Easton Sprint sunglasses

haha i've had these sunglasses for about two years and haven't been able to figure it out. I've pulled on them pretty hard and the lens hasn't budged.

Any help would be greatly appreciated.

Cant't tell exactly but look like the Oakley M frames where you pull down the lens from above the nose guard and release the lens from the frame.

http://www.baseballwarehouse.com/store/Baseball_Accesso...SSES___A162709?Args=

http://oakley.com/search/replacement+m+frame+lens

The protrusions at both ends go into the frame and the area above the nose guard goes back in last.

You may be able to tell from the replacement lens which I have not been able to find on the web.

My son has these. Make sure you are holding the frame and then pull on the lens from close to the frame. It takes some effort but they do come out.