Dry eye disease among Glaucoma patients on topical hypotensive medications, in a tertiary hospital, Ethiopia

BACKGROUND: Dry eye disease is a multifactorial disease; causing various ocular symptoms with potential damage to the ocular surface. Applying hypotensive eye drops are presumed to initiate or exacerbate existing dry eye disease. The purpose of this study was to determine the frequency of signs and symptoms and severity of dry eye disease among glaucoma patients on topical hypotensive medications and controls. METHODS: A cross-sectional comparative study, involving 320 glaucoma patients and controls. Ocular Surface Disease Index (OSDI) symptoms score and Schirmer, tear breakup time and corneal staining tests were used to assess dry eye disease. Data was analyzed using SPSS version 24 software; p-value less than 0.05 was considered as statistically significant. RESULTS: Among the 160 study glaucoma patients, the mean duration of topical hypotensive medication use was 5.2 ± 5.21 years (range, 4 months - 32 years). Mild to severe level of OSDI score was found in 122 (76%) glaucoma patients and in 137 (86%) controls (p = 0.033). Mild to sever abnormal clinical tests in the glaucoma patients and control, respectively, were 106 (66%) vs 80 (50%) corneal staining (p = 0.045), 79 (49%) vs 72 (45%) TBUT (p = 0.021), and 91 (57%) vs 83 (52%) Schirmer test (p = 0.242). Test results at the level of sever: 2 (1%) vs 0 (0%) corneal staining, 50 (31%) vs 39 (24%) TBUT and 65 (41%) vs 60 (38%) Schirmer test in the glaucoma patents and controls, respectively. Corneal staining and TBUT had correlation with the number of drugs (p = 0.004 and 0.031, respectively), and more relationship of the two tests with total number of drops applied per day (p = 0.01 and p < 0.001, respectively). Patients on pilocarpine and timolol had more corneal staining and lower TBUT [(p = 0.011 and p < 0.001) and (p = 0.04 and 0.012), respectively]. CONCLUSIONS: The study has identified glaucoma patients to be more affected by dry eye disease than non-glaucoma patients, and presence of significantly lower TBUT and higher corneal staining in the glaucoma patients on multidrops and multidose per day. We recommend consideration of evaluation and management of DED for glaucoma patients on multidrops and multidose hypotensive medications.