What is exotropia?

What is exotropia? (crossed eyes)?

There are four types of strabismus, and one of them is exotropia. Strabismus, or squint, means that one or both eyes are not aligned straight and forward. With exotropia specifically, the eyes turn outwards.¹ It is unlikely that “Crossed eyes” is referring to exotropia, it instead refers to esotropia, where the eyes turn inwards, with “wall eye” being used for exotropia. This type of misalignment usually occurs in young children and can be corrected if treated at an early age.

Children usually develop exotropia between the age of 1 and 4 years old, but it can also occur at birth. It is more common for exotropia to occur in children when they are tired, ill, daydreaming, or if they frequently focus on distant objects. Exotropia can be constant or intermittent, severe or mild. If left untreated, exotropia can worsen, and it is more difficult to treat in adults.

An optometrist may advise children with exotropia to wear glasses to correct their vision.

Exotropia can be difficult to detect, since it is not visible when a child is looking at a nearby object. It is only noticeable when they are looking at distant objects, such as the clouds, or a classroom board. Another common symptom can be the inability to perceive images with depth and clarity.²

The types of exotropia

There are several types of exotropia:

Sensory exotropia: This is when the eye’s outward direction is caused by a person’s low vision. In this type of exotropia, the eyes fail to work in coordination.⁴
Congenital exotropia: This is also referred to as infantile exotropia, as it usually affects infants immediately after birth, or a few months after birth.⁵
Acquired exotropia: This type of exotropia can occur after the eye suffers a traumatic eye injury or disease. Down’s syndrome or a stroke can also be contributing factors.⁶
Intermittent exotropia: As the name suggests, this is when exotropia occurs intermittently. With intermittent exotropia, one or both eyes look in an outward direction only when the person is ill or tired, or when they are looking into the distance (intermittent distance exotropia). The rest of the time their eyes are aligned straight (as normal).⁷
Alternating exotropia: This is when the left and right eyes take turns to look outwards.

How is exotropia diagnosed?

Exotropia can be easy to spot, but proper diagnosis is carried out by an optometrist or an ophthalmologist. He or she will inquire about a person’s family history, as well as whether or not the person has additional health conditions, in order to determine which type of exotropia it is and advise on the right course of treatment. If you suspect you or your child has exotropia, eye tests will give you a definitive answer.

Your optometrist will carry out an eye examination that includes:⁸

Asking you to read letters from a chart to see how well you see (visual acuity)
Placing a variety of lenses in front of your eyes to determine what prescription might be needed to correct blurred or distorted vision (refraction)
An examination of your outer and inner ocular health

How is exotropia treated?

Exotropia treatment depends on the severity of the misaligned eye.

If the eye is not entirely misaligned, and occasionally moves outward, the optometrist may simply suggest glasses or contact lenses to limit the eye’s movement. If, however, the eye is continuously moving in an outward direction, exotropia surgery may be required to correct and align the eyes.⁹,¹⁰

Medically reviewed by Dan McGhee on September 29, 2022

Sources

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