Exploring flavoprotein fluorescence as a biomarker for open-angle glaucoma

Abstract

Purpose : To investigate macula and optic nerve (ON) mitochondrial metabolic activity using flavoprotein fluorescence (FPF) in normal, glaucoma suspect (GS), and open-angle glaucoma (OAG) eyes.

Methods : This was a cross-sectional, observational clinical study. All subjects had visual acuity of 20/40 or better. Exclusion criteria included uncontrolled hypertension/diabetes or retinal/vitreous/macular pathology. Two images from each subject's eye were scanned with the OcuMet Beacon (OcuSciences Inc., Ann Arbor, MI), one focused and centered on the foveal pit (macula) and one centered at the ON head. The high-quality images were saved as 512 × 512-pixel 16-bit grayscale TIFF files and were analyzed using proprietary software to determine the FPF scores. One-way analysis of variance was used to compare the FPF metrics between normal, GS, and OAG eyes. Linear regression models investigated the correlation between FPF metrics and structural and functional parameters.

Results : Seventeen normal eyes, 8 GS eyes, and 25 OAG eyes were included. The average age ± standard deviation was 58.9 ± 17.9, 68.9 ± 11.0, and 68.3 ± 10.5 for normal, GS, and OAG groups, respectively (p=0.072). There was no significant difference in race, sex, intraocular pressure, visual acuity, lens status, and spherical equivalent between groups. Glaucomatous eyes had worse visual field (VF) mean deviation (MD) compared to GS (p=0.007). There were no significant differences between the macula and ON mitochondrial metabolic activity measured by FPF between normal, GS, and OAG eyes (Table 1; p≥0.415). Additionally, FPF metrics were not correlated with cup-to-disc ratio, retinal nerve fiber layer thickness, or VF MD in glaucomatous eyes (p≥0.237).

Conclusions : In contrast to prior studies, no significant differences were found in ON and macula mitochondrial metabolic activity measured by FPF between normal, GS, and OAG eyes. Further research is needed to evaluate the role of mitochondrial metabolic activity measurements in glaucoma.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Example of the glaucoma testing in a glaucomatous eye. (A) optic coherence tomography (OCT) of optic nerve; (B) OCT of macula; (C) Visual field plot; (D) Flavoprotein fluorescence score.

 

Summary of flavoprotein fluorescence (FPF) of the nerve and macula and structural and functional parameters between normal, glaucoma suspects, and open-angle glaucoma (OAG) group.