I saw my Frilled do this about 2 weeks ago. Freaked me out to say the least. I came home, looked in the cage and both eyes were closed but bulged way out. As soon as I opened his cage he had them drawn back in and opened his eyes and looked at me like, "what's the problem". I'm not saying it's normal because I don't know that for sure. I've never seen him do it before and he is healthy as can be. I'm personally not going to worry about it unless I see him do it again or it causes a problem. I think maybe this is one of those things they do when we aren't looking. This is my personal opinion of course.