To evaluate the efficacy of different botulinum toxin A injection patterns in treating benign essential blepharospasm and to compare their influence on condition of eye surface .

The authors performed a prospective double-blinded randomised clinical trial of 60 patients with an established diagnosis of benign essential blepharospasm from February 2013 to December 2015. Patients received a full injection pattern of 5 sites on one eye and a medial lower eyelid waived injection pattern of 4 sites on the other eye randomly. They were surveyed on ocular surface disease index (OSDI), Jankovic rating scale (JRS), blepharospasm disability index (BSDI) prior to injection and 1week, 1month and 3 months after injection. At these time points, closure of the eyelid, tear break up time (BUT), Schirmer test Ｉ, and lower lid tear meniscus height (TMH) were also measured.

Inclusion Criteria:

• had a confirmed diagnosis of bilateral BEB
• a minimum of 24-week period since the last injection was required for all patients who had previously received multiple injections of BoNT-A.

Exclusion Criteria:

• blepharospasm of known etiology (caused by medication, injury, etc.)
• history of surgical intervention for BEB (myectomy or neurectomy)
• current ophthalmologic infection
• apraxia of eyelid opening associated with levator palpebrae dysfunction