A central dystonia causes spastic lower eyelid entropion: a hypothesis.

This article presents a novel hypothesis on what causes an involutional entropion. The theory herein proposes that the pathophysiology of entropion is that of an idiopathic dystonia with the locus of dysfunction posed in the rostral brain stem and with stimuli for its causation mediated through the seventh cranial nerve--the facial nerve--by a cord of fibers making its path to the upper, ie, temporooculo-zygomatic ramus of the nerve. In a word, involutional entropion is but a variant of essential blepharospasm and one of the clinical entities within the oculo-oro-facial-cervical family of dystonia disorders.