What is the difference between open and closed angle glaucoma?
Primary open angle glaucoma, (OAG) the most common form of glaucoma, is caused by a gradual blockage of aqueous outflow from the eye despite an apparently open pathway for the fluid to escape. Drainage canals for the fluid eventually become clogged causing a gradual and damaging rise in pressure. Unfortunately, OAG has no symptoms, can develop over a number of years and can cause gradual, permanent vision loss. With early diagnosis and treatment, OAG typically responds well. Closed angle glaucoma (CAG) can develop quickly or over time. If it develops quickly, it can become a medical emergency and is referred to as acute narrow angle glaucoma. Such an emergency requires immediate attention in order to preserve sight in the eye. Gradual onset CAG is caused when the angle between the cornea and iris becomes too narrow or closed and thus the aqueous pressures build high enough to damage the optic nerve before the fluid can escape. CAG is more common in far-sighted eyes due to the physical
