Dystonia, focal, due to blepharospasm: The involuntary, forcible closure of the eyelids. Focal dystonia due to blepharospasm is the second most common focal dystonia. The first symptom may be uncontrollable blinking. Only one eye may be affected initially, but eventually both eyes are usually involved. The spasms may leave the eyelids completely closed, causing functional blindness even though the eyes and vision are normal. Uncontrollable blinking may also be caused by tic disorders, including Tourette syndrome.