I'll see if I can find something .. but my feel on this would be it's only a disabilty if you have upstream/negative thoughts about it .. and a non-issue if you see it as part of your life blessing... and to focus on all the othr things you are blessed with is what creates happiness. Looking at the lack of something creates unhappiness.
I know a blind man who walks 3 dogs in the park. He has a different seeing to me, but he has sight, most definitely.