Exotropia is a type of strabismus, which is a misalignment of the eyes. Exotropia is a condition in which one or both eyes turn outward away from the nose. It’s the opposite of crossed eyes.
Roughly 4 percent of people in the United States have strabismus. Exotropia is a common form of strabismus. While it can affect anyone at any age, it’s commonly diagnosed early in life. Exotropia accounts for up to 25 percent of all eye misalignments in young children.
Read on to learn more about this condition.
Types of exotropia
Exotropia is generally classified by its type.
Congenital exotropia is also called infantile exotropia. People with this condition have an outward turning of the eye or eyes from birth or early in infancy.
Poor vision in the eye causes it to turn outward and not work in tandem with the straight eye. This type of exotropia can occur at any age.
This type of exotropia is the result of a disease, trauma, or other health condition, particularly those that affect the brain. For example, stroke or Down syndrome may increase your risk for this condition.
This is the most common form of exotropia. It affects twice as many females as males.
Intermittent exotropia causes the eye to sometimes move outward, often when you’re tired, sick, daydreaming, or looking in the distance. Other times, the eye stays straight. This symptom may occur infrequently, or it can happen so often it eventually becomes constant.
What are the symptoms of exotropia?
Eyes that don’t focus and work in conjunction with each other can cause a variety of problems with vision and physical health.
When the eyes don’t focus together, two different visual images are sent to the brain. One image is what the straight eye sees and the other is what the turned eye sees.
Other symptoms may include:
- one or both eyes turning outward
- frequent rubbing of the eyes
- squinting or covering one eye when looking into bright light or trying to see objects that are far away
This condition can also lead to complications. The following may be a sign of exotropia:
- problems reading
- blurry vision
- poor 3-D vision
Nearsightedness is also common in people with this condition. According to a study published in the American Journal of Ophthalmology, over 90 percent of children with intermittent exotropia become nearsighted by the time they’re 20. The study notes that nearsightedness developed regardless of whether or not children were treated for the condition.
Causes of exotropia
Exotropia occurs when there’s an imbalance in eye muscles or when there’s a signaling issue between the brain and eye. Sometimes a health condition, like cataracts or stroke, can cause this to occur. The condition may also be inherited.
Approximately 30 percent of children with strabismus have a family member with the condition. When no family history, illness, or condition can be identified, doctors aren’t sure what causes a strabismus like exotropia to develop.
It’s not thought to be caused by watching TV, playing video games, or doing computer work. But these activities can make the eyes tired, which can cause exotropia to worsen.
How is exotropia diagnosed?
A diagnosis is usually made based on family history and vision testing. An ophthalmologist or optometrist — doctors who specializes in eye issues — are best equipped to diagnose this disorder. They’ll ask you about symptoms, family history, and other health conditions to help them make a diagnosis.
Your doctor will also conduct a number of vision tests. These can include:
- reading letters from an eye chart if your child is old enough to read
- placing a series of lenses in front of the eyes to see how they refract light
- tests that look at how the eyes focus
- using dilating eye drops to help widen the pupils of the eyes and allow a doctor to examine their internal structure
How is exotropia treated?
When eye misalignment occurs early in life and the drifting is infrequent, your doctor may recommend to just watch and wait. Treatment may be advised if the drifting starts to worsen or doesn’t improve, especially in a young child whose vision and eye muscles are still developing.
The goal of treatment is to get the eyes to align as much as possible and improve vision. Treatments include:
- Glasses: Glasses that help correct near- or farsightedness will help keep the eyes aligned.
- Patching: People with exotropia tend to favor the aligned eye, so vision in the eye turned outward can weaken, resulting in amblyopia (lazy eye). To improve strength and vision in the misaligned eye, some doctors will recommend patching the “good” eye for up to several hours a day to encourage you to use the weaker eye.
- Exercises: Your doctor may suggest a variety of eye exercises to improve focus.
In some cases, your doctor may also recommend surgery to readjust eye muscles. The surgery is done under general anesthesia for a child and with a local numbing agent for an adult. Sometimes the surgery has to be repeated.
In adults, the surgery doesn’t usually improve eyesight. Instead, an adult may choose to have the surgery to make their eyes appear straight.
What’s the outlook?
Exotropia is common and treatable, especially when diagnosed and corrected at a young age. By about 4 months of age, the eyes should be aligned and able to focus. If you notice misalignment after this point, have it checked out by an eye doctor.
Experts note that untreated exotropia tends to get worse over time and will rarely spontaneously improve.