If you have read thru the many responses to this thread, how could you possibly consider visual impairment (or other disability) "inappropriate"?
It's inappropriate in the same way that it would be inappropriate to do a middle school play for the movie Brokeback Mountain.
You're talking about a martial art based on an opponent approaching you to strike you. Without vision, you can not effectively train against that. There are a billion and one things a blind person can do, like play piano. I personally believe that it is not an appropriate choice to pick Aikido of all things as their choice of study. Tai chi, maybe.