Glaucoma is a leading cause of blindness in the United States. But the loss of sight from glaucoma is preventable if you get treatment early enough. Glaucoma is a disease of the optic nerve. The optic nerve carries the images we see to the brain. Many people know that glaucoma has something to do with pressure inside the eye. The higher the pressure inside the eye, the greater the chance of damage to the optic nerve. The optic nerve is like an electric cable containing a huge number of wires. Glaucoma can damage nerve fiber, causing blind spots to develop. Often, people don't notice these blind areas until much optic nerve damage has already occurred. Early detection and treatment by your ophthalmologist are the keys to preventing optic nerve damage and blindness from glaucoma.