Glaucoma affects four million people in the United States. Half of those people are unaware they have it.
According to Dr. Kjell Dahlen, an opthamologist with Eye Care for the Adirondacks in Plattsburgh, glaucoma is an eye disease that not only affects the elderly, as it is often assumed.
"The chances of glaucoma increase as we get older, it's much more common in an 80-year-old than it would be in a 30-year old," he explained. "But, it can happen at any age."
Dahlen added even infants can be born with the disease.
"Glaucoma is a disease of the optic nerve, generally caused by high pressure in the eye," Dahlen added. "The most common type of glaucoma is what's called primary open-angle glaucoma. There is no cause for it, it just happens."
In the eye, there is a fluid called aqueous which is formed behind the pupil, he explained. From there, it passes through the pupil to the front of the eye, then goes into a drainage system and into the blood circulation.
"Fluid is being formed all the time and being drained all the time," Dahlen said. "Most types of glaucoma, the problem is the fluid is being formed, but there is some obstruction in the drainage system so the pressure builds up."
The pressure being built up damages the optic nerve, which becomes less resistant to the pressure over time, he explained. To determine whether one has glaucoma, a pressure test was often done, with the typical pressure being between 12-22 mm Hg (millimeters of Mercury), according to the Glaucoma Research Foundation.
Testing for glaucoma
Now it is known some people may have a high pressure, but not have glaucoma. Others may have a lower pressure, but in fact have the disease. So, instead of just doing a pressure test, you may have your peripheral visual field tested.