Robin was born without eyes, and has learned to ‘see’ by barking and listening to the echo, similar to bats. The brain actually grows stronger in the other senses. There was actually a cheesy super hero movie with the same concept-Daredevil. But there actually are blind people who use this same technique appropriately called echolocation.
Here is a science special of one the most famous people in the world who can truly ‘see’ with sound. He never uses a cane or guide dog. Ben is a true ‘Daredevil’ superhero.