Abstract
Purpose :
To assess the presence and thickness of subretinal hyperreflective material within regions of atrophy in eyes being treated with anti-vascular endothelial growth factor therapy for neovascular age related macular degeneration (nvAMD).
Methods :
Forty five eyes of 45 subjects with nvAMD were enrolled in this IRB-approved retrospective analysis. Color fundus photos (CFP) and spectral domain optical coherence tomography (Cirrus SD-OCT, Zeiss, USA) images were collected for all study eyes. Regions of atrophy and fibrosis in color fundus images were delineated manually using GRADOR reading center software and the CFP annotations were registered over SD-OCT images. Atrophy was identified based on the presence of a well-demarcated area of depigmentation with increased visibility of underlying choroidal vessels. Fibrosis was identified based on the presence of whitish well-demarcated lesions deep to the retina. The inner and outer borders of the subretinal hyperreflective material (SHRM) on OCT B-scans was manually delineated using reading center 3D-OCTOR software and SHRM thickness measurements were generated in corresponding regions of atrophy and fibrosis. Thickness values were compared between the regions using a paired t test (SPSS 18.0).
Results :
On the color photos, atrophy was present in 43 eyes and fibrosis was evident in 42 eyes, the mean area of atrophy was 12.54 mm2 and the mean area of fibrosis was 6.85 mm2. The mean SHRM thickness within regions of CFP-identified atrophy was 64.12 μm (±SD: 23.48; range: 24.90 – 129.70 μm), which was significantly thinner (p=0.0005) compared to regions of CFP-identified fibrosis on CFP images where the SRHM thickness measured 90.27 μm (±SD: 39.55; range: 34.40 – 224.30 μm). Loss of the overlying photoreceptors was apparent on OCT both in regions of CFP-defined atrophy and fibrosis, which otherwise appeared morphologically similar on OCT.
Conclusions :
Although atrophy and fibrosis are thought to be very different end-stage outcomes in eyes with neovascular AMD, they appear morphologically similar on OCT, mainly distinguished by the thickness (not the presence/absence) of SHRM, which is generally thicker in regions of fibrosis. Given these similarities, these regions of nvAMD-associated atrophy may be better-termed “atrosis” to distinguish from typical atrophy in the absence of neovascular disease.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.