There are 4 main types of glaucoma:
Primary Open Angle Glaucoma (the most common)
Primary open angle glaucoma (POAG), or chronic glaucoma, is the most common form of the disease. POAG develops slowly over time and is not painful. Most patients are unaware of a problem until permanent damage has been done. The drainage canals in the eye become clogged over a period of time, causing inner eye pressure to rise. This condition requires a lifetime of regular monitoring and treatment.
Primary Closed Angle Glaucoma
Primary closed angle glaucoma (PCAG), or acute glaucoma, is more common in people of Chinese or Japanese decent. PCAG develops suddenly and can be very painful. Eye pressure can rise very swiftly, as the drainage canal is blocked or covered. In this condition, the iris and cornea is not as wide as it should be, resulting in the outer edge of the iris blocking the drainage canal when the pupil enlarges too much or very quickly. If immediate treatment is given, vision may be completely recovered, but if treatment is delayed permanent damage can occur.
Secondary Open Angle and Secondary Closed Angle Glaucoma
Secondary open angle and secondary closed angle glaucoma are caused by conditions secondary to primary conditions of the eye. The conditions of both the primary cause and the secondary cause may allow vision to return to normal, and need no further treatment. In some cases the eye may be permanently damaged and require lifetime treatment.
Secondary conditions can include trauma to the eye, inflammation, tumor, cataract, diabetes, or can be caused by the use of certain drugs like steroids
Developmental glaucoma is a rare condition present at birth. This condition occurs when the eye has failed to form correctly, or due to other developmental eye abnormalities. Surgery and eye drops are used to treat this type of glaucoma.
For more information on Glaucoma, visit these websites:
American Glaucoma Society
American Health Assistance Foundation
ElderWeb - Glaucoma Quiz
eMedicine - Glaucoma
EyeSearch - Glaucoma
Glaucoma Associates of New York
Glaucoma Research Foundation
International Glaucoma Association - United Kingdom
National Association for Visually Handicapped
The Glaucoma Foundation
The New York Glaucoma Research Institute
The Pediatric Glaucoma & Cataract Family Association
Vision Channel - Glaucoma