Abstract
Purpose: :
To describe Spectral-Domain Optical Coherence Tomography (SD-OCT) findings and simultaneous autofluorescence (AF) images in macular dystrophy
Methods: :
Retrospective analysis of SD-OCT (Spectralis HRA+OCT, Heidelberg Engineering) and simultaneous AF images of 10 eyes with adult-onset vitelliform dystrophy (AOVD), 4 eyes with Stargardt's disease (StD), 6 eyes with cone dystrophy (CD), and 2 eyes with Bietti’s Crystalline Dystrophy (BD). Retinal pigmented epithelium (RPE) and neuroepithelium (NE) thickness were measured using SD-OCT
Results: :
In AOVD SD-OCT allowed exact localization of hyperautofluorescent foveal deposit, easily differentiating them from RPE below. Mean RPE thickness was 40,3±8,8. Mean NE thickness was 97,9±40,7. In StD flecks appear in AF as typical, localized, hyperautofluorescent spots: SD-OCT allows to locate them exactly as adjacent, but separate, elements above RPE. Mean RPE thickness was 18,5±5,44. Mean NE thickness was 56,5±18. In CD,AF reveals a hyperautofluorescent halo surrounding hypoautofluorescent foveal region: in SD-OCT images this halo corresponds to a thinner outer nuclear layer with less lipofuscin autofluorescence absorption from intact RPE below. Mean RPE thickness was 25±5,83. Mean NE thickness was 45,1±14,3. In BD, AF shows diffuse hyperautofluorescent spots on the entire retinal surface, corresponding in SD-OCT to calcific drusen or intraretinal crystalloid deposits, localized at various level in retinal layers. Mean RPE thickness was 16,5±0,5. Mean NE thickness was 255,5 ±54,4. Comparison between CD and AOVD, StD and AOVD, and BD and AOVD on central RPE thickness resulted in significative difference (p=0,0021, p=0,0007,and p=0,0043 respectively). Comparison between CD and AOVD central neuroepithelium thickness resulted in significative difference (p=0,00091)
Conclusions: :
The simultaneous acquisition of AF and SD-OCT allows a point-by-point correlation. In particular, it is possible to determine if increased autofluorescence is due to lipofuscin elements or to thinning of overlying NE with enhanced passage of signal. RPE thickness could be measured using SD-OCT: it is reduced in degenerative dystrophies (CD, StD and BD),while in AOVD RPE is thickened, probably for intracellular lipofuscin accumulation
Keywords: degenerations/dystrophies • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • ipofuscin