Standard Rigid Gas Permeable (RGP) lenses do not permanently reshape the cornea under normal daily wear, though they do provide sharp optics by masking irregular corneal shapes like keratoconus. However, a specialized subset of RGP lenses called Orthokeratology (Ortho-K) lenses are specifically engineered to be worn overnight while sleeping. These custom therapeutic lenses gently and temporarily flatten the central cornea overnight, allowing patients to experience clear daytime vision without wearing any corrective lenses during waking hours.