Ultra-Widefield Fundus Autofluorescence Imaging of Patients with Retinitis Pigmentosa: A Standardized Grading System in Different Genotypes

Abstract

To report a genotype-phenotype correlation study of patients with retinitis pigmentosa (RP) based on ultra-widefield (UWF) fundus autofluorescence (FAF) imaging. Case series. Thirty-four patients with RP. This retrospective study included RP patients with confirmed causative genetic variants and UWF FAF imaging data. Qualitative grading criteria including the pattern of macular abnormal autofluorescence, decreased autofluorescence (DAF), and its extent and distribution were applied to evaluate the genotype-phenotype correlation. The main parameters measured were increased or decreased patterns and extent of autofluorescence. Thirty-four unrelated patients 38±19 years of age (range, 9-82 years) were enrolled. Mutations in 17 different genes were detected in patients, including 7 patients having mutations in USH2A, 4 in DHDDS, 4 in RPGR, 3 in PRPF31, and 3 in RP1. Patients with nummular DAF and widespread DAF were significantly older (59±14 years and 56±19 years, respectively). All 3 patients with PRPF31 mutations showed an abnormal macular ring hyperautofluorescence and a circular pattern of coarse DAF distributed in Early Treatment Diabetic Retinopathy Study fields 1, 2, and 3 with sparing of the far periphery. In other genotypes, no specific DAF or macular abnormal autofluorescence pattern could be discerned. Specific UWF FAF characteristics in RP patients were correlated strongly with patient age and stage of the disease. Particular UWF FAF characteristics were found to be more prominent in a unique genotype.