Open angle glaucoma is the type seen most frequently in the United States. It is usually detected in its early stages during routine eye examinations. Closed angle glaucoma, also called acute glaucoma, usually has a sudden onset. It is characterized by eye pain and blurred vision. Secondary glaucoma occurs as a complication of a variety of other conditions, such as injury, inflammation, vascular disease and diabetes.
Congenital glaucoma is due to a developmental defect in the eye's drainage mechanism.
Early detection of open angle glaucoma is extremely important, because there are no early symptoms. Routine eye exams, common after age 45, are a major factor in early detection. People with a family history of glaucoma should be checked at intervals in their 30s to establish a baseline. Initially, detection is based often on intraocular pressure readings, but also includes observation of the optic nerve as well as evaluation of optic nerve function using visual field tests. Glaucoma is a leading cause of blindness, but high pressure within the eye does not inevitably cause sight loss.