Ocular surface changes in primary open-angle glaucoma on anti-glaucoma medications versus treatment-naïve patients

Purpose: To examine the ocular surface disease in primary open-angle glaucoma (POAG) patients already on treatment versus POAG patients without treatment. Methods: A prospective cohort study was conducted on 120 eyes of 60 POAG patients: 60 treatment-naïve eyes (group I) and 60 eyes already on topical anti-glaucoma medications (AGMs) (group II). All patients had filled out the Ocular Surface Disease Index (OSDI) questionnaire and underwent a comprehensive glaucoma workup. Tear break-up time (TBUT) test, Schirmer's test (type I), corneal sensitivity, anterior segment-optical coherence tomography (AS-OCT), and corneal and conjunctival staining were done at day 1, 1 month, 3 months, 6 months, and 12 months follow-up. Results: On presentation, TBUT, Schirmer's test, tear meniscus height (TMH), and tear meniscus depth (TMD) were significantly higher in group I compared to group II. No significant difference was noted in OSDI score, corneal sensitivity, and tear meniscus area (TMA) between the groups on presentation. Both, lissamine green and rose bengal staining, had higher grades in group II compared to group I. Worsening of ocular surface disease was noted in both groups on follow-up. OSDI score, TBUT, Schirmer's test, TMH, and TMD had better values in group I in comparison to group II on follow-up. Conclusion: The study has identified glaucoma patients on AGMs to be more affected by dry eye disease (DED) compared to treatment-naive glaucoma patients. We found statistically significant differences in values of TBUT, Schirmer tests, lissamine and rose bengal staining, and AS-OCT parameters at baseline and 3, 6, and 12 months follow-up. OSDI scores showed significant differences at 6 and 12 months of follow-up. We recommend consideration of evaluation and management of DED/ocular surface disease in glaucoma patients on topical AGMs, particularly multiple drugs and doses.