"Contralateral Dry Eye in Hemifacial Spasm:" A New Clinical Sign

Hemifacial spasm (HFS) is a benign condition characterized by unilateral, involuntary, paroxysmal clonic and tonic contractions of the facial muscles. This condition usually results from a focal demyelination at the root entry zone of the 7^th cranial nerve secondary to a vascular loop compression, and hence, it responds to microvascular decompression (MVD) surgery, similar to trigeminal neuralgia. Herein, we report an interesting clinical finding of a contralateral dry eye in the case of HFS, which has not been described previously and discuss the possible underlying mechanisms. A 53-year-old man presented with a 6-month history of involuntary twitching movements of the left hemiface that persisted during sleep, consistent with the diagnosis of HFS. The patient's attempts to voluntarily control the troublesome involuntary left-sided eye blinking led to the development of dryness and reddening of the right eye. Corneal reflex, both direct and consensual, was intact bilaterally, and an ophthalmological examination ruled out the diagnosis of conjunctivitis. The patient underwent MVD of the facial nerve. To our surprise and validating our supposition, his contralateral conjunctival hyperemia and dry eye resolved within a day of surgery, along with complete resolution of the HFS. HFS can lead to the contralateral dry eye from the voluntary suppression of ocular blinking which resolves following MVD. We demonstrate this finding for the first time and believe its recognition may be of value in the patient management.