Congenital Unilateral Trochlear-Oculomotor Nerve Synkinesis: A Case Report

Involuntary muscle stimulation by a nerve other than the normal muscle innervation leads to ocular synkinesis. The most common form of ocular synkinesis, which involves the extraocular muscles, occurs between the abducens and oculomotor nerves.

We describe a case of congenital unilateral trochlear-oculomotor synkinesis in a healthy 31-year-old woman, along with a review of the related literature. The patient shows unusual lid retraction when she depresses and adducts her left eye. Additionally, we discuss the proposed mechanisms underlying the pathophysiology, the ophthalmic workup, and suggested management strategies.

Given its rarity and potential to cause diagnostic confusion, physicians need to be aware of this condition.