Eye problems affect more than 12 million children in the United States. This includes 5 percent of preschoolers and 25 percent of school-aged children, according to the American Academy of Ophthalmology. Left untreated, these problems can lead to permanent vision loss, or to less serious but still substantial problems such as learning difficulties that may be attributed to a disability.

The eye is a complex organ. Its structure – a fluid-filled body exposed to the outside – makes it susceptible to injury. The mechanisms inside the eye responsible for producing visual signals are equally complex. Light enters the eye through the cornea, which sits in front of the opening of the pupil. The iris controls the amount of light that passes through the pupil by causing the pupil to close more in bright light and open more in dim light.

As light is allowed in, a thin layer of tissue at the back of the eye called the retina sends nerve signals along the optic, which are then transmitted to the brain to create an image. In addition, the structures and glands around the eye protect it and keep it functioning. These include the tear glands, eyelids and eyelashes.

Several different factors may cause eye problems. The shape of a person’s eye is often responsible for vision impairments. In addition, diseases or disorders, allergies or injuries can cause eye problems. Left untreated, eye problems can lead to long-term visual impairment, academic problems and social development problems.

In some cases, an eye problem is severe enough that vision cannot be corrected to normal level. This is known as a visual impairment, and it may involve the loss of visual acuity (where the eye does not see things as clearly as normal) or loss of visual field (where the eye cannot see as wide an area as usual without moving the eyes or turning the head). Visual impairment is uncommon in children, according to the Centers for Disease Control and Prevention (CDC). Most cases of visual impairment in children are associated with children with developmental disabilities such as mental retardation or cerebral palsy. More than 55,000 children in the United States are diagnosed as legally blind, according to the American Foundation for the Blind.

Contrary to popular belief, watching too much television or looking at a computer screen for many hours cannot damage your vision, and neither can reading in low light. Parents are urged to contact a physician if their child has red eye, persistent pain in the eye, foreign objects in the eye or any changes in vision. Parents should take their child to a hospital emergency department if their child’s eye is injured and there is bleeding, loss of vision or change in the eye’s appearance.