this is a torn iris, that he got poked in the pupil and it tore the muscle that opens and closes it. Watch him to make sure he feeds well. He might have trouble in complete darkness, maybe get a night light if it's a problem. There's nothing u can do, one of my friends got jumped and his eye is the same. It looks to be cured over fine, he's just a little blind(1/2) in certain light conditions, too bright or too dark. If he was totaly blind in that eye, the pupil would be greyish blue. Just a mild handicap, if he's eating good, it's fine.