Ocular surface changes induced by topical antiglaucoma monotherapy

Purpose: To investigate the expression of inflammatory markers HLA-DR in impression cytology specimens from patients receiving topical antiglaucoma monotherapy. Methods: Impression cytology specimens were obtained from patients taking no topical medication (n = 13) and from primary open-angle glaucoma or ocular hypertensive patients taking one topical medication for at least 3 months (latanoprost n = 14; betaxolol n = 12; timolol n = 14). None of the patients had any signs of ocular surface inflammation as detected by slit-lamp examination, a normal Schirmer’s test and tear breakup time. The expression of HLA-DR on epithelial cells and T lymphocytes was analysed by flow cytometry. Results: A significant increase in HLA-DR on epithelial cells in patients on monotherapy was detected (latanoprost p < 0.05; betaxolol p < 0.01; timolol p < 0.01). Although the duration of treatment differed significantly between individual groups, there was no significant correlation between the length of monotherapy and the expression of inflammatory markers by epithelial cells and T lymphocytes. In the latanoprost group, the increased expression of HLA-DR was associated with a shorter duration of treatment. Conclusions: The flow-cytometric results indicate that administration of a single topical medication preserved with benzalkonium chloride, irrespective of type, for 3 months or more induced a significant degree of subclinical inflammation detected as increased expression of HLA-DR on conjunctival epithelial cells.