Angle-closure glaucoma, the next most common type, is a largely inherited disorder caused by a too-narrow angle in the passageway where aqueous fluid would normally drain. This type of glaucoma may occur in two ways:
- The chronic type progresses slowly and, like open-angle glaucoma, can result in optic nerve damage.
- The acute (also called closed-angle) type begins suddenly when the normal flow of aqueous humor between the iris and lens is blocked. This condition is a medical emergency and must be treated immediately. Without treatment, blindness can result in one or two days.
There are subtypes of both open-angle and closed-angle glaucoma.