Soft contact lenses are generally more comfortable to wear. They are able to stay in place better and are easier to adjust to than hard contact lenses. The flexible plastic is combined with water to allow oxygen to pass through the contact lens to the cornea. This increases comfort and maintains eye health.
Rigid gas permeable lenses
Your eye doctor may call them GPs or RGPs. GP contacts are made of a firm, durable plastic that transmits oxygen. They offer excellent eye health: because they don't contain water like soft lenses do, they resist deposits and are less likely than soft contacts to harbor bacteria.
Bifocal contacts lenses have two prescriptions in the same lens. Multifocal contact lenses have a range of powers (similar to progressive eyeglass lenses) in each lens. "Multifocal contacts" also is used as a catch-all term for all contact lenses with more than one power, including bifocal contacts.