Health Encyclopedia

Blindness

Definition

Blindness is a lack of vision. It may also refer to a loss of vision that cannot be corrected with glasses or contact lenses.

Partial blindness means you have very limited vision.
Complete blindness means you cannot see anything and do not see light.

People with vision worse than 20/200 are considered legally blind in most states in the United States.

Alternative Names

Loss of vision

Common Causes

Blindness has many causes. In the United States, the leading causes are diabetes, glaucoma, macular degeneration, and accidents (such as chemical burns or sports injuries).

Worldwide, the leading causes of blindness are cataracts, onchocerciasis (river blindness), trachoma, leprosy, and vitamin A deficiency.

Other causes include:

Blocked blood vessels
Complications of premature birth (retrolental fibroplasia)
Complications of eye surgery
Lazy eye
Optic neuritis
Stroke
Tay-Sachs disease
Retinitis pigmentosa
Retinoblastoma
Lead poisoning
Optic glioma

Home Care

It is important for a blind person to be able to dress, eat, function independently, and stay safe. Many services are available that provide the training and support that allow blind people to function independently.

Call your health care provider if

Sudden vision loss is always an emergency, even you have not completely lost all vision. You should never ignore loss of vision, thinking it will get better.

Contact an ophthalmologist or go to the emergency room immediately. Most serious forms of vision loss are painless, and the absence of pain in no way diminishes the urgent need to get medical care. Many forms of vision loss only give you a short amount of time to be successfully treated.

What to expect at your health care provider's office

A complete and thorough eye examination will be performed. The treatment plan will depend on the cause.

Review Date:8/22/2008
Reviewed By:Paul B. Griggs, MD, Department of Ophthalmology, Virginia Mason Medical Center, Seattle, WA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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