About Glacoma

Glaucoma is a common eye disease that can cause loss of sight due to optic nerve damage. Over three million Americans have glaucoma, according to the Glaucoma Research Foundation, yet half are unaware they have the condition. Increased pressure in the eye causes the majority of the cases; there are several effective treatment options available to reduce pressure and preserve sight.

Identification

• A clear fluid, called the aqueous humor, normally flows in and out of the eye near the area where the iris, the colored part of the eye, and the cornea, the transparent layer that covers the iris, meet. If the drainage canals in this area become clogged and the fluid cannot drain at the normal rate, pressure builds within the eye, damaging the optic nerve. Because the optic nerve is needed to carry images from the eye to the brain, damage to it can result in blind spots in your field of vision or total blindness if damage is severe.

Common Glaucoma Types

• Primary open angle glaucoma, the most common form of the disease, occurs when the drainage canals gradually become clogged over a long period of time. This type of glaucoma can cause a slow loss of vision if untreated. Angle closure glaucoma, also called "narrow angle" or "acute" glaucoma, occurs when the iris is pushed against the drainage canals, blocking them and causing a sudden increase in pressure in the eye.

Other Glaucoma Types

• Some people experience optic nerve damage even though pressure in the eye is not increased. This form of glaucoma, called normal tension glaucoma, seems to particularly affect people with systemic heart disease and those of Japanese ancestry. Pediatric glaucoma is present at birth or in the early years, while secondary glaucoma develops as a result of an eye injury, tumor or inflammation of the eye. Glaucoma can also be caused by pigments from the iris (pigmentary glaucoma) or flakes from the lens (pseudoexfoliative glaucoma) collecting in the drainage canals and blocking them. Neovascular glaucoma occurs when new blood vessels form over the iris and block the drainage canals. Irido corneal endothelial syndrome, a particularly rare form of glaucoma, develops when cells on the back of the cornea block the drainage canals and cause adhesions in the iris.

Symptoms

• Vision loss in primary open-angle glaucoma usually occurs so slowly you may not notice that your peripheral, or side, vision is gradually decreasing. If the disease isn't treated, you may eventually notice you have developed tunnel vision. In contrast, symptoms of acute angle-closure glaucoma are difficult to miss. If you have this form of the disease, you may experience sudden, severe pain in your eye, nausea, vomiting, blurred vision, redness in the eye, halos around lights and other visual disturbances. If you notice any of these symptoms, you should visit an emergency room immediately to prevent irreversible vision loss. Symptoms in the other forms of the disease will depend on how quickly the drainage canals become blocked.

Diagnosis

• Your doctor may use one or more tests to diagnose glaucoma. Tonometry measures the pressure in the eye with the use of numbing eye drops and a special measuring device. Your eyes are also numbed if your doctor wants to perform gonioscopy, an eye test that involves using a special microscope called a slit lamp to examine the angle where the cornea meets the iris of your eye. A visual fields test is helpful in determining if you have experienced any vision loss in your peripheral vision. Your doctor may also use an ophthalmoscope, a special instrument that magnifies the image of your eye, in order to examine the optic nerve.

Treatment

• Glaucoma treatment is aimed at reducing the pressure in the eye through the use of eye drops, surgery or laser procedures. Eye drops work by decreasing the fluid produced by the eye and helping the fluid in your eye to drain faster. Laser surgery is used to make small scars in the drainage canals to increase drainage, while open surgery involves cutting drainage holes in your eyes.