Save Your Sight - Glaucoma Screening

Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: Barbara K. Hecht, PhD

Glaucoma is the term applied to a group of eye diseases that gradually result in loss of vision by permanently damaging the optic nerve, the nerve that transmits visual images to the brain. The leading cause of irreversible blindness, glaucoma often produces no symptoms until it is too late and vision loss has begun.

An elevation in the pressure within the eye (the intraocular pressure, or IOP) is generally, but not always, associated with the development of glaucoma, although additional factors are also likely to play a role in its development. The optic nerve fibers inside the eye are damaged, resulting in vision loss that begins in the peripheral fields of vision. Glaucoma usually affects both eyes, but one eye may be more severely affected than the other.

There are many kinds of glaucoma. The most common form of glaucoma involves blockage in the drainage canals of the eye, so that fluid builds up within the eye and causes the increased IOP. This type of glaucoma, known as open angle glaucoma, usually progresses slowly over many years.

Another kind of glaucoma, called closed angle glaucoma, typically has a sudden (acute) onset. In this type of glaucoma, the angle in the front of the eye where the drainage canals are located is not as wide as it should be and the edge of the iris bunches up over the drainage canals when the pupil enlarges.