Contact lenses come in two basic categories: hard and soft. The most popular hardlenses in use today are rigid, gas-permeable lenses (RGP for short). In addition to plastics, they also contain silicone and fluoropolymers. By maintaining their form, hard lenses let the unrestricted passage of oxygen to the cornea. When the cornea has enough astigmatism (is shaped like an egg instead of an orange) that a soft lens will not offer crisp vision for, RGP lenses may be the best option. Contact Lense Surgeon in Ahmedabad. When someone has allergies or a tendency for their contacts to develop protein deposits, they could also be preferred. We take contact lens fitting, instruction on proper lens care, and follow-up care very seriously. We fit all types of contact lenses including the latest disposable, bifocal, colored contacts and gas permeable lenses.