Glaucoma, a common condition that threatens vision, affects many Americans. It essentially involves a buildup of pressure inside of the eyeball. This leads to pressure on the main, or optic, nerve in the back of the eye, which impairs vision. The fluid that normally fills the eyeball, aqueous humor, is produced by cells called the ciliary body and flows through the pupil of the eye, in an area called the angle, to the space in front of the lens, where it exits the eye. Glaucoma occurs when an abnormality develops along this pathway.
Three main types of glaucoma affect adults. The most common in the United States, open-angle glaucoma, results from an over-accumulation of fluid in the eye. Another type, angle-closure glaucoma, happens when the normal the flow of fluid, from the back to the front of the eye, becomes obstructed. A third type, secondary glaucoma, occurs after some other disease process affects the eye.
Open-angle glaucoma usually occurs slowly over time, most often without symptoms until later in the course of the disease. A common type of glaucoma test, the one that puffs air at the eye, measures the eye’s resistance to that puff of air. You may have taken this painless test during a visit for eyeglasses, as part of your annual physical, or maybe even at a health fair. Unfortunately, some people can have damage to the nerve in the back of the eye or partial loss of vision even though they have normal eye pressure. On the other hand, some people with elevated eye pressure don’t have loss of vision. Visual screening tests, such as those in which you read eye charts, are generally not sensitive enough to find disease early. Thus, diagnosis is more complicated that it would seem on the surface.
Once diagnosed, open-angle glaucoma can be treated either medically or with surgery. Medical therapy most often begins with eye drops that either decrease production of aqueous fluid or help increase the flow of fluid from the back to the front of the eye. Some pills may be used to affect aqueous pressure as well. Laser and traditional surgeries focus on creating more pathways for fluid to travel.
Angle-closure glaucoma can occur suddenly, acute angle-closure glaucoma, or over a period of time, chronic angle-closure glaucoma. The patient with acute angle-closure glaucoma has a red, painful eye and decreased vision, often accompanied by headache, nausea, and vomiting. This condition needs immediate treatment to prevent loss of vision and is best treated with emergency surgery to open the angle of the eye. Often, the other eye is treated as a preventive measure as well. Chronic angle-closure glaucoma develops more slowly, often without symptoms, and its treatment also focuses on surgery.
Because glaucoma usually occurs slowly, its presence often goes unnoticed by people who have the disease. Once diagnosed, treatments are available to help stop visual impairment. If you are experiencing loss of vision, it is important to see an eye care professional. And, if you have sudden loss of vision with a red eye, it could be a medical emergency and needs to be evaluated as soon as possible.
Debra Buckler, DO, is a Freeman Health System physician specializing in geriatric and nursing home medicine. Additionally, she serves as Medical Director for Joplin Health and Rehabilitation Center, Co-medical Director for National Health Care of Joplin, and Associate Medical Director for Hospice Compassus.
