OCT Biomarkers in a Cohort of Patients With PRPF31-Associated Retinitis Pigmentosa

Purpose: With degeneration of the photoreceptors in retinitis pigmentosa (RP), the reflectivity of the ellipsoid zone (EZ) decreases. We aimed to study characteristics of the EZ and its reflectivity in a cohort of patients with PRPF31-associated autosomal-dominant RP (PRPF31-adRP) and a possible relationship to EZ width and best-corrected visual acuity (BCVA). Methods: EZ width and relative EZ reflectivity (rEZR) were assessed in 32 patients with PRPF31-adRP. EZ width was measured on a horizontal SD-OCT scan through the fovea of the right eye. On the same OCT scans, rEZR was measured at the foveola, temporal and nasal parafoveola and fovea. Results: Total EZ width revealed a significant negative correlation with age (r _s  = -0.418, p=0.017). Foveolar rEZR revealed a significant negative correlation with age (r _s  = -0.403, p=0.022), but was not significantly correlated with BCVA (foveolar: r _s  = -0.151, p=0.410), in contrast to parafoveolar rEZR (r _s  = -0.365, p=0.0399), which was significantly correlated with BCVA. The ratio of foveal and parafoveolar rEZR correlated significantly with total EZ width (r _s  = 0.358, p=0.044). Conclusions: The EZ reflectivity (EZR) can be measured reliably using freely available software. The correlation we observed between rEZR and BCVA leads us to the conclusion that rEZR may be an additional marker in observational and therapeutic trials.