A moment of incognisance while attempting to digest material.
For instance, when you've read an entire page of a book and you cant recall a single word.
Deriving from the overwhelming moment in a restaurant when you are trying to read the menu but really you are just looking at it and thinking about how irritating the person next to you is chewing.
Waiter: Are you ready to order?
Me: Um no. Sorry, I had menu eyes.
A state of mindlessness. When you are physically reading but none of the information is processing.
Derives from (but not limited to) the moment when you are reading a menu for 10 minutes and yet you are incognisant of a single word you read.
I had to reread that whole chapter because I had menu eyes.