Bulging eyes when straining?

[Benefitsben]

Recently (the last few days) I've noticed that whenever my boy's straining (like when trying to chew open a toilet roll tube to get to his food) his eyes bulge a lot. When he's doing anything else his eyes are completely fine, no bulging, no discharge/redness, and he can blink like normal. However when I give him his food in a toilet roll tube his eyes look like they're about to fall out, but they go back to normal whenever he stops. You can see it in this (http://imgur.com/a/xqJgCpc) video. He's otherwise fine, eating and drinking like normal, and it doesn't even seem to bother him as if it was hurting him he'd probably stop chewing, but he doesn't. I just want to know if he's OK, and if it's safe for me to give him his food in toilet paper rolls still as I don't want him to damage his eyes.

[Ria P]

I can't open the video or i'd have a look but not something i've come across before.

[Benefitsben]

Originally Posted by Ria P

I can't open the video or i'd have a look but not something i've come across before.

I can't figure out how to edit my post, but here's the link - You can see the most difference near to the end - Album on Imgur

[Ria P]

I saw the video now and wished i'd know the answer to your question but i don't. Maybe someone else and more experienced will.

I'm just trying to think what i would do. I'd probably scatter feed until i could find out if this is normal or not.

[Benefitsben]

Originally Posted by Ria P

I saw the video now and wished i'd know the answer to your question but i don't. Maybe someone else and more experienced will.

I'm just trying to think what i would do. I'd probably scatter feed until i could find out if this is normal or not.

OK thank you :)

[sushi_78]

Rodents have a muscle connected to the jaw that runs through the eye sockets, so all I can think is that action of chewing engages that muscle and causes his eyes to become more prominent, similar to how rats' eyes boggle when they grind their teeth.

This article talks a bit about the facial muscles: Mouse-Like Rodents: Myomorpha

That doesn't explain why it's only recently been happening though and I'm not sure why that would be.