How common is vision impairment?
Vision
impairment is not very common among children. To learn just how common
it is, CDC is tracking the number of children with vision impairment in
a five-county area in metropolitan Atlanta, Georgia. This activity is
part of the Metropolitan Atlanta Developmental Disabilities Surveillance
Program (MADDSP). In 1996, an estimated 1.4 per 1,000 8-year-olds in
metro Atlanta, or about 1 in 715, had vision impairment. In 2000, the
prevalence was an estimated 1.2 per 1,000, or about 1 in 833,
8-year-olds. About one half (2000) to two thirds (1996) of children with
vision impairment also had one or more other developmental disabilities
tracked by MADDSP. [Read more about MADDSP]
CDC also studied how many children in
metropolitan Atlanta were legally blind in the mid-1980s. This project
was done as part of the Metropolitan Atlanta Developmental Disabilities
Study (MADDS), which studied how common certain disabilities were in
10-year-old children. We found that nearly 7 of every 10,000
children 10 years of age had legal blindness. Two-thirds of the children
also had another disability, such as mental retardation, cerebral palsy,
or epilepsy. [Read
a summary of the article about legal blindness in MADDS] [Read
more about MADDS]
Vision impairment is more common in older
people than in children.. A 2002 report by the National Eye Institute
and Prevent Blindness America estimates that more than 1 million people
ages 40 years or older in the United States are blind (best corrected
visual acuity of 20/200 or worse or a visual field of less than 20
degrees). Another 2.4 million are visually impaired (best
corrected visual acuity of 20/40 or worse). The report states that
the number of adults with vision impairment likely will double over the
next 30 years. [Read the
report on adult vision impairment]
[Return to Topics]
What causes vision impairment? Can it be
prevented?
Vision impairment can be caused by damage
to the eye itself that affects its ability to receive or process visual
information. Impairment can also be due to the eye being shaped
incorrectly, which can make it harder to focus on things. Vision
impairment can also occur if the brain does not process visual
information correctly. Vision impairment can occur anytime during
a person's life, even before birth.
CDC studied the causes of low vision and
blindness in 3- to 10-year old children in metropolitan Atlanta,
Georgia. We found that most of the causes happened before the
child was born or before they were 1 month old. The most common
cause was retinopathy of prematurity (ROP), which refers to abnormal
blood vessel growth or scarring of the retina of the eye. Children
who are born very early or who have very low birth weight are most at
risk of having this condition. ROP usually gets better on its own
before severe damage can occur, and if not, it can often be treated.
However, a small percentage of children with ROP have a severe form and
will have low vision or blindness. Other common causes of vision
impairment found in the CDC study were albinism (a genetic condition
that results in decreased skin pigmentation and affects parts of the
eye), hydrocephalus (a condition in which there is too much fluid in the
brain), congenital cytomegalovirus (a viral infection that occurs before
a baby is born), and birth asphyxia (where a baby does not get enough
oxygen before or during birth). [Read
a summary of the article about causes of vision impairment in children]
The most common causes of vision
impairment among adults in the United States are diabetic retinopathy,
age-related macular degeneration, cataracts, and glaucoma.
Diabetic retinopathy is a common complication of diabetes in which the
blood vessels in the retina break down, leak, or become blocked, leading
to vision impairment. Age-related macular degeneration affects the
part of the retina that is responsible for sharp central vision.
Cataracts are a clouding of the eye's lens, which is normally clear.
Glaucoma is increased fluid and pressure within the eye that leads to
enlargement of the eyeball. The risk of vision loss from many of
these conditions can often be reduced if the condition is found early
and treated. [Read
more about the causes of vision impairment in adults]
If you would like to learn more about a
specific genetic condition that you think could cause vision impairment,
you can go to the National Library of Medicine's Genetics Home Reference
Web site. Information on each genetic condition includes symptoms, how
common it is, related genes, treatments, and links to resources where
you can learn more about the condition. The Genetics Home Reference also
can help you learn more about genetics, including genetic testing,
genetic counseling, and gene therapy. [Go
to the Genetics Home Reference Web site]
You can search for CDC guidelines on
preventing vision impairment by visiting the "CDC Recommends: The
Prevention Guidelines System" Web site. The guidelines include
information about vision problems caused by diabetes, infections, eye
injuries caused by fireworks, and other topics. [Go
to CDC Recommends: The Prevention Guidelines System.
Enter "blindness" or "low vision" in the Search For box, then click the
"Search" button.]
Healthy People 2010 is a national effort
to promote health and prevent disease. It includes goals related
to vision impairment, such as preventing eye injuries, increasing the
number of people who have their eyes examined, decreasing the number of
children under 17 years old who are blind or visually impaired,
decreasing the number of people who lose their vision due to diabetes,
and others. The National Eye Institute (NEI) has created a Web
site named "Healthy Vision 2010" that provides more information about
the vision-related goals in Healthy People 2010. [Learn
more about Healthy Vision 2010]
[Return to Topics]
References
Batshaw ML. Children with disabilities
(4th edition). Baltimore MD: Paul H. Brookes Publishing Co.;1997.
Holbrook MC (Editor). Children with visual
impairments: a parents' guide. Bethesda, MD: Woodbine House; 1996.
Mervis CA, Yeargin-Allsopp M, Winter S,
Boyle C. Aetiology of childhood vision impairment, metropolitan
Atlanta, 1991-93. Paediatric and Perinatal Epidemiology
2000;14:70-77. [Read
abstract of this paper]
Prevent Blindness America and the National
Eye Institute. Vision problems in the U.S.: prevalence of adult
vision impairment and age-related eye disease in America, 2002. [Read
report]
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What is the cost or economic impact associated with vision impairment?
Many people with vision impairment need
long-term services. The average lifetime cost for one person with vision
impairment is estimated to be $566,000 (in 2003 dollars). This
represents costs over and above those experienced by a person who does
not have a disability.
It is estimated that the lifetime costs
for all people with vision impairment who were born in 2000 will total
$2.5 billion (in 2003 dollars). These costs include both direct and
indirect costs. Direct medical costs, such as doctor visits,
prescription drugs, and inpatient hospital stays, make up 6% of these
costs. Direct nonmedical expenses, such as home modifications and
special education, make up 16% of the costs. Indirect costs, which
include the value of lost wages when a person dies early, cannot work,
or is limited in the amount or type of work he or she can do, make up
77% of the costs.
These estimates do not include other
expenses, such as hospital outpatient visits, emergency department
visits, and family out-of-pocket expenses. The actual economic costs of
vision impairment are, therefore, even higher than what is reported
here.
[Return to Topics]
References
Centers for Disease Control and
Prevention. Economic costs associated with mental retardation, cerebral
palsy, hearing loss, and vision impairment --- United States, 2003. MMWR
2004;53:57-9. [Read
this article on economic costs]
Honeycutt AA, Grosse SD, Dunlap LJ,
Schendel DE, Chen H, Brann E, al Homsi G. Economic costs of mental
retardation, cerebral palsy, hearing loss, and vision impairment. In:
Altman BM, Barnartt SN, Hendershot GE, Larson SA, editors. Using survey
data to study disability: results from the National Health Interview
Survey on Disability. Research in social science and disability, volume
3. Amsterdam: Elsevier; 2003. p. 207-28.
Date: October 29, 2004
Content source: National Center on Birth Defects and Developmental
Disabilities