Intermittent Exotropia

Intermittent exotropia is a very common type of eye misalignment. One or both eyes turn out toward the ear occasionally. Only one eye turns out at a time while the other eye points straight forward.

Cause of intermittent exotropia

The cause of this condition is not known. Most experts believe that the brain of affected patients has trouble controlling the position of the eye.

Signs and symptoms of intermittent exotropia

• Abnormal outward movement of the eye happens most often when the child is focusing on distant targets, such as watching television. It can also occur when focusing on a near target, but this is less noticeable
• Sometimes, the eye deviation may happen only when the child is daydreaming, is ill or is tired
• The eye movement may occur infrequently or can occur throughout the day
• A few children will report double vision, but most do not
• A few children will report eye strain and/or headaches, but most do not
• Squinting in sunlight is very common
• Excess blinking is often present

Treatment of intermittent exotropia

Treatment recommendations depends on the severity of the problem, on the signs and symptoms, and on the patient and family desires.

When the drifting eye movement is mild, observation may be all that is needed. Sometimes, the condition will remain the same over a long period of time or may even get better. 

When the drifting eye movement is more pronounced, several treatment options may be considered.

• Eye exercises – Used to help strengthen control of the eyes. Eye exercises work best for smaller amounts of eye drifting
• Eyeglasses – Used to stimulate convergence (movement of the eyes toward the nose) by prescribing glasses that are too strong (called "over minus" lenses)
• Eye muscle surgery – Used to loosen or tighten eye muscles in one or both eyes to improve eye alignment. Eye muscle surgery is usually a better option when there is a large amount of eye drifting
• Patching one or both eyes – The value of eye patching for the purpose of improving eye alignment is unclear. Patching usually does not change the natural course of the problem

Prognosis

Regardless of the treatment used, recurrence of the eye drifting is very common. Exercises and over minus lenses often must be continued long term and surgery often must be repeated. Most children with intermittent exotropia will have excellent vision and excellent depth perception.