I looked at myself in the foggy mirror and saw that my eyes were encircled by two weird rings of alternating light and dark areas. They weren't colourful, just took on an almost black or white shade. It looked like I had weird cartoony eyes. I tried taking photos, below, but that was difficult as I have a black camera and you probably need a lighter colour in the background.
Do it yourself after your next shower! Simply look through the fog straight into your eyes reflected in the mirror and you will see the optical illusion.
How is this caused? I think it is a result of the tiny water droplets that have condensed on the mirror's surface. As light passes through the droplets, it is bent and refracted and polarised in the water droplets in the same way a sundog creates a ring of reflected light with airborne ice crystals. The reason it is centered around your eyes is because of your perspective - the image of your eye is light bouncing off your eye, reflecting off the mirror and back to your eye, and the angle is almost exactly 180 degrees. The ring shape is caused by the distance of the cells in the retina from dead-centre in the field-of-view. Move further away and the light reflected changes radially from light to dark and back again.
Check out my photos: centered directly over the camera lens is the dog.
Closer detail of the image with the contrast boosted a bit to hopefully bring it out a little.
Uber-sized original: http://farm7.static.flickr.com/6077/607 ... 4bc6_o.jpg
