Dear Customer, thank you for your comments. It is important to choose a suitable lens index according to your prescription, which will not only impact aesthetics/thickness of the lens but also with more comfort. Be advised that the more complex your prescription, the thicker (and heavier) the lens which means higher prescriptions require a higher index to keep the lens thin, light, and free of distortion. The thick lens can not only cause vision blurry and distortion but also can cause headaches, dizziness, and other discomforts. You may want to check this link for more information: https://www.firmoo.com/help-p-23.shtml
. We offer 30-Day Exchange&Return
: Unsatisfactory glasses can be exchanged or refunded within 30 days of receiving. Please feel free to contact us if you need. Stay safe and healthy! Thanks!