Exophoria is a condition in which your eyes drift outward out of your control. It usually appears for a short time while you’re doing certain types of tasks. It’s not a serious condition and can be corrected with the right treatment.
What Is Exophoria?
Your two eyes each see at slightly different angles. Your brain automatically blends the images from each eye to create a single image instead of double vision. With exophoria, one of your eyes drifts so far out of coordination with the other that your brain can’t blend the two images.
Symptoms of Exophoria
Exophoria symptoms usually first appear early in life, from elementary to high school. It tends to happen while you’re looking at things close to your eyes, like reading, writing, or using a computer. It’s also likely to happen while you cover one of your eyes.
Symptoms can include:
- Sore eyes
- Trouble reading
- Double vision
- Underperformance in sports
- Squinting or closing one eye in bright light
- Trouble focusing in school
Types of Exophoria
Exophoria has several different types depending on when and how it occurs.
Divergence excess. This is when your eye drifts out when you’re looking at objects far away. Your eyes split paths (diverge) farther than they’re supposed to. Exophoria can include symptoms of divergence excess.
Convergence insufficiency. This is when your eye drifts out when you’re looking at objects very close to your face. Your eyes can’t properly align together or converge. Exophoria often includes symptoms of convergence insufficiency.
Similar Conditions to Exophoria
Similar eye issues also make your eyes drift out of coordination. They differ from exophoria in their intensity and how often they happen.
Exotropia. Exotropia causes your eyes to drift outward like exophoria. With exotropia, the drifting happens more often and more noticeably. Untreated exophoria often intensifies into exotropia.
Exotropia may happen only sometimes during certain situations. It may happen more often if it runs in your family, if you’ve recently gotten eye surgery, or if you have additional vision problems.
Esophoria. Esophoria is when your eye drifts inwards towards your nose instead of outwards. This can make you look like your eyes are crossed. Like exophoria, esophoria symptoms appear when you’re looking at something close up or when you cover one eye.
Lazy eye (amblyopia). Like exophoria, a lazy eye causes one eye to drift outward regularly. Amblyopia has more to do with the overall communication between your eye and brain than with specific visual triggers like reading. With amblyopia, your brain relies more often on one eye, which can weaken muscles in your other eye.
An eye doctor can diagnose exophoria with a vision test. They’ll also ask about your symptoms.
To find problems with eye coordination, they’ll likely perform a cover test. This involves covering one of your eyes slowly or quickly. They'll observe your eye movements during the process. The doctor may put a prism near your eye to see if it improves your vision.
A child’s first eye exam should take place when they’re six months old, again at age three, then before they start the first grade. School-offered eye exams don’t always test for exophoria and other eye coordination problems. Visit a vision specialist's office to get a full exam.
Sometimes, a child with exophoria may be misdiagnosed with another condition like ADHD, learning disabilities, and dyslexia. These conditions have similar symptoms, like difficulty reading and concentrating. Exophoria isn't always obvious. It may be the underlying reason for these symptoms.
Causes of Exophoria
Experts aren’t sure what causes exophoria. Likely factors include eye muscle weakness, nervous system problems, and the size and shape of your eye. Close-up activities can also put extra strain on your eyes that leads to exophoria.
Treatments for Exophoria
You can easily reverse exophoria with consistent treatment. Some common treatment methods include:
Glasses. You can get special glasses that have prisms in the lenses. These prisms can help reverse the outward eye movement of exophoria and lessen eye strain. Prism lenses ease symptoms, but they don’t fully fix exophoria.
Eye exercises. You may have to physically train your eyes to move in coordination with games and other tools. Some of these exercises can take place at home. One common exercise is a pencil push-up. With this exercise, you move a pencil towards your face from arm's length and try to avoid seeing double as you look at it.
Other exercises can be more effective when they take place in a professional vision care office. A specialist can observe you while you perform exercises and keep track of your progress.