Group of conditions
January is National Glaucoma Awareness Month, the perfect time to spread the word about a disease that affects roughly 60 million people around the world. Glaucoma is a group of serious eye conditions that, left untreated, will eventually cause blindness. Even with treatment, about 10 percent of people with glaucoma still experience some loss of vision. It’s estimated that over three million Americans have some form of glaucoma but only half of them are aware they have it. In the U.S., more than 120,000 adults are blind due to glaucoma, accounting for between nine and 12 percent of all cases of blindness in the country. Although there is no cure for glaucoma and any vision lost cannot be restored, with medication or surgery, it is possible to halt any further loss of vision. And because it is a chronic condition, glaucoma must be monitored for life. Seeing a trained eye specialist and getting diagnosed is the first step to preserving your vision.
Glaucoma is the result of damage to the optic nerve. As this nerve gradually deteriorates, blind spots develop in your visual field. According to ophthalmologist Dr. Grant Morshedi from the Jones Eye Institute at UAMS, this nerve damage is usually related to increased pressure in the eye. Elevated eye pressure is due to a buildup of a fluid that flows throughout your eye. This fluid normally drains into the front of the eye through tissue at the angle where the iris and cornea meet. When the drainage system doesn’t work properly, the fluid can’t flow out at its normal rate and pressure builds up. Because glaucoma gives few warning signs, Dr. Morshedi recommends that adults over the age of 40 have a complete eye examination every four years. Screening examinations may include testing for optic nerve damage, measuring eye pressure, and measuring corneal thickness. People considered at risk for glaucoma, such as those with a family history of the disease, should be screened every two years.
There are several forms of glaucoma, the group of diseases that can damage the eye’s optic nerve. Open-angle glaucoma is the most common form of the condition, accounting for 90 percent of all glaucoma cases in the U.S. “Open angle” means that the angle where the iris meets the cornea is as wide and open as it should be. People with this form of glaucoma may lose their peripheral vision or develop tunnel vision. It is caused by the slow clogging of the eye’s drainage canals, which results in increased eye pressure. The pressure in the eye slowly rises and the cornea adapts without swelling. If the cornea were to swell, which is usually a signal that something is wrong, symptoms would be present. But as this is not the case, this disease often goes undetected. It is painless, and the patient often does not realize that he or she is slowly losing vision until the later stages of the disease. However, by the time the vision is impaired, the damage is irreversible.
Angle-closure glaucoma is a less common form of the disease and unlike other forms of glaucoma, it develops very quickly and has symptoms that develop very quickly. There is a tendency for this disease to be inherited, and often several members of a family will be afflicted. It is most common in people of Asian descent and people who are far-sighted. It occurs when the iris bulges forward to narrow or block the drainage angle formed by the cornea and iris. As a result, fluid can’t circulate through the eye and pressure increases. Some people have narrow drainage angles, putting them at increased risk of angle-closure glaucoma. Severe pain in the eyes accompanied by nausea or vomiting, haloes or “rainbows” around lights and blurred vision are some of the symptoms of this form of glaucoma, which can be triggered by sudden dilation of the pupils. It should be considered a medical emergency and anyone having these symptoms should be seen by a trained eye specialist.
The first step
The damage caused by glaucoma cannot be reversed but treatment and regular check-ups can slow or prevent vision loss, especially if the disease is caught in its early stages. Prescription eye drops are usually the first step. They can help decrease eye pressure by improving how fluid drains from the eye or by decreasing the amount of fluid the eyes make. If eye drops alone don’t bring the patient’s eye pressure down to the desired level, an ophthalmologist may also prescribe an oral medication, such as a carbonic anhydrase inhibitor. Surgery, which involves the creation of a new opening for fluid to leave the eye, sometimes done with a laser, may be recommended. A flexible plastic tube known as a shunt may be placed in the eye to help drain fluid. In some cases, a single surgery isn’t enough to slow down the progress of the glaucoma. In those cases, repeat surgery and continued treatment with medicines may be necessary.
These programs were first broadcast the week of January 18, 2016.
T. Glenn Pait, M.D., of UAMS is the host of the program.