deCODE Glaucoma™
A novel DNA-based test that assesses risk for exfoliation glaucoma. Individuals testing positive are at 2.4-times the population average risk of developing exfoliation glaucoma.
Screening and prevention
How deCODE Glaucoma™ can help.
deCODE Glaucoma™ identifies those who are at increased genetic risk of developing open angle glaucoma
The deCODE Glaucoma™ risk results are independent of and complementary to other known risk factors such as family history of glaucoma or elevated eye pressure.
Those who test positive may derive greatest benefit from regular eye exams, with the aim of detecting more disease earlier and treating it to slow progression and preserve vision.
Glaucoma is the second most common cause of blindness in the world and is one of the leading causes of preventable blindness.
Glaucoma 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.
Glaucoma is a heterogeneous group of disorders that share a distinct pattern of optic nerve damage. There are two basic forms of glaucoma, open- and closed angle glaucoma.
In most populations, open-angle glaucoma, characterized by painless loss of vision, constitutes the majority of glaucoma cases. Open-angle glaucoma is defined as a progressive loss of neuro-retinal rim tissue within the optic disk and consequent excavation of the optic disk with corresponding loss of visual field and is divided into primary open-angle glaucoma and secondary glaucoma. Primary open angle glaucoma is without an identifiable cause of aqueous outflow resistance, whereas in secondary glaucoma including exfoliation glaucoma, the outflow resistance is of a known cause.
Exfoliation syndrome is the most common identifiable cause of secondary glaucoma in most populations and may be responsible for 10 to 30% of all glaucoma, depending on the population. The prevalence of exfoliation glaucoma increases with age, and although the disease is found worldwide, a number of studies have pointed to a geographical clustering of the syndrome. According to recent studies the 15-year risk of exfoliation syndrome conversion to exfoliation glaucoma is about 60% (23-25). Exfoliation glaucoma is characterized by rapid progression, high resistance to medical therapy, and a worse prognosis than in primary open angle glaucoma. Family history is an important risk factor for both primary open angle glaucoma and exfoliation syndrome which, together with ethnic differences in prevalence of primary open angle glaucoma, points to a role of genetic factors in the risk of suffering from these conditions.
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:
Medline Plus Article on Glaucoma
This content was last reviewed on March 16, 2011.