Stevie Wonder, Ray Charles, Marcus Roberts, Frank Emilio Flynn (my new favorite artist, and the one who got me started on this).
Is there something about the piano that makes it easier than other instruments to play if you can’t see?
There probably are as many blind guitarists in popular culture. Blind Lemon Jefferson. Jose Feliciano. Blind Willie Johnson. Sonny Terry.
And I think that’s the simplest of possible explanations. The piano and the guitar are the two most commonly found instruments. By 1920, pianos were found in one of every four households, and uprights were extremely cheap comparatively. Same with guitars.
Both instruments could be found used and just as importantly could be played if kicked around and banged-up.
Most other instruments were rarer, harder to come by, more expensive, and needed better care.
Just a WAG.
Availablity maybe? More blind pianists: George Shearing, Art Tatum, Lennie Tristano.
But also consider other blind players who made it on other instruments. Rahsaan Roland Kirk, many old blues guitarists who were “Blind somebody” along with the harmonica types with the same naming conventions. Doc Watson, though not jazz, has an excellent reputation on guitar. Joe Morello could barely see and didn’t have trouble finding his drums.
It might be fun to see some counts by instrument of the blind players.
The Braille nature of the placement of the black keys may be a contributing factor?
There are a lot of blind guitarists as well, especially blues guitarists.
I think it has to do with the ubiquity of the instruments, and has nothing to do with how easy or hard they are to play. Ireland, I know, had a long tradition of blind harpers and pipers, the most well-known of which is the harpist/composer Turlough O’Carolan.
Okay, fine, guitar too. 
The “ubiquity of the instrument” argument makes sense – Exapno’s 25% statistic (and if I were obnoxious, I’d ask for a cite) is interesting – one forgets how radically the availablity of recording media has changed the nature of home entertainment – from active to passive – over the last century. (Just had a conversation with my sidekick about whether or not anyone plays charades any more.)
Agree, Zeldar, a breakdown would be interesting. And interesting across cultures, perhaps, as Kelly5078 suggests.
Wow, I never knew he was blind.
As to the inevitable question as to why there are so many blind musicians, well, if you’re blind what else are you gonna do? You’ve got to do something to support yourself, and blindness doesn’t interfere with playing most musical instruments.
And of course, wikipedia has an article on blind musicians:
To my knowledge, Tatum was severely visually impaired, but not blind.
Yep - here in wikipedia it states that he was blind in one eye and impaired in the other.
Add to that the fact that he drank like a fish and I’m sure he was blind drunk!
Anyway - I think **Exapno **is onto something - pianos and guitars are simply quite common, and so the likelihood that a blind person would come into contact with them is more likely than with other instruments.
I would also expect that the versatility of the instruments work in their favor - both can play chords or single-note lines, both can be played and sung simultaneously, etc.
One thought - both lend themselves to improvisation and just messing around - without having to read music. Most wind, brass, and classical string players typically read music I think - whereas most guitar players just wing it and piano can be self-taught in a straightforward manner…
Just thinkin’ out loud…
The fantastic book, Our Own Devices: The Past and Future of Body Technology, by Edward Tenner, p. 169.
If I were obnoxious I’d point out the speciousness of a breakdown, since all you’d likely get is a bunch of nonrandom “famous” names rather than a true count. 
Good thing neither of us is obnoxious, eh?
I’ve always known Sonny Terry to be the singing and harmonica-playing half of the Sonny Terry and Brownie McGhee duo. Not saying he couldn’t play guitar, but I’ve never seen or heard him do it. Does he actually play to the extent that you’d classify him as a blues guitarist?
All I have to say is “duh! Doc Watson is blind!”
Once again “Duh?”
The Wiki page says this:
Sonny Terry is surrounded by guitar players in that sentence, so I could have misinterpreted it.
Snap. Not only is it instruments which can lend themselves to learning to play and participate aurally, but it is also musical cultures. The piano, for the OP, has such roles anywhere from ragtime onwards. The guitar in blues through to rock. And as kelly5078, other instruments in other folk cultures. I’ve also heard of blind sitar players, for example.
Because they can’t play in a marching band.
I was going to say, because they misplaced the sax?
Then I thought better of it.
“Streets of Gold” by Evan Hunter is a good novel about about a blind piantist, told in the first person. While it is a work of fiction, it goes into how the protagonist learns music and plays it (I never realized music could be written in Braille).
Johnny Winter, legally blind, and an accomplished guitarist.
His brother Edgar, not only a keyboardist but a sax player as well.
See Rahsaan Roland Kirk for an example of a sax player who not only played better than most other saxophonists, while blind, he also was able to play up to three instruments AT ONCE. Whoa dynamite. I guess technically this doesn’t address the OP at all, but I think any discussion of blind musicians should include his presence, IMHO the greatest of them all.
The instruments most commonly played by blind musicians - piano, guitar and harmonica - can all play chords, so are more interesting as solo instruments than, say trumpet or sax. I suspect that blind musicians gravitate toward instruments that they can make a living with as soloists. Social isolation from the sighted world could have something to do with it. Also, a blind musician who can’t read normal sheet music might have a hard time getting a job as a studio musician or a sideman - another reason to prefer a career as a soloist.