All customers need to visit an eye doctor to get a contact lens prescription, because the contact lens prescription will measure the shape of your eye.  Just ask for a non-corrective contact lens prescription.  We recommend trying both the tint and a sample disposable contact lens, respectively, before investing in a non-refundable pair of our tinted contact lenses.  All non-prescription lenses in our frames can be returned within 30 days of purchase for a full refund or exchange credit, so its a great way to try out the tint.  Technical information is available by emailing Support@AxonOptics.com.