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Panoramic Fundus Autofluorescence Clinical Applications and Limitations Abstract: Fundus AutoFluorescence (FAF) is a novel, non-invasive imaging method that yields abnormalities that are often invisible to ophthalmoscopy and standard fundus photography. It allows mapping of lipofuscin distribution in the outer retina which are crucial findings in complex retinal diseases. FAF, however, is limited to outer retinal disorders. I. Background Information A) FAF is based upon the lipofuscin concentration and distribution within the Retinal Pigment Epithelium (RPE) cells. B) Lipofuscin (LF)-autofluorescent storage material that accumulates as a result of cell agingïƒ accumulation due to lysosomal dysfunction, autophagy, and cellular stress C) Retinal Pigment Epithelium (RPE)-failure of RPE lysosomal system to degrade LF results in high levels of LF leading to cell dysfunctionïƒ photoreceptor dysfunction and degeneration D) Crystalline Lens-main barrier of AF due to highly fluorescent characteristics in short-wavelength range E) Accumulation of LF=appears hyper (increased FAF signal) F) Degradation of RPE/photoreceptors=appears hypo (decreased FAF signal) II. Imaging Techniques of FAF A) Fundus Spectrophotometer-developed to measure excitation and emission spectra of AF from small retina areas of fundus (2° diameter); minimized contribution of AF from crystalline lens; however field of view is small and not practical for analyzing FAF in clinical setting or large patient population B) Confocal Scanning Laser Ophthalmoscopy (cSLO)-address limitations of low intensity AF signal and interference of crystalline lens; projects low-power laser beam on retain that is swept across the fundus in a raster pattern; allows imaging over larger retinal areas (standard: 30° x 30°, additional lens: 55°, and composite mode images even larger areas) C) Fundus Camera-uses single flash and images the entire retinal area (for example, 30° x 30°) at the same time D) Panoramic Imaging-single capture and images 200° of the retinal area III. Clinical Applications (panoramic AF images of each are presented) A) Useful for obtaining information in the outer retina, such as: 1. RPE/photoreceptor problems 2. RPE migration 3. Retinal dystrophies 4. Retinal degeneration 5. Central Serous Chorioretinopathy (CSC) 6. Chorioretinal Inflammatory Disorders 7. Cone-rod dystrophy 8. Bulls eye maculopathy 9. Macular holes 10. Pigmentary atrophy 11. Hypertrophy 12. Acute Zonal Occult Outer Retinopathy (AZOOR) 13. Large and basal laminar drusen 14. Bests Disease 15. AMD 16. Stargardt Disease 17. Leber Congenital Amaurosis 18. Pattern Dystrophies 19. Maternal Inherited Diabetes and Deafness 20. Choroidal Nevus and Melanoma 21. Trauma 22. Disc Drusen and Angioid Streaks 23. Other Macular Dystrophies 24. Other Retinal Dystrophies B) Because lipofuscin is commonly found in the outer retina, FAF reflects very limited information about the inner and middle retina, such as: 1. Hemorrhages 2. Exudates 3. Glaucoma 4. Retinal Nerve Fiber Layer (RNFL) 5. However, vascular aneurismal dilatations in the mid and far peripheral retina show up very well with AF because they appear black which contrast to the AF glow. IV. Exemplary cases (in detail) A) Bulls eye maculopathy of various etiologies B) Stargardt Disease C) Acute Zonal Occult Outer Retinopathy (AZOOR) D) Retinal degeneration 1. Note: in vast majority of inherited retinal disorders, symmetric panoramic AF in both eyes is encountered. E) Retinal toxicity (Accutane/Plaquenil) F) Fundus albipunctatus G) Cone-rod dystrophy H) Coats Disease (in which vascular aneurysmal dilatations appear black and by contrast of the underlying glow become visible.) V. Summary and Conclusions A) FAF of both central and peripheral often yield abnormalities that are invisible to any form of ophthalmoscopy. B) Abnormalities affecting the RPE and photoreceptors are well documented with FAF. C) Abnormal findings in other retinal layers, such as exudates, hemorrhages, and RNFL deficits are most often not visualized with AF. Hence, AF does not substitute for ophthalmoscopy and standard color fundus photography. D) Recently available panoramic FAF of 200° of the retina in one image is proving to be of significant value in the early detection of the host of outer retinal disorders.