Tear lipid layer thickness change and topical anti-glaucoma medication use

Purpose To investigate the effects of topical anti-glaucoma medications on tear lipid layer thickness (LLT) and the ocular surface. Methods This retrospective study examined ocular surface disease (OSD) subjects who had (n = 34) and who did not have (n = 51) open-angle glaucoma (OAG). OSD was evaluated with lipid layer thickness (using LipiView interferometer), tear breakup time (TBUT), total corneal and conjunctival staining (Oxford grading scale), and Ocular Surface Disease Index (OSDI). Four variables (total duration of anti-glaucoma medication use, duration of current anti-glaucoma medication use, total number of daily anti-glaucoma medication drops applied, and total number of anti-glaucoma medications [bottles]) related to anti-glaucoma medication were used to verify associations with LLT. Results Among the parameters, only LLT showed significantly lower values in the OAG group. In both groups, total staining showed a significant negative correlation between LLT and TBUT. Only in the OAG group, the OSDI showed significant correlations with number of medications (r = 0.389, p = 0.012) and daily number of drops (r = 0.354, p = 0.02); LLT showed significant correlations with TBUT (r = 0.381, p = 0.026) and total medication duration (r = -0.387, p = 0.013). In multivariate analyses, TBUT and total medication duration showed significant correlations with LLT (p = 0.032 and p = 0.015, respectively) in the OAG group. Conclusions Topically medicated OAG subjects with OSD had a lower tear LLT than those with OSD who did not have OAG. Therefore, our results indicate that one should evaluate ocular surface disease status in patients who take anti-glaucoma medications.