Abstract
Purpose :
Subfoveal fibrosis is a predictor for poor visual acuity in eyes with neovascular AMD (nAMD) and is an exclusionary criterion in clinical trials. Fibrosis is traditionally identified from color fundus photographs (CFP) and fluorescein angiography (FA). The scope of this retrospective study is to characterize the SD-OCT features of fibrosis in nAMD eyes.
Methods :
Treatment naïve eyes with nAMD and SF identified from CFP were included. Corresponding SD-OCT scans were evaluated for location and area of SF. On SD-OCT, fibrosis was defined as the presence of dense, uniform hyperreflectivity located in the subretinal space either adjacent to or incorporated into the neovascular complex. Areas of hyper-reflectivity were measured using custom developed OCT split tool that allows for mapping areas of retinal layer changes on co-registered infrared (IR) images. The perimeter was identified on each B scan and annotated on the corresponding IR image to obtain area.
Results :
In all 10 eyes with fibrosis on CFP, graders identified subretinal hyperreflectivity on SD-OCT. The median area of fibrosis on SD-OCT was 0.80 mm2 (range 0.17-0.97) compared to 0.29 mm2 (0.06 – 0.59 mm2) on CFP (p<0.05). In all eyes, the area of hyperreflectivity on OCT was larger than the area of fibrosis from CFP. On OCT, the dense hyperreflective area was located in the subretinal layer alone in 7/10 eyes and was present in both subretinal and sub retinal pigment epithelial layers in 3/10 eyes. Subretinal fluid was present in 8 eyes and choroidal hyper-transmission was seen in 4 eyes.
Conclusions :
Analysis of all eyes in our series showed that a dense, uniform hyper-reflective mound on SD-OCT corresponded to an area of subretinal fibrosis as identified from CFP. The hyperreflective area on SD-OCT was larger than the fibrotic area in all eyes. Our series showed that with SD-OCT, the borders of fibrosis could not be distinguished from surrounding cnv in 1/3 of the eyes. From a research perspective, it is still recommended that both CFP and SD-OCT be used to identify fibrosis when grading images for nAMD trials.
This is a 2020 ARVO Annual Meeting abstract.