All Monokel Eyewear sunglasses are designed and crafted to hold both sun- and prescription lenses. This allows you to install any lens of your choice in a Monokel Eyewear sunglasses frame, as long as the lens has the correct base. Our frames all hold base 4 lenses. We are currently unable to exchange or install different lenses in-house. A local optician should be able to help you install new lenses.