Glaucoma Tests Can Prevent Blindness

An estimated 1 million Americans with glaucoma are unaware that they have the condition, the second leading cause of blindness in the United States.

Glaucoma is an especially acute problem for black Americans, for whom it is the leading cause of blindness. Black Americans have a fourfold higher incidence of the disease than do whites, and blindness caused by glaucoma is six to eight times more prevalent among black Americans than whites. The reason for the difference is not known.

Glaucoma is usually described as a condition in which fluid pressure builds up in the eye, causing damage to the optic nerve. This can result in blindness if not treated. However, the relationship between ocular pressure and vision damage appears to be more complicated than previously thought.

Ophthalmologists have found that perhaps 20% of patients with glaucoma have fluid pressure in the normal range.

Although the traditional way to detect glaucoma is to test for an increase in fluid pressure in the eye above the normal range, a more thorough examination is required to definitely rule out the presence of glaucoma. These tests include but are not limited to examining the field of vision and taking a careful assessment of the health of the optic nerve.

Five to 10 million Americans have intraocular pressure above the normal range.

Although all patients with pressures above the normal range are at risk for developing glaucoma, some individuals with high fluid pressure may not have the disease. They are described as having ocular hypertension, but they may not require treatment.

The basic treatment for glaucoma is reduction of pressure in the eye, commonly with eyedrops. Reduction of pressure has been found to slow or stop damage to the optic nerve in most cases. Several classes of compounds are used in the form of eyedrops.

When eyedrops fail to control glaucoma, oral medications may be used. Laser surgery is often the next treatment. In this, brief bursts of laser light are used to reduce fluid pressure in the eye by improving the drainage process. In some cases in which other treatments are ineffective, conventional surgery is performed to create better drainage of fluid from the eye.

Several new drugs have shown promise in early patient testing and could be made widely available in the next few years.

Glaucoma is an age-related condition, one that affects 2% of those 40 and older. Early detection of glaucoma is a major reason why ophthalmologists recommend an annual eye examination for people over 50. Risk factors for glaucoma include nearsightedness, diabetes and a family history of the condition.

The most common form of the condition, open angle glaucoma, damages vision slowly over a number of years. Those with this condition are often unaware of the decreased field of vision until it becomes severe, making annual testing a must.

Closed angle glaucoma is a much faster-moving disorder in which patients can experience severe eye pain and sudden loss of vision. One of its symptoms is the appearance of halos around lights. This condition requires immediate attention.