Dry eye: prevalence and attributable risk factors in a hospital-based population

PURPOSE: To study the prevalence of dry eye in a hospital-based population and to evaluate the various risk factors attributable to dry eye. MATERIALS AND METHODS: In this cross-sectional study, 500 patients above 20 years of age were screened randomly for dry eye. A 13-point questionnaire, Lissamine Green test, Tear film break-up time (TBUT), Schirmer's test and presence of strands/filaments were used to diagnose dry eye. The diagnosis was made when at least three of the tests were positive. The role of air pollution, sunlight, excessive winds, smoking, drugs and refractive status as dry eye risk factors was assessed. RESULTS: Ninety-two (18.4%) patients had dry eye. Dry eye prevalence was maximum in those above 70 years of age (36.1%) followed by the age group 31-40 years (20%). It was significantly higher (P = 0.024) in females (22.8%) than in males (14.9%), more common in rural residents (19.6%) than in urban (17.5%) and highest among farmers/labourers (25.3%). A 2.15 fold increase was found in the odds for dry eye in those exposed to excessive wind, 1.91 fold to sunlight exposure, 1.42 to smoking, 1.38 to air pollution and 2.04 for persons on drugs. Dry eye prevalence was 14% in emmetropes, 16.8% in myopes and 22.9% in hypermetropes. It was 15.6% in those with corrected and 25.3% in those with uncorrected refractive errors. CONCLUSION: Dry eye is an under-diagnosed ocular disorder. Reduction in the modifiable risk factors of dry eye is essential to reduce its prevalence.