That eye definitely needs some TLC, he may have something in the eye that has infected it. Personally, I'd go to the vet on that one, but if you want to try something at home first, I would use plain saline solution (you get it in the contact lens aisle at the drug store). You'll have to pick him up and squirt the eye until the turret balloons up. That may wash out the offending item. He will hate you for this, but thankfully chams have a short memory. Better to do that than have him lose an eye... Good luck with your little guy!