Prevalence of strabismus in Pakistan: a systematic review and meta-analysis

Purpose: Strabismus is an ocular condition characterized by misalignment of the visual axis. The global prevalence of strabismus is about 2-3%, which varies between different countries and ethnicities. The aim of this study was to conduct a meta-analysis of studies, which had previously reported the prevalence of strabismus in Pakistan, in order to obtain the overall prevalence of strabismus in the country. Methods: All community-based studies reporting the prevalence of strabismus from Pakistan were searched using international databases and local ophthalmology journals. Information about sample size, number of individuals with strabismus, and location and duration of the study was recorded. Statistical analysis including heterogeneity testing, pooled prevalence calculation and regression analysis were done using the R software. Results: Heterogeneity tests, P_{heterogeneity} < .01, suggested high heterogeneity between the different studies. The pooled prevalence of strabismus was 0.7% [95% confidence interval (CI): 0.39%-1.23%] according to the random effects model, with a decreasing trend in prevalence from 1995 to 2020. Esotropia was more frequent than exotropia in both population-based and clinic-based studies. Conclusion: The prevalence of strabismus in Pakistan is comparatively lower than the worldwide prevalence, and it appears to be decreasing over the last three decades, consistent with global trends.