Cumulative incidence of myopia and risk factors in rural south India: results from the Andhra Pradesh Eye Disease Study III.

CLINICAL RELEVANCE: Understanding the epidemiology and risk factors for the onset of myopia is essential to implementing its prevention and control strategies.

BACKGROUND

Myopia is becoming a major public health condition affecting 30-35% of the global population and is expected to affect 50% by 2050. This study aimed to determine the 15-year cumulative incidence and risk factors of myopia among participants of the Andhra Pradesh Eye Disease Study.

METHODS

A population-based longitudinal cohort study was conducted to follow-up participants at a mean of 15 years across three rural districts of two south Indian states. Participants underwent a comprehensive eye examination, including dry refraction. Incident myopia was defined as spherical equivalent of < -0.50D in the right eye at follow-up, excluding participants with baseline myopia or nuclear sclerosis (≥2.5 on LOCS III grading scale) or had undergone cataract surgery at follow-up.

RESULTS

Of 7,771 baseline participants, 5,395 (69.4%) were examined at follow-up. A total of 2,071 participants <30 years and, 755 ≥30 years at baseline were analysed. The overall cumulative myopia incidence was 8.0% (95%CI: 7.0-9.0). It was 8.0% (95%CI: 6.9-9.3) and 7.8% (95%CI: 6.0-10.0) among the younger and older participants respectively. The incidence was higher in younger females (9.9%) than males (6.1%), but it was higher in older males (10.4%) than females (5.5%). In multivariable analysis, female gender and residence at Mahabubnagar and Adilabad districts were risk factors among those <30 years, whereas current alcohol consumption was a significant risk among ≥30 age group.

CONCLUSION

Although the overall estimates were similar between younger and older participants, in the latter, the incidence may be linked to residual nuclear sclerosis. Future studies should consider including other modifiable risk factors associated with myopia, which could aid in developing suitable intervention strategies to address the rising global prevalence.