What is the definition or description of: acute angle closure glaucoma?

Short eye anatomy: Angle closure glaucoma is a rapid, usually painful, elevation in eye pressure (from < 20 to over 40 and higher) induced by forward movement of the lens. This occludes the pupil, causing the site of aqueous outflow (the iris-corneal angle) to close. The eye becomes red and painful, and vision foggy. Treatment should be prompt; extended high pressure can irreversibly damage the optic nerve.

Red, painful eye: This is an uncommon condition in which the pressure suddenly rises because of blockage of the normal drainage mechanism inside of the eye. It is very painful, accompanied by blurred vision, nausea and sometimes abdomenal pain. It is an urgent problem because of the risk of permanent vision loss if it is not treated.