I have a cat that is about 11 to 12 years old, a few days ago I noticed his third eyelid showing in his right eye, he has also sneezed a few times but not a lot maybe once or twice a day. What could this be? It's been almost a week now and I'm going to call the vet Monday. The same day I noticed his eyelid I had also turned my air conditioner on so I didn't know if that had anything to do with it? But I don't see how it could? Other than his third eyelid showing in ONE EYE (it is not in both eyes) and the one or two sneezes a day nothing else appears to be wrong, he's eating and going to the bathroom and has all his normal habits like rolling over for a belly rub, making biscuits, etc. Initially I wondered if he got something in it or got into a fight with the other cat in the house but it's been almost a week like this and I assumed it would clear up by now. Anyway I guess my question would be what would make only one eye's third eyelid show (covers almost half the eye) yet not show any other visible symptoms aside from a sneeze or two? And do you think there's any hope of it clearing up? I feel so bad for him but he doesn't act like it bothers him? What should I expect when I go to the vet will they do tests or just give me eye drops?