Crossed eyes

Definition

Strabismus is a disorder that causes one eye to be misaligned with the other when focusing.

Alternative Names

Causes

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:

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

Acquired strabismus in adults can be caused by injuries to the orbit of the eye or injuries to the brain, including closed head injuries and strokes. People with diabetes may have loss of circulation, causing a condition known as acquired paralytic strabismus. Loss of vision in one eye from any cause will usually cause the eye to gradually turn outward (exotropia). Because the brains of adults are already developed for vision, the problems associated with amblyopia do not occur with adult strabismus.

Some disorders associated with strabismus in adults include:

• Diabetes
• Vision loss from any eye disease or injury
• Stroke
• Traumatic brain injury
• Paralytic shellfish poisoning (PSP)
• Guillain-Barre syndrome
• Botulism

A family history of strabismus is a risk factor. Farsightedness

Symptoms

• Eyes that appear crossed
• Eyes that do not align in the same direction
• Uncoordinated eye movements (eyes that do not move together)
• Double vision
• Vision in only one eye, with loss of depth perception (depth perception is our ability to see three dimensions, and recognize the order of objects in the space around us)

Exams and Tests

Your child's health care provider will first determine if the child truly has strabismus. If the child has strabismus, a workup will be done to determine the cause.

The physical examination will include a detailed examination of the eyes. The patient may be asked to look through a series of prisms to determine the differences between the eyes. The eye muscles will be tested to determine the strength of the extraocular muscles.

Tests include:

• Standard ophthalmic exam
• Visual acuity
• Retinal exam
• Neurological examination

Treatment

Initially, strategies to strengthen the weakened muscles and thereby realign the eyes are attempted. Glasses may be prescribed. Eye muscle exercises may be prescribed.

If amblyopia is present, patching of the preferred eye may be done to force the child to use the amblyopic eye. Surgery may be required to realign the eye muscles if strengthening techniques are unsuccessful.

Outlook (Prognosis)

With an early diagnosis, the defect can usually be corrected. With delayed treatment, vision loss in one eye may be permanent.

Possible Complications

• Loss of vision in one eye due to amblyopia
• Embarrassment over facial appearance with eye patch

When to Contact a Medical Professional

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

• Complains of double vision
• Has difficulty seeing
• Appears to be cross-eyed
• The eyes do not appear to fix on the same point

Also call if there are problems at school, which could possibly be related to the child being unable to see the blackboard or the reading material.