Evaluating the Peripapillary Choroidal Vascularity Index and Peripapillary Retinal Nerve Fibre Layer Thickness in Retrobulbar Optic Neuritis Patients: A Comparative Study

Objective: This study sought to determine whether the peripapillary choroidal vascular index (pCVI) could be used to diagnose and track retrobulbar optic neuritis (RBON) and to compare the clinical and electrophysiological characteristics of RBON patients to those of controls. Methods: The study involved 60 eyes, and evaluations included magnetic resonance imaging (MRI), optical coherence tomography (OCT), visual field (VF) testing, and pattern visual evoked potential (VEP) testing. Results: Twenty eyes with RBON, twenty fellow eyes, and twenty healthy control eyes were enrolled. Age, gender, and axial length did not significantly differ between groups. Best-corrected visual acuity (BCVA) was significantly lower in RBON eyes compared to both fellow and control eyes (p < 0.0167). The peripapillary choroidal vascular index (pCVI) was also significantly reduced in RBON eyes compared to control eyes (p < 0.001). Although RBON eyes showed longer P100 latency (p = 0.019) and reduced temporal peripapillary retinal nerve fiber layer (pRNFL) thickness (p = 0.045), these differences did not reach statistical significance. Conclusion: Our findings demonstrate a significant reduction in pCVI and visual acuity in RBON eyes compared to controls, suggesting a potential role of vascular dysfunction in the disease process. Although other structural and electrophysiological changes were observed, they did not remain statistically significant.