Glaucoma is the general name for a group of diseases that affect the eye and can damage the eye’s optic nerve resulting in vision loss and blindness.
Glaucoma occurs when the fluid pressure inside the eyes slowly rises to abnormal levels because of insufficient recirculation of the fluid of the eye. In glaucoma, deterioration of the optic nerve leads to progressive loss of the field of vision. Open Angle Glaucoma (OAG), which is characterized by painless loss of vision, constitutes the majority of glaucoma cases. OAG may be divided into Primary Open Angle Glaucoma (POAG) and Secondary Glaucoma (SG). POAG is without an identifiable cause of aqueous outflow (eye fluid recirculation) resistance, whereas in SG the outflow resistance is of a known cause. The most common cause of SG is Exfoliation Glaucoma (XFG) that may be responsible for 10 to 30% of all glaucoma, depending on the population.
Glaucoma is the second most common cause of blindness in the world and is one of the leading causes of preventable blindness. It affects over 60 million people worldwide. Early diagnosis before optic nerve damage, and management of the fluid pressure within in the eye with medication or other treatments may prevent blindness.
Genetic factors are known to contribute considerably to the development of glaucoma. Two sequence variants in a gene called LOXL1 have been found to increase the risk of developing exfoliation glaucoma. The effect is thought to be caused by exfoliation syndrome (XFS), which is characterized by accumulation of abnormal deposits on surfaces in the front part of the eye.
The deCODEme Genetic Scanidentifies genetic variants in the LOXL1 gene in customers of European descent and provides interpretation of their associated risk for developing exfoliation glaucoma. Currently no data are available for people of other ethnicities for the variants listed above.
risk factors
Age, ethnicity and family history are the most important risk factors in the development of glaucoma.
- Age: Glaucoma most commonly affects people over 60 years of age but can begin as early as 30 or 40 years of age.
- Race/Ethnicity: Glaucoma is five times more likely to occur among African Americans than Caucasians and about four times more likely to cause blindness in African Americans compared with Caucasians. Additionally, glaucoma is about 15 times more likely to cause blindness in African Americans between the ages of 45-64 than in Caucasians of the same age group.
- Hypertension: A number of studies also suggest that there is a correlation between glaucoma and high blood pressure.
- Family history/Genetics: Men who have one relative with glaucoma are twice as likely to develop the disease, while those with two or more relatives are nearly four times more likely to be diagnosed. This suggests that genetic risk variants play a significant role in the risk of developing the disease.
prevention and treatment
Most people who become blind from glaucoma are already blind on at least one eye by the time of diagnosis, which emphasizes the need for increased awareness and early diagnosis. Studies have shown that the early detection and treatment of glaucoma, before it causes major vision loss, is the best way to control the disease.
Individuals who may be at high risk for glaucoma include African Americans over age 40; everyone over age 60, especially Mexican Americans; and people with a family history of the disease. These individuals should have a comprehensive eye exam at least once every two years according to recommendations by the National Eye Institute (NEI) . Lowering eye pressure in glaucoma’s early stages slows progression of the disease and helps preserve vision.
A comprehensive eye exam can also reveal other associated eye abnormalities that can increase the risk of glaucoma, such as high eye pressure, thinness of the cornea, and abnormal optic nerve anatomy. In some people with certain combinations of these high-risk factors, eye drops reduce the risk of developing glaucoma by about half. Additional therapies such as laser treatments may be beneficial, especially for the XFG form of glaucoma.
more information
You can find out more information about glaucoma by talking with your doctor and visiting these Web sites:
The American Glaucoma Society
The Glaucoma Foundation
National Eye Institute
Medline Plus Article on Glaucoma
Wikipedia Article on Glaucoma