Abstract
Purpose :
Endogenous flavoprotein fluorescence (FPF) imaging is an emerging functional assessment of optic neuropathies and retinopathies. An increase in FPF indicates oxidative stress in vivo that reflect accumulation of oxidized flavoprotein. Mitochondrial stress is a key pathogenic mechanism for multiple optic neuropathies, including nonarteritic anterior ischemic optic neuropathy (NAION), the most common acute optic neuropathy in adults over 50 years of age, and in optic disc drusen (ODD), the most common cause of biomineralization of the optic nerve and most important risk factor for young onset NAION. In this study, we performed FPF imaging in patients with ODD and NAION and compared FPF spatial and temporal patterns.
Methods :
We performed a prospective case-control study of 138 eyes with ODD (77 patients), 64 eyes with NAION (47 patients), and 48 healthy control eyes (33 patients). We quantified visual acuity, static perimetry (Zeiss), optical coherence tomography (OCT) (Zeiss) for retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thickness, and optic disc and macular FPF (OcuSciences), which was measured using custom areas of interest and custom scripts.
Results :
Optic disc but not macular FPF was significantly higher in ODD and NAION patients compared with controls (P<0.00001). Visual acuity, static perimetry mean deviation, RNFL, and GCIPL were also significantly worse in the ODD and NAION group (P<0.00001 for all except LogMAR for ODD P=0.04). Disc FPF negatively correlated with RNFL and GCIPL thickness. Optic discs of ODD patients exhibited highest FPF signal (P<0.00001), and autosomal dominant ODD patients had overall highest optic disc FPF signal. In ODD, FPF was highest in the nasal quadrant, while NAION and control eyes exhibited highest level of FPF in the temporal quadrant. Despite vision loss, elevated FPF is not measured in acute NAION when there is avid disc edema but typically develops about 1 month after onset of vision loss.
Conclusions :
Optic discs of patients with ODD and NAION exhibit significant increase in flavoprotein fluorescence – an indicator of mitochondrial stress in vivo. This increase in FPF signal occurs in distinct spatial and temporal patterns for different optic neuropathies, highest in the nasal quadrant in ODD and temporal quadrant for control and NAION.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.