Strabismus (aka crossed eyes) is a condition were poor eye movement control causes the eyes to be misaligned and look at two objects simultaneously. Poor alignment of the eyes can be caused by nerve or eye muscle palsy or a large uncorrected hyperopic (i.e. "farsighted") prescription.
When the eyes are not working together, one eye may be looking in, out, up or down, and cause the individual to experience double vision. The same eye can be affected or the eye-turn can alternate between the eyes. The frequency of the eye-turn may also vary from constant to intermittent, and will most likely increase when the individual is fatigued or with prolonged near work.
Strabismus most often occurs in young children of a developmental age, but can occur in older children and adults. Children cannot "grow out" of strabismus and it is important they receive treatment as soon as possible. If left untreated, it can cause poor cosmesis, improper and painful neck posture in attempt to decrease or eliminate double vision, limited depth perception, or a permanent decrease and impaired vision (amblyopia) in one or both eyes.
Treatment for strabismus includes glasses or contact lenses, prism lenses, vision therapy, or surgery. Depending on the cause of the strabismus, the correction of a large farsighted prescription with glasses or contacts can eliminate a strabismus. Prism can also be placed in glasses to alter the pathway of light entering the eye. There by, decreasing the amount of turning required by the eye to view an object or eliminate the strabismus completely. Vision therapy can be used to strengthen and reinforce proper eye-teaming and focusing as well and the connection between the brain and eyes. With appropriate exercise treatments, the eye muscles can strengthen themselves allowing proper eye alignment. If amblyopia occurs secondary to strabismus, patching and vision therapy may be required to improve vision in the affected eye. Surgery can alter muscle length and placement to align the eyes and improve cosmesis and function. However, vision therapy may be required post-surgery to improve functional coordination between the two eyes and prevent reversion to pre-surgical misalignment.
The diagnosis of strabismus can be made through a comprehensive eye exam. In the exam, the presence of strabismus is determined by obtaining proper patient history, evaluating the visual ability of each eye and both eyes together (visual acuity), testing eye-teaming skills and coordination, determination of refractive error, and complete health evaluation.