OCT and Autofluorescence Phenotypic Features in Autosomal Dominant RHO-Associated Retinitis Pigmentosa Variants

Background/Objectives: To describe retinal imaging characteristics and the natural history of rhodopsin (RHO)-associated autosomal dominant retinitis pigmentosa (ADRP) by evaluating ellipsoid zone (EZ) width loss and measuring the degree of constriction of the area within and including the hyperautofluorescent ring. Methods: Eighteen patients with molecularly confirmed RHO variants were retrospectively evaluated. EZ width on spectral-domain optical coherence tomography (SD-OCT) and the area within and including the hyperfluorescent ring on fundus autofluorescence (FAF) were measured. The correlation between EZ width and hyperfluorescent ring area was assessed using a linear mixed-effects model. Results: Mean best corrected visual acuity (BCVA) (logMAR) was 0.21 at baseline and 0.29 at last visit over a mean follow-up of 5 years. Nine patients presented with sectoral RP, eight with typical RP, and one with unilateral RP. The mean EZ width constriction rate was −93.43 µm/year (SD = 130.58), and the area within and including the hyperautofluorescent ring decreased by −0.54 mm2/year (SD = 0.50). A strong positive association was observed between the EZ width and hyperfluorescent ring area at baseline (β = 151.7 ± 17.9, p < 0.001) and at the final visit (β = 185.7 ± 18.2, p < 0.001). Conclusions: In this study, patients with RHO-associated ADRP appeared to show a relatively slow rate of progression. Quantitative imaging markers, such as EZ width and the area within and including the hyperautofluorescent ring, may offer potentially reproducible measures of disease progression. These imaging biomarkers could be useful as outcome measures in future natural history studies and therapeutic trials, pending further validation.