Blindness and Vision Impairment
Blindness is a severe vision impairment, not correctable by standard glasses, contact lenses, medicine, or surgery. It interferes with a person's ability to perform everyday activities. "Legal blindness" is defined as vision with best correction in the better eye worse than or equal to 20/200 or a visual field of less than 20 degrees in diameter. "Legal blindness" is significant in determining eligibility for disability benefits from the federal government, but it does not reflect the precise functional impairment and disability. Vision impairment (VI) is defined as having 20/40 or worse vision in the better eye even with eyeglasses. However, people with the slightest VI can experience challenges in their daily activities. For example, people with vision less than 20/40 cannot obtain an unrestricted driver's license in most states.
The major blinding eye diseases are: cataracts, age-related macular degeneration, diabetic retinopathy, and glaucoma.
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A cataract is a clouding of the eye's lens. The cataract blocks or changes the passage of light needed for vision. The lens of the eye is located behind the pupil and the colored iris, and normally is transparent. Its role is to help focus images onto the retina (the back layer of the eye), the area that transmits the images to the brain. Cataracts can cause vision to become blurred or dimmed because light cannot be transmitted properly through the lens to the retina.
Age-related macular degeneration affects the part of the retina responsible for sharp central vision. There are two forms: dry (non-exudative) and wet (exudative).
Diabetic retinopathy is an eye disease that affects the tiny blood vessels in the retina of people with diabetes. Diabetes causes the small blood vessels in the retina to become weak and break down or become blocked. Diabetic retinopathy is the leading cause of blindness among working-age adults.
Glaucoma is a group of diseases usually associated with increased pressure within the eye. This pressure can cause damage to the cells that form the optic nerve that carries information from the eye to the brain. The damage is progressive with loss of peripheral vision first, followed by reductions in central vision and, potentially, blindness.
Blindness and irreversible visual impairment cost the federal government more than $4 billion annually. The cost includes treatment, education, loss of personal income, and associated costs, such as Social Security disability benefits.
Blindness and visual impairment can severely affect quality of life. Blind people have difficulty with their daily activities (e.g., driving, reading, sewing, and walking), attaining education, and social interactions.
More than one million Americans are legally blind and 12 million are visually impaired. Most blind people are 65 years of age and older and the prevalence of blindness rises sharply by age. African-Americans and Hispanics are at higher risk for blindness and vision impairment than Caucasians because they are at higher risk for developing diabetes, diabetic retinopathy, and glaucoma. Caucasians are at higher risk for macular degeneration than other ethnic groups. Females and low-income families are more affected by blindness and vision impairment than males. As the U.S. population ages and changes demographically, the impact of vision loss and vision impairment will grow substantially in the future. Projections estimate that the number of blind and visually impaired people will double by 2030 unless corrective action is taken.
It is estimated that half of all blindness can be prevented. Because most of the major blinding eye diseases do not have symptoms in their earlier stages, interventions are most useful before the disease begins to develop or in early stages of development. Screening and early treatment for most of the major blinding eye diseases are available and some are also very cost-effective. Most people with blindness can benefit from vision rehabilitation, environmental modifications, and assistive devices that can maximize their residual vision and help them maintain an independent, productive life. However, these services are not used as often as needed. Barriers to screening and using services include lack of awareness and education about services and lack of insurance coverage for these services.
- People at high risk for major blinding eye diseases include: diabetics, African-Americans aged 40 years and older, and seniors.
- The risk of blindness from eye disease can be reduced through early detection and treatment.
- Vision rehabilitation and assistive devices can maximize the residual vision of people with blindness and VI and help them maintain an independent, productive life.
- Regular eye exams are an important part of protecting and preserving your vision.
- Pearl is 67 years old and suffering from macular degeneration. She retired several years ago and moved to Florida. However, most of her family still lives in New York. Her vision has diminished so significantly during the past year that many of her daily activities have become extremely difficult. What distresses her most about her impaired vision is her inability to use the computer. Her daughter gave her a computer last year so she could easily keep in contact with her family up north through chat rooms on the Internet. Pearl calls a center that provides information on vision impairment and vision rehabilitation to find out if there is a magnifying glass she can buy that will allow her to use her computer. The center tells her about low vision services and introduces her to the options a visually impaired person has available to navigate the Internet. They send her a list of various software programs and adaptive computer hardware to help people with impaired vision. They also send her a list of low vision specialists in her area. In addition, they refer Pearl to an organization that provides information about how the use of technology can help people with disabilities. Pearl was able to try out the various technologies and select the best one for her. Now Pearl is delighted to be able to communicate again with her family via the Internet.
- Sean is a 35-year-old lawyer and was diagnosed with diabetes two years ago. While buying vitamins, he sees a pamphlet at his pharmacy. The pamphlet recommends all people with diabetes should have annual eye exams. Sean is concerned because he has not had an eye exam since he entered college 15 years ago. Sean's girlfriend urges him to get his eyes checked as soon as he can, so he schedules an appointment for the following week. Sean's eye doctor tells him his diabetes has caused a condition that affects the blood vessels in his retina, known as diabetic retinopathy. Sean immediately panics and worries that he will become blind like his aunt, who also has diabetes. The doctor tells Sean the most important step he can take to prevent blindness it to keep his blood glucose levels near normal and get annual eye exams. Sean is very relieved and promises to follow the doctor's recommendations. Ten years later, there has been no progression of Sean's diabetic retinopathy.
- Page last reviewed: February 8, 2011
- Page last updated: February 8, 2011
- Content source:
- Centers for Disease Control and Prevention
- Page maintained by: Division of Public Affairs (DPA), Office of the Associate Director for Communication (OADC)