Rabbit with discharging eyes

Question
My rabbit has recently had a collar placed around his neck to stop him from irritating an area of mite bites. Our vet said we could remove the collar for a few hours to let the rabbit clean himself. It's now been about three weeks and there have been improvements but now whenever we put the collar back on our rabbits eyes go dull and a creamy substance appears in around the tear duct on the eyes spreading about a quarter of a centre meter inwards towards his pupils. We have taken him to the vets on this subject but they don't know what the problem is but we are still concerned because it looks like his eyes are about to pop out of their sockets. Do you know what's going on?  

Answer
Well, the first thing that comes to mind is that he doesn't like the e-collar and his third eyelid is protruding.  That would be normal for a scared bunny.

However, if you wish to check out other possibilities, go to http://homepage.mac.com/mattocks/morfz/rabrefs.html#eye and possibly you can see something else there.

A scared rabbit does look like their eyes are bulging out.

Kim