Glaucoma is a group a diseases that can damage the optic nerve, possibly resulting in vision loss or blindness.
It is estimated that over 3 million Americans have glaucoma, but only half of them know it. The good news is, if caught early, glaucoma can be effectively treated. The earlier the disease is found, the greater the chances for preventing serious vision impairment. This is one reason why scheduling regular eye exams is so important.
Certain populations are at greater risk of developing glaucoma than others. They include:
- African-Americans over the age of 40
- Everyone over age 60, especially Mexican-Americans
- People with a family history of glaucoma
Other possible risk factors include high eye pressure, a thin cornea or an abnormal optic nerve.
The most common form of glaucoma is called open-angle glaucoma. It occurs when normal fluid pressure in the eye begins to rise and subsequently damages the optic nerve. The process begins in a space at the front of the eye called the anterior chamber. Clear fluid flows in and out of this chamber to nourish nearby tissue. Normally, fluid flows out through a spongy meshwork at an open angle where the cornea and iris meet. In open-angle glaucoma, the fluid passes too slowly through this angle and results in increased eye pressure that may damage the optic nerve, and over time, cause vision loss.
In the early stages of glaucoma, there are no symptoms. As the disease progresses, however, peripheral (side) vision may begin to decrease. Eventually, peripheral vision may be completely lost, creating tunnel vision. In the final stages of the disease, straight-ahead vision may decrease to the point where no vision remains at all.
Once vision is lost to glaucoma, there is no way to restore it. Early intervention, however, can significantly delay progression of vision loss. The most common treatment for glaucoma is medicine in the form of pills or eye drops. The medicine generally does one of two things - either lowers eye pressure or causes the eye to make less fluid. Sometimes, physicians will also treat glaucoma with Selective Laser Trabeculoplasy (SLT), a procedure that uses a laser to stretch drainage holes in the meshwork to encourage better fluid drainage.
It is also possible to develop glaucoma without increased eye pressure. This is called low-tension or normal-tension glaucoma. It has similar symptoms as open-angle glaucoma, and is generally treated the same way - by decreasing eye pressure. Other, less common forms of glaucoma also include: angle-closure glaucoma, congenital glaucoma and secondary glaucoma.