I can't wear contacts due to astigmatism, so I have tried several OTG goggles. Not counting the fan versions Smih has three, I think: Knowledge, Prophesy and IO/X. I had the Knowledge but finally quit using it because it was just too big for my face and created breathing problems. The Prophesy is meant for smaller faces and fit much better. Changing lenses in either one is a huge PIA. I haven't used the IO/X but I think the fit is similar to the Prophesy and changing lenses is pretty easy. I also used an OTG goggle by Bolle, X-9, IIRC that I liked a lot. I needed a new helmet this season and got a Salomon so I got a pair of Salomon X-Max goggles, not OTG, but with some modification they work. If you wear a helmet, take the helmet with you and go try on OTG goggles to make sure they they fit your face and don't leave the dreaded gaper gap at the top of the goggles. FWIW, a lower volume goggle seems to reduce the chance of your glasses fogging. I had a fair amount of trouble with fogging when using the Smith Knowledge, but almost zero problems with the other goggles I mentioned, all of which are lower volume.