The Bolle Z5 goggles are designed with an 'OTG' ('Over the Glasses') fit so you can wear your glasses with them; at the same time they're not so bulky that you wouldn't want to use them if you're not a glasses wearer.
Indeed, they feel extremely comfortable both with and without glasses, in large part due to the ample cushioning offered by the thick, double layer face foam which we liked very much.
Venting is via Bollé's 'Flow Tech' system with vents along the top and bottom of the frame, and the double lens has both anti-fog and anti-scratch coatings and is offered in six different colours to handle any light conditions (although it isn't interchangeable).
The Z5 are designed for medium to large faces and have more than adequate peripheral vision, especially considering that the frame has to be thicker in order to allow the OTG fit.
The strap has a sticky silicon strip along its entire length to keep it in place on your helmet, and although the quite plain looks and classic frame design may not appeal to everyone, we quite liked this combination.
It's a shame the Z5 don't come with interchangeable lenses, but given the price that's no real surprise. Even so, for goggles that can be worn quite comfortably with or without glasses the Z5 is a good buy.