Standard Rigid Gas Permeable (RGP) contact lenses cannot be worn while sleeping. Because RGP lenses cover a smaller portion of the cornea compared to scleral lenses, sleeping in them restricts essential oxygen transmission to the eye surface, leading to corneal hypoxia, swelling, and a sharply elevated risk of serious microbial infections or corneal abrasions. Lenses must always be taken out and stored in cleaning solution before bedtime, unless your eye doctor has specifically prescribed specialized overnight orthokeratology lenses.