Exploring topical anti-glaucoma medication effects on the ocular surface in the context of the current understanding of dry eye

To assess tear film parameters, ocular surface characteristics, and dry eye symptomology in patients receiving topical anti-glaucoma medications.Thirty-three patients with a diagnosis of open angle glaucoma or ocular hypertension, receiving unilateral topical anti-glaucoma medication for at least 6 months, were recruited in a cross-sectional, investigator-masked, paired-eye comparison study. Tear film parameters, ocular surface characteristics, and dry eye symptomology of treated and fellow eyes were evaluated and compared.The mean ± SD age of the participants was 67 ± 12 years, and the mean ± SD treatment duration was 5.3 ± 4.4 years. Treated eyes had poorer non-invasive tear film breakup time (p = 0.03), tear film osmolarity (p = 0.04), bulbar conjunctival hyperaemia (p = 0.04), eyelid margin abnormality grade (p = 0.01), tear meniscus height (p = 0.03), and anaesthetised Schirmer value (p = 0.04) than fellow eyes. There were no significant differences in dry eye symptomology, meibomian gland assessments, and ocular surface staining between treated and fellow eyes (all p > 0.05).Adverse changes in tear film stability, tear osmolarity, conjunctival hyperaemia, and eyelid margins were observed in treated eyes. This suggests that inflammatory mechanisms may be implicated in the development of dry eye in patients receiving long term topical anti-glaucoma therapy.