What is Intermittent Exotropia?
Exotropia is a misalignment of the eyes in which one eye drifts outward. It is called intermittent exotropia when the eye only occasionally drifts outward. Under normal conditions, the eyes are straight and perfectly aligned.
What might a parent notice in a child with Intermittent Exotropia?
Parents may notice that when their child is tired or ill, one eye tends to turn out. It may also be noted at the dinner table, while the child is watching TV, or in any circumstance in which the child is very relaxed and looking in the distance. Other indications include:
- The child often closes one eye in bright light or sun
- He/she may also rub one eye on occasion
What are some other details about Intermittent Exotropia?
It usually occurs in children who are between 1 and 10 years of age. The frequency of turning out usually increases as children grow older. Adults, as well as children, can have intermittent exotropia.
The eyes usually are straight for reading or near work but wander for distance viewing. Children with Intermittent Exotropia rarely see double (diplopia) and are often unaware that one of their eyes is turning out. This is because the brain "turns off" or suppresses messages from that eye. Children do not do it "on purpose," and often have no control over the turning.
Although children can lose vision in one eye if it is turned constantly, vision loss or amblyopia is less likely to occur with this intermittent form of exotropia. The vision usually remains good in both eyes. The use of both eyes together (binocularity or fusion) is usually normal when the eyes are straight. Binocularity can deteriorate with frequent misalignment and suppression, and surgery may be necessary if other forms of treatment cannot control the misalignment.
How can Intermittent Exotropia be treated?
Orthoptic Treatment: Eye exercises may be taught by an orthoptist or ophthalmologist usually in the form of home therapy. Usually the child will return periodically for assessment of progress and to be taught the next step of therapy. Depending on a child's abilities, cooperation, and progress, treatment may take a few weeks or months. Patching may be effective in the control of the intermittent exotropia.
Surgical Treatment: If orthoptic treatment or medical therapy are not effective in controlling the eye misalignment, or if the turning is more constant than intermittent, the best therapy is often surgery on the eye muscles. Surgery may need to be repeated if under or over correction occurs. The timing of surgery depends on the age of the child, the frequency of the deviation, and the binocularity.
Most children have improved control and alignment after surgery although additional wandering can occur months to years later.