It’s no more visually-impaired friendly than the traditional text/numbers CAPTCHA codes [1] (those “type in the string above” verification used in comment forms for many blogs), but the KittenAuth [2] test is not probably harder to hack (since humans can tell the difference between a baby bunny and a kitten, but computer can’t — yet), it’s just so damned cute.
KittenAuth is a new system for human-checking that forgoes all the useless random string crap that people cannot read, and replaces the whole lot with pictures of cute animals.
The current 9*9 design displays 9 pictures and requires that the user clicks 3 pictures of kittens. The location of the kittens in the grid is random and to make things more fun the contents of the pictures changes too.
Like I said, cute!