How reliable is the clinical diagnosis of subretinal fibrosis in neovascular age-related macular degeneration?

Abstract

Purpose : To compare different current imaging modalities with respect to their ability to assess subretinal fibrosis in neovascular age-related macular degeneration (AMD).

Methods : In this cross-sectional study 30 eyes of 30 patients with neovascular AMD with a minimum history of 1 year of anti-vascular endothelial growth factor (anti-VEGF) therapy were included.
Each patient underwent microperimetry (MP) testing with color fundus photography (CFP) and eye-tracking assisted polarization-sensitive optical coherence tomography (PS-OCT).
PS-OCT is capable of automatically detecting the presence of fibrosis based on tissue birefringence. Retinal morphology in CFP and PS-OCT was evaluated independently for the presence of fibrosis at the corresponding microperimetry sensitivity spots.
Microperimetry results and morphologic findings in CFP and PS-OCT were analyzed.

Results : Mean patient age was 74,5 ± 14.2 years. In total 1350 MP spots were evaluated in CFP and PS-OCT for impact of fibrosis according to a standardized protocol.
Intact retinal morphology diagnosed in CFP and PS-OCT was associated with a median retinal sensitivity of 26 dB (quartiles: 22 dB; 28 dB) and 26 dB (24 dB; 28 dB), respectively.
In CFP 318 (23.6 %) spots were graded as fibrosis and showed a median retinal sensitivity 0 dB (0 dB; 12 dB).In PS-OCT 174 spots (12.9 percent) of all tested MP spots were classified as fibrosis and showed a median retinal sensitivity of 0 dB (0 dB; 7.5 dB).
The difference in retinal sensitivity between spots showing signs of fibrosis and spots not showing signs of fibrosis was statistically significant in CFP (p<0.001) and PS-OCT (p<0.001), respectively. Most importantly, retinal sensitivity was significantly lower(p<0.05) in areas showing fibrosis in PS-OCT with a median of 0 dB (0 dB; 7.5 dB) than in spots showing fibrosis in CFP with a median of 0 dB (0 dB; 12 dB).

Conclusions : PS-OCT shows a very high capability of detecting the fibrotic alterations in neovascular AMD.
Areas of subretinal fibrosis identified by PS-OCT demonstrate more severe loss of retinal sensitivity than areas detected solely by CFP confirming advanced damage to the neurosensory retina. CFP is not a reliable tool for differentiating between clinically relevant fibrosis and intact retina . Selective imaging of collagen components by PS-OCT may be used for clinical classification of fibrosis in advanced AMD.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.