What causes vision impairment? Can it be prevented?

by CDC

(Page 2 of 2)

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).

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.

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.

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.

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.

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.

About the Author

www.cdc.gov
The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.