Glaucoma is an eye disease that causes vision loss without any early symptoms, and early detection is critical. It is not diagnosed by eye pressure alone, but is technically defined as a permanent and irreversible damage to the optic nerve. The optic nerve transmits information from the eye to the brain; if the nerve is damaged, the picture from the eye is degraded. This damage is most often related to the eye pressure being higher than the nerve can tolerate.
In early glaucoma, there is often structural nerve damage without any detectable change in vision. In fact, over half of the people in the US who have glaucoma have no idea it is present. While vision loss can usually be limited by lowering the eye pressure, some glaucoma patients will progress to total vision loss and blindness despite the very best treatment. However, glaucoma can usually be stabilized by lowering the eye pressure by medical, laser, and/or surgical treatments. The true goal of glaucoma treatment is not achieving a particular number of eye pressure, but lies in achieving a certain range of eye pressures over time to preserve vision so that patients can continue to do their daily activities.