Strabismus: Ocular Malalignment

Abstract

Strabismus is a clinical condition of the eyes where the visual axes of the two eyes are not both directed at the object of regard. The common deviation is “crossed eyes” (esotropia). While most Strabismus has its onset in infancy or the first two years of life, adult onset does occur in association with neurological and vascular disease or trauma. Under normal circumstances the two eyes are under exquisite control with the visual axes aligned within a few seconds of arc by the six extraocular muscles of each eye. Several neurological inputs including the vestibular system and neck proprioceptive signals serve to align the eyes even without visual feedback. The final alignment is locked in when the two eyes are operating together, fusing into a single image the signals from corresponding points from the two eyes.