Regular special fx contact lenses cover only the colored part of your eye, the iris, but scleral lenses are much larger and also cover the white part of your eye, the sclera. For this reason, we urge you to see an optometrist to ensure a proper fit will be possible before you order scleral contact lenses. Diameter for full sclera lenses is set at 22, and the base curve is 9.0. Your unique eyes may or may not be suited to wearing this type of lens. Because they are bigger than regular lenses, scleral contacts can be difficult to insert. Be prepared to practice. Abundant lubrication (eye drops made for contact lenses) is also recommended. Limit wear time to a maximum of 3 or 4 hours, and use contact-safe eye drops often. Scleral lenses may also diminish your vision more than regular theatrical contacts because in addition to having a fixed, small “pupil,” the large diameter of the lenses themselves prevents them from having the same range of motion as your eyeballs. This vision hindrance compounds the effects of the “haze” (also present in other theatrical lenses) which varies from slight to extreme depending on the amount of available light. Avoid wearing them in low light situations, or exercise extreme caution if you must enter a dim area.