Forms of Glaucoma

There are two main forms of glaucoma: open-angle (the most common form affecting approximately 95% of individuals) and closed-angle. There are also several other forms of glaucoma, including normal-tension, open-angle, congenital, juvenile and secondary.

Open-angle glaucoma is the most common form of the disease, is progressive and characterized by optic nerve damage. The most significant risk factor for the development and advancement of this form is high eye pressure. Initially, there are usually no symptoms, but as eye pressure gradually builds, at some point the optic nerve is impaired, and peripheral vision is lost. Without treatment, an individual can become totally blind.

Normal-tension glaucoma occurs when eye pressure is normal, yet the optic nerve is damaged and peripheral vision is lost. Lowering eye pressure through medication sometimes slows the progress of the disease, but this type of glaucoma may worsen despite low pressure. Treatment is generally the same as for open-angle glaucoma with high eye pressure.

Closed-angle glaucoma may be acute or chronic. In acute closed-angle glaucoma the normal flow of eye fluid (aqueous humor) between the iris and the lens is suddenly blocked. Symptoms may include severe pain, nausea, vomiting, blurred vision and seeing a rainbow halo around lights. Acute closed-angle glaucoma is a medical emergency and must be treated immediately or blindness could result in one or two days. Chronic closed-angle glaucoma progresses more slowly and can damage the eye without symptoms, similar to open-angle glaucoma.

Congenital glaucoma affects infants born with defects that prevent the normal drainage of fluid from the eye.

Juvenile glaucoma is open-angle glaucoma that affects children, adolescents and young adults.

Secondary glaucoma can be open-angle or closed-angle, and is the result of some other medical condition in the eye or the body. Examples of secondary glaucoma include:

• Pigmentary glaucoma, a rare form, in which pigment granules from the iris flake off into the eye fluid (aqueous humor) and clog the eye’s drainage system (trabecular meshwork).
  
  
• Pseudoexfoliation Syndrome occurs when white material appears to flake off the lens of the eye and block normal flow of the aqueous humor.
  
  
• Neovascular glaucoma occurs when abnormal blood vessel growth blocks the eye’s fluid drainage channels and leads to increased eye pressure. This abnormal growth can be caused by low blood supply to the eye due to diabetes, insufficient blood flow to the head because of blocked neck arteries, or blood vessel blockage in the back of the eye.
  
  
• Iridocorneal Endothelial Syndrome (ICE) has a number of features, including the breaking off of cells from the cornea, which blocks the drainage channels in the eye and leads to increased eye pressure. Scars may also connect the iris to the cornea.

Further Information

The following publications from AHAF can provide you with more information:

• The Essential Facts on Glaucoma

Source: Some of the information in this page was obtained from the National Eye Institute. The American Health Assistance Foundation is grateful to Carla J. Siegfried, M.D. at Washington University in St. Louis, Missouri for reviewing aspects of the above content.

Last Reviewed On: 12/18/09