It’s sneaky and it’s subtle. It’s referred to as “…the silent thief of sight.” “It” is glaucoma. Most types of glaucoma cause no pain and produce no symptoms. What glaucoma does do, however, is cause damage to the optic nerve. The main function of the optic nerve is sending electrical transmissions to the brain. Damage to it can lead to serious problems with vision that eventually lead to blindness.

Glaucoma is caused by increased pressure in the eye. This pressure is from a buildup of fluid, called aqueous humor, in the front of the eye. The elevated pressure is often extremely subtle with no symptoms until the disease has already caused significant damage.

In the U.S., approximately 2.2 million people age 40 and older have glaucoma, and of these, as many as 120,000 are blind, according to the American Health Assistance Foundation. An estimated 3.3 million of Americans could have glaucoma by the year 2020.

Glaucoma is a leading cause of blindness among African Americans and Hispanics in the U.S. Three times as many African Americans have glaucoma than Caucasians, and four times as many are blind. Between the ages of 45 and 64, glaucoma is fifteen times more likely to cause blindness in African Americans than in Caucasians.

Because people may not know they have glaucoma, a simple and painless glaucoma test, performed by an ophthalmologist, is vital. These tests allow the doctor to measure pressure in the eye, examine the optic nerve, check the visual field and determine the fluid drainage angle in the eye.

According to seniormag.com, there are actually two major types of glaucoma – open angle and closed angle. Typically open angle glaucoma has no symptoms in its early stages and vision remains normal. As the optic nerve becomes more damaged, blank spots begin to appear in one’s vision, but such spots can be unnoticeable at first. If the optic nerve is significantly damaged, these spots become large. If all the optic nerve fibers die, blindness results.

Some eyes are formed with the iris too close to the drainage angle. In these eyes, which are often small and farsighted, the iris can be sucked into the drainage angle and block it completely. This is called closed-angle glaucoma. Since the fluid cannot exit the eye, pressure inside the eye builds rapidly and causes an acute closed-angle attack. Symptoms that occur suddenly can include blurry vision, halos around lights, eye pain, nausea and vomiting. Medical attention should be immediate.

Early detection is key

Early detection through eye exams, visual field tests and optic nerve imaging, and management through medications and laser treatments (to relieve eye pressure) are keys to preventing optic nerve damage and blindness from glaucoma.

Be aware

• Everyone older than age 60 is at increased risk.
• For certain population groups such as African-Americans, the risk is much higher, and they should have eye pressure monitored before age 30. Hispanic, Asian and Japanese Americans also face an increased risk. The reasons for these differences aren’t clear.
• If there’s a family history of glaucoma, there is a much greater risk of developing it. A form of juvenile open-angle glaucoma has been clearly linked to genetic abnormalities.
• Diabetes increases the risk of developing glaucoma. A history of high blood pressure, heart disease, or hypothyroidism can increase risk as well.
• Severe eye injuries can result in increased eye pressure. Injury can also dislocate the lens, closing the drainage angle. Other risk factors include retinal detachment, eye tumors or eye inflammations.
• Being nearsighted, which generally means that objects in the distance look fuzzy without glasses or contacts, increases the risk of developing glaucoma.
• Using corticosteroids for prolonged periods of time appears to increase the risk of getting secondary glaucoma. This is especially true if someone uses corticosteroid eye drops.