A simple glaucoma screening, which can be done in fewer than 10 minutes, can diagnosis a potentially blinding disease.

Glaucoma, in simplest terms, is a disease of the optic nerve, says Tonya Bourn, an optometrist with Bergh-White Opticians in Springfield, Ill. It can be caused by pressure or a lack of healthy nourishment to the nerve.

Routine eye exams are necessary to detect the signs of glaucoma because it has no symptoms.

“It’s virtually impossible to diagnose on your own because you see the world with both eyes. The eyes have visual fields that overlap completely,” Bourn explains. “You don’t know that you’re losing vision in one eye because the other eye compensates. That’s why an eye exam is vital. Each individual field of vision has to be assessed professionally.”

Left untreated, glaucoma can lead to blindness, though progress of the disease varies. People tend to associate tunnel vision with glaucoma-related vision loss, but Bourn says central vision loss is also possible early in the disease. Treatment options include medicine, laser treatment and surgery. Current treatment methods cannot reverse existing damage but can prevent further vision loss, according to Prevent Blindness America’s Web site (www.preventblindness.org).

Founded in 1908, Prevent Blindness America is a volunteer eye health and safety organization dedicated to fighting blindness and saving sight. Focused on promoting a continuum of vision care, it operates nationwide.

If lack of insurance or the cost of an exam is a problem, PBA can provide a list of community programs that assist those who can’t afford to see a doctor.

In addition, Medicare covers glaucoma exams, according to Sarah Hecker, director of media relations for PBA.

A variety of exams can detect glaucoma. Most look directly at the optic nerve to assess how it functions, measure the fiber layers and monitor for deterioration over time, Bourn says. A scanning laser, for example, can measure optic nerve layer thickness. This creates a digital image that is then compared to a normal optic nerve based on the patient’s age. Bourn calls the exam very easy and is done quickly. The digital image is then stored as part of the patient’s record, allowing the doctor to compare results each year and look for major changes to the optic nerve.

One common mistake people make is relying on eyeglasses available without prescription in lieu of regular eye exams. While the glasses may correct the vision, they eliminate the opportunity for glaucoma screening.

“It’s OK to use over-the-counter readers, but they should not substitute for regular eye exams. The worst cases I’ve seen are in people who have used over-the-counter readers and haven’t seen a doctor for six or eight years,” Bourn says