Abstract
Purpose :
Numerous inner retinal changes with specific spatial patterns have been reported in early age-related macular degeneration (AMD). The prognostic value of these changes however is unclear from limited longitudinal data. This study determined the spatial distribution of inner retinal changes, namely vessel perfusion and thickness, relative to time and conversion to late AMD.
Methods :
79 eyes with intermediate AMD from 79 individuals attending the Centre for Eye Health, Sydney, Australia for at least two visits were included: 7 eyes that converted to late AMD at follow-up and 72 non-converter eyes (mean follow-up time = 2.6±0.4 years). OCTA macular cube scans (6x6mm, Cirrus HD-OCT, Zeiss) were extracted for each eye at the oldest and most recent visit, skeletonised, divided into 126x126 grids (47.62×47.62µm) and assessed for change in vessel perfusion per year in the superficial and deep vascular slabs according to ETDRS sectors. Analysis was repeated for retinal thickness using 512x128 OCT macular cube scans segmented to layers corresponding to vascular slabs of OCTA scans.
Results :
In the superficial slab, loss in perfusion and thickness per year was greatest paracentrally (perfusion: -0.56%/yr, p<0.0001; thickness: -1.66%/yr, p<0.001). Meanwhile, gain in perfusion and thickness were observed in the extra and central macula respectively (perfusion: 0.17%/yr, p<0.0001; thickness: 1.42%/yr, p<0.0001). In the deep slab, perfusion changed similarly to the superficial slab over time but with lesser magnitude (-0.15 – 0.36%/yr), while thickness over time decreased at all locations except the central macula (-0.91 – -0.29%/yr, p<0.0001). Sub-analysis showed a greater magnitude of perfusion and thickness change over time for converters versus non-converters. Odds ratios adjusted for age, sex, race, CVD status, refraction, IOP, image quality, drusen volume, RPD and fellow eye status indicated association of late AMD conversion for every 1% decrease in vessel perfusion superiorly (OR: 3.03 [1.30 – 7.69], p<0.05) or 1% decrease in thickness pericentrally or temporally in the superficial slab (1.37 [1.05 – 1.82]; 2.22 [1.23 – 5], p<0.05).
Conclusions :
Inner retinal perfusion & thickness demonstrate dynamic rates of spatial changes in intermediate AMD. These spatially-delineated changes may also hold prognostic values for predicting the conversion to late AMD.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.