Strabismus

About Strabismus

Strabismus is the misalignment or wandering of one or both eyes either inward (called esotropia), outward (exotropia), up (hypertropia), or down (hypotropia). The condition can be constant or parents may only notice it occasionally; for instance, when their child is tired or looking at something very close up.

Strabismus can be present at birth or develop in childhood. In most cases, the cause is unknown, although kids with a family history of strabismus are at an increased risk for it.

Most kids are diagnosed between 1 and 4 years of age. Rarely, a child might develop strabismus for the first time after 6 years of age. If this happens, it's important to contact your doctor immediately, who will then refer your child to a pediatric ophthalmologist and possibly a neurologist to rule out any underlying conditions that may be causing the problem.

How Vision Is Affected

When eyes are misaligned, the straight or straighter eye becomes dominant. The vision strength (acuity) of the straight eye remains normal because the eye and its connection to the brain are functioning as they should. The misaligned or weaker eye, however, does not focus properly and its connection to the brain is not formed correctly.

If strabismus is left untreated, the brain will eventually suppress or ignore the image of the weaker eye, resulting in amblyopia (or "lazy eye," when an eye is unable to focus on details) or permanent vision loss. Longstanding eye misalignment also might impair the development of depth perception (stereopsis) or the ability to see in 3D.

Signs & Symptoms

Most kids with strabismus don't complain of eye problems. Usually, it's a family member or teacher who notices a misalignment of the eyes.

Some kids may complain of double vision (seeing two objects when there's only one in view) or have trouble seeing things in general. Younger children who are not yet able to verbalize their vision problems may squint frequently and turn or tilt their heads in an attempt to see more clearly.

If your child has any of these signs or symptoms, tell your doctor. If necessary, he or she can refer you to a pediatric ophthalmologist for proper evaluation and treatment.

Treatment

Treatment for strabismus depends on the underlying cause and the severity of the eye misalignment. The condition usually is corrected with either glasses or eye muscle surgery. In some cases, the use of eye patching or eye drops may be helpful too.

Farsightedness (hyperopia), nearsightedness (myopia), and astigmatism (a form of blurry vision) can sometimes cause crossed eyes in very young children. These kids might benefit from wearing glasses.

A child who has amblyopia as well as strabismus might be prescribed eye patches to be worn over the unaffected or straight eye. These block out all light and force the misaligned or weaker eye to do the "seeing" work. Over time, consistent patching may strengthen the vision in the weaker eye. Sometimes it can help strengthen the muscle of the weaker eye and restore proper alignment.

Typically, kids must wear the patch 2 to 3 hours per day during waking hours for several months or years depending on the severity of the condition. In more extreme cases, patches may be worn up to 6 hours or longer every day.

For parents of babies and toddlers with strabismus, enforcing the use of an eye patch can seem challenging. But after the initial adjustment period, most kids adapt well and the patch just becomes part of their daily routine, like brushing their teeth.

Sometimes, though, despite a parent's best efforts, a child will refuse to wear an eye patch. In these cases, atropine drops might be used instead. Just as an eye patch blocks the vision in the unaffected or straight eye, the atropine drops will temporarily blur out vision in the straight eye, forcing the misaligned eye to work harder.

If glasses and/or patching or atropine drops do not achieve the proper alignment, eye muscle surgery may be recommended. Surgery involves loosening or tightening the muscles that cause the eye to wander. Although it is an invasive measure, surgery is considered safe and effective and usually does not require an overnight hospital stay.

Outlook

How well children fare with correction of strabismus depends not only on the severity of their condition, but also on how quickly it was recognized and treated.

Kids reach full visual maturation at around 8 years old. It is during these early years of development that vital connections between the eyes and the brain are formed. So early intervention is critical. The earlier strabismus is diagnosed and treated, the better a child's chances are of having straight eyes and developing good vision and proper depth perception. Studies show, however, that older kids and teens and even many adults with strabismus might still benefit from treatment.

The social aspect to strabismus also should not be overlooked. Properly aligned eyes are important for a healthy self-image and good interpersonal relationships in kids and adults.

Fortunately, when strabismus is recognized and treated effectively, it can be cured and permanent vision loss prevented.

Reviewed by: Jonathan H. Salvin, MD
Date reviewed: September 2011