What is glaucoma? Glaucoma is the name for a number of conditions that damage the optic nerve, usually as a result of increased pressure within the eye that results when the naturally occurring fluid (aqueous humor) in the eye does not drain properly out of the eye. Slow drainage may occur with normal eye anatomy (open-angle glaucoma) or with structural problems in the drainage mechanism (angle-closure glaucoma). The optic nerve damage of glaucoma usually affects your peripheral vision first, leading to tunnel vision, and moves progressively to involve your central vision. The most common type of glaucoma is called open-angle, or chronic, glaucoma and is caused by a gradual buildup of pressure in the eye over time. A less common form of open-angle glaucoma, called normal-tension glaucoma, shows optic nerve damage even though the eye pressure is normal. Another type of glaucoma is angle-closure, or acute, glaucoma, in which the drainage mechanism becomes blocked and causes an abrupt increase in eye pressure. Glaucoma can also be present at birth (congenital glaucoma) or may occur as a result of medications, medical conditions, or surgery (secondary glaucoma). Although glaucoma can affect anyone, it is generally found in people over the age of 60 years. In addition, African Americans are about five times more susceptible to developing glaucoma than other patient populations and may develop it at an earlier age. Finally, those with a family history of glaucoma are more likely to develop glaucoma themselves (Source: NEI). In most cases, glaucoma progresses silently, without any symptoms, until visual damage has already occurred. Thus, it is essential to get regular eye examinations, especially if you are African American or have a family history of glaucoma. Timely treatment can usually stop the progression of glaucoma. Left untreated, glaucoma can cause permanent vision alterations or blindness. Although glaucoma is not life threatening, it can have serious visual complications. In most cases, visual loss occurs slowly over time. However, angle-closure, or acute, glaucoma can come on suddenly and cause permanent eye damage or vision loss if not immediately treated. Seek immediate medical care (call 911) for serious symptoms, including eye pain, blurred vision, headache, halos seen around lights, loss of vision, or nausea with vomiting.