"No, it’s not crazy. Yes, it is normal. It’s what the brain does in response to loss of visual input."

I first read about this in a book by Oliver Sacks, the doctor who wrote a fascinating series of books for general readers filled with real-life examples from his neurology practice.

The brain is stranger (and cooler) than we know!

I recommend his books for anyone who wants to dive deeper into this subject but doesn't have time to get a medical degree first.