A rare disorder in which the muscles of the eyelids (orbiculares oculi) do not function properly, and that includes intermittent and involuntary contractions or spasms of the muscles around the eyes. Although the eyes themselves are unaffected, the patient may eventually become functionally blind because of an inability to open the eyelids. Benign essential blepharospasm is a form of dystonia, which is a group of neuromuscular disorders characterized by muscle spasms. More about dystonia.