A person with a number of conditions may show an increased frequency of nonvoluntary eyelid blinking.
Conditions associated with frequent blinking:
(1) reflex to stimulus (strong light, loud noise, corneal irritation, etc)
(2) blepharospasm
(3) child with facial tic and spasm
(4) dry eye
(5) Parkinson's disease
(6) pseudobulbar palsy
(7) drugs (over 50)