One of the leading causes of blindness in the United States, glaucoma occurs when the pressure inside the eye is high enough to damage the optic nerve. It is slowly progressive and without discomfort, therefore many patients are unaware of the disease until it is too late. Any loss of vision cannot be restored. The high eye pressure associated with glaucoma is caused by decreased fluid circulation in the eye. People at the greatest risk include those who are over the age of 40, diabetic, near-sighted, African-American, or who have a family history of glaucoma.