Glaucoma is an eye disease that can cause vision loss and even blindness, but it can come on so gradually that many people do not notice until some vision loss has occurred. Studies have shown, however, that the early detection and treatment of glaucoma before it causes major vision loss is the best way to control the disease. For those who fall into one of the high-risk groups outlined below, the National Eye Institute, part of the National Institutes of Health, recommends an examination for glaucoma every two years.
In the normal human eye, clear fluid flows in and out of a small space in the front of the eye to bathe and nourish nearby tissues. In open-angle glaucoma, for reasons still unknown, the fluid drains out too slowly; and pressure builds up, damaging the optic nerve, which connects the eye to the brain. Open-angle glaucoma is by far the most common form of glaucoma and the main topic of this article. Other forms of glaucoma may be caused by blockages, defects, eye structure or complications of other diseases. Glaucoma may develop in one or both eyes.
Who Is at Risk?
In its early stages, there are no warning signs or symptoms—no noticeable vision loss, no pain. As the disease progresses, however, people with glaucoma may notice their side vision gradually failing; they can still see objects to the front, but not to the side. As the disease worsens, the field of vision narrows; and over time even straight-ahead vision may decrease until all vision is gone. Vision loss caused by glaucoma can never be restored, but further vision loss can be slowed.
Although anyone can get glaucoma, some people are at higher risk
African-Americans over age 40
Everyone over age 60
People with a family history of glaucoma
A comprehensive eye exam can reveal more risk factors, such as increased pressure in the eye, thinness of the cornea, and abnormal optic nerve anatomy. The exam may include several tests, but glaucoma is most often found during an eye examination when the pupils are dilated. Drops are placed in each eye to widen or dilate the pupils, and a special magnifying lens is used to examine the eye and the optic nerve for signs of damage and other eye problems. After the exam, close-up vision may be blurry for several hours.
Eye tests require specialized skills and equipment. To obtain a referral to an ophthalmologist, a physician specializing in eye care, contact the local county medical society.
The Goal is Control
Although the most common form of glaucoma cannot be cured, it can usually be controlled. The National Eye Institute lists these common forms of treatment.
Medications in the form of drops or pills can reduce the pressure on the eye by slowing the flow of fluid or by improving drainage flow. For most people with glaucoma, regular use of medications will control the increased fluid pressure, but these drugs may stop working over time, or they may cause side effects. If a problem occurs, the dose may be adjusted or other drugs or other forms of treatment tried.
Laser surgery uses a strong beam of light to produce a series of small changes that make it easier for fluid to leave the eye. Over time, however, the effect of laser surgery may wear off. Patients who have laser surgery may need to also take drugs for glaucoma.
Surgery can also help fluid escape from the eye, although this method of treatment is usually reserved for patients whose pressure cannot be controlled with eye drops, pills or laser surgery. Sometimes a combination of surgery and medication is recommended.
For additional information about glaucoma, visit the website of the National Eye Institute at www.nei.nih.gov.