Health Encyclopedia

Strabismus

Definition

Strabismus is a disorder in which the eyes do not line up in the same direction when focusing. The condition is more commonly known as "crossed eyes."

Alternative Names

Crossed eyes; Esotropia; Exotropia; Squint; Walleye

Causes, incidence, and risk factors

Strabismus is caused by a lack of coordination between the eyes. As a result, the eyes look in different directions and do not focus at the same time on a single point.

In most cases of strabismus in children, the cause is unknown. In more than half of these cases, the problem is present at or shortly after birth (congenital strabismus).

In children, when the two eyes fail to focus on the same image, the brain may learn to ignore the input from one eye. If this is allowed to continue, the eye that the brain ignores will never see well. This loss of vision is called amblyopia, and it is frequently associated with strabismus.

Some other disorders associated with strabismus in children include:

Apert syndrome
Cerebral palsy
Congenital rubella
Hemangioma near the eye during infancy
Incontinentia pigmenti syndrome
Noonan syndrome
Prader-Willi syndrome
Retinopathy of prematurity
Retinoblastoma
Traumatic brain injury
Trisomy 18 (a child has 3 copies of chromosome 18, instead of the normal 2 copies)

Strabismus that develops in adults can be caused by:

Botulism
Diabetes (causes a condition known as acquired paralytic strabismus)
Guillain-Barre syndrome
Injuries to the eye
Shellfish poisoning
Stroke
Traumatic brain injury
Vision loss from any eye disease or injury

A family history of strabismus is a risk factor. Farsightedness may be a contributing factor. In addition, any other disease causing vision loss may cause strabismus.

Symptoms

Crossed eyes
Double vision
Eyes that do not align in the same direction
Uncoordinated eye movements (eyes do not move together)
Vision loss in one eye, includes a loss of the ability to see in 3-D (loss of depth perception)

Signs and tests

A physical examination will include a detailed examination of the eyes. Tests will be done to determine the strength of the eye muscles.

Eye tests include:

A neurological examination will also be performed.

Treatment

Treatment involves strategies to strengthen the weakened muscles and realign the eyes. Glasses and eye muscle exercises may be prescribed.

If the condition is caused by a lazy eye, the doctor may prescribe an eye patch. Some children may need surgery. For more information on treating lazy eye, see: Amblyopia

Expectations (prognosis)

With early diagnosis and treatment, the problem can usually be corrected. Delayed treatment may lead to permanent vision loss in one eye.

Calling your health care provider

Strabismus requires prompt medical evaluation. Call for an appointment with your health care provider or eye doctor if your child:

Appears to be cross-eyed
Complains of double vision
Has difficulty seeing

Note: Learning difficulties or problems at school can sometimes be due to a child's inability to see the blackboard or reading material.

References

Hatt SR, Leske DA, Kirgis PA, Bradley EA, Holmes JM. The effects of strabismus on quality of life in adults. Am J Ophthalmol. 2007 Nov;144(5):643-7.

Review Date:7/28/2008
Reviewed By:Manju Subramanian, MD, Assistant Professor in Ophthalmology, Vitreoretinal Disease and Surgery, Boston University Eye Associates, Boston, MA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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