Adverse effects of topical antiglaucomatous medications on the conjunctivaand the lachrymal (Brit. Engl) response

Background: Increasing evidence indicates that long-term use of topically a dministered medication can induce changes in the conjunctiva and lachrymal function. Methods: In order to evaluate changes in the conjunctiva and lach rymal response after prolonged use of topically administered antiglaucoma m edications and preservatives found in antiglaucomatous medication solutions (benzalkonium chloride), we tested lachrymal function (Schirmer I., Jones, BUT, Ferning tests) and used the conjunctival impression cytology techniqu e. Materials: A group of patients with primary open angle glaucoma (POAG) r eceiving topical antiglaucomatous medication were recruited. A second group received only preservative instillations while a control group was formed of similarly aged subjects with no eye disease and was given topical or sys temic medical therapy. Excluded from the trial were patients with a history of external eye disease or who had received conjunctival surgery. Results: Tear secretion was reduced against that of the control group in those subj ects who received protracted administration of antiglaucomatous eyedrops (t imolol and/or pilocarpine). A statistically significant degree of conjuncti val metaplasia was associated with long-term use of topical medication. The subjective symptoms reported by those patients receiving chronic topical a ntiglaucomatous therapy and the objective observations on them were found t o be proportional to the observed tearing response. Changes were more prono unced in subjects who received only benzalkonium chloride. Conclusion: Our study results suggest that long-term use of antiglaucoma medication induces changes in both tear film and conjunctival surface. Such changes may be re lated to the medication or the duration of treatment, but may also be due t o the preservatives used in the commercial product.