A strabismus is defined as a condition in which the eyes deviate (turn) when looking at the object of regard. The object of regard would be the target that you, the patient, regards (aims eyes toward, looks at!). Eye doctors generally look for the presence of a strabismus when looking at distance (20 feet or more); at near (16 inches for an adult and 13 inches for a child); and the lateral and vertical directions (up, down, left, or right).
When the eye turn occurs all of the time, it is called constant strabismus. When the eye turn occurs only some of the time, it is called intermittent strabismus. With intermittent strabismus, the eye turn might be observed only occasionally, such as during stressful situations or when the person is ill.
This is one of the most important findings the eye doctor makes! It is important for you as a parent or patient to understand the difference between constant and intermittent strabismus. This distinction has great bearing on timing and types of treatment.
When the eye turn occurs at all distances and at all times, it is called constant strabismus. When the eye turn occurs only some of the time, it is called intermittent strabismus or alternating strabismus. With intermittent strabismus, the eye turn might be observed only occasionally, such as during stressful situations or when the person is ill. Please note that if the eye turn is constant at a certain
Up to the first 6 months of age, intermittent strabismus is a normal developmental milestone. After 6 months, it needs to be evaluated.
Constant turns are to be dealt with immediately if one wants to re-establish proper use of both eyes. Treatment for this condition should be early and aggressive. If the eye turn is constant and simple things like patching, drops, and/or glasses (bifocal, prismatic, etc) do not eliminate the eye turn, Vision Therapy, Orthoptics, or Surgery needs to be considered.
Keep in mind that ophthalmologists are eye surgeons and they infrequently offer or recommend Vision Therapy or orthoptics as treatment options. See Is Eye Muscle Surgery the Only Strabismus Treatment? For information on Vision Therapy or Orthoptics as treatment options, consult a developmental (or behavioral) optometrist.
With intermittent strabismus, the eye does not turn in all the time, so the brain is probably receiving adequate stimulation for the development of binocular vision.
After 6 months of age, this condition does need attention, but neither the eye doctor nor parent needs to panic. As long as the eyes are straight some of the time, the brain will develop normal functioning of the eyes (stereoscopic depth perception). Children with intermittent eye turns should be handled with judicious patching, special glasses, and/or Vision Therapy. Surgery, if considered at all, should be a last resort. See Eye Muscle Surgery as Treatment for Strabismus, including Intermittent Exotropia .