Frequency of myopia and associated risk factors in the adolescent population (10-16 years) of Karachi, Pakistan: a cross-sectional study.

Objective: To estimate the prevalence of myopia and explore its risk factors in adolescents aged 10-16 years in Karachi, Pakistan. Methods and analysis: This cross-sectional analytical study was conducted with 335 adolescents from 4 public and 2 private schools in Karachi. Data were collected using a structured questionnaire. Cox proportional hazards regression analysis was used to assess associations between myopia and various risk factors. Results: The study found that the prevalence of myopia was 54% among participants. Multivariate analysis revealed a significant association between myopia and sleep quality as well as time spent on reading/writing activities. Adolescents with a sleep quality score greater than or equal to 4 had a 1.63 times higher likelihood of myopia compared with those with lower scores (95% CI 1.21 to 2.19, p=0.001). Myopia was 1.63 times more common among those spending 1-2 hours on reading/writing (95% CI 1.02 to 2.61, p=0.04) and 1.95 times more prevalent in those spending over 4 hours on these activities during weekends (95% CI 1.12 to 3.40, p=0.02) compared with those with no such activities. Conclusions: The study indicates a high prevalence of myopia in the study population, and this can be significantly attributed to poor sleep quality and extended reading/writing times. The results suggest the potential for targeted interventions to address these risk factors and mitigate the rising prevalence of myopia. Furthermore, this study lays the groundwork for future longitudinal research to establish causal relationships between these risk factors and myopia.