Soft lenses can be tinted to enhance or change the colour of the eyes. Rigid Rigid lenses are made from plastics which are less flexible than those used for soft lenses. Some of the newer materials allow almost as much oxygen to reach the eye as if no lens was being worn. Rigid lenses provide better vision than soft lenses, as the optics can be better controlled, and are suitable for a wider range of refractive errors. In some conditions in which the front surface of the eye becomes distorted, such as keratoconus, rigid lenses are the only way of satisfactorily correcting vision.
Rigid lenses require some adaptation on the part of the wearer.
Typically they are less comfortable than soft lenses for the first week or two of wear, but after that they do not cause any discomfort. Rigid lenses are more durable than soft lenses, so they do not need to be replaced as often. No contact lens lasts forever, but different types of lenses need to be replaced at different intervals, both because the lenses wear out and to maintain good eye health. Conventional Rigid lenses are typically replaced every one to two years. Often the replacement is necessary because the wearer's prescription has changed.