Glaucoma is a complex disease. It is often referred to as “the sneak thief of sight” because the symptoms are not noted until late within the disease process. More than 2.2 million Americans over the age of 40 have open-angle glaucoma, the most common form of glaucoma. At least half don’t even know they have it. Once vision is lost, it can not be restored. Glaucoma is one of the leading causes of blindness in the United States. Glaucoma causes damage to the optic nerve leads to progressive, irreversible vision loss.