Angle closure glaucoma is a condition that causes vision loss and is caused by a blockage in the drainage system of the eye. This condition is also known as acute angle-closure glaucoma, narrow-angle glaucoma, or closed-angle glaucoma. It occurs when the iris bulges forward, closing off the angle between it and the cornea. This can put pressure on the drainage system of the eye, leading to damage to the optic nerve and vision loss. It is important to diagnose and treat the condition early to prevent permanent vision loss. Other synonyms for angle closure glaucoma may include narrow-angle closure glaucoma, pupil block acute angle-closure, and primary angle-closure glaucoma.