Abstract
Purpose :
Oxidative stress has been implicated as a driver of various vision-impairing retinal diseases, including age-related macular degeneration (AMD). Oxidized retinal mitochondrial flavoproteins emit green light (535 nm) when excited by blue light (467 nm). This flavoprotein fluorescence (FPF) can be measured and used as a quantifiable marker for oxidative damage-induced mitochondrial dysfunction. This study aims to measure FPF average intensity and heterogeneity in patients with early, intermediate, and advanced non-exudative AMD as well as neovascular AMD.
Methods :
This prospective cohort study enrolled patients with isolated AMD of any Beckman stage between 2017 and 2021 excluding patients with comorbidities such as glaucoma, ocular hypertension, concomitant retinopathy or uveitis, history of non-cataract ocular surgery, or fluorescein angiogram prior to imaging. Controls were healthy age-matched individuals. In instances of bilateral involvement, each eye was treated separately. FPF average intensity and heterogeneity were recorded using the OcuMet Beacon (OcuSciences, Ann Arbor, MI).
Results :
The final analysis included images of 654 eyes (327 AMD eyes, 327 control eyes). The multivariable regression included stage of AMD, age, gender, ethnicity, and smoking status. Intermediate and advanced non-exudative AMD as well as neovascular AMD were correlated with significantly increased FPF average intensity (4.86, CI 2.37-7.34, p < 0.001; 11.9, CI 7.70-16.11, p < 0.001; 7.24, CI 4.61-9.88, p < 0.001, respectively), but early non-exudative AMD was not. Early, intermediate, and advanced non-exudative AMD as well as neovascular AMD were correlated with significantly increased FPF heterogeneity (0.19, CI 0.08–0.30, p = 0.001; 0.43, CI 0.36–0.51, p < 0.001; 0.59, CI 0.46–0.71, p < 0.001; 0.58, CI 0.51–0.66, p < 0.001, respectively).
Conclusions :
All stages of AMD were associated with increased FPF average intensity and heterogeneity, except early non-exudative AMD, which was only associated with increased heterogeneity. Because FPF imaging provides insight into the health of the retina on a cellular level, this finding of an isolated increase in FPF heterogeneity in early non-exudative AMD could assist with early detection of disease before structural changes are seen on optical coherence tomography.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.