By Dan Coden, MD, Scripps Health
If you’re not having vision problems, do you really need an annual eye exam? Consider this: Glaucoma, the second leading cause of blindness in the United States, has virtually no symptoms until significant damage has already been done.
Glaucoma is a group of eye conditions that increase the pressure in the eye. The eye is filled aqueous humor, which is a clear fluid that is constantly being produced. Normally, the fluid drains out of the eye through the anterior chamber angle. When the fluid cannot flow freely out of the eye, it builds up and creates pressure, which can eventually damage the optic nerve. A damaged optic nerve cannot correctly transmit information from the eye to the brain, so vision is impaired or completely lost.
There are two main types of glaucoma. The most common is open-angle or chronic glaucoma, which occurs when pressure in the eye gradually and painlessly increases over time. Peripheral or side vision is the first to be affected; as it progresses, all vision can be lost. The cause is unknown, but this type of glaucoma tends to run in the family. If you have a parent or grandparent with it, you may have a higher risk of developing it.
Angle-closure or acute glaucoma may develop if the anterior chamber angle is suddenly blocked, causing pressure to rise quickly. Angle-closure glaucoma can be instantaneous and very painful, and may feel like the eye is swollen. Vision may be impaired or cloudy, and you may see rainbow-like halos around lights. Nausea or vomiting may also occur. This type of glaucoma is an emergency that requires immediate medical attention. Certain types of medications may cause acute glaucoma, and if it occurs in one eye, the risk of a second attack in the other eye is increased.
Glaucoma is diagnosed through several tests. First, the optometrist or ophthalmologist will use drops to numb the eye, and a tonometry test is then done to measure the pressure inside the eye. Additional drops are then used to dilate your pupils, which enables the inside of the eye to be examined. Because some people with glaucoma have normal eye pressure, the doctor may perform additional tests if glaucoma is suspected.
While glaucoma cannot yet be cured, it can be successfully treated and managed. Open-angle glaucoma is most commonly treated with medicated eye drops to help relieve the pressure. Treatment may be lifelong.
If medications do not control the condition, surgery may be recommended. Argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT) use a laser to treat the angle and improve drainage, thereby decreasing pressure. A newer form of laser surgery known as micropulse laser trabeculoplasty (MLT) may provide the same benefits as ALT and SLT, but uses shorter bursts of energy for longer periods and may cause less inflammation and fewer spikes in eye pressure that may occur after laser treatment.
Canaloplasty is another procedure used to drain fluid from the eye. The doctor first makes a small incision in the eye, and then inserts a tiny catheter into the drainage canal and enlarges it. The catheter is removed, and a suture is put into the canal to keep it open.
Another surgical treatment, Trabectome, is a minimally invasive, outpatient procedure that gently removes part of the clogged tissue from the eye to restore drainage.
Angle-closure glaucoma is generally treated with eye drops and oral or intravenous medications to lower the pressure. In some cases, a laser procedure called an iridotomy may be required to open a new drainage pathway in the eye. If angle-closure glaucoma is not treated immediately, blindness may result within days.
Early detection can make the difference between saving your sight or losing it. People who have a family history of glaucoma, are of African American descent or are older than age 60 may have an increased risk of developing open-angle glaucoma. Have an annual eye exam after age 40 to test for glaucoma. If you have sudden or severe eye pain or loss of vision, get emergency medical care immediately.
Dan Coden, MD, is a ophthalmologist at Scripps Health. “To Your Health” is brought to you by the physicians and staff of Scripps Health. For a referral to a Scripps physician, call 1-800-SCRIPPS (1-800-727-4777).