Everyone's face is different. That's why Smith offers sunglasses with varying lens sizes, shapes, and base curves. Their Vxe has a base curve of 7, meaning the lenses have a medium curve. They fit close enough to offer full-coverage protection, but aren't as curvaceous as the Threshold. The Vxe design includes a sweeping frame that ties the temples to the nosepiece across the top, behind the lens. And though it may look like the Vxe has a one piece frame, the temples are hinged to make storage in a jersey pocket possible.The lens on the Vxe is Smith's Carbonic TLT. The TLT stands for Tapered Lens Technology, and this means that the thickness of the lens tapers from the optical center, towards the edges. This thinning allows for less refraction and therefore less distortion for the light waves passing through the lens. You'll get the greatest possible clarity all the way out to the periphery of the lenses -- a good thing for high speed activities like cycling. The Carbonic lens is also highly resistant to impacts. This is a great thing to know when you think about the things that could threaten your eyes on a bike ride. They exceed ANSI Z80.3 specifications, and they protect your eyes from 100% of the UVA, UVB, and UVC rays.The Ballistic xe frame is flexible, tough, and super lightweight. And the hydrophilic Megol nose and temple pads keep them locked in place on your face. They won't slip. They won't slide. They won't fall off.The Smith Vxe is available in Black w/Platinum and White w/Yellow Mirror. With either color option, you'll get two extra lenses. The Ignitor lens is great for overcast days as it increases definition and depth perception in low light. The Clear Mirror lens is best for very low light conditions. The Vxe offers medium coverage, and Smith considers them a medium fit.