A novel mechanism for benign essential blepharospasm.
The purpose of this study is to test the hypothesis that the photophobia of benign essential blepharospasm (BEB) is caused by sympathetically maintained pain.
Nineteen patients with photophobia and BEB were enrolled in an unblinded prospective treatment trial. The intervention was blockade of the superior sympathetic ganglion with local anesthetic. Outcome measures included the patient’s subjective report of ocular surface dryness, foreign body sensation, and eyelid spasm. We also obtained video recordings of eyelid movements.
Of the 19 patients, 13 reported subjective improvement in BEB symptoms after cervical sympathetic blockade (CSB). Thirteen of 19 patients also had objective evidence of decreased light-induced eyelid spasm after CSB. Ocular surface disease was present in 18 of 19 patients.
These data support the hypothesis that in many patients with BEB there is a sympathetically maintained pain syndrome associated with external ocular disease. We speculate on a neurologic circuit that may explain these findings.