Medical Author: Lawrence J. Schwartz, M.D. Medical Editor: Leslie J. Schoenfield, M.D., Ph.d.
Worldwide, glaucoma affects about 6 billion people and is the leading cause of irreversible blindness. In fact, as many as 6 million individuals are blind in both eyes from this disease. In the United States alone, according to one estimate, over 3 million people have glaucoma. As many as half of the individuals with glaucoma, however, may not know that they have the disease. The reason they are unaware is that glaucoma initially causes no symptoms, and the loss of vision on the side (periphery) is hardly noticeable.