[Unilateral congenital ptosis with ipsilateral superior rectus muscle overaction]

Congenital ptosis may be frequently accompanied by weakness of the ipsilateral superior rectus muscle. We report a case of ptosis with ipsilateral superior rectus muscle overaction. The 45-year-old patient presented with unilateral congenital ptosis. Ipsilateral superior rectus muscle overaction was found in the upgaze, with an inferior sclera show. This can be found in 40% of congenital ptosis. The authors give two possible causes: either an exaggerated Bell reflex or misdirection innervations of the superior rectus muscle by the superior division of the oculomotor nerve, initially innervating the upper eyelid elevator muscle. Histological or electrophysiological studies can be useful to determine the physiopathology of this association.