1, refractive error: especially high myopia, high hyperopia, cone cornea bifocal refractive disparity, corneal irregular astigmatism or mixed astigmatism. In addition, some arts or sports workers, due to the needs of the profession, are optional contact lenses. 2, certain stubborn keratoconus: soft contact lenses can be used to treat stubborn corneal edema, retained keratitis, dry keratitis, etc. 3, for cosmetic purposes: If the color is painted on the lens can cover up the white spots on the cornea to increase the beauty. Coating the lens with the same color as the sclera around the lens and keeping the central part transparent can eliminate the photophobic symptoms in albino patients and patients with congenital or traumatic iris defects.