Objectives: To investigate and compare the tear volume, tear film stability, Meibomian gland loss of healthy and glaucoma subjects from the Bulgarian population and to assess the relationship between clinical findings and glaucoma therapy.
Methods: In this observational cross-sectional study, a random cohort of 68 subjects was enrolled and divided into patients with primary open-angle glaucoma or ocular hypertension (POAG/OHT group; n=19) and healthy controls (HC group; n=49). Ocular surface was analysed objectively by Noninvasive tear Break-Up Time (NIBUT), Meibomian gland loss, and Schirmer test for basal secretion. In addition, Central Corneal Thickness (CCT) was measured with pachymetry.
Results: Loss of Meibomian glands (39.85% ± 14.49%), as well as a decrease in Schirmer test values (7.29 mm ± 3.92 mm) and NIBUT (8.26 s ± 4.73 s), were typical in the POAG/OHT group, regardless of disease duration. Significant factors affecting the ocular surface state were age, anti-glaucoma treatment (type and duration), and the presence of preservatives. A worsening of all clinical parameters was evident in the glaucoma patients. A correlation between CCT and NIBUT was established (p=0.037; r=0.167).
Conclusions: Local glaucoma treatment affects the ocular surface objective parameters according to its duration and the composition of treatment eye drops.