The good folks at Riders Discount provided me with a pair of the Bobster Phoenix Over-the-Glasses Interchangeable Goggles that go on over your normal glasses. I sometimes like to ride without the face plate in my Arai Tour-X helmet, especially when it is hot, so I thought they might be worth a try.
They are very comfortable over my glasses and seat very well in the channel made for goggles on the Arai helmet. I assume they would fit even better over a standard open face helmet, but I cannot confirm that. They were breathable and did not fog up, which is a situation that I am very sensitive too. (i.e. I would have thrown them out, if they did).
The one downside was when I got onto busy roads. The goggles give you tunnel vision, so when there is a lot of lane changing going on, it takes a while to get used to them.
Otherwise, they seem a good piece of kit for those of you who like to wear goggles. There is a very big upside to these goggles too if you are a snowboarder. These should make great winter mountain goggles too!

The Bobster provided features are as listed;

  • A distinct groove on each side accommodates standard prescription glasses, ensuring a comfortable fit and enabling all to ride in style
  • 3 sets of interchangeable lenses are included (anti-fog smoke, amber and clear), allowing continued use through transient weather conditions and times of day
  • Scratch-resistant polycarbonate lenses shield the eyes while supplying 100% UVA and UVB protection
  • Flexible polyurethane frame creates a molded seal over the face, cushioned by a dense layer of sweat-absorbent, neoprene foam
  • Highly ventilated on both the top and bottom of the frame, these goggles also provide anti-fog coating to further prevent any degradation of clarity