Abstract
Purpose :
Oxidative stress and apoptosis have been implicated as drivers of various vision impairing retinal diseases. These stressors increase the pool of oxidized retinal mitochondrial flavoproteins relative to reduced ones. Oxidized flavoproteins display autofluorescence when excited by 467 nm light, emitting 535nm light in response. The emission signal, termed flavoprotein fluorescence (FPF), can be measured and used as a quantifiable marker for oxidative damage-induced mitochondrial dysfunction. In retinal dystrophies there is a high level of oxidative strain in the retina, which has not been characterized by retinal FPF signal measurements and patterns in a large cohort. Furthermore, these measurements may provide physiologically relevant metrics of disease progression that can complement currently utilized fundus autofluorescence (FAF) imaging.
Methods :
This prospective cohort study examined 70 eyes from 35 patients with isolated genetically confirmed Cone-rod dystrophies (Retinitis Pigmentosa, Usher Syndrome), Stargardt disease, and Bardet-Biedl syndrome between 2020-2021. Patients with other ocular pathology were excluded. 70 control eyes from 40 patients were healthy age-matched individuals. In instances of bilateral involvement, each eye was considered separately. FPF score intensity and heterogeneity were recorded using the OcuMet Beacon (OcuSciences, Ann Arbor, MI). Statistical analysis was done to compare scores.
Results :
The final analysis included 140 images of 75 patients. Mean FPF intensity was significantly increased between age matched controls and patients with confirmed rod-cone dystrophy, Stargardt disease, and Bardet-Biedl syndrome (P=0.0014, P<0.0001, and P<0.0001). Mean FPF heterogeneity was significantly increased between age matched controls and patients with confirmed cone-rod dystrophy, Stargardt disease, and Bardet-Biedl syndrome (P<0.0001, P<0.0001, and P<0.0001). FPF lesions were noted to visually correlate with patterns of FAF signals in cases with macular involvement.
Conclusions :
FPF intensity and heterogeneity are significantly increased in patients with retinal dystrophies compared to matched controls. Correlation of the pattern of FPF lesions with FAF lesions suggests FPF has capacity to be explored as a measurable indicator of disease progression in these patient populations.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.