Most commonly found during early childhood, exotropia is a form of strabismus where one or both eyes face outward. Exotropia can lead to poor vision and hindered depth perception if left untreated.
What Is Exotropia?
Strabismus, or hypertropia, is a condition when one or both of the eyes are not properly aligned. This ocular misalignment has two main types: esotropia and exotropia. Esotropia is when an eye faces inward, and exotropia is when an eye faces outward.
Certain factors are associated with exotropia, including genetics and health conditions. Exotropia can usually be treated, and has a better chance of being treated, if the condition is detected early. If left untreated, exotropia can lead to vision and depth perception problems.
Key Facts About Exotropia
- Up to 60 percent of newborn babies develop minor exotropia, but the condition is usually resolved on its own within the first six months of the child’s life.
- Most children with exotropia are nearsighted by adulthood.
- Even though esotropia is more common in the U.S., exotropia is the most common type of strabismus reported worldwide.
- Certain cases of exotropia can enhance peripheral vision.
What Are the Different Types of Exotropia?
These are the various types of exotropia:
Intermittent exotropia is the most common type of exotropia. With intermittent exotropia, the eyes are both straight and occasionally one eye turns outward.
This ocular misalignment typically occurs when a person is fatigued, sick, or when the eyes are resting and staring off at nothing. Intermittent exotropia is usually not serious, but the misalignment can worsen and become permanent.
Sensory exotropia occurs in an eye with poor vision that is attempting to stay in sync with a healthy eye that has good vision. The eye with reduced vision is not able to keep up with the healthy eye, so it begins to face outward.
Unlike other types of exotropia, sensory exotropia is not exclusive to childhood and can occur at any age.
Alternating exotropia is when both eyes are misaligned and face outward, but separately and at different times. Exotropia can alternate between the two eyes, or it can occur intermittently. The focus of the eyes can be switched during alternating exotropia, which can enhance peripheral vision when the misaligned eye is focused.
Also referred to as infantile exotropia, this type of exotropia is rare and found at birth or during early childhood. Congenital exotropia is typically associated with neurological conditions, such as cerebral palsy. Infantile ocular misalignment can also be attributed to the imbalance of eye muscles.
In addition to the four main types of exotropia, a high percentage of people also have a slightly misaligned eye that is only detectable during an eye exam. This exophoria is not noticeable outside of an optometrist’s office and does not interfere with the eye’s functionality.
Pseudoexotropia is a condition common during infancy when one or both eyes appear to be facing outward due to certain morphological features, but they are actually properly aligned.
What Causes Exotropia?
There are certain cases of intermittent exotropia that have no known cause. However, there are several factors that can lead to and are associated with the condition:
- Genetics: People with exotropia can pass the condition on to their children.
- Poor muscle or nerve function: Muscles and nerves that control eye movement can sometimes become weakened and lose functionality, resulting in exotropia. Convergence insufficiency, which is the lack of proper communication between the muscles and nerves, can also lead to exotropia.
- Signal error between the brain and the eye: The visual center of the brain coordinates with the eyes to produce vision. Many eye issues can occur, including exotropia, when the retinal neurons that carry this signal become damaged.
- Neurological disorders: There are many neurological disabilities that are associated with exotropia, including having a stroke, cerebral palsy, and trauma.
- Poor vision: If one of the eyes has poorer vision than the other, the weaker eye can begin to exhibit exotropia symptoms.
What Are the Symptoms of Exotropia?
In addition to the outward divergence of one or both eyes, other symptoms of exotropia can include the following:
- Frequent squinting
- Double vision
- Blurry vision
- Pain and discomfort
- Motion sickness
- Impaired depth perception
Even though vision in the outward facing eye can be negatively affected, exotropia does not typically lead to complete vision loss.
How Is Exotropia Diagnosed?
If one or both of the eyes appear to be facing outward, medical intervention is necessary for a proper diagnosis. The first thing an eye doctor typically does is try to figure out if there is a family history of exotropia. If the condition does run in the family, there is a good chance that it was passed down genetically.
Testing visual acuity with the commonly used Snellen chart and examining how eyes react and focus to light can also help to diagnose exotropia. In certain cases, the inner structure of the eyes are also examined to detect internal anomalies that might contribute to exotropia.
Is the Condition Dangerous?
The severity of the exotropia factors into how dangerous the condition can potentially be. Small exophoria is usually harmless and does not lead to other eye conditions. If left untreated, more prominent cases of exotropia can eventually lead to some loss of vision.
Typically, exotropia can be properly managed if it is diagnosed and treated early enough.
Who Is at Risk?
These children are more at risk for exotropia:
- Children with a family history of exotropia
- Children born prematurely or with a low birth weight
- Children with mothers who smoked during pregnancy
- Children born with Down syndrome
- Children born with cerebral palsy
- Children born with genetic disorders that change the shape of the head and the face, such as Crouzon syndrome.
Treatment Options for Exotropia
A doctor may recommend any of these treatment options for exotropia:
Corrective lenses may help with exotropia. Overminus glasses are made with special lenses that challenge a patient’s eyes to work harder in order to see clearly.
Wearing an eye patch over the eye with superior vision forces the other eye to work harder and potentially develop better vision.
Low dose atropine (LDA) eye drops are used to treat intermittent exotropia. Similar to wearing an eye patch, the atropine temporarily blurs vision in the healthier eye. This allows for the weaker eye to work harder and potentially develop better vision.
Certain eye exercises may help treat exotropia by making the eyes stronger and more focused. Here are some examples:
- Pencil push-ups: Keep the eyes focused on a pencil that is held directly in front of the eyes at arm’s length. Slowly move the pencil toward the nose while maintaining focus.
- Barrel convergence card: When a card has three differently sized barrels in red next to three differently sized barrels in green, the eyes can focus on the card from a distance until it becomes one image with both colors.
- Brock string: One end of a string features three small differently colored beads. This is held to the nose at one end and tied to a fixed point at the other, allowing the patient to focus on the beads.
Surgery is a common treatment for exotropia that either tightens or loosens the eye muscle to help realign the outward facing eye(s). The procedure does not take long, and patients typically only report minor pain.
The recurrence rate of exotropia after surgery is high. Follow-up surgeries may be required.
Can exotropia be corrected?
Yes, most cases of exotropia can be corrected through various treatments, exercises, or surgeries. The earlier the diagnosis, the better the long-term prognosis.
What is exotropia caused by?
Exotropia can be passed down genetically or develop due to other medical conditions. It can also be the result of trauma to the eye.
What happens if exotropia is left untreated?
Milder cases of exotropia can stop progressing and are manageable. More severe cases keep progressing and can ultimately lead to vision and depth perception loss if left untreated. Earlier treatment is more effective, so early diagnosis is crucial.
Is exotropia the same as a lazy eye?
Exotropia is not the same as a lazy eye, but it can develop into a lazy eye if the misaligned eye weakens and begins to lose vision.
Can exotropia lead to blindness?
If left untreated, exotropia can lead to blindness in the outward-facing eye.
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Last Updated February 28, 2023
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