Glaucoma is a group of diseases that damage the eye’s optic nerve and can result in vision loss and blindness. This nerve carries information from the light-sensitive layer in your eye, the retina, to the brain where it is perceived as a picture. However, with early detection and treatment, you can often protect your eyes against serious vision loss.
Causes: A layer of cells behind the iris (the colored part of the eye) produce a watery fluid, called aqueous. This fluid passes through a hole in the center of the iris (called the pupil) to leave the eye through tiny drainage channels. These are in the angle between the front of the eye (the cornea) and the iris and return the fluid to the bloodstream. Normally the fluid produced is balanced by the fluid draining out, but if it cannot escape, or if too much is produced, then your eye pressure will rise.
If the optic nerve comes under too much pressure then it can be injured. How much damage there is will depend on how much pressure there is and how long it has lasted, and whether there is a poor blood supply or other weakness of the optic nerve.
Symptoms: At first most people do not have any symptoms. It causes no pain, vision stays normal. Without treatment, people with glaucoma will slowly lose their peripheral (side) vision. As glaucoma remains untreated, people may miss objects to the side and out of the corner of their eye. They seem to be looking through a tunnel. Over time, straight-ahead (central) vision may decrease until no vision remains.