Interesting that you mention all this. I also have fairly serious tinnitus plus a whole range of sound I am deaf to. However, I can usually hear a deer walking even when it's damp. My eyes have cataracts and don't focus well; nevertheless I can see deer while others with much better eyesight miss them entirely. I think it has everything to do with knowing what you are seeing and hearing. I've never been alerted by a squirrel but have been tormented by the angry individual. I've detected deer just from seeing an eyeball (as to opposed to a leaf), an ear tip or part of a leg. It's all in knowing what you're seeing and not just good vision or hearing.