Concentration of latanoprost ophthalmic solution after 4 to 6 weeks' use in an eye clinic setting.

Purpose: To determine the concentration of latanoprost in bottles of latanoprost ophthalmic solution 0.005% after 4 or 6 weeks of use in patients in an eye clinic setting.

Methods: Patients treated with latanoprost for open-angle glaucoma or ocular hypertension were randomly assigned to refill their prescriptions either at the Doheny Eye Institute clinic or a local pharmacy.