This article gives an overview of glaucoma, looking at glaucoma symptoms; the causes of glaucoma; how glaucoma is diagnosed by your doctor and finally glaucoma treatment.
Glaucoma is a group of eye diseases in which damage to the nerve located in the back of the eye (optic nerve) results in loss of eyesight. At first, side (peripheral) vision is lost. If glaucoma is not treated, vision loss may continue, leading to total blindness over time.
There are three basic types of glaucoma:
Open-angle glaucoma (OAG) is the most common form of glaucoma in the United States and in the United Kingdom. In open-angle glaucoma, the optic nerve is slowly damaged, usually causing gradual loss of vision. Both eyes can be affected at the same time, although one may be affected more than the other. Sometimes much of your eyesight can be affected before you notice a change.
Closed-angle glaucoma (CAG) is less common, accounting for about 10% of all glaucoma cases in the United States. In closed-angle glaucoma, the colored part of the eye (iris) and the lens block the movement of fluid between the chambers of the eye, causing pressure to build up and the iris to press on the drainage system (trabecular meshwork) of the eye. It may cause sudden blurred vision with pain and redness, usually in one eye first; symptoms may also include nausea and vomiting. A related type, acute closed-angle glaucoma, is often an emergency situation and needs immediate medical care to prevent permanent damage to the eye.
Congenital glaucoma is a rare form of glaucoma that is present in some infants at birth. Glaucoma that develops during the first few years of life is called infantile glaucoma. Infants with congenital or infantile glaucoma usually have cloudy eyes that are sensitive to light and have excessive tearing. Symptoms may not develop until 6 months to 1 year after birth. If the problem is not detected early and treated, the child may have severe vision loss and may go blind. People between the age of 3 years and young adulthood can develop a similar type of glaucoma called juvenile glaucoma.
What causes glaucoma?
Damage to the optic nerve is thought to be caused by increased pressure in the eye (intraocular pressure, or IOP). This may result from excess fluid, called aqueous humor, building up in the eye because the eye produces too much or drains too little of the fluid. However, many cases of glaucoma develop without increased IOP. In these cases, decreased blood flow to the optic nerve may cause the damage. Glaucoma may develop after an eye injury, after eye surgery, from the growth of an eye tumor, or as a complication of a medical condition such as diabetes. Certain medications (corticosteroids) may cause glaucoma when they are used to treat eye inflammation or other diseases. Glaucoma that develops as a result of another condition is called secondary glaucoma.
How is glaucoma diagnosed?
Your health professional will take a medical history and do a physical exam. If glaucoma is suspected, you usually will be referred to an eye specialist (ophthalmologist) for further testing and treatment. The initial evaluation by a specialist may require up to 3 visits.
Treatment for glaucoma focuses on preserving eyesight by slowing the damage to the nerve in the back of the eye (optic nerve). Most treatment aims to prevent further damage to the optic nerve by lowering the pressure in the eyes (intraocular pressure, or IOP). Glaucoma is usually treated with medications such as eye drops. Laser treatment or surgery is often needed.
Copyright 2006 Michael Saville