Asymmetric Blepharospasm Treated with Botulinum Toxin-A: Case Report

Benign essential blepharospasm (BEB) is the second most common focal dystonia after cervical dystonia which is caused by involuntary contraction of orbicularis oculi, procerus and neighbouring corrugator muscles (1,2). The excessive activity of these muscles causes the eye to open and close too frequently or too vigorous to increase the blink frequency or cause functional blindness (2). Pathogenesis of the disease, as of all dystonias, is unknown; although it is thought to develop as a result of dysfunction in cortico-striato-thalamo-cortical circuits (3). Rarely, it may start unilaterally or asymmetrically, but almost always involves involuntary closure of both eyes (1). In patients who do not have typical onset or course, the diagnosis and treatment process may be delayed due to misdiagnosis. In this article; a patient with BEB who started unilaterally and still went on asimetrically for long years was reported with literature review. Case Report