Caused by obvious loose overhang of upper lid skin
Trap:
many patients with blepharospasm are initially misdiagnosed as having ptosis or dermatochalasis, triggering inappropriate surgery for these conditions
Post-paretic facial contracture
Follows facial palsy, is almost always unilateral, and is never intermittent
Orbicularis oculi contraction is less than in benign essential blepharospasm and differs in being triggered by bright light (“photophobia-induced squinting”)