Note: They are able to read perfectly fine. They are able to do everything perfectly fine, but understand different times of day and clocks.
def. a person who cannot tell the difference in certain times of day. They may sleep during the day and stay awake during the night, not because it's part of their job description or because they may presumably enjoy it, but because they do not know the time between night and day. This is why they may prefer sex in the morning instead of the night, as they do not know the difference between night and day. They do not know the difference between 10:05 and 5:10. They are completely out of it, which is why most time dyslexics are shunned from the world as they easily get lost.
The first season from the television show Full House. Joey forgot that Danny's mother was coming into town, proving that Joey was a "time dyslexic."
Danny: Mum, what are you doing here so early? Joey said you’ll be here at 5:12.
Claire: Try 12:05.
Joey: Guess you had to find out sooner or later. My name is Joey, and I’m a time dyslectic.