I use transitional lenses. However, when I was fitted for them, I took along a hair dryer and let them know that the glasses had to do a very good job of blocking the wind and protecting my eyes when I was riding. Much to my surprise, and the person fitting me, the larger sunglasses didn't do as good a job as the small lens glasses I actually bought. These smaller lens glasses seem to work because the fit the contour of my face and form a good barrier right around the eye socket. Hence, I'm now a believer that it's not the size, but the shape that counts. If I have a complaint about the transitional lens it is that they do not darken the same amount in hot and cold weather.