Strabismus can make it impossible for both eyes to focus on the same thing at the same time. In the long run, up to half of the children with an eye that deviates will lose vision in that eye, unless the problem is identified and treated early.
When the eyes don’t line up or move together properly, we call it strabismus or heterotropia. If an eye deviates inward, it is esotropia (cross eyed); if it deviates outward, it is exotropia (walleyed). Eyes may also deviate up or down.
The misalignment of strabismus is often caused by a mismatch in the strength of the muscles moving the eye. One or both eyes may be affected.
Strabismus is one of the most common eye problems of childhood. Some children are born with strabismus. Others develop it along the way. Esotropia is more common than exotropia.
Normal newborns will sometimes have eyes that wander from time to time, especially when tired. This is not strabismus, and is discussed in the article on pseudostrabismus.
Sometimes the misalignment of the eyes is obvious. Often, however, a misalignment serious enough to cause severe vision loss (amblyopia) will be quite subtle – only a few degrees of deviation. This might be not noticed with even a careful look, and is usually only detected on vision screening tests.
Strabismus will usually last until treated.
Often strabismus is detected on informal vision screening, when the position of a spot of light reflected off the eyes is asymmetric.
It is important to distinguish strabismus from pseudostrabismus – a much more common condition that does not result in vision loss.
Strabismus is common in children, but most young children go untested and unidentified. A March 2002 policy statement by the American Academy of Pediatrics (AAP) recommends that all babies should have vision screening (including screening for strabismus and amblyopia) at the earliest possible age, and at regular intervals throughout childhood.
Rather than relying on informal or subjective assessments of vision, the policy discusses photoscreening, a new test that can make checking vision easier and more accurate for even very young babies. A specially equipped camera takes their picture and a computer or a person analyzes the eye data obtained. Ask your pediatrician about having your baby screened.
A complete eye exam is important if there is any question on the screening test or on a pediatrician’s examination.
Exercise of the eye muscles alone usually will not correct strabismus. Glasses, eye drops, and/or surgery are often necessary to create and maintain good alignment.
Surgery is best done on infants and toddlers. Several operations may be required, and glasses or other treatments may still be necessary after surgery, during the years of visual development.
Any associated amblyopia must also be treated.
Strabismus is difficult to prevent, but it is possible to prevent years of undiagnosed strabismus and the vision loss that results. All children should have vision screening early, and at regular intervals around well-child exams. Premature babies, and especially those with retinopathy, should have formal eye exams.