Glaucoma is a group of eye disorders that can lead to progressive loss of vision, often without any symptoms. Visual loss results from damage to the optic nerve, which transmits signals from the eye to the brain, much like an electrical cable. Once nerve fibers are damaged by glaucoma, the information they supply can no longer reach the brain. Peripheral vision is usually lost first. Because central vision is preserved until late in the disease and pain is usually absent, most people with glaucoma don’t realize that anything is wrong. It is estimated that as much as one to two percent of the US population has open angle glaucoma, and that half of those affected have not been diagnosed.
It was once believed that glaucoma is caused by high pressure within the eye, known as intraocular pressure, or IOP. While IOP plays a large part in glaucoma, it is now considered a major risk factor for the development of the disease. The higher the pressure the more likely one is to get glaucoma. However, 20 to 30 percent of patients with glaucoma have normal intraocular pressures, indicating that other factors must be involved. Nutrition, blood flow, and toxins may all play a part, though details are currently not well understood. Extensive research is being conducted to identify these factors.