Dose response measurements of low dose atropine eye drops over time

This study is measuring the effects of low-concentration atropine eye drops on the eyes at different doses. Atropine is well known at high concentrations for dilating the pupil and blurring near vision, and it has recently attracted interest in very low concentrations as a treatment to slow the progression of short-sightedness (myopia) in children. Before it can be widely used in this way, researchers need to precisely measure what each concentration does to the pupil and the eye's ability to focus. Healthy adults aged 18–40 will receive different concentrations of atropine eye drops on separate occasions, and their pupil size and near focusing ability will be carefully measured at multiple time points after each dose. The study will build a clear dose-response picture to inform safe and effective prescribing. You may be eligible if you are a healthy adult aged 18–40 with no eye diseases, no history of allergy to eye medications, and no glaucoma risk. Women who are pregnant, breastfeeding, or planning pregnancy are not eligible. People currently using any eye medications or systemic MAOIs are also excluded.