There are 4 main types of glaucoma:

1. 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.

2. 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.

3. 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

4. Developmental Glaucoma
   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:

AgingEye
http://www.agingeye.net/glaucoma/glaucomaeyeexam.php

American Glaucoma Society
http://www.glaucomaweb.org/

American Health Assistance Foundation
http://www.ahaf.org/glaucoma/about/glabout.htm

ElderWeb - Glaucoma Quiz
http://www.elderweb.com/?PageID=2398

eMedicine - Glaucoma
http://www.emedicinehealth.com/articles/14545-1.asp

EyeSearch - Glaucoma
http://www.eyesearch.com/glaucoma.htm

Glaucoma Associates of New York
http://www.glaucoma.net/gany/gany.html

Glaucoma Australia
http://www.glaucoma.org.au/article-apr2004.htm

Glaucoma Research Foundation
http://www.glaucoma.org/learn/index.html#poag

International Glaucoma Association - United Kingdom
http://www.glaucoma-association.com/nqcontent.cfm?a_id=176&=fromcfc&tt=article&lang=en&site_id=0

Mayo Clinic
http://www.mayoclinic.com/invoke.cfm?id=DS00283

Medical Library
http://www.medem.com/MedLB/article_detaillb.cfm?article_ID=ZZZC6A6EIVC&sub_cat=2012

Medline Plus
http://www.nlm.nih.gov/medlineplus/glaucoma.html

National Association for Visually Handicapped
http://www.navh.org/glaucoma.html

The Glaucoma Foundation
http://www.glaucomafoundation.org/

The New York Glaucoma Research Institute
http://www.glaucoma.net/nygri/nygri.html

The Pediatric Glaucoma & Cataract Family Association
http://www.pgcfa.org/

Vision Channel - Glaucoma
http://www.visionchannel.net/glaucoma/

VisionRX
http://www.visionrx.com/library/exam/exam_glaucoma.asp