Lagophthalmos in acquired oculomotor synkinesis

Two consecutive patients who exhibited classic signs of unilateral acquired oculomotor synkinesis demonstrated an inability to appose eyelid margins on the affected side, when attempting gentle closure of the eyes. In one patient, this occurred in conjunction with a unilateral upper eyelid crease on the affected side, and in the other patient it was associated with accentuation of the crease in comparison with that of the opposite side. Bilateral eyelid closure normally induces a contraction of the superior recti muscles. The lagophthalmos and accentuated upper eyelid crease observed in our patients when they attempted gentle eyelid closure presumably resulted from inappropriate coactivation of the levator palpebrae superioris muscle by impulses destined for the superior rectus muscle.