By Dr. Winston J. Garris
One of the most common causes of blindness in the United States is glaucoma, a disease that damages the optic nerve of the eye. The optic nerve is like the electric cable that transmits all of the information that your eye sees to the brain for processing. A normal eye consists of two separate chambers that are connected via the pupil. The pupil is the dark circle in the center of the colored part of your eye. A healthy eye produces a fluid called aqueous humor in the back chamber where it flows through the pupil and into the front chamber where it is drained at a rate similar to the rate it is produced. In glaucoma, the ability of the eye to drain fluid is compromised while the rate of production remains constant. As a result, the pressure inside the eye increases, leading to optic nerve damage.
Optic nerve damage from glaucoma is usually permanent and can lead to devastating vision loss. It is the second leading cause of blindness in the world and is the most frequent cause of non-reversible blindness in African-Americans. The problem is that glaucoma usually affects the peripheral vision first, is slowly progressive, and rarely has early symptoms. As a result, most people do not realize that anything is wrong until severe damage has occurred. In fact, of the 3 million Americans afflicted with glaucoma, only half are aware that they have the condition.
There are a number of factors that increase the chance that someone will develop glaucoma. Those risk factors include age (over 60), race (black or Hispanic), family history, and a number of other factors that can be determined by an eye exam. Currently there is no cure, so early detection and treatment are critical to prevent vision loss. Individuals with risk factors need to be screened more often than those without them. If you have any risk factors or symptoms you should be examined as soon as possible. All individuals 40 or over should receive a screening examination, and individuals 65 or older should receive an exam every 1-2 years or as frequently as recommended by your eye doctor.
Treatment for glaucoma is aimed at either decreasing the amount of aqueous humor that the eye produces, or to increasing the amount that is drained from the eye. The result is a decrease in eye pressure with the goal of preventing further optic nerve damage. This is usually accomplished with eye drops that need to be used daily. However, laser treatments and surgical interventions are sometimes required to prevent vision loss. New minimally invasive surgical techniques such as the iStent® are expanding the number of safe alternatives to drug therapy. A discussion with your doctor can help determine which treatment is most appropriate.