Download Panoramic Fundus Autofluorescence

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 aging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 dysfunction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.