ESS recently unveiled its new Rollbar ballistic sunglasses designed with a new "Rapid Lense Exchange" feature. The Rollbar features "military-grade polycarbonate to deliver crisp and accurate field of view, plus ANSI Z87+ and MIL SPEC ballistic protection."
ESS boasts that the Rollbar's Lense Gate technology takes the hassle out of changing lenses. Check out the how-to video on the ESS website. I just wish they would come up with a way to swap lenses without having to put your thumbprints all over them. The Rollbar features a medium-to-large fit and cost $115.