Visual impairment and blindness due to retinitis pigmentosa in India: 15-year follow-up of the Andhra Pradesh Eye Disease Study cohort.

Abstract

To assess the incidence, visual impairment, and blindness due to retinitis pigmentosa (RP) in a rural southern Indian cohort. This is a population-based longitudinal cohort study of participants with RP from the Andhra Pradesh Eye Disease Study (APEDS) cohorts I and III, respectively. The study included participants with RP of APEDS I who were followed until APEDS III. Their demographic data along with ocular features, fundus photographs, and visual fields (Humphrey) were collected. Descriptive statistics using mean ± standard deviation with interquartile range (IQR) were calculated. The main outcome measures were RP incidence, visual impairment, and blindness as per the World Health Organization (WHO) definitions. At baseline (APEDS I), 7771 participants residing in three rural areas were examined. There were nine participants with RP with a mean age at baseline of 47.33 ± 10.89 years (IQR: 39-55). There was a male preponderance (6:3), and the mean best-corrected visual acuity (BCVA) of 18 eyes from nine participants with RP was 1.2 ± 0.72 logarithm of minimum angle of resolution (logMAR; IQR: 0.7-1.6). Over a mean follow-up duration of 15 years, 5395/7771 (69.4%) were re-examined, which included seven RP participants from APEDS 1. Additionally, two new participants with RP were identified; so, the overall incidence was 370/ million in 15 years (24.7/million per year). The mean BCVA of 14 eyes of seven participants with RP who were re-examined in APEDS III was 2.17 ± 0.56 logMAR (IQR: 1.8-2.6), and five of these seven participants with RP developed incident blindness during the follow-up period. RP is a prevalent disease in southern India that warrants appropriate strategies to prevent this condition.