Dubbed the sneak thief of sight, glaucoma refers to a group of diseases affecting the optic nerve which result in optic neuropathy, or damage to the nerve. Its main characteristic is increased pressure in the fluid that fills the eye (ocular hypertension). It’s this increased pressure that is responsible for the damaged nerve.
Most forms of glaucoma fall into one of two categories: open angle (chronic) or closed angle (acute). Either form of the disease eventually jeopardizes visual acuity and irreparable blindness can result. On a global basis, glaucoma is the second most common cause of blindness. One of every hundred people, age 50 and younger, is affected by glaucoma. By age 80, one in ten is affected.
It’s currently impossible to prevent glaucoma or to cure it once it’s developed but early detection can preserve the vision as long as possible. The disease is often identified during routine eye examinations before any symptoms become apparent to the patient.
Symptoms a glaucoma patient might experience include a loss of contrast, which causes a fuzziness in visual acuity. Patchy peripheral vision is another sign that nerve cells are becoming damaged. One patient may be able to withstand an extremely high amount of ocular pressure with no damage or loss of vision while the next patient may suffer damage when ocular pressure is only slightly elevated.
The eye produces fluid that flows from the interior of the eye out the pupil. From here, it normally drains through a series of meshwork that drains the fluid off the eye and into the bloodstream, where it is absorbed. In open angle (chronic) glaucoma, the meshwork doesn’t allow ample amounts of fluid to drain into the bloodstream. The undrained fluid is the source of pressure within the eye. In closed angle (acute) glaucoma, pressure pushes the iris too tightly against the meshwork for adequate drainage to occur.
Ethnicity plays a large role in one’s risk of developing glaucoma as does gender. The average woman runs a risk for glaucoma at a rate three times higher than the average man because her eye chambers are typically smaller. Eye shape determined by race or ethnicity, as well as other factors, increases risk as follows:
- People of African heritage are at three times greater risk for open angle glaucoma.
- The shallower eye chamber of people of Asian descent increases their chance of closed angle glaucoma.
- The Inuit population faces a risk 20 to 40 times higher than Caucasians.
- Myopic (nearsighted) individuals, those who have thin corneas, and older people are at higher risk.
- A family history of glaucoma increases one’s risk by about 6%.
Prolonged steroid use, diabetes, trauma, and other conditions also heighten one’s risk of developing glaucoma. In other cases, the cause of the disease is genetic. Hypertension has been associated with but not proven to be a cause of glaucoma. Studies on vitamin deficiencies and supplements have been inconclusive thus far.
While there is no way to prevent glaucoma, early detection and diligent maintenance efforts are vital for preventing blindness. Eye drops that ease the pressure are most effective and are usually the first order of treatment. Regular eye exams are critical. Failure to comply with medical orders and missed eye exams are the main reason glaucoma patients lose their vision.
There are a number of drugs available to treat glaucoma and still more under study or development. Only an eye care professional can diagnose glaucoma and only an eye care professional can know which patient is most likely to receive benefit from a particular course of treatment.
In cases where surgery is an option, a hole is made through the meshwork surrounding the pupil. By enlarging the hole through which intraocular fluid drains, pressure within the eye is relieved. In some surgical procedures, lasers are used but others involve the placement of tubular catheters to induce drainage.