strabismus

Heterotropia, or strabismus is a condition where the eyes are misaligned such that binocular fixation is not achieved under normal viewing conditions. It occurs when the foveal line of sight of one eye fails to intersect the object of fixation, resulting in the inability to fuse images from both eyes. Strabismus can be inward, outward, upward, or downward, and may be constant or intermittent.