Updated May 18, 2006

Glaucoma

A disease of the eye that can lead to vision loss due to damage to the retina and optic nerve. The risk of developing glaucoma increases with age. People with diabetes are twice as likely to develop glaucoma as others.

The eye is neither hollow nor solid. Rather, it is composed of two segments filled with fluids called the aqueous and vitreous humors. The aqueous humor is constantly being replenished as the excess is drained away. If the drainage is too slow or if it is blocked, pressure will gradually build up in the eye. Ophthalmologists and optometrists can measure this pressure, called intraocular pressure, with a procedure called tonometry. In glaucoma, the pressure is elevated. The increased pressure constricts the blood vessels of the eye, which can damage the retina or optic nerve and result in blind spots or loss of peripheral vision. With early diagnosis and treatment, vision can almost always be spared, but the damage caused by glaucoma is not reversible.

There are several types of glaucoma, including open-angle, closed-angle, and neovascular. Open-angle glaucoma, the most common, is a gradual process in which damage may not be evident until later stages. It generally has no noticeable symptoms in the early stages. Closed-angle glaucoma tends to affect only one eye and may be characterized by a sudden increase in pressure in the eye, causing pain, nausea, and visual effects such as halos around lights. Neovascular glaucoma can but does not always cause sudden, severe loss of vision. It may accompany or be related to diabetic retinopathy. Treatment depends on the type of glaucoma and the severity of the problem and may include the use of drugs, lasers, or surgery.

To maintain the health of your eyes, follow the recommendations of your physician and eye-care specialist. A dilated eye exam is recommended every year for people with diabetes, especially those over 30, those who have had diabetes for five or more years, pregnant or soon-to-be pregnant women, and those experiencing any eye problems. While dilation may be uncomfortable or seem inconvenient, it is necessary to conduct a complete exam. Remember to bring your own sunglasses when you have your exam unless you'd prefer to wear those blocky, oversized plastic sunglasses home.

This article was written by Robert S. Dinsmoor, a contributing editor of Diabetes Self-Management

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