Blink.

Emma is an attractive girl in her 20s who has been blind for 20 years. A new type of eye operation partially restores her sight, but she is having problems: sometimes she doesn't "remember" what she's seen until later. One night she is awakened by a commotion upstairs. Peering out of her door, she sees a shadowy figure descending the stairs. Convinced that her neighbour has been murdered she approaches the police, only to find that she is unsure if it was just her new eyes playing tricks on her.