If you want to customize sunglasses or photochromic glasses with a prescription, the prescription should be exactly the same as that used for regular prescription glasses. The main purpose of these glasses is to protect the eyes from direct exposure to light, which can lead to excessive eye strain and cause symptoms like eye fatigue, pain, bulging, soreness, or the sensation of a foreign body in the eye. Typically, it is acceptable to use such glasses for prescriptions up to 500 degrees. However, it is generally not advisable for patients with high myopia, as these glasses do not provide clear vision.