The Beijing Angle Closure Progression Study

This study is following people with narrow angles in both eyes — a condition where the drainage area in the eye is structurally narrow — to understand how often this progresses to angle-closure glaucoma over time. Participants will not receive experimental treatment; they will be monitored with eye exams and vision tests. **You may be eligible if...** - A detailed eye exam (gonioscopy) shows that the drainage angle in both your eyes is narrow (6 or more clock-hours blocked), with normal eye pressure, optic nerve, and visual field - You are able to give informed consent **You may NOT be eligible if...** - You already have primary angle-closure (elevated eye pressure or scarring in the angle) - You have had previous eye surgery or laser treatment (including cataract surgery, trabeculoplasty, or iridectomy) - You have signs of a prior acute glaucoma attack - You have structural abnormalities in the front of the eye - You have a serious illness (end-stage heart, kidney, or lung disease, or terminal cancer) - You have severe eye conditions (advanced cataract, macular disease, retinal detachment) Talk to your doctor to see if this trial is right for you.