Here's a very interesting article on Jon Jones' arms. The author is arguing that he's not being dirty, but that what he's really doing is using an old-school Muay Thai stance that most fighters don't use anymore in order to throw more powerful elbows (which he was definitely doing), and the eye pokes are just an unfortunate side-effect.
http://www.bloodyelbow.com/2014/4/28...-mma-judo-chop