Thank you for this email. Axon Optics glasses block the light that has been implicated in triggering sensitivity to light and migraine. Our SpectraShield FL-41 is effective for about 90% of our customers. Axon Optics offers a 30 day return/purchase price refund policy so customers can test our product for a trial period. Whether you have perfect vision or need prescription lenses, we recommend first trying our non-prescription lenses in one of our frames to be sure the lens helps you before investing in a nonrefundable custom order. One week is the perfect amount of time to try out our lenses. Most customers know by then if they are effective. If you wear prescription glasses all of the time, I recommend the Cover Rx frame. All non-prescription Axon Optics frames have the 30 day return policy and are covered by a 1 year warranty. You can shop our glasses at http://www.axonoptics.com/product-category/migraine-glasses/ You can find additional information, our full return policy, and our return form on our FAQ page at http://www.axonoptics.com/natural-migraine-relief-help-faq/