Diplopia, commonly known as
double vision, is the simultaneous
perception of two images of a single object that may be displaced horizontally, vertically, diagonally (i.e., both vertically and horizontally), or rotationally in relation to each other. It is usually the result of impaired function of the
extraocular muscles (EOMs), where both eyes are still functional but they cannot converge to target the desired object. Problems with EOMs may be due to mechanical problems, disorders of the
neuromuscular junction, disorders of the
cranial nerves (
III,
IV, and
VI) that stimulate the muscles, and occasionally disorders involving the supranuclear oculomotor pathways or ingestion of
toxins.