AIM: To compare the tear functions and the impression cytology scores of the patients with primary open angle glaucoma(POAG), ocular hypertension(OHT)and normal subjects with healthy ocular surface both functionally and clinically.

METHODS: Eleven eyes of 11 patients with POAG(mean age: 62.7±6.1y), 12 eyes of 12 patients(mean age: 62.8±6.4y)with OHT and 12 eyes of 12 normal subjects(mean age: 62.9±6.03y)were included to this prospective study. The patients with POAG and OHT had been recently diagnosed with these diseases and none of them had taken anti-glaucoma treatment before. In addition to conjunctival impression cytology, tear break-up time(TBUT)and basal Schirmer's tests(BST)were performed. Impression cytology specimens of each group were graded and scored in the range of 0-3 according to Nelson's method. Kruskal-Wallis analysis and Dunn's multiple comparison tests were used for statistical analysis.

RESULTS: The mean BST values were 10.4±1.3, 10.9±1.2 and 11.1±1.1 mm/5min of POAG, OHT and control groups respectively. The differences among the BST values of the POAG, OHT and control group were not statistically significant(P=0.33). The mean TBUT values were 11.2±1.1, 11.3±1.1 and 11.8±1.2s in POAG, OHT and normal subjects respectively. The differences among the BUT values of the POAG, OHT and control group were not statistically significant(P=0.35). Six eyes(54.5%)revealed grade 0 and 5 eyes(45.5%)revealed grade 1 impression cytology scores in POAG group. Six eyes(50%)revealed grade 0 and 6 eyes(50%)revealed grade 1 impression cytology scores in OHT group and 6 eyes(50%)revealed grade 0 and 6 eyes(50%)revealed grade 1 impression cytology scores in normal subjects(P=0.97).

CONCLUSION: Oxidative stress may cause glaucoma, ocular surface diseases, lacrimal gland malfunction and a decrease in mucus secretion ofgoblet cells in all of the body. There were no significant differences between the impression cytology scores of patients with POAG, OHT and normal subjects.