Thinking about our senses compared to other animals ours are pretty rubbish. We often develope eye side problems like short-sighted or long-sighted as well which makes us even more disabled. I have never heard of such problems in the natural animal world. Only domesticated get disabled through diseases and lack of care. I guess it is our fault because we bred them like that.

I have read "The Hound of the Baskervilles" in school. I cannot remember details. It was shorten as well for silly German students as we were at that time. I don't think very much of shortened versions. The best parts are just taken out. I saw a film of that book much later. It was not like the book.