That blinking sight-screen! (6)
I believe the answer is:
eyelid
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for eyelid that I've seen before include "Natural optic covering" , "Protection for organ of sight" , "Natural optic occluder" , "The blinking thing!" , "Facial feature" .)