Glaucoma is a group of diseases that affect the optic nerve, which connects the eye to the brain. It is a leading cause of vision loss and blindness in the United States and worldwide. It is the leading cause of blindness in working-age African-Americans.

Glaucoma can affect one or both eyes. It typically involves gradually increased pressure inside the eye, although some people with normal eye pressure can develop glaucoma.  It usually is gradual, painless and has no other signs or symptoms. There are also acute forms of glaucoma that are sudden, painful and a medical emergency.

The disease destroys peripheral (side) vision. Loss of eyesight is often so gradual it goes unnoticed until vision is significantly impaired. Any damage is irreversible, but diagnosis and treatment can avert further loss of vision.

There is an increased risk of glaucoma in people over age 60, diabetes patients, people with a family history of glaucoma and certain racial groups. Other risk factors include high blood pressure, eye injury and use of certain medications, such as corticosteroids.

Early detection and treatment can minimize or prevent eye damage. Tests to detect glaucoma include the dilated pupil examination, pachymetry (testing of corneal thickness), optic nerve tomography (scanning the optic nerve to judge its health) and tonometry (a measure of pressure inside the eye). Prescription eye drops can reduce the risk of developing glaucoma by about half. Other medications, laser therapy and surgery may also be options for treatment.