Glaucoma, a disease of the optic nerve, can become quite advanced before someone with the condition recognizes he or she has a problem. To prevent irreversible vision loss, Wallace Alward, MD, University of Iowa professor of ophthalmology and visual sciences and director of the UI Glaucoma Service, suggests that people with certain risk factors or those who have never been examined for glaucoma set up an examination with their eye doctor.

The encouragement is part of Glaucoma Awareness Month, an effort being made each January by the American Academy of Ophthalmology (AAO) to reduce the incidence of blindness due to undetected glaucoma. The disease is the second leading form of permanent blindness in America and the leading cause among African-Americans, who also are more likely to have the disease at a younger age.

"Nearly half of Americans with glaucoma don't know that they have it," Alward said. "The optic nerve gradually becomes damaged, and people tend to very slowly lose vision. In addition, people can have profound vision loss in one eye and not know it because when both eyes are open, the functional eye makes up for the loss."

The AAO recommends glaucoma screenings for people who have a family history of glaucoma, are over age 40, are of African ancestry or who have not had a medical eye exam in the last two years.

Glaucoma damages the optic nerve, which normally takes information from the eye to the brain so the brain can determine what the eye is seeing, Alward said.

"Glaucoma usually takes away the peripheral vision first, and leaves the straight-ahead, reading-the-eye-chart type of vision to the very end," he said. "With advanced glaucoma, it can be like looking at life through a soda straw."

Alward said it is important for people to get a complete eye exam, not just an eye pressure check. A glaucoma examination includes a check of the optic nerve and/or measurement of the visual field to check for side vision loss. It is not sufficient only to check eye pressure because a person can have normal eye pressure and still have glaucoma.

Alward explained that high pressure in the eye is a risk factor for glaucoma, similar to the relationship between high blood pressure and heart attacks.

"Not everybody with a heart attack has high blood pressure, and not everyone with high blood pressure gets a heart attack," Alward said. "But the higher your blood pressure, the higher your risk for developing a heart attack. That's the exact same relationship between eye pressure and glaucoma."

He added that the main reason eye pressure is often the focus of glaucoma treatment is because the other risk factors--age, race or family history--cannot be changed, and the optic nerve damage cannot be reversed.

"We can change eye pressure, so that's why you hear about it so much in relation to glaucoma," Alward said. "But it is important to keep in mind that a thorough glaucoma evaluation includes assessment of the optic nerve or visual field."

Drug and surgical treatments are available to stop the blindness caused by glaucoma.

As with all medical care, it is best to consult with your health care provider before making any changes to your health care routine.