Alternative Names
Glaucoma
Symptoms & Characteristics
Glaucoma is a group of eye diseases in which the optic nerves connecting the eyes and the brain are progressively damaged. This damage can cause a reduction in peripheral vision and eventual blindness. Other signs and symptoms of glaucoma may include pain and headache, tearing, and abnormal sensitivity to light (photophobia). Often, glaucoma does not cause any noticeable symptoms, which is why regular eye exams are important.
In most affected people, the damage to the optic nerves is caused by increased pressure within the eyes (intraocular pressure). Intraocular pressure is dependent upon a balance between fluid entering and leaving the eyes, coupled with adequate flow through the veins draining the area. Usually glaucoma develops in older adults, which is referred to as "late-onset glaucoma." The term "early-onset glaucoma" is often used when the disorder appears before the age of 40. The risk to develop early-onset glaucoma depends mainly on heredity.
The most common type of glaucoma is open angle glaucoma, which can be further divided into primary open angle glaucoma and secondary glaucoma. The most common form of secondary glaucoma is exfoliation glaucoma, which involves insufficient recirculation of fluid in the eye and a slow build up of pressure.
Treatment
Early diagnosis and treatment of glaucoma may help to preserve vision. Treatment may include prescription eyedrops and/or surgery.
How Common Is It?
Glaucoma is one of the leading causes of blindness in the United States. Over 2 million Americans are believed to be affected with glaucoma.
Genetics & Inheritance
Late-onset glaucoma is most likely a multifactorial condition, which means it involves a combination of genetic and environmental factors.
- Risk factors for late-onset glaucoma may include increasing age, high blood pressure (hypertension), diabetes, African-American or Mexican ancestry, eye injuries as well as prolonged corticosteroid use.
It is well established that some cases of late-onset glaucoma run in families. Researchers believe that there are probably a number of genes that affect the development and symptoms of glaucoma.
- Over 12 genes areas have been associated with susceptibility to primary open angle glaucoma.
- Susceptibility to exfoliation glaucoma has been associated with variations in the LOXL1 gene. Single nucleotide polymorphisms (SNPs) are small variations in a single "letter" of DNA that can be found throughout our entire genetic make-up. Some researchers have proposed that specific SNPs may cause susceptibility to exfoliation glaucoma in some people. Research is currently often limited to specific ethnic groups. Further research is needed to replicate study findings across different ethnic groups and clearly establish associations.
- Other yet to be identified or adequately classified genes also likely contribute to late-onset glaucoma.
Genetic Testing
Clinical genetic testing for some types of late-onset glaucoma may be available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.
Informational genetic testing for susceptibility to one form of glaucoma, exfoliation glaucoma, is available online (over the internet) as part of a whole genome scan. Whole genome scanning involves analyzing thousands of SNPs at once related to a number of different health conditions.
- At this point, many genetic professionals do not consider this testing clinically useful or medically relevant, but for informational purposes only. Go to the Tests tab to link to providers, compare providers and read provider reviews.
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