Prevalence of Ocular Surface Disease in Glaucoma Patients on Long-Term Antiglaucoma Medications

Objective: Long term use of preservative-containing medications has been associated with the development or worsening of ocular surface disease (OSD). This study aimed to determine the prevalence of OSD in glaucoma patients on long-term antiglaucoma medications. Methods: A cross-sectional hospital-based study was carried out on 208 respondents using Ocular Surface Disease Index (OSDI) questionnaire, tear break-up time (TBUT), and Schirmer 1 test. Data analysis was done using Statistical Package for Social Science version 22.0 (SPSS Inc, Chicago, Illinois, USA). Results: The prevalence of OSD was higher in those on antiglaucoma medication using all modalities of assessment. Prevalence of OSD in glaucoma patients on antiglaucoma drugs was highest using TBUT- 69.2% (P = 0.031), with OSDI questionnaire it was 62.5% (P = 0.005), and it was lowest for Schirmer 1 test - 59.6%. For those nonglaucoma cases/not on any antiglaucoma medication, the prevalence using TBUT was 42.3%, using OSDI it was 16.3%, and with Schirmer 1 test it was 25.9%. Prevalence also increased with the increase in the number of eye drops from 1 to 2 drops/day using all modalities of assessment (P = 0.004). Using multivariate analysis, adjusting for sex and age, subjects who instilled 2 drops/day had four to five times the odds of having OSD. Conclusion: The prevalence of OSD is higher in patients with glaucoma on topical antiglaucoma medication than the nonglaucoma population studied and this increased with the increase in number of drops per day.