Within a normal eye, the lens and cornea are continually being bathed by a thin clear fluid. After circulating, the fluid drains out through special channels. Glaucoma results when this fluid no longer drains properly and pressure builds up in the eye. If the pressure is not controlled, it eventually destroys cells in the optic nerve. How much pressure it takes to damage the optic nerve varies from person to person.
Vision begins to blur, the visual field narrows, and ultimately, total blindness results.
Glaucoma affects side vision long before central vision is affected, which is why this silent thief of sight , as it is sometimes described, frequently goes undetected. There are four basic types of glaucoma. According to the American Academy of Ophthalmology, more than 90 percent of adult glaucoma patients have chronic open angle glaucoma . This type of glaucoma develops gradually, as the drainage portion of the eye becomes less efficient. Often symptomless, it is usually detected during routine eye examinations.