Abstract
Purpose :
To compare SD-OCT defined iRORA and nGA lesions to Fundus Autofluorescence (FAF) and Color Fundus Photography (CFP)
Methods :
Subjects enrolled in the Age-Related Eye Disease Study 2 (AREDS2) from the University of Wisconsin were included. Subjects underwent SD-OCT, FAF and CFP imaging. SD-OCT images were graded for iRORA using Consensus of Atrophy Meetings (CAM) group OCT guidelines and were graded for nGA on the presence of (i) subsidence of the inner nuclear layer (INL) and outer plexiform layer (OPL) and/or (ii) a hypo-reflective wedge-shaped band within the limits of the Henle’s fiber layer. Using a custom-developed OCT split tool, locations of iRORA and/or nGA from SD-OCT images were mapped on co-registered IR images and were overlayed with the corresponding FAF and CFP images. The images were assessed for abnormalities within the mappings which localized iRORA or nGA lesions.
Results :
A total of 43 iRORA and 26 nGA lesions were identified from 29 eyes with intermediate AMD from 25 participants. On FAF, 59% of iRORA lesions showed predominantly hypo-FAF, 21% showed predominantly hyper- FAF and 21% had no abnormalities. About 62% of the nGA lesions showed predominantly hypo-FAF, 15% showed predominantly hyper-FAF and 23% had no abnormalities. On CFP, 51% of iRORA lesions showed fading drusen, 14% showed soft drusen, 7% showed calcified drusen, and 28% had no abnormalities. About 42% of nGA lesions showed fading drusen, 19% showed soft drusen, 15% showed calcified drusen, 23% had no abnormalities. Furthermore, 56% of iRORA lesions had no pigmentary changes on CFP, 40% had increased pigment and 5% had depigmentation. About 73% of nGA lesions had no pigmentary changes and 27% had increased pigment.
Conclusions :
iRORA and nGA coincide with a variety of FAF and CFP features with a majority showing hypo-FAF and fading drusen without pigmentary changes. The natural progression of dry AMD involves conversion of drusen to depigmentation followed by the development of atrophy. Our data suggest that iRORA and nGA represent a stage after drusen development but before depigmentation. These results provide insight on how GA precursors present across multiple imaging modalities.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.