I'd want a vet to check it if it was me. I'd also be stressed about it!!!! Sometimes animals loose the usage of their eyes - in horses its called wall-eye or something. Doesn't really look very nice! Did something maybe get in his eye? - Try giving him a bath to wash it slightly. Also see how he react if you try and touch hime there - you'll know if he's in pain if he flinches and I would drop everything and take hime to the vets if he's in pain. Hope this is helpfull! He might also be dehydrated!!