Prevalence of corneal diseases in the rural Indian population: the Corneal Opacity Rural Epidemiological (CORE) study

Objective The present population-based study was undertaken to estimate the prevalence, determinants and causes of corneal morbidity and blindness in a rural North Indian population. Design Population-based study in India with 12 899 participants of all ages. Methods Participants were recruited from 25 village clusters of district Gurgaon, Haryana, India using random cluster sampling strategy. All individuals were examined in detail with a portable slit lamp for evidence of any corneal disease during the door-to-door examination. Comprehensive ocular examination including logMar visual acuity, slit lamp biomicroscopy, non-contact tonometry and dilated retinal evaluation was performed at a central clinic site in the respective villages. Results Overall, 12 113 of 12 899 people (93.9% response rate) were examined during the household visits. Prevalence of corneal disease was 3.7% (95% CI 3.4% to 4.1%) and that of corneal blindness was 0.12% (95% CI 0.05% to 0.17%). Multivariable analysis demonstrated that corneal disease was significantly higher in the elderly (p<0.0001) and illiterates (p<0.0001). Common causes of corneal opacity in the study population were pterygium (34.5%), ocular trauma (22.3%) and infectious keratitis (14.9%). Corneal diseases contributing to blindness were post-surgical bullous keratopathy (46.2%) and corneal degenerations (23.1%). Conclusions The study findings demonstrate that currently ocular trauma, infectious keratitis, post-surgical bullous keratopathy, and corneal degenerations are responsible for the major burden of corneal blindness and morbidity in the Indian population. The prevalence of corneal morbidity due to vitamin A deficiency and trachoma was low in this rural population.