I had a blind chick once...she was able to form a tight relationship with another mother-like hen who kept her by her side. They found food and water together. Eventually, a predator got her, but she seemed to have a wonderful quality of life....you can't miss what you don't have, so the duck would never know other ducks have eyes. If it's fighting to thrive, I'd give it a chance. God took a chance on me!
Good luck in whatever you decide.

Good luck in whatever you decide.