Glaucoma is the second leading cause of blindness in the US only behind macular degeneration. It is caused by a build-up of fluid in the eye that puts pressure on the optic nerve, retina, and lens. The pressure can permanently damage the eye if not treated.
The cause is the accumulation of waste related to aging, high blood pressure, prescription drugs, and other eye-related illnesses. Medical treatment is essential to prevent further damage.