferative diabetic retinopathy with clinically significant macular edema. –44– DIABETIC MACULAR EDEMA Nonproliferative Diabetic Retinopathy: Color fundus photograph shows clinically significant macular edema, venous beading and tortuosity, superficial hemorrhages and cotton-wool spots. –45– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Proliferative Diabetic Retinopathy: Color fundus photograph shows neovascularization of the disk, fibrous proliferation along superotemporal vascular arcade with clinically significant macular edema, and preretinal and vitreous hemorrhage –46– DIABETIC MACULAR EDEMA OPTICAL COHERENCE TOMOGRAPHY The scan profile allows the appraisal of intraretinal changes, of the shape of the inner boundary of the thickened macula, and of the presence of possible subretinal detachment or incomplete vitreomacular separation, findings which are often missed by clinical examination alone. Optical coherence tomography is very useful to determine whether edema threatens or involves the macular center. In some cases the edges of the macula may be thickened, even though the foveal center retains a normal contour. Macular thickening may be asymmetric, especially in focal edema, and may only involve a sector of the macular area. –47– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Intraretinal Changes Diffuse swelling appears as thickening of the retina without definite cystic spaces. The outer plexiform layer and outer nuclear layer are often the most prone to thickening and hyporeflectivity. Cystoid cavities are hyporeflective spaces of various sizes, mainly located in the outer retina (Henle fiber and outer plexiform layers), and sometimes also in the inner plexiform layer. In the most advanced stages, one or several large central cysts are responsible for significant thickening of the foveola. Foveolar detachment may be associated with diabetic macular edema which was not detected or even suspected on biomicroscopy. Hard exudates appear as hyperreflective intraretinal deposits, mostly located in the outer plexiform layer of the retina. They mask the reflectivity of the underlying tissue. They may accumulate in the fovea, in which case the macula is often thickened by edema. However, in other cases, the foveal thickness is normal or nearly normal although the exudates surrounding the focal edema accumulate in the fovea. This is not surprising; if one considers that the exudate deposit occurs at the limit of the area of fluid reabsorption. –48– DIABETIC MACULAR EDEMA Inner Retinal Boundary In scans passing through the macular center, the shape of the inner retinal boundary indicates the severity of central macular edema. The earliest sign of foveolar edema on OCT scans is the flattening of the foveal pit. When macular edema is definitely present, the inner retinal boundary tends to be dome-shaped. A dome-shaped profile is more frequently observed when the posterior hyaloid remains attached to the macular center, i.e. detached from the macular area except at the foveolar center. However, this convex profile may also exist if the posterior hyaloid is detached. The Posterior Hyaloid The posterior hyaloid is only visible on OCT when it is partly or slightly detached from the retinal surface. Following situations may occur: • Perifoveolar vitreous detachment with a normal posterior hyaloid. • Perifoveolar vitreous detachment with a thick posterior hyaloid. Posterior hyaloid traction may also be combined with an epiretinal membrane which causes or increases macular thickening. Preretinal hemorrhages may completely mask the underlying features. Intraretinal hemorrhages, on the contrary are rarely visible as their reflectivity is weak. –49– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Lamellar hole may be the endstage of longstanding macular edema with central cyst, combined with vitreomacular traction. Tractional Macular Edema Tractional macular edema is strongly suggested upon OCT from the visualization of a combination of hyperreflective, thick posterior hyaloid adhering to an elevated foveal center and convex slopes of the thickened macula. Otani, Kishi and Maruyama have described following patterns of diabetic macular edema: 1. Sponge-like thickening of retinal layers 2. Large cystoid spaces involving variable depth of the retina with intervening septae 3. Subfoveal serous detachment 4. Tractional detachment of fovea 5. Taut posterior hyaloid. –50– DIABETIC MACULAR EDEMA Macular Edema in Moderate Nonproliferative Diabetic Retinopathy. Red-free fundus photograph shows intraretinal hemorrhages, microaneurysms, and hard exudates. Fluorescein angiography, early and late phases, shows mild cystoid macular edema. Color map shows diffuse macular thickening (Alain Gaudric, MD, France). –51– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Macular Edema in Moderate Nonproliferative Diabetic Retinopathy. Horizontal 6 mm scan. Retinal thickening is more prominent on the nasal side of the macula. The posterior hyaloid is only partially detached on this side (yellow arrows). Optical coherence tomography shows intraretinal cystic spaces in a moderately thickened retina and the presence of a small shallow foveolar detachment (large arrow) (Alain Gaudric, MD, France). –52– DIABETIC MACULAR EDEMA Severe Cystoid Macular Edema in Severe Nonproliferative Diabetic Retinopathy. Fluorescein angiography, early phase, shows areas of capillary nonperfusion. Fluorescein angiography, late phase, shows cystoid macular edema (lines A and B refer to the direction of the linear scans below) (Alain Gaudric, MD, France). Severe Cystoid Macular Edema in Severe Nonproliferative Diabetic Retinopathy. Color map shows diffuse macular thickening. Central macular thickness is 598 µm (Alain Gaudric, MD, France). –53– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Severe Cystoid Macular Edema in Severe Nonproliferative Diabetic Retinopathy. Six mm scan (A) shows that a large central foveal cyst is surrounded by smaller cysts, resulting in significant macular thickening. Six mm scan (B) shows that on a perpendicular scan, the central cyst appears larger (Alain Gaudric, MD, France). –54– DIABETIC MACULAR EDEMA Severe Macular Edema with Hard Exudates in Nonproliferative Diabetic Retinopathy. Color fundus photograph shows several rings of hard lipid exudates, which join in the fovea. Color map shows diffuse macular thickening (Alain Gaudric, MD, France). Severe Macular Edema with Hard Exudates in Nonproliferative Diabetic Retinopathy. Horizontal 6 mm scan shows diffuse swelling and thickening of the macula, and the accumulation of hard exudates in the outer part of the fovea (Alain Gaudric, MD, France). –55– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Tractional Diabetic Macular Edema in Severe Nonproliferative Diabetic Retinopathy. Nine mm retinal scan, shows an incompletely detached, thick, hyperreflective posterior hyaloid (asterix) still attached to the optic disc, the foveal center, and the border of the posterior pole. An epiretinal membrane is also present, and adheres to the retinal surface, causing small superficial retinal folds (arrow). The hole-like appearance is due to the presence of a large foveal cyst (Alain Gaudric, MD, France). –56– DIABETIC MACULAR EDEMA A The Increasing Severity of Diabetic Macular Edema on Optical Coherence Tomography. Minor diffuse retinal thickening (Alain Gaudric, MD, France). B The Increasing Severity of Diabetic Macular Edema on Optical Coherence Tomography. Central foveal cyst, but minor thickening of the macular area (Alain Gaudric, MD, France). –57– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES C The Increasing Severity of Diabetic Macular Edema on Optical Coherence Tomography. Foveal thickness is less than in B, but the macular area thickening is more diffuse. D. Severe cystoid macular edema (Alain Gaudric, MD, France). D The Increasing Severity of Diabetic Macular Edema on Optical Coherence Tomography. Severe cystoid macular edema (Alain Gaudric, MD, France). –58– DIABETIC MACULAR EDEMA E The Increasing Severity of Diabetic Macular Edema on Optical Coherence Tomography. Severe cystoid macular edema, with hyperreflective hard exudates (Alain Gaudric, MD, France). F The Increasing Severity of Diabetic Macular Edema on Optical Coherence Tomography. Severe cystoid macular edema, with hyperreflective hard exudates (Alain Gaudric, MD, France). G The Increasing Severity of Diabetic Macular Edema on Optical Coherence Tomography. Severe cystoid macular edema with foveal detachment (Alain Gaudric, MD, France). –59– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Fluorescein Angiography and Optical Coherence Tomography in Ischemic Maculopathy. Color fundus photograph shows numerous dot hemorrhages in the macula. Fluorescein angiography shows extensive nonperfusion of macular capillaries in an area of about 2 disk diameters (Alain Gaudric, MD, France). Fluorescein Angiography and Optical Coherence Tomography in Ischemic Maculopathy. Horizontal retinal scan and center average thickness show significant macular edema and retinal thickening. The use of optical coherence tomography alone would have missed the ischemic component of this edema (Alain Gaudric, MD, France). –60– DIABETIC MACULAR EDEMA Epiretinal Membrane and Diabetic Macular Edema in Proliferative Diabetic Retinopathy. Horizontal retinal scan shows diffuse thickening of the macula, superficial retinal folds, and a large area of adherence between of a preretinal thick, hyperreflective, taut, epiretinal tissue to the macular center (Alain Gaudric, MD, France). Epiretinal Membrane and Diabetic Macular Edema in Proliferative Diabetic Retinopathy. Vertical retinal scan shows that this epiretinal tissue in fact consists of the thickened, taut , incompletely detached posterior hyaloid (asterix) and of an epiretinal membrane (arrows) which adheres both to the retinal surface and the posterior hyaloid (Alain Gaudric, MD, France). –61– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Tractional Diabetic Macular Edema in Proliferative Diabetic Retinopathy: Result of Surgery. Horizontal and vertical retinal scans, show a thickened posterior hyaloid partially detached from the posterior pole and exerting traction on the fovea, which exhibits large intraretinal cystic cavities (Alain Gaudric, MD, France). Tractional Diabetic Macular Edema in Proliferative Diabetic Retinopathy: Result of Surgery. Optical coherence tomography, two months after pars plana vitrectomy and posterior hyaloid detachment, the macular profile has almost returned to normal (Alain Gaudric, MD, France). –62– DIABETIC MACULAR EDEMA THREE-DIMENSIONAL RETINAL IMAGING Three-dimensional imaging on spectral-domain optical coherence tomography shows altered retinal contour and retinal thickness in clinically significant macular edema. Sequential 3D imaging in x, y and z planes show increased retinal thickness, cystic changes, hard exudates and serous retinal detachment and associated color coded changes in retinal thickness maps present a novel perspective. Alterations in retinal nerve fiber layer (RNFL) and RNFLretinal pigment epithelium (RPE) thickness maps and alterations in RPE deformation map are also observed. Imaging of the 3D structures of the proliferative membrane in proliferative diabetic retinopathy is also possible. The 3D structure of the proliferative membrane can be clearly visualized. The OCT image may show the presence of multiple adhesions between the retina and the proliferative membrane and separation of the proliferative membrane. –63– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Clinically Significant Macular Edema. Spectral-domain optical coherence tomography 3D image shows alterations in retinal contour and retinal thickness. –64– DIABETIC MACULAR EDEMA Clinically Significant Macular Edema. Spectral-domain optical coherence tomography shows 3D image in the x plane. Increased retinal thickness on color-coded retinal thickness map and hard exudates are observed. –65– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Clinically Significant Macular Edema. Spectral-domain optical coherence tomography shows 3D image in the y plane. Increased retinal thickness on color-coded retinal thickness map and hard exudates are observed. –66– DIABETIC MACULAR EDEMA Clinically Significant Macular Edema: Spectral-domain optical coherence tomography shows 3D image in the z plane. –67– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Clinically Significant Macular Edema: Spectral-domain optical coherence tomography 3D image shows retinal nerve fiber layer thickness map. Significant thinning is observed. –68– DIABETIC MACULAR EDEMA Clinically Significant Macular Edema. Spectral-domain optical coherence tomography 3D image shows retinal nerve fiber layer-retinal pigment epithelium thickness map. –69– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Clinically Significant Macular Edema. Spectral-domain optical coherence tomography 3D image shows alterations in retinal pigment epithelium deformation map. –70– DIABETIC MACULAR EDEMA A B Evolution of Diffuse Cystoid Macular Edema after Injection of 4 mg Intravitreal Triamcinolone Acetonide. (A) Severe cystoid macular edema, with foveal detachment before injection. Visual acuity: 20/400. Central average thickness: 805 µm. (B) Two days after intravitreal triamcinolone acetonide central average thickness: 767 µm (Alain Gaudric, MD, France). –71– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES C D Evolution of Diffuse Cystoid Macular Edema after Injection of 4 mg Intravitreal Triamcinolone Acetonide. (C) Seven days after intravitreal triamcinolone acetonide central average thickness: 477µm. (D) Two weeks after IVTA central average thickness: 314 µm (Alain Gaudric, MD, France). –72– DIABETIC MACULAR EDEMA E F Evolution of Diffuse Cystoid Macular Edema after Injection of 4 mg Intravitreal Triamcinolone Acetonide. (E) Three weeks after intravitreal triamcinolone acetonide central average thickness: 264 µm. (F) Two months after IVTA central average thickness is now almost normal (225 µm). Foveal detachment has progressively stabilized. The posterior hyaloid is detached from the macular surface. Visual acuity has improved to 20/100 (Alain Gaudric, MD, France). G Evolution of Diffuse Cystoid Macular Edema after Injection of 4 mg Intravitreal Triamcinolone Acetonide. (G) Five months after intravitreal triamcinolone acetonide macular edema has recurred; central average thickness: 633 µm. Visual acuity: 20/400 (Alain Gaudric, MD, France). –73– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Intravitreal Bevacizumab in the Management of Clinically Significant Diabetic Macular Edema. Spectral-domain optical coherence tomography shows altered foveal contour with cystic spaces and increased retinal thickness in diabetic macular edema. Restoration of normal foveal contour is observed following treatment. –74– DIABETIC MACULAR EDEMA Intravitreal Bevacizumab in the Management of Clinically Significant Macular Edema. Spectral-domain optical coherence tomography 3D image shows increased retinal thickness on colorcoded retinal thickness map. Decrease in retinal thickness is observed following treatment. –75– 4 Retinal Vein Occlusion OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES BRANCH RETINAL VEIN OCCLUSION Branch retinal vein occlusion (BRVO) is a common retinal vascular disorder. The disease is bilateral in 10-15% of the patients. Branch retinal vein occlusion always occurs at the arteriovenous crossing site when idiopathic. Arteriovenous crossing sites are known to change anatomically in association with arteriosclerosis and hypertension. Mechanical narrowing of the venous lumen at these intersections is thought to play an etiopathological role. Clinically, in the acute phase (first 4-6 months), segmental intraretinal hemorrhage has its apex at approximately the location of the obstructed vein. The hemorrhage follows the distribution of the obstructed venous system. Cotton-wool spots may be scattered throughout the posterior aspect of the occluded segment. Macular edema is frequent if the occluded vein subserves the macular circulation. Cystoid spaces often with layering of intraretinal hemorrhage within the cystoid spaces may occur, with the largest cyst in the center of the fovea. Perfused macular edema and ischemic macular edema may occur. –78– RETINAL VEIN OCCLUSION Neovascularization at the disk and / or the periphery may occur. A segment of ischemia of at least 5 disk diameters wide is required to produce neovascularization. In the chronic phase (9-12 months), retinal vascular abnormalities remain, which persist in a segmental manner. The retinal vascular abnormalities include: Collateral vessels along blockage site, collateral vessels across the temporal raphe, retinal capillary telangiectasia throughout the involved segment, and areas of capillary nonperfusion along the involved segment. –79– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Branch Retinal Vein Occlusion. Color fundus photograph shows retinal hemorrhages along inferotemporal retinal vein along with hard exudates. –80– RETINAL VEIN OCCLUSION Branch Retinal Vein Occlusion. Color fundus photograph shows retinal hemorrhages along sheathed inferotemporal retinal vein, hard exudates at macula and early neovascularization elsewhere. –81– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES CENTRAL RETINAL VEIN OCCLUSION Central retinal vein occlusion (CRVO) is a common retinal vascular disorder with potentially blinding complications. Most of the patients are over the age of 50 years. Central vein occlusion may be seen in young adults and is usually associated with a systemic disease. Pathological evidence suggests the site of obstruction is situated at the lamina cribrosa. The anatomy of the normal central retinal vein appears to show a constriction of the vein as it passes through the lamina cribrosa. This may predispose the vein to occlusion, thereby reducing its retinal blood flow. Secondary ischemia of the retina occurs from the stasis of blood flow in the capillaries caused by back pressure from the occluded venous system. Clinically, critical signs include diffuse retinal hemorrhages in all quadrants of the retina and dilated and tortuous retinal veins. The clinical picture varies from a few scattered retinal hemorrhages and a few cotton-wool spots to a marked hemorrhagic appearance. Central retinal vein occlusion is of two types. –82– RETINAL VEIN OCCLUSION Ischemic central retinal vein occlusion shows— • Marked tortuosity and engorgement of the retinal vessels • Extensive hemorrhage involving both the peripheral retina and posterior pole and widespread capillary nonperfusion on fluorescein angiography • Multiple cotton-wool spots • Severe optic disk edema and hyperemia • Macula covered by hemorrhages, possibly showing cystoid changes • Relative afferent pupillary defect, and • Visual acuity at presentation less than 20/200. Nonischemic central retinal vein occlusion shows— • Mild fundus changes • No afferent pupillary defect • Visual acuity often better than 20/200. The two major complications include persistent macular edema and neovascular glaucoma secondary to iris neovascularization. Vitreomacular attachment may play a role in the pathogenesis and chronicity of macular edema. –83– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Retinal Vein Occlusion. Color fundus photograph shows superficial retinal hemorrhages in all the four quadrants of fundus with obscured optic disk. –84– RETINAL VEIN OCCLUSION Nonischemic Central Retinal Vein Occlusion (Muna Bhende, MS, India). –85– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Ischemic Central Retinal Vein Occlusion (Muna Bhende, MS, India). –86– RETINAL VEIN OCCLUSION OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography has become an important tool in the management of eyes with macular edema in venous occlusion. On OCT, diffuse retinal swelling, cystic changes and serous retinal detachments may be observed. Observation of cystoid macular edema (CME) enables visualization of its spatial extent in each retinal layer and discernment of its relationship to the external limiting membrane. Pathomorphologic features of cystoid macular edema may be visualized. Cystoid spaces are seen often in the inner nuclear layer and outer plexiform layer, but are detected to some extent in all retinal layers. THREE-DIMENSIONAL RETINAL IMAGING The 3D SD-OCT shows a thin back-reflecting line corresponding to the external limiting membrane. Cystoid spaces are located on the inside of the external limiting membrane and appear to be in contact with the external limiting membrane. In some cases the external limiting membrane line cannot be seen clearly beneath the large foveal cystoid spaces. Observation of cystoid macular edema using 3D SDOCT enables visualization of its spatial extent in each retinal layer. The use of 3D SD-OCT thus may improve the monitoring of CME progression and its response to –87– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES treatment. Optic disk traction may be well-recognized on OCT in central retinal vein occlusion. Three-dimensional imaging on SD-OCT shows altered retinal contour and retinal thickness. Alterations in retinal nerve fiber layer (RNFL) and RNFL-retinal pigment epithelium (RPE) thickness maps and alterations in RPE deformation map are also observed. –88– RETINAL VEIN OCCLUSION Spectral-Domain Optical Coherence Tomography. Serous detachment of the retina and cystoid macular edema is observed. –89– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Branch Retinal Vein Occlusion. Color photograph shows branch retinal vein occlusion along the superotemporal arcade with characteristic intraretinal hemorrhages, venous tortuosity and cotton-wool spots distal to an AV crossing (arrow). Fluorescein angiography shows areas of capillary nonperfusion (Sharon Fekrat, MD. FACS, USA). –90– RETINAL VEIN OCCLUSION Branch Retinal Vein Occlusion: Intravitreal Triamcinolone Acetonide. Optical coherence tomography shows cystoid macular edema and accompanying serous retinal detachment. Macular thickness map shows foveal thickness as 697±24 microns (Sharon Fekrat, MD,FACS, USA). Branch Retinal Vein Occlusion: Intravitreal Triamcinolone Acetonide. Optical coherence tomography one week after an intravitreal triamcinolone acetonide (4mg) injection. Scan along the 270° meridian shows resolution of the serous fluid and a marked decrease in foveal thickness, measuring 532±31 microns (Sharon Fekrat, MD, FACS, USA). –91– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Branch Retinal Vein Occlusion: Postintravitreal Triamcinolone. Optical coherence tomography one month post-injection. Scan along 270° meridian demonstrates further resolution of the cystoid macular edema. The macular thickness map also showed a decrease in foveal thickness, 250±17 microns (Sharon Fekrat, MD, FACS, USA). Branch Retinal Vein Occlusion: Postintravitreal Triamcinolone. Optical coherence tomography, at three months post-injection, shows recurrence of cystoid macular edema. The foveal thickness has increased to 313 ± 26 microns (Sharon Fekrat, MD, FACS, USA). –92– RETINAL VEIN OCCLUSION Intravitreal Bevacizumab in Perfused Central Retinal Vein Occlusion. Color fundus photograph shows intraretinal hemorrhages and venous tortuosity are present. Cystoid macular edema is present (Sharon Fekrat, MD, FACS, USA). –93– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Intravitreal Bevacizumab in Perfused Central Retinal Vein Occlusion. Color fundus photograph, four months later, shows that the intraretinal hemorrhages have largely reabsorbed. The patient had received three intravitreal bevacizumab injections in the interim (Sharon Fekrat, MD, FACS, USA). –94– RETINAL VEIN OCCLUSION Intravitreal Bevacizumab in Perfused Central Retinal Vein Occlusion. Optical coherence tomography reveals marked cystoid macular edema on presentation (Sharon Fekrat, MD, FACS, USA). Intravitreal Bevacizumab in Perfused Central Retinal Vein Occlusion. Four months later, after the effect of bevacizumab had worn off, recurrent cystoid macular edema is present (Sharon Fekrat, MD, FACS, USA). –95– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Retinal Vein Occlusion. Spectral-domain optical coherence tomography 3D image shows altered retinal contour. –96– RETINAL VEIN OCCLUSION Retinal Vein Occlusion. Spectral-domain optical coherence tomography 3D image shows retinal thickness map. –97– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Retinal Vein Occlusion. Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography 3D imaging. –98– RETINAL VEIN OCCLUSION Retinal Vein Occlusion. Retinal nerve fiber layer-retinal pigment epithelium thickness map on spectral-domain optical coherence tomography 3D imaging. –99– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Retinal Vein Occlusion. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –100– 5 Retinal Artery Occlusion OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION Retinal artery occlusion is relatively common etiology for sudden vision loss in aged adults. The embolization and thrombosis are the common cause of artery obstruction. The ophthalmic artery is the first branch of the internal carotid artery so that embolic material from either the heart or the carotid arteries has a direct route to the eye. Clinically, features of retinal artery occlusion depend on the size and location of the obstructed vessel and its severity and distribution. Retinal arterial occlusive disease includes central retinal artery occlusion (CRAO), branch retinal artery occlusion (BRAO), cilioretinal artery occlusion and occlusion of precapillary arterioles (cotton-wool spots) based on the location of affected vessel and its distribution. The retina of patients with CRAO appears whitening or opacification as a result of cloudy swelling due to intracellular edema, especially in the macular area (posterior pole) where the inner retinal structure is thickest. Since the central fovea (foveola) lacks these layers, the orange-red appearance is evident in the central fovea in contrast to the surrounding opaque retina (cherry red spot). The retinal arteries are thinned associated with irregularities in caliber. Segmentation or boxcarring of the blood column can be seen in both arterioles and venules. In 20-25% of eyes with CRAO, a portion of the papillomacular bundle is supplied by one or more cilioretinal arterioles from the ciliary circulation. –102– RETINAL ARTERY OCCLUSION If the cilioretinal sparing in papillomacular bundle reaches the foveola, the central vision may be preserved. The retina of patients with BRAO reveals a localized region of superficial retinal whitening, which is most prominent in the posterior pole along the distribution of the obstructed vessel. OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography images of ischemic retina due to CRAO and BRAO correlate with the histopathological findings of acute retinal ischemia. The affected area demonstrates increased thickness and reflectivity in the inner retina. The marked difference from retinal edema due to other retinal vascular disease such as retinal vein occlusion or diabetic maculopathy is lack of areas or cystic spaces of low reflectivity due to fluid accumulation. After the resolution of retinal cloudy edema inner retina becomes atrophic and thin. –103– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Retinal Artery Occlusion. Color fundus photograph shows one week old central retinal artery occlusion. Opacification of the superficial retina is present. A cherry-red spot can be seen in the fovea. The opacification is most pronounced in the macula, where the retina is the thickest (Sharon Fekrat, MD, FACS, USA). –104– RETINAL ARTERY OCCLUSION Central Retinal Artery Occlusion. Optical coherence tomography, vertical scan, shows enhanced reflectivity with mild increase of inner retinal thickness (Keisuke Mori, MD, PhD, Japan). Central Retinal Artery Occlusion. Optical coherence tomography, horizontal scan, demonstrates cilioretinal arteries sparing in papillomacular bundle (Keisuke Mori, MD, PhD, Japan). –105– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Hemiretinal Artery Occlusion. Color fundus photograph shows threeday-old inferior hemiretinal artery occlusion with a visible cholesterol embolus (arrow). Myelinated nerve fibers are also observed (Sharon Fekrat, MD, FACS, USA.). –106– RETINAL ARTERY OCCLUSION Hemiretinal Artery Occlusion. Optical coherence tomography 72 hours after onset reveals thickening of the affected inferior macula (Sharon Fekrat, MD, FACS, USA). Hemiretinal Artery Occlusion. Optical coherence tomography 9 months later reveals retinal atrophy of the affected inferior macula (Sharon Fekrat, MD, FACS, USA). –107– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Branch Retinal Artery Occlusion. Color fundus photograph shows retinal cloudy swelling is present in the distribution of the occluded artery running through inferior macula (Keisuke Mori, MD, PhD, Japan). –108– RETINAL ARTERY OCCLUSION Branch Retinal Artery Occlusion. Optical coherence tomography, vertical scan, shows the inferior retina with increased reflectivity and thickness contrast with normal superior retina (Keisuke Mori, MD, PhD, Japan). –109– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES THREE-DIMENSIONAL RETINAL IMAGING Three-dimensional imaging on SD-OCT shows altered retinal contour and retinal thickness. Alterations in retinal nerve fiber layer (RNFL) and RNFL- retinal pigment epithelium (RPE) thickness maps and alterations in RPE deformation map are also observed. –110– RETINAL ARTERY OCCLUSION Spectral-Domain Optical Coherence Tomography. The extent of macular edema differs widely and does not affect visual prognosis in CRAO eyes. No correlation has been found between the initial macular edema height and visual improvement. –111– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Retinal Artery Occlusion. Spectral-domain optical coherence tomography 3D image shows altered retinal contour. –112– RETINAL ARTERY OCCLUSION Central Retinal Artery Occlusion. Spectral-domain optical coherence tomography 3D image shows retinal thickness map. –113– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Retinal Artery Occlusion. Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography 3D imaging. –114– RETINAL ARTERY OCCLUSION Central Retinal Artery Occlusion. Retinal nerve fiber layer-retinal pigment epithelium thickness map on spectral-domain optical coherence tomography 3D imaging. –115– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Retinal Artery Occlusion. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –116– 6 Age-Related Macular Degeneration OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION The International community in a published classification has identified two phases in age-related macular degeneration: i. Age-related maculopathy including all type of drusen and retinal pigment epithelium disturbances. ii. Age-related macular degeneration including the exudative (or neovascular) form and the atrophic form (with extra or juxtafoveal atrophic patches). Choroidal neovascularization. –118– AGE-RELATED MACULAR DEGENERATION FLUORESCEIN ANGIOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY Fluorescein angiography remains the gold standard for diagnosis and distinction of these two forms. Leakage is the key symptom of choroidal new vessels in the exudative form. Optical coherence tomography (OCT) examination provides useful information about quantification of retinal thickness and accumulation of fluid in between or within the retinal layers. In selected cases, OCT may identify the presence of neovascular membrane, fibrous tissue or vitreoretinal adherence or traction. SOFT DRUSEN Optical coherence tomography reveals soft drusen as localized multiple elevation of the hyperreflective band of the retinal pigment epithelium-Bruch’s membranechoriocapillaris complex. During progression of the disease, their elevation might increase in size, in height and become confluent or indistinct. Drusen themselves have moderate reflectivity, with no shadowing backwards to choroid. There is neither any subretinal nor intraretinal fluid accumulation. The different retinal layers remain normally organized. A normal morphology of the overlying neurosensory retina with no –119– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES change in thickness of the sensory retina and with conservation of the parallelism of the different reflective bands is observed. Pieroni and associates, on ultrahigh resolution optical coherence tomography, have described three patterns: (i) distinct retinal pigment epithelium excrescences (ii) a few saw-toothed pattern of retinal pigment epithelium (iii) nodular drusen. –120– AGE-RELATED MACULAR DEGENERATION Soft Drusen.Red-free fundus photograph shows numerous macular soft drusen partially confluent. Fluorescein angiography shows latestaining drusen. Scanning laser ophthalmoscope-based ICGAngiography late phase shows soft drusen of various sizes, small or large, and confluent, persistent in the late phase (Gisele Soubrane, MD, France). –121– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Soft Drusen. Optical coherence tomography shows corrugated iron like elevations of the retinal pigment epithelium-Bruch’s membrane complex, with no shadowing towards the choroid (Gisele Soubrane, MD, France). –122– AGE-RELATED MACULAR DEGENERATION Confluent Soft Drusen. Red-free photograph and fluorescein angiography show confluent drusen or moderate drusenoid pigment epithelium detachment, relatively well-demarcated and surrounded by many drusen small or large. SLO-ICG angiography shows confluent drusen as dark and well-delimited. Neither hyperfluorescence nor signs of the presence of CNV are evident at this stage (Gisele Soubrane, MD, France). –123– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Confluent Soft Drusen. Optical coherence tomography shows irregular elevation of the retinal pigment epithelium band due to larger confluent drusen, with no shadowing towards the choroid (Gisele Soubrane, MD, France). –124– AGE-RELATED MACULAR DEGENERATION Geographic Atrophy with Foveal Sparing. Color and autofluorescence photographs demonstrate a perifoveal, beagle-like, slightly irregular but well-demarcated discolored area. In its center, a small, darker area of preserved xanthophyll pigment is seen. There is absence of autofluorescence of all the atrophic area (Gisele Soubrane, MD, France). –125– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Geographic Atrophy with Foveal Sparing. Fluorescein angiography shows progressive hyperfluorescence and window defect with central sparing. Several soft drusen can be seen in the inferior region (Gisele Soubrane, MD, France). –126– AGE-RELATED MACULAR DEGENERATION Geographic Atrophy with Foveal Sparing. ICG angiography shows large choroidal vessels crossing the area of atrophy (Gisele Soubrane, MD, France). –127– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Geographic Atrophy with Foveal Sparing. Optical coherence tomography shows hyper-reflectivity extending deep towards the choroid with retinal thinning throughout the atrophic area. The central area, which is spared, presents abnormal retinal pigment epithelium-Bruch’s membrane band with back shadowing (Gisele Soubrane, MD, France). –128– AGE-RELATED MACULAR DEGENERATION CHOROIDAL NEOVASCULAR MEMBRANE On OCT, typically, classic choroidal neovascular membrane (CNV) presents as a hyperreflective area of thickening above and adjacent to the retinal pigment epithelium usually separated by a thin less reflective band. Optical coherence tomography shows active classic CNV revealing direct and indirect exudative features. The direct signs are not always clearly defined corresponding to the dimension, location, shape and the stage of progression of CNV (associated occult CNV, fibrosis, hemorrhage). Typically, classic CNV disclose as a hyperreflective, fusiform area of thickening, above and adjacent to the retinal pigment epithelium usually separated by a thin less reflective band. The shadowing underneath the retinal pigment epithelium towards the choroid is usually marked. The indirect signs associate increase of thickness of the sensory retina due to intraretinal fluid accumulation, and flattening of the foveal depression. Conversely, the eventual persistence of the foveal depression provides additive landmarks for the exact location and extension of the CNV. Retinal pigment epithelium detachment (serous or hemorrhagic) may be present if classic CNV are associated with occult CNV. The exudative reaction may be accentuated and elevated in active classic CNV or usually more limited as spontaneous fibrosis progressively develops. –129– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Recent-Onset Typical Classic Choroidal Neovascularization. Fluorescein angiography shows small “cartwheel”-shaped hyperfluorescence surrounded by hyperpigmented ring, that will be masked by late leakage. ICG-angiography shows rapid filling of the CNV with late staining (hyperfluorescence). This aspect is similar to that of the image seen on fluorescein angiography but on late-phase ICG, there is minimal leakage (Gisele Soubrane, MD, France). –130– AGE-RELATED MACULAR DEGENERATION Recent-Onset Typical Classic Choroidal Neovascularization. Optical coherence tomography shows that intraretinal fluid accumulates and forms cystic spaces in the sensory retina. Classic CNV presents as a hyperreflective band anterior to the retinal pigment epithelium, separated by a less reflective area and inducing posterior shadowing in the area between the arrows (Gisele Soubrane, MD, France). –131– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES TYPICAL OCCULT CHOROIDAL NEOVASCULARIZATION On optical coherence tomography, direct signs of neovascularization are difficult to confirm in this initial stage but can visualize the presence of a hyperreflective thickened band confounded with the retinal pigment epithelium usually irregular and sometimes fusiform (cigar-like) with shadowing towards the choroid in the corresponding area. In a number of eyes a small and limited elevation of the retinal pigment epithelium might be underlying the hyperreflectivity of the CNV. The indirect signs are less prominent at this early stage. Subretinal and/or intraretinal accumulation of serous fluid with or without intraretinal cystoid edema confirms the presence of exudation from the CNV. Optical coherence tomography can also demonstrate a limited retinal pigment epithelium detachment, in the vicinity of the hyperreflective CNV. –132– AGE-RELATED MACULAR DEGENERATION Typical Occult Choroidal Neovascularization. Fluorescein angiography shows stippled, poorly demarcated hyperfluorescence with pinpoints and leakage suggestive of occult CNV. Scanning laser ophthalmoscope-based ICG-angiography shows a 1.5 DD CNV delineated from the early phase, with late hyperfluorescence and a dark halo. This membrane is centered on the fovea. The occult CNV on fluorescein angiography is “converted” into a well-defined CNV network, entirely localized. (Gisele Soubrane, MD, France). –133– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Typical Occult Choroidal Neovascularization. Optical coherence tomography shows slight elevation and increase of thickness of the sensory retina and the retinal pigment epithelium with moderate shadowing (Gisele Soubrane, MD, France). –134– AGE-RELATED MACULAR DEGENERATION Typical Occult Choroidal Neovascularization: Progression to Ingrowth of Classic Choroidal Neovascularization. Fluorescein angiography shows recent and rapid progression of an active classic CNV (arrow). ICG-angiography shows well-defined occult CNV network in the upper part of the lesion. Rapid wash-out of the classic component (arrow) is observed (Gisele Soubrane, MD, France). –135– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Typical Occult Choroidal Neovascularization: Progression to Ingrowth of Classic Choroidal Neovascularization. Optical coherence tomography shows marked exudative reaction with cystoid edema (Gisele Soubrane, MD, France). –136– AGE-RELATED MACULAR DEGENERATION Simultaneous Confocal Scanning Laser Ophthalmoscopy Imaging in Choroidal Neovascularization. Simultaneous confocal scanning laser ophthalmoscopy imaging combined with high-resolution, spectraldomain OCT shows choroidal neovascularization (Carsten H. Meyer, MD, Germany). –137– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Monitoring of New Therapy Approaches using Ultra-high Resolution Optical Coherence Tomography. Patient with drusen and occult choroidal neovascularization before (left) and 15 weeks after anti-VEGF therapy (right) (Wolfgang Drexler, PhD, Austria). –138– AGE-RELATED MACULAR DEGENERATION SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY Spectral-domain High-resolution Optical Coherence Tomography of Drusen. –139– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Spectral-domain OCT shows promise as an instrument for documenting the status of drusen in dry AMD with volumetric analysis. Currently, a number of pharmacologic agents are being evaluated in clinical and preclinical investigations for the treatment of dry AMD. In future, if dry AMD can be addressed pharmacologically with the same degree of success as treatment of exudative AMD, then this instrument is capable of detecting and documenting changes in drusen. –140– AGE-RELATED MACULAR DEGENERATION Spectral-domain High-resolution Optical Coherence Tomography of Choroidal Neovascularization. –141– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Spectral-domain optical coherence tomography is suitable for monitoring treatment of CNV with anti-VEGF therapy. Development of high-resolution OCT systems in conjunction with development of novel treatment options for exudative diseases offers promising perspectives. –142– AGE-RELATED MACULAR DEGENERATION THREE-DIMENSIONAL RETINAL IMAGING Three-dimensional imaging on SD-OCT, in exudative AMD, shows altered retinal contour and retinal thickness. Sequential 3D imaging in x, y and z planes show the CNV and associated color coded changes in retinal thickness maps present a novel perspective. Alterations in retinal nerve fiber layer (RNFL) and RNFL-retinal pigment epithelium (RPE) thickness maps and alterations in RPE deformation map are also observed. –143– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Exudative Age-Related Macular Degeneration. Optical coherence tomography shows choroidal neovascular membrane with elevation of retina. –144– AGE-RELATED MACULAR DEGENERATION Exudative Age-Related Macular Degeneration. Spectral-domain optical coherence tomography 3D image shows altered retinal contour. –145– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Exudative Age-Related Macular Degeneration. Spectral-domain optical coherence tomography 3D image shows retinal thickness map. –146– AGE-RELATED MACULAR DEGENERATION Exudative Age-Related Macular Degeneration. Sequential retinal thickness maps on spectral-domain optical coherence tomography 3D imaging in x plane. –147– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Exudative Age-Related Macular Degeneration. Retinal thickness map on spectral-domain optical coherence tomography 3D imaging in y plane. –148– AGE-RELATED MACULAR DEGENERATION Exudative Age-Related Macular Degeneration. Sequential retinal thickness maps on spectral-domain optical coherence tomography 3D imaging in z plane. –149– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Exudative Age-Related Macular Degeneration. Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography 3D imaging. –150– AGE-RELATED MACULAR DEGENERATION Exudative Age-Related Macular Degeneration. Retinal nerve fiber layer-retinal pigment epithelium thickness map on spectral-domain optical coherence tomography 3D imaging. –151– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Exudative Age-Related Macular Degeneration. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –152– 7 Central Serous Chorioretinopathy OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION Central serous chorioretinopathy (CSR) is characterized by idiopathic serous detachment of the macula, seen most commonly in young to middle-aged males. It is believed to be due to choroidal hyperpermeability and retinal pigment epithelium dysfunction. It is self-limiting with almost normal recovery of vision but has a 50% predilection for recurrence and involvement of the contralateral eye. It results in significant visual impairment in approximately 5% of patients. Associations with type-A personality and steroid intake have been described. Clinical features include: • Serous retinal detachment at the macula. The subretinal fluid may be clear or turbid with subretinal precipitates or fibrin. • Pigment epithelial detachment either alone or under a serous retinal detachment. • Retinal pigment epithelium atrophic tracks – these are flask-shaped and extend inferiorly from the macula. They are indicative of previous episodes of CSR. • Bullous retinal detachments with subretinal fibrin. These usually occur in cases of bilateral disease. –154– CENTRAL SEROUS CHORIORETINOPATHY Central Serous Chorioretinopathy. Fluorescein angiography shows ink blot appearance (Muna Bhende, MS, India). –155– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Serous Chorioretinopathy. Fluorescein angiography shows smoke stack appearance (Muna Bhende, MS, India). –156– CENTRAL SEROUS CHORIORETINOPATHY Indocyanine green angiography demonstrates that the primary abnormality is in the choroidal circulation. It is of particular importance if no definite leak is seen on fluorescein angiography. Multiple foci of choroidal hyperpermeability may be seen. The area of pigment epithelium detachment is hypofluorescent with a hyperfluorescent halo in the late phase. Indocyanine green angiography shows multiple hyperfluorescent areas at the posterior pole suggesting basic pathology in the choroid (Muna Bhende, MS, India). –157– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography reveals neurosensory detachment and pigment epithelial detachment. Diagnosis of the disease: Optical coherence tomography can aid in the diagnosis of the disease. Detection of neurosensory detachments can be of special use in conditions where fluorescein angiography may be contraindicated but the clinical suspicion is high. Following the progress of the disease: The neurosensory thickening as well as elevation is seen to reduce with resolution of the disease either spontaneously, after laser photocoagulation or photodynamic therapy. Prediction of visual acuity recovery: Prediction of visual acuity recovery after macular reattachment may be made depending on the optical coherence tomography of the outer plexiform layer. Explanation of poor visual acuity recovery: Optical coherence tomography can provide an explanation for poor visual recovery in the presence of apparent resolution—may detect shallow persistent neurosensory detachment at the fovea, foveal atrophy or cystoid changes at the fovea. –158– CENTRAL SEROUS CHORIORETINOPATHY THREE-DIMENSIONAL RETINAL IMAGING Three-dimensional imaging on SD-OCT shows altered retinal contour and retinal thickness in central serous chorioretinopathy. Sequential 3D imaging in x, y and z planes show increased retinal thickness, serous retinal detachment and associated color coded changes in retinal thickness maps. Alterations in retinal nerve fiber layer (RNFL) and RNFL-retinal pigment epithelium (RPE) thickness maps and alterations in RPE deformation map are also observed. –159– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Serous Chorioretinopathy. Optical coherence tomography shows serous detachment of retina with pigment epithelium detachment. –160– CENTRAL SEROUS CHORIORETINOPATHY Central Serous Chorioretinopathy. Spectral-domain optical coherence tomography 3D image shows altered retinal contour along with serous retinal detachment. –161– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Serous Chorioretinopathy. Spectral-domain optical coherence tomography shows 3D image in the x plane. Increased retinal thickness on color-coded retinal thickness and serous retinal detachment are observed. –162– CENTRAL SEROUS CHORIORETINOPATHY Central Serous Chorioretinopathy. Spectral-domain optical coherence tomography shows 3D image in the y plane. Increased retinal thickness on color-coded retinal thickness and serous retinal detachment are observed. –163– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Serous Chorioretinopathy. Spectral-domain optical coherence tomography shows 3D image in the z plane. Increased retinal thickness on color-coded retinal thickness is observed. –164– CENTRAL SEROUS CHORIORETINOPATHY Central Serous Chorioretinopathy. Spectral-domain optical coherence tomography 3D image shows retinal nerve fiber layer thickness map. –165– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Central Serous Chorioretinopathy. Spectral-domain optical coherence tomography 3D image shows retinal nerve fiber layer-retinal pigment epithelium thickness map. –166– CENTRAL SEROUS CHORIORETINOPATHY Central Serous Chorioretinopathy. Spectral-domain optical coherence tomography 3D image shows alterations in retinal pigment epithelium deformation map. –167– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Acute Central Serous Chorioretinopathy: Ultra-high Resolution optical coherence tomography. Ultra-high resolution optical coherence tomography images of the foveal region. Arrow indicates different appearance of the photoreceptor and outer nuclear layer. Asterisk indicates impairment of the external limiting membrane (Wolfgang Drexler, PhD, Austria). –168– CENTRAL SEROUS CHORIORETINOPATHY Chronic Central Serous Chorioretinopathy: Ultra-high Resolution optical coherence tomography. Ultra-high resolution optical coherence tomography images of the foveal region. Arrows indicate different appearance of the photoreceptor and outer nuclear layer. Asterisk indicates impairment of the external limiting membrane (Wolfgang Drexler, PhD, Austria). –169– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY: CURRENT CONCEPTS Morphologic alterations in the retinal pigment epithelium, detached retina, and subretinal space around the fluorescein leakage sites may be observed in the acute form of the disease. Among the leakage sites, retinal pigment epithelial abnormalities can be observed in the majority of cases. Pigment epithelial detachment and protruding or irregular retinal pigment epithelium layer can be observed. Fibrinous exudates in the subretinal space and sagging/dipping of the posterior layer of the neurosensory retina above the leakage sites may also be noted. The posterior surface of the detached retina may be smooth or granulated. Primarily the outer segment layer is altered. Visual prognosis can be linked to retinal morphological changes. Presence of correlation between foveal thickness and visual acuity has been observed. –170– 8 Myopia OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES MYOPIC FOVEOSCHISIS Myopic foveoschisis is not a retinal detachment but a foveal detachment with retinoschisis around the fovea. Recent improvements in instrumentation including development of OCT demonstrate more precisely the architecture of the posterior retina. Myopic foveoschisis is specific to high myopia, which generally is defined as a refractive error greater than -8.0 diopters. Clinically, patient’s visual complaints include visual loss, metamorphopsia, relative central scotoma, or all of these; however, some patients may be asymptomatic. The incidence of myopic foveoschisis has been reported to be 10% of highly myopic patients with posterior staphyloma. Optical coherence tomography is an essential tool for diagnosing myopic foveoschisis. Spontaneous resolution, probably resulting from posterior vitreous detachment may occur but is rare. –172– MYOPIA Myopic Foveoschisis: Morphologic Subtypes. Myopic foveoschisis accompanied by foveal detachment. It typically presents with a foveal detachment and retinoschisis of the surrounding retina (Late Yasuo Tano, MD, Japan). –173– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Myopic Foveoschisis: Morphologic Subtypes. Myopic foveoschisis accompanied by a lamellar hole (Late Yasuo Tano, MD, Japan). –174– MYOPIA Myopic Foveoschisis: Morphologic Subtypes. Myopic foveoschisis accompanied by a macular hole (Late Yasuo Tano, MD, Japan). –175– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Myopic Foveoschisis in Myopic Staphyloma. Color fundus photograph montage of the right eye (Alain Gaudric, MD, France). –176– MYOPIA Myopic Foveoschisis in Myopic Staphyloma. Montage of vertical optical coherence tomography scans, showing the outer schisis and inner schisis (Alain Gaudric, MD, France). Myopic Foveoschisis with Vitreomacular Traction. Optical coherence tomography shows myopic foveoschisis combined with vitreomacular traction (white arrows) and foveal detachment (yellow arrow). Horizontal OCT scan, on the top, shows foveoschisis combined with premacular structure, which was probably partially detached and thickened posterior hyaloid membrane. Structure exerted an oblique traction on retina. Note that foveal detachment and lamellar macular hole were also present (Alain Gaudric, MD, France). –177– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Myopic Foveoschisis with Vitreomacular Traction. Color fundus photograph shows staphyloma. Optical coherence tomography, after 12 months of surgery shows, normal foveal thickness and complete regression of foveoschisis and foveal detachment, but persistence of small lamellar hole (Alain Gaudric, MD, France). –178– 9 Epiretinal Membranes OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION An idiopathic epiretinal membrane (ERM) usually develops after a partial or complete posterior vitreous detachment, and appears as a translucent membrane over the inner retinal surface in the macular area by ophthalmoscopy or biomicroscopy. Contraction of these membranes can result in various retinal pathology, such as retinal distortion, increased thickness of the macula with or without increased permeability of retinal vessels, and cystoid macular edema. –180– EPIRETINAL MEMBRANES IDIOPATHIC EPIRETINAL MEMBRANES Classification scheme for epiretinal membrane proposed by Gass: Grade 0 (cellophane maculopathy): Translucent membranes unassociated with retinal distortion. Grade 1 (crinkled cellophane maculopathy): Membranes that cause irregular wrinkling of the inner retina. Grade 2 (macular pucker): Opaque membranes that cause obscuration of the underlying vessels and marked fullthickness retinal distortion. –181– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography demonstrates ERMs as thin, highly reflective bands anterior to the retina. Based on morphologic characteristics, ERMs can be classified into two distinct groups; those with focal points of attachment to the retina and those with global adherence to the retina. Majority of ERMs (approximately 70%) are globally adherent to the retina. The remaining eyes have focally adherent ERMs. Occasionally OCT cannot distinguish between the ERM and the anterior surface of the retina if the ERM is globally adherent to the retina. Discriminating features may be a difference in contrast between the ERM (higher reflectivity) and the retina (lower reflectivity) and the appearance of a membrane tuft or edge contiguous with the retinal surface. –182– EPIRETINAL MEMBRANES When correlated to clinical pathogenesis, secondary ERMs are more likely to be characterized by focal retinal adhesion than are idiopathic ERMs. Idiopathic ERMs tend to be globally adherent. An OCT image of fovea with secondary ERM typically demonstrates diffuse thickening with loss of foveal pit. In idiopathic ERMs mean central macular thickness measured with OCT correlates with visual acuity. –183– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES OPTICAL COHERENCE TOMOGRAPHY FOR MONITORING SURGICAL REMOVAL OF EPIRETINAL MEMBRANE Optical coherence tomography provides beneficial information in monitoring surgical removal of ERM and decrease of intraretinal edema after vitreous surgery. The foveal pit reappears occasionally in successful cases. Preoperative and postoperative mean macular thicknesses do not correlate with postoperative vision, thus indicating that preoperative macular thickness is not predictive of postoperative visual outcome. –184– EPIRETINAL MEMBRANES Idiopathic Epiretinal Membrane. Preoperative color fundus photograph shows cellophane maculopathy. Preoperative optical coherence tomography image from a 5 mm horizontal scan over the macula shows a small epiretinal membrane. The foveal thickness is 331 µm. Preoperative optical coherence tomography map shows that macular thickening is present. The diameters of circles are 1, 3, and 6 mm (Hiroko Terasaki, MD, Japan). –185– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Idiopathic Epiretinal Membrane. Color fundus photograph six months after vitrectomy. Postoperative optical coherence tomography image six months after surgery shows that the foveal depression has recovered. The foveal thickness is 224 µm. Postoperative optical coherence tomography map 6 months after surgery shows mild macular thickening (Hiroko Terasaki, MD, Japan). –186– EPIRETINAL MEMBRANES Secondary Epiretinal Membrane Associated with Chronic Retinal Vasculitis. Color fundus photograph shows macular edema associated with the advanced secondary epiretinal membrane. Optical coherence tomography, horizontal scan, delineates partially adherent epiretinal membrane to the retinal surface. Optical coherence tomography depicts increased retinal thickness and spaces of reduced optical reflectivity consistent with intraretinal cystic fluid accumulation (Keisuke Mori, MD, PhD, Japan). –187– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY Spectral-domain OCT images of eyes with ERM are diverse. Morphological changes in the retina, such as edema with cystic spaces, lamellar macular holes, macular pseudoholes and photoreceptor defects are well-defined. Estimation of these changes may be an important prognostic factor. The SD-OCT with 3D image reconstruction provided unprecedented visualization of vitreomacular traction and idiopathic ERM. THREE-DIMENSIONAL RETINAL IMAGING Three-dimensional imaging on SD-OCT shows altered retinal contour and retinal thickness. Alterations in retinal nerve fiber layer (RNFL) and RNFL-retinal pigment epithelium (RPE) thickness maps and alterations in RPE deformation map are also observed. Optical coherence tomography also enables us to understand vitreomacular traction force due to membrane adherent to macula with attachment to the posterior hyaloid. –188– EPIRETINAL MEMBRANES Spectral-domain Optical Coherence Tomography. Focally adherent epiretinal membrane is visible. –189– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Epiretinal membrane. –190– EPIRETINAL MEMBRANES Epiretinal Membrane. Spectral-domain optical coherence tomography 3D image shows altered retinal contour. –191– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Epiretinal Membrane. Spectral-domain optical coherence tomography 3D image shows retinal thickness map. –192– EPIRETINAL MEMBRANES Epiretinal Membrane. Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography 3D imaging. –193– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Epiretinal Membrane. Retinal nerve fiber layer-retinal pigment epithelium thickness map on spectral-domain optical coherence tomography 3D imaging. –194– EPIRETINAL MEMBRANES Epiretinal Membrane. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –195– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES PSEUDOHOLES Epiretinal membranes occasionally induce retinal distortion that creates macular pseudoholes. Continuous contraction of ERMs may induce appearance of pseudohole to change from round or oval to slit-like, but usually vision decrease is limited. Visual prognosis of eyes with macular pseudoholes is generally good since foveal structure is unaffected. Optical Coherence Tomography Optical coherence tomography provides useful information for understanding the pathology of macular pseudoholes. It is beneficial in distinguishing macular pseudoholes from ophthalmoscopically similar-appearing lesions such as macular holes, macular lamellar holes, and macular cysts. Typical OCT configuration of macular pseudohole is the contour of the foveal pit, a thickening of the macular edges, a steeper foveal pit contour and the presence of normally reflective retinal tissue at the base of the pseudohole. The majority of eyes with macular pseudoholes are associated with globally adherent membranes. –196– EPIRETINAL MEMBRANES Macular Pseudohole with Idiopathic Epiretinal Membrane. Color fundus photograph shows an oval macular pseudohole surrounded by idiopathic epiretinal membrane. Optical coherence tomography, horizontal scan, shows deep and steep foveal pit with lamellation and thinning at the base of the fovea. Epiretinal membrane is globally adherent to the inner surface of the retina and difficult to distinguish from sensory retina (Keisuke Mori, MD, PhD, Japan). –197– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY: CURRENT CONCEPTS Greyscale images make more precise identification of the inner segment/outer segment (IS/OS) junction. The appearance of the IS/OS junction in the OCT images at the fovea can be graded from 0 to 2: 0: IS/OS line not visible; 1: abnormal (discontinuous) IS/OS line; and 2: normal (well-preserved) IS/OS line. Eyes in which a normal IS/OS junction is detected after surgery have significantly better visual acuity than those without a normal IS/OS junction. This correlation between the presence of a normal IS/OS junction and better postoperative visual acuity is probably due to better morphological recovery of the macular photoreceptor cells. –198– 10 Vitreomacular Traction Syndrome OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION Macula is one of the regions of physiological vitreoretinal adhesions, which plays a keyrole in vitreomacular traction in an idiopathic macular hole development. In cases with incomplete posterior vitreous detachment, persistent vitreomacular traction results in morphological distortion of macula, termed vitreomacular traction syndrome. Vitreoretinal attachment in vitreomacular traction syndrome may vary from a broad area around the optic nerve and macula to narrow foveal zone with a perifoveal vitreous detachment and focal adhesion to the fovea. Macular distortion induced persistent macular traction results in cystoid macular edema associated with central vision decrease and metamorphopsia. OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography enables us to understand vitreomacular tractional force due to membrane adherent to macula with attachment of the posterior hyaloid, inducing significant retinal elevation and edema. Optical coherence tomography is also useful in demonstrating anatomic response after surgery for vitreomacular traction syndrome. –200– VITREOMACULAR TRACTION SYNDROME THREE-DIMENSIONAL RETINAL IMAGING The spectral-domain optical coherence tomography with 3D image reconstruction provides unprecedented visualization of vitreomacular traction (VMT) and idiopathic epiretinal membrane (ERM). The vitreous attachment to the macula can be subclassified into two subgroups, each having specific induced alterations in retinal anatomy: a. Focal VMT and b. Broad VMT. Most of the eyes with VMT had concurrent ERM, whereas several eyes with idiopathic ERM had attachment of the vitreous to some portion of the ERM, which suggests there is significant overlap between VMT and idiopathic ERM. –201– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Epiretinal Membrane with Vitreomacular Traction: High-definition Optical Coherence Tomography. High-definition optical coherence tomography shows epiretinal membrane with vitreous attachment above (Lawrence P. Chong, MD, USA). –202– VITREOMACULAR TRACTION SYNDROME Epiretinal Membrane with Vitreomacular Traction: High-definition Optical Coherence Tomography. Three-dimensional image demonstrates significant vitreomacular traction (Lawrence P. Chong, MD,USA). –203– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Idiopathic Epiretinal Membrane with Vitreoretinal Traction. Epiretinal membrane with vitreomacular traction is visible. –204– VITREOMACULAR TRACTION SYNDROME Vitreomacular Traction. Spectral-domain optical coherence tomography 3D image shows altered retinal contour. –205– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Vitreomacular Traction. Spectral-domain optical coherence tomography 3D image shows retinal thickness map. –206– VITREOMACULAR TRACTION SYNDROME Vitreomacular Traction. Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography 3D imaging. –207– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Vitreomacular Traction. Retinal nerve fiber layer-retinal pigment epithelium thickness map on spectral-domain optical coherence tomography 3D imaging. –208– VITREOMACULAR TRACTION SYNDROME Vitreomacular Traction. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –209– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Pars Plana Vitrectomy for Vitreomacular Traction Syndrome with Branch Retinal Vein Occlusion. Color fundus photograph, before surgery, demonstrates advanced branch retinal vein occlusion with glistening epiretinal fibrosis (Keisuke Mori, MD, PhD, Japan). –210– VITREOMACULAR TRACTION SYNDROME Pars Plana Vitrectomy for Vitreomacular Traction Syndrome with Branch Retinal Vein Occlusion. Fluorescein angiography, of early and late phases, demonstrate capillary occlusion and intensive vascular leakage (Keisuke Mori, MD, PhD, Japan). –211– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Pars Plana Vitrectomy for Vitreomacular Traction Syndrome with Branch Retinal Vein Occlusion. Optical coherence tomography, horizontal and vertical cross-sectional images, show dense membrane adherent to macula with attachment of the posterior hyaloid (arrows). Color fundus photograph one-month after pars plana vitrectomy with membrane peeling (Keisuke Mori, MD, PhD, Japan). –212– VITREOMACULAR TRACTION SYNDROME Pars Plana Vitrectomy for Vitreomacular Traction Syndrome with Branch Retinal Vein Occlusion. Optical coherence tomography, vertical scan, demonstrates release of macular traction, resolution of macular edema, relative increase of intraretinal exudation and significant reduction of retinal thickness (Keisuke Mori, MD, PhD, Japan). –213– 11 Idiopathic Macular Hole OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION Recent advances in the pathogenesis, classification, and surgical intervention of idiopathic macular holes have generated a renewed interest in this entity. Idiopathic macular hole Gass proposed a theory whereby shrinkage of adherent cortical vitreous and subsequent tangential vitreous traction first cause a circumscribed foveolar detachment (stage I) followed by early retinal dehiscence (stage II), then enlargement of the macular hole with vitreofoveal separation (stage III) and finally complete posterior vitreous detachment (stage IV). –216– IDIOPATHIC MACULAR HOLE Idiopathic Macular Hole: Biomicroscopic Staging (Gass) Stage 1A: Yellow spot, foveal dehiscence, posterior hyaloid attached to internal limiting membrane Stage 1B: Yellow ring, lateral spread of photoreceptors Stage 2: Full thickness macular hole, can opener tear or pseudooperculum, <400 µm diameter Stage 3: Full thickness macular hole, pseudooperculum, >400 µm diameter Stage 4: Full thickness macular hole with complete posterior vitreous detachment –217– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Idiopathic Macular Hole: Optical Coherence Tomography Staging Stage 1A: Partial thickness pseudocyst with perifoveal posterior vitreous detachment Stage 1B: Full thickness pseudocyst with roof Stage 2A: Full thickness macular hole with partial opening of the roof, focal vitreous attachment to flap Stage 2B: Full thickness operculated macular hole, traction to retina released Stage 3: Full thickness operculated macular hole, traction released, >400 µm diameter Stage 4: Full thickness macular hole with complete posterior vitreous detachment, vitreous face may or may not be evident on optical coherence tomography. –218– IDIOPATHIC MACULAR HOLE OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography has been found effective in distinguishing full-thickness macular holes from partial thickness holes, macular holes, and cysts. It has been successful in staging macular holes and providing a quantitative measure of hole diameter and the amount of surrounding macular edema. It can also detect small separations of the posterior hyaloid from the retina. Optical coherence tomography can also provide information concerning the risk of developing a macular hole within an individual eye because OCT delineates the anatomy in more detail than biomicroscopy. Measurements of macular hole diameter with OCT have been correlated with surgical results. –219– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Stage 1A Idiopathic Macular Hole. OCT highlights perifoveolar posterior vitreous detachment with continued foveolar adherence and obliquely oriented tractional forces. Retinal tissue remains at the base of the pseudocyst. –220– IDIOPATHIC MACULAR HOLE Stage 2A Idiopathic Macular Hole. The roof of the pseudocyst is torn which continues to have traction exerted by the vitreous attachments. –221– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Stage 3 Idiopathic Macular Hole. The retinal elements have separated apart and the retina has thickened. An operculum is attached to the visible posterior hyaloid face. –222– IDIOPATHIC MACULAR HOLE Stage 4 Idiopathic Macular Hole. The posterior hyaloid face is detached off the surface of the retina. –223– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY Spectral-domain three-dimensional imaging of macular holes with high-speed OCT based on SD-OCT technology offers 3-dimensional overviews that facilitate understanding of the abnormalities in the vitreofoveal interface. It also provides consecutive orthogonal images that allow much more precise and minute observation of 3-dimensionally extending intraretinal structural changes associated with a macular hole than conventional OCT imaging, especially in the photoreceptor inner and outer segments. –224– IDIOPATHIC MACULAR HOLE Stage 4 Idiopathic Macular Hole: Spectral-domain Optical Coherence Tomography. Full-thickness macular hole with cystoid changes is observed. –225– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES A (A) Idiopathic Macular Hole: High-definition Optical Coherence Tomography. High-definition optical coherence tomography of retina through the fovea demonstrates a partial posterior vitreous detachment with evidence of macular traction (Lawrence P Chong, MD, USA). –226– IDIOPATHIC MACULAR HOLE B C (B and C) Idiopathic Macular Hole: High-definition Optical Coherence Tomography. Three-dimensional images of vitreomacular traction over the macular hole (Lawrence P Chong, MD, USA). –227– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES THREE-DIMENSIONAL RETINAL IMAGING Three-dimensional imaging on SD-OCT shows macular hole with altered retinal contour and retinal thickness. Alterations in retinal nerve fiber layer (RNFL) and RNFLretinal pigment epithelium (RPE) thickness maps without alterations in RPE deformation map are also observed. Three-dimensional imaging of macular holes with highspeed OCT based on SD-OCT technology offers 3-dimensional overviews that facilitate understanding of the abnormalities in the vitreofoveal interface. It also provides consecutive orthogonal images that allow much more precise and minute observation of 3-dimensionally extending intraretinal structural changes associated with a macular hole than conventional OCT imaging, especially in the photoreceptor inner and outer segments. –228– IDIOPATHIC MACULAR HOLE Idiopathic Macular Hole. Spectral-domain optical coherence tomography 3D image shows altered retinal contour. Macular hole can be discerned very well. –229– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Idiopathic Macular Hole. Spectral-domain optical coherence tomography 3D image shows retinal thickness map. –230– IDIOPATHIC MACULAR HOLE Idiopathic Macular Hole. Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography 3D imaging. –231– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Idiopathic Macular Hole. Retinal nerve fiber layer-retinal pigment epithelium thickness map on spectral-domain optical coherence tomography 3D imaging. –232– IDIOPATHIC MACULAR HOLE Idiopathic Macular Hole. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –233– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Lamellar Macular Hole: Spectral-domain High-resolution Optical Coherence Tomography. Simultaneous confocal scanning laser ophthalmoscopy imaging combined with high-resolution, spectral-domain optical coherence tomography show lamellar macular hole with an epiretinal membrane (Carsten H Meyer, MD, Germany) –234– IDIOPATHIC MACULAR HOLE Ultra-high Resolution Optical Coherence Tomography in Macular Hole. Horizontal ultra-high resolution OCT image of patients with different stages of macular holes (upper), magnification of the central foveal region with quantification of the PR layer thickness (lower) ; ELM, external limiting membrane; IS PR, inner segments of photoreceptors; OS PR, = outer segments of photoreceptors; RPE, retinal pigment epithelium (Wolfgang Drexler, PhD, Austria). –235– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Ultra-high Resolution Optical Coherence Tomography in Macular Hole. Horizontal ultra-high resolution OCT image of patients with different stages of macular holes (upper), magnification of the central foveal region with quantification of the PR layer thickness (lower) ; ELM, external limiting membrane; IS PR, inner segments of photoreceptors; OS PR, = outer segments of photoreceptors; RPE, retinal pigment epithelium (Wolfgang Drexler, PhD, Austria). –236– IDIOPATHIC MACULAR HOLE Ultra-high Resolution Optical Coherence Tomography in Macular Hole. Horizontal ultra-high resolution OCT image of patients with different stages of macular holes (upper), magnification of the central foveal region with quantification of the PR layer thickness (lower) ; ELM, external limiting membrane; IS PR, inner segments of photoreceptors; OS PR = outer segments of photoreceptors; RPE, retinal pigment epithelium (Wolfgang Drexler, PhD, Austria). –237– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Successfully repaired macular holes have been subdivided into three patterns based on OCT configuration: The U-type with normal foveal contour, the V-type with steep foveal contour and the W type with a foveal defect of the neurosensory retina. These patterns have also be shown to correlate with postoperative visual acuity (U>V>W). Macular Hole Surgery: Optical Coherence Tomography. Optical coherence tomography shows a full thickness macular hole. Intraretinal changes of neurosensory retina at the hole edge are observed. Postoperative optical coherence tomography after successful macular hole surgery shows well-maintained foveal contour. –238– IDIOPATHIC MACULAR HOLE Monitoring of Surgical Intervention with in vivo Ultra-high Resolution Optical Coherence Tomography. Horizontal ultra-high resolution optical coherence tomographic image; bars and arrows indicate extent of photoreceptor impairment well beyond the margin of the macular hole (Wolfgang Drexler, PhD, Austria). –239– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Monitoring of Surgical Intervention with in vivo Ultra-high Resolution Optical Coherence Tomography. Horizontal ultra-high resolution optical coherence tomography image; bars and arrows indicate extent of residual postoperative photoreceptor impairment 3 months following macular hole surgery (Wolfgang Drexler, PhD, Austria). –240– IDIOPATHIC MACULAR HOLE Monitoring of Surgical Intervention with in vivo Ultra-high Resolution Optical Coherence Tomography. Magnification of previous image with labeling of retinal layers: The outer retina remains abnormal 3 months after surgery; IS PR, inner segments of photoreceptors; OS PR, outer segments of photoreceptors; RPE, retinal pigment epithelium (Wolfgang Drexler, PhD, Austria). –241– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY: CURRENT CONCEPTS A disruption of the IS-OS junction is observed in all eyes with macular holes. The photoreceptor layer appears to be involved for a much larger area than that occupied by the macular hole itself. The abnormality in the IS-OS boundary line may reflect perturbation of a higher level of retinal organization and not an absolute loss of photoreceptor outer segments. The postoperative IS/OS junction may play an important role in visual recovery after macular hole surgery. With macular hole closure, IS/OS line heals in varying degrees. The visual outcomes were significantly better in eyes with a continuous IS/OS line than in those with a disrupted IS/ OS line. The normal IS/OS junction is associated with good visual recovery after macular hole closure. The presence of normal IS/OS junction may be important for visual recovery. –242– 12 Cone-Rod Dystrophy OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION Cone-rod dystrophy is characterized by primary cone involvement or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms: Decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field. This is later followed by progressive loss in peripheral vision and night blindness. PROGRESSIVE CONE DYSTROPHY Progressive cone dystrophy is a heterogeneous group of rare disorders. Patients with pure cone dystrophy initially –244– CONE-ROD DYSTROPHY have only cone dysfunction. Depending on the genetic defect, this inherited disorder is either limited to or additional rod dysfunction may develop. OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography reveals a large central full thickness defect that reflects a general atrophy of all retinal layers with the accentuation of physiological foveal depression. Two different types can be distinguished: Type 1, gradually foveal atrophy; type 2, abrupt foveal atrophy. In type 1 foveal thickness is more or less impaired going until the total absence of all retinal layers in foveal area, but the curve of foveal atrophy is progressive from normal thickness in periphery until total central atrophy. In type 2 there is an abrupt foveal atrophy and is not possible to see the progressive curve of retinal atrophy from the periphery to the center. –245– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Progressive Cone Dystrophy. Bull’s eye appearance on color fundus photograph. Linear scan (5 mm) on optical coherence tomography reveals a large central full thickness defect, progressive from periphery until the center, that reflects a general atrophy of all retinal layers with the accentuation of physiological foveal depression (type 1) (Eric H. Souied, MD, PhD, France). –246– CONE-ROD DYSTROPHY Progressive Cone Dystrophy. Total foveal atrophy of the retina and of the choriocapillaris on color fundus photograph. Optical coherence tomography reveals a large abrupt central full thickness defect of the macula (type 2) (Eric H Souied, MD, PhD, France). –247– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY Imaging using SD-OCT achieves considerably improved visualization of intraretinal layers, especially the photoreceptor layer. Three-dimensional imaging on SDOCT shows altered retinal contour and retinal thickness. Alterations in retinal nerve fiber layer (RNFL) and RNFLretinal pigment epithelium (RPE) thickness maps and alterations in RPE deformation map are also observed. –248– CONE-ROD DYSTROPHY Cone Dystrophy. Spectral-domain optical coherence tomography shows foveal atrophy with thinning of photoreceptor layer. –249– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Cone Dystrophy. Spectral-domain optical coherence tomography 3D image shows depressed retinal contour. –250– CONE-ROD DYSTROPHY Cone Dystrophy. Spectral-domain optical coherence tomography 3D image shows altered retinal thickness map. –251– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Cone Dystrophy. Retinal nerve fiber layer thickness map on spectral-domain optical coherence tomography 3D imaging. –252– CONE-ROD DYSTROPHY Cone Dystrophy. Retinal nerve fiber layer-retinal pigment epithelium thickness map on spectral-domain optical coherence tomography 3D imaging. –253– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Cone Degeneration. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –254– 13 Optic Disk Pit Maculopathy OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES INTRODUCTION Optic disk pit is a congenital oval or round depression within the optic nerve head. It is believed to develop secondary to a defect in the development of the primitive papilla. Some optic disk pits may be associated with colobomas of optic nerve head. Optic nerve head pits are associated with various retinal changes. Most of the retinal changes are temporal to the disk, located between the temporal vascular arcades. Occurrence of optic disk pit is rare and can be bilateral in 10-15% of cases. –256– OPTIC DISK PIT MACULOPATHY About one-third of optic disk pits are located centrally and two-third eccentrically on the disk. Majority are located on the temporal side. Serous detachment of the macula is now known as a common complication of optic disk pits. Between 40% and 50% of patients with optic disk pit have either an associated serous retinal detachment or retinal changes suggestive of previous detachment. The majority of the detachments are located in the macular region. OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography has confirmed the bilaminar structure of the macular detachment. A schisis-like cavity starts in the outer retina adjacent to the optic disk pits and extends to the fovea. The schisis-like cavity mimics a true schisis cavity in some cases although vertical retinal elements can be detected on OCT in the inner retina. Another feature seen is the presence of subretinal precipitates. The OCT shows a hyperreflectivity of these deposits. Most of the cases do not have outer wall breaks in eyes with macular detachment. The possibility does exist that the breaks are minute and their resolution occurs so that these breaks are not detected on OCT. In other eyes a lamellar hole may be a defect in the outer retina. The pseudohole is covered by a thin inner foveal tissue. Variability in the thickening of the central macula –257– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES depends of the schisis-like extension in the fovea and the neurosensory elevation from the retinal pigment epithelium. Optical coherence tomography images provide a detailed understanding of the pathogenesis of macular changes associated with optic disk pit. Pneumatic displacement of the outer layer detachment is associated with improvement in central visual acuity; however, it is temporary as the OCT reveals that the inner layer separation or the schisis cavity persists thus providing a conduit for the continuous flow of fluid from the pit to the subretinal space. Optical coherence tomography allows enhanced visualization of retinal changes in these eyes revealing the collection of fluid at several distinct levels of retina. Optical coherence tomography may reveal a connection between the optic nerve pit and schisis cavity in the inner retinal layers. Optical coherence tomography is a useful tool for monitoring the therapeutic effect of this surgery. –258– OPTIC DISK PIT MACULOPATHY Optic Disk Pit Maculopathy. Color fundus photograph shows the limits of schisis lesion (long arrows) and retinal detachment (short arrows) are observed. An irregular laminar macular hole is present (Borja F Corcostegui, MD, Spain) –259– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Optic Disk Pit Maculopathy. Optical coherence tomography shows clearly the neurosensory retinal detachment with a discontinuity (arrow), corresponding to an outer layer hole. A large schisis-like separation in the overlying and surrounding retina is present (Borja F Corcostegui, MD, Spain) –260– OPTIC DISK PIT MACULOPATHY Optic Disk Pit Maculopathy. Color fundus photograph shows serous retinal detachment in a patient with large optic pit or small coloboma of the optic nerve (Borja F Corcostegui, MD, Spain). –261– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Optic Disk Pit Maculopathy. Optical coherence tomography shows an inner layer separation, and an outer layer detachment. Hyperreflectivity dots are corresponding to the subretinal exudates (arrows) (Borja F Corcostegui, MD, Spain). –262– OPTIC DISK PIT MACULOPATHY Optic Disk Pit Maculopathy. Color fundus photograph shows a domeshaped retinal elevation in the macula. Fluid is in connection with an optic pit at the temporal side of the optic nerve head. A lamellar hole is present centrally with a small surrounding retinal detachment (Borja F Corcostegui, MD, Spain). –263– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Optic Disk Pit Maculopathy. Optical coherence tomography, vertical scan through the fovea, shows a neurosensory retinal detachment with overlying and surrounding outer edema (Borja F Corcostegui, MD, Spain). –264– 14 Intraocular Tumors OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES RETINOBLASTOMA Retinoblastoma is the most common intraocular malignancy of childhood. Retinoblastoma occurs in approximately 1 in 14,000-34,000 live births. The majority of cases of retinoblastoma are sporadic. Retinoblastoma occurs as a result of loss of the tumor suppressor gene located on band 14, on the long arm of chromosome 13 (13q14). In genetically transmitted disease, the abnormality results in the development of usually bilateral, multifocal tumors in relatively younger patients. Based on the growth pattern, retinoblastoma can be classified into endophytic, exophytic, mixed (both endophytic and exophytic) and diffusely infiltrative tumors. –266– INTRAOCULAR TUMORS Optical Coherence Tomography Optical coherence tomography shows an optically dense appearance with shadowing of the deep tissues. Intralesional calcification can cause higher internal reflectivity (backscattering) and denser shadowing posterior to the tumor. There is abrupt transition of the normal retinal architecture to the retinal mass. If the mass is intraretinal, full thickness retina is involved. An endophytic retinoblastoma may be difficult to image due to overlying vitreous seeds. An exophytic tumor shows retinal detachment overlying the neoplasm. In rare cases, intraretinal empty cavities can be visualized and these are usually found in well-differentiated portions of the tumor. Optical coherence tomography is a useful test in monitoring reasons for visual loss following treatment of retinoblastoma. In some instances, eyes with total retinal detachment from retinoblastoma have recovered complete function of the retina both clinically and anatomically, confirmed on OCT. –267– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Retinoblastoma. Color fundus photograph shows retinoblastoma with cavities (arrow). Optical coherence tomography shows a dense homogeneous retinal mass with cavities anteriorly (Carol L Shields, MD, and Jerry A Shields, MD, USA). –268– INTRAOCULAR TUMORS Retinoblastoma. Color fundus photograph shows advanced retinoblastoma with total retinal detachment in the right and the left eye (Carol L Shields, MD, and Jerry A Shields, MD, USA). –269– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Retinoblastoma. Color fundus photograph following chemoreduction and thermotherapy shows regressed tumor and the retina flattened in the right and the left eye (Carol L Shields, MD, and Jerry A Shields, MD, USA). –270– INTRAOCULAR TUMORS Retinoblastoma. Optical coherence tomography six years following stable regression. The right eye shows normal macular architecture without edema or subretinal fluid but with blunted foveal depression. The left eye shows normal superotemporal macular architecture without edema or subretinal fluid and with normal foveal depression, but with retinal pigment epithelial thickening (Carol L Shields, MD, and Jerry A Shields, MD, USA). –271– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES CHOROIDAL METASTASIS Intraocular metastasis is thought to be the commonest form of intraocular malignancy. Cancer metastatic to the choroid is probably more common than generally realized. Ninety percent of metastatic tumors affect choroid. Breast in women and the lung in men are the common sites of origin of metastasis. Choroidal metastases can be unilateral and unifocal or bilateral and multifocal. The bilateral lesions are related to breast carcinoma in nearly 70% of cases. Lung carcinoma metastasis is usually unifocal. Tumors of the thyroid, prostate, alimentary tract, pancreas, kidney and other organs may rarely metastasize to the eye. –272– INTRAOCULAR TUMORS Choroidal metastasis from carcinoma breast. –273– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Choroidal metastasis from carcinoma lung. –274– INTRAOCULAR TUMORS OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography shows a poorly imaged lesion but the overlying retinal and retinal pigment epithelium changes can be illustrated. Optical coherence tomography can depict overlying subretinal fluid, retinal pigment epithelium hyperplasia, retinal pigment epithelium detachment, and clumps of orange pigment. Resolution of subretinal fluid on OCT can be documented following therapy of the metastasis. THREE-DIMENSIONAL RETINAL IMAGING Optical coherence tomography can depict overlying subretinal fluid, retinal pigment epithelial hyperplasia and retinal pigment epithelium detachment. Spectral-domain optical coherence tomography with 3D imaging shows a poorly imaged/ well-defined lesion with altered retinal thickness, serous detachment of the retina and retinal pigment epithelium deformation. Resolution of subretinal fluid can be documented following therapy. –275– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Choroidal Metastasis from Carcinoma Breast. Spectral-domain optical coherence tomography 3D image shows retinal thickness map with elevated retina. –276– INTRAOCULAR TUMORS Choroidal Metastasis from Carcinoma Breast. Retinal thickness map on spectral-domain optical coherence tomography 3D imaging in x plane shows serous detachment of the retina with retinal elevation and altered retinal thickness. –277– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Choroidal Metastasis from Carcinoma Lung. Spectral-domain optical coherence tomography 3D image shows retinal thickness map with elevated retina. –278– INTRAOCULAR TUMORS Choroidal Metastasis from Carcinoma Lung. Retinal pigment epithelium deformation map on spectral-domain optical coherence tomography 3D imaging. –279– 15 Intermediate and Posterior Uveitis OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES OPTICAL COHERENCE TOMOGRAPHY Optical coherence tomography demonstrates a variety of characteristic morphological changes, some that may point towards a specific disease process. It is especially helpful in detecting complications such as epiretinal membrane, vitreoretinal traction, cystoid macular edema and choroidal neovascularization. Ophthalmologists should be aware of the variety of retinal morphological characteristics that can present on OCT in uveitic disease. Recognition may aid in the diagnostic process, which is complementary to conventional fundus photography and fluorescein angiography. This can facilitate earlier diagnosis and more importantly the initiation of specific treatment. THREE-DIMENSION RETINAL IMAGING Spectral-domain OCT helps in elucidating morphological changes in lesions that were not apparent on clinical examination, which may expand the clinical spectrum of the disease. –282– INTERMEDIATE AND POSTERIOR UVEITIS Intermediate Uveitis. Color fundus photograph shows media haze with cystoid macular edema (Jyotirmay Biswas, MS, India). Intermediate Uveitis. Optical coherence tomography scan through the fovea reveals cystoid macular edema (CME) and neurosensory detachment (NSD) (Jyotirmay Biswas, MS, India). –283– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Multifocal Choroiditis with Choroidal Neovascularization. Color fundus photograph shows healed multifocal choroiditis with choroidal neovascularization (Jyotirmay Biswas, MS, India). –284– INTERMEDIATE AND POSTERIOR UVEITIS Multifocal Choroiditis with Choroidal Neovascularization. Fluorescein angiography shows a classic choroidal neovascular membrane (Jyotirmay Biswas, MS, India). –285– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Multifocal Choroiditis with Choroidal Neovascularization. Optical coherence tomography line scans passing through different points on the choroidal neovascularization show areas of disrupted retinal pigment epithelium with increased hyperreflectivity from the outer retinal layers with adjacent hyporeflective areas suggesting of the presence of intraretinal fluid. There are areas of pigment epithelial detachment with underlying choroidal scars and areas of neurosensory detachment (Jyotirmay Biswas, MS, India). –286– INTERMEDIATE AND POSTERIOR UVEITIS Harada’s Disease. Color fundus photograph shows disk edema with serous retinal detachment (Jyotirmay Biswas, MS, India). –287– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Harada’s Disease. Optical coherence tomography shows serous retinal detachment (Jyotirmay Biswas, MS, India). –288– INTERMEDIATE AND POSTERIOR UVEITIS Healed toxoplasmosis. –289– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Healed Toxoplasmosis. Spectral-domain optical coherence tomography 3D imaging shows retinal thickness map and retinal pigment epithelium deformation map in an excavated lesion. –290– INTERMEDIATE AND POSTERIOR UVEITIS Healed Toxoplasmosis. Spectral-domain optical coherence tomography scan reveals discontinuation of photoreceptor layer and hyperreflective retinal pigment epithelium can be observed. In the center of the lesion, break in the continuity of inner retinal layers may be noted. Retinal nerve fiber layer is found to be absent. Choriocapillaris/ choroidal/ scleral relative hyperreflectivity is also observed in the center of lesion. –291– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Healed toxoplasmosis. –292– INTERMEDIATE AND POSTERIOR UVEITIS Healed Toxoplasmosis. 3D retinal imaging on spectral-domain optical coherence tomography shows an excavated lesion. –293– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Healed Toxoplasmosis. 3D retinal imaging on spectral-domain optical coherence tomography shows marked changes in retinal thickness in the retinal thickness map. –294– INTERMEDIATE AND POSTERIOR UVEITIS Healed Toxoplasmosis. Spectral-domain optical coherence tomography scan, at the edge of the lesion, reveals splitting of retina at the level of the outer nuclear layer. Discontinuation of photoreceptor layer and hyperreflective retinal pigment epithelium can be observed. In the center of the lesion, break in the continuity of inner retinal layers may be noted. Retinal nerve fiber layer is found to be absent. Choriocapillaris/ choroidal/ scleral relative hyperreflectivity is also observed in the center of lesion. –295– Index INDEX A Age-related macular degeneration 118 Age-related maculopathy 118 Anatomic architecture of retina 14 Axial resolution 6 B Branch retinal artery occlusion 108 Branch retinal vein occlusion 78 Bruch’s membrane complex 14 C Central fovea 102 Central retinal vein occlusion 82 complications 83 types 82 ischemic 83 nonischemic 83 Central serous chorioretinopathy 28, 154 features 154 Choroidal metastasis 272 Choroidal metastasis from carcinoma breast 277 Choroidal metastasis from carcinoma lung 279 Choroidal neovascular membrane 129 Choroidal neovascularization 118 Chronic central serous chorioretinopathy 169 Cirrus high-definition OCT 6 Clinically significant macular edema 67 Cone dystrophy 249 Cone-rod dystrophy 243 Confluent soft drusen 123 Copernicus spectral-domain high-resolution OCT 8 Cystoid cavities 48 –297– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES D G Diabetic macular edema 43 Diabetic retinopathy 42 levels 42 nonproliferative diabetic retinopathy 42 proliferative diabetic retinopathy 42 Diffuse retinal hemorrhages 82 Diffuse swelling 48 Geographic atrophy with foveal sparing 125 E Epiretinal membrane and diabetic macular edema in proliferative diabetic retinopathy 61 Explanation of poor visual acuity recovery 158 Exudative age-related macular degeneration 145 F Fluorescein angiography and optical coherence tomography in ischemic maculopathy 60 Fourier-domain 3 Frequency-domain 3 H Harada’s disease 287 Hard exudates 48 Healed toxoplasmosis 291, 293 Hemiretinal artery occlusion 106 Henle fiber 48 I Idiopathic epiretinal membranes 181 Idiopathic macular hole 217 Increasing severity of diabetic macular edema on OCT 57 Inner retinal boundary 49 Intermediate uveitis 283 Intravitreal bevacizumab 74 IS/OS-RPE thickness map 20 L Lamellar hole 50 Lamina cribrosa 82 –298– INDEX M Q Macular pseudohole with idiopathic epiretinal membrane 197 Macular thickening 47 Multifocal choroiditis 284 Myopic foveoschisis 172 Quantification of retinal thickness 119 Quantitative mapping of retinal layers 16 N Nodular drusen 120 O Opaque retina 102 Optic disk pit maculopathy 255 P Papillomacular bundle 102 Pars plana vitrectomy 211 Peeling and layer separation in three dimensional imaging 36 Posterior hyaloid 49 Prediction of visual acuity recovery 158 Preretinal hemorrhages 49 Progressive cone dystrophy 244 Pseudoholes 196 R Recent-onset typical classic choroidal neovascularization 130 Retinal artery occlusion 102 features 102 Retinal deformation graph 22, 23 Retinal nerve fiber layer 110 Retinal nerve fiber layer thickness map 16 Retinal pigment epithelium 6, 110 Retinal thickness map 18 Retinoblastoma 266 RNFL thickness graph 22 RNFL thickness map 19 RPE deformation map 21 RTVUE-100 Fourier-domain OCT 8 S Severe cystoid macular edema 53 Soft drusen 119 –299– OPTICAL COHERENCE TOMOGRAPHY IN RETINAL DISEASES Spectral-domain 3 Spectral-domain optical coherence tomography 23 Spectral-domain optical coherence tomography and 3D imaging 26 Spectralis HRA+OCT 10 Stratus OCT 4,17 T U Ultra-high resolution optical coherence tomography 12 V Visual acuity 71 Vitreomacular traction 205 Vitreomacular traction syndrome 199 X Three-dimensional retinal imaging 63, 87, 110 Time-domain 3 Tractional diabetic macular edema 56 Tractional macular edema 50 Typical occult choroidal neovascularization 132 x plane 27 Y y plane 27 Z z plane 27 –300–