*waves* Long time lurker here but thought I'd add my 2cents.
I was actually talking to a pal about this the other night, and she pointed out that at the time that episode was taped those sort of sunglasses (very light tint) were rather popular. You saw a lot of pictures of celebs and such wearing them in and outdoors.
I think they are simply those type of sunglasses and George wore them to whatever event that one picture is from.
There are a lot of huge very detailed close-up shots of George and I have never noticed contact lines (which are often visable in those type of photos)in any of them.
So my thinking is either George is blessed with good eyesight, or he had that lasac (spelled?) surgery, or if he wears contacts they aren't showing up in photos.
*grins* Obviously I have too much free time on my hands...