Effect of Benzalkonium Chloride Preserved and Preservative-free Latanoprost Eye Drops on Conjunctival Goblet Cells

This study is comparing two types of eye drops used to treat glaucoma (high eye pressure that can damage vision): a standard version preserved with benzalkonium chloride (a common preservative that can irritate the eye surface) versus a preservative-free version. The goal is to see whether the preservative-free version is kinder to the cells on the surface of the eye. **You may be eligible if...** - You are over 18 years old and speak Danish - You have open-angle glaucoma or high eye pressure (ocular hypertension) - Your average eye pressure is 22 mmHg or above **You may NOT be eligible if...** - You have significant eye disease other than glaucoma or high eye pressure - You have used steroids in the last 3 months - You have significant untreated health conditions (e.g., uncontrolled high blood pressure, diabetes, heart failure, autoimmune diseases) - You are pregnant or breastfeeding - You use unsafe contraception (for women of childbearing age) - You are allergic to the trial medications - You have surface defects on the eye or need more than one eye pressure-lowering medication - You cannot cooperate with eye examination Talk to your doctor to see if this trial is right for you.