Blindness is a lack of vision. It may also refer to a loss of vision that cannot be corrected with glasses or contact lenses.
People with vision that is worse than 20/200 with glasses or contact lenses are considered legally blind in most states in the United States.
Vision loss refers to the partial or complete loss of vision. This vision loss may happen suddenly or over a period of time.
Some types of vision loss never lead to complete blindness.
Vision loss has many causes. In the United States, the leading causes are:
The type of partial vision loss may differ, depending on the cause:
Other causes of vision loss include:
Total blindness (no light perception) is often due to:
When you have low vision, you may have trouble driving, reading, or doing small tasks such as sewing or making crafts. You can make changes in your home and routines that help you stay safe and independent. Many services will provide you with the training and support you need to live independently, including the use of low vision aids.
Sudden vision loss is always an emergency, even if you have not completely lost vision. You should never ignore vision loss, 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.
Your health care provider will do a complete eye exam. The treatment will depend on the cause of the vision loss.
For long-term vision loss, see a low-vision specialist, who can help you learn to care for yourself and live a full life.
Reviewed By: Franklin W. Lusby, MD, ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.