Although the specific cause of glaucoma is not known, most cases are associated with increased intraocular pressure that can lead to optic nerve damage. This pressure is related to a buildup of aqueous humor, the fluid that is produced by the front of the eye. This fluid is normally draining from the eye at the angle where the iris and cornea meet. Depending on the patient’s individual type of glaucoma, the angle for drainage may be blocked or too narrow, causing the fluid to drain too slowly and buildup as the pressure in the eye increases.
There are two main types of glaucoma: open-angle and angle-closure. Open-angle glaucoma is the most common type of glaucoma, and involves fluid in the eye not draining properly through the trabecular meshwork. Angle-closure glaucoma involves a sudden buildup of pressure in the eye, as well as poor drainage, because the angle between the iris and cornea is too narrow.
Some of the other types of glaucoma include normal-tension glaucoma, pigmentary glaucoma, secondary glaucoma and congenital glaucoma, which is present at birth.
Certain patients may be at a higher risk for developing glaucoma, including those who:
- Are over the age of 60
- African Americans over the age of 40
- Latinos over the age of 60
- Have a family history of glaucoma
- Have poor vision
- Have diabetes
- Have hypertension (high blood pressure)
- Have cardiovascular disease (heart disease)
It is important for patients to be aware of these risk factors and be tested regularly if they are considered to be at a higher risk. Glaucoma often does not produce symptoms until the disease has progressed, making early detection difficult without regular testing. Patients should have a comprehensive dilated eye exam at least once every two years. Older patients may be encouraged to be tested more frequently.
Most patients with glaucoma do not experience any symptoms until the condition has already begun to affect vision, at which point they may experience:
- Gradual loss of peripheral vision
- Tunnel vision
- Eye pain
- Blurred vision
- Halos
- Redness
- Nausea and vomiting
These symptoms may vary depending on the type of glaucoma diagnosed and may be the result of an associated condition, such as eye injury, inflammation, cataracts or diabetes.
While glaucoma can affect patients of any age or race, it is most common in older patients, especially those who are of African American descent. Patients who have a family history of glaucoma are also more likely to develop this condition, as glaucoma may have a genetic link.
Treatment for glaucoma may vary depending on the type and severity of the condition. There is no cure for glaucoma, so treatment focuses on relieving symptoms and preventing further damage from occurring. Most cases can be treated with eye drops, laser procedures or microsurgery.
Eye drops are used to reduce fluid production in the front of the eye, or to help drain excess fluid, but can lead to redness, stinging, irritation or blurry vision. Patients should tell their doctor about any allergies they have to minimize the risk of side effects.
Laser surgery for glaucoma aims to increase the outflow of fluid from the eye or eliminate fluid blockages through laser trabeculoplasty, iridotomy or cyclophotocoagulation.
Microsurgery involves a surgical procedure called a trabeculectomy, which creates a new channel to drain fluid from the eye and reduce the pressure that causes glaucoma. Surgery is often performed after medication and laser procedures have failed.
