Hello lovely boy, and what dashing whiskers you have!
It's not a diagnosis but I could remember seeing this post last year so linking it in
Eye disease?
The pig in those photos has a similar looking eye and there is a link to some information about this condition and also a little reassurance. Remember we aren't vets but if your boy is otherwise healthy, eating, pooping, maintaining his weight and being active he's showing you it's not bothering him. If he starts behaving differently or eating less - showing smaller poops and weight loss - then you know he's being affected by something.
One more thing to look out for with eyes is whether one is protruding more compared to the other. Eyes are handy because there are (usually) two so you can compare any suspected problem eye with the other one! If one eye starts to look obviously more bulging than the other then I'd take him to the vets.