Correlation between Visual Function and Structural Characteristics of the Macula in Advanced Retinitis Pigmentosa

Abstract

We aimed to correlate the visual function and structural characteristics of the retina and choroid in advanced retinitis pigmentosa (RP) patients. A cross-sectional, retrospective review was conducted of medical records of 149 RP patients who reported visual field constriction on a central 30-2 Humphrey visual field chart. Using spectral domain-optical coherence tomography, central foveal thickness (CFT), ellipsoid zone (EZ) length, macular volume (MV), and submacular choroidal thickness (SMChT) were measured. A control cohort (68 eyes of 68 patients) was included for comparing the macular structure. Quantitative correlations between visual function indices [visual field index (VFI) and best-corrected visual acuity (BCVA)] and structural indices (CFT, EZ length, and SMChT) were evaluated. Mean age was 46.3 ± 15.5 years; mean illness duration was 60.7 ± 60.0 months. SMChT was thinner than that in normal controls. Per Pearson’s correlation, BCVA and VFI exhibited a progressive worsening related to age and disease duration. In multivariate linear regression, BCVA and VFI were significantly correlated with CFT, EZ length, and MV at the central 1-mm area. Among RP patients with visual field constriction within 30°, VFI and BCVA closely correlate with the degree of retinal structural change, including the CFT, EZ length, and MV. SMChT uniformly decreased in this study population and exhibited no significant correlation with BCVA or VFI degree.