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Gas permeable contact lenses are rigid lenses made of durable plastics that allow oxygen to pass through the lens. These lenses are also called gas permeable lenses, hard lenses, hard contacts, RGP contact and oxygen permeable lenses.
The first types of rigid contact lenses were made of glass, and later, in 1936, a type of plastic called polymethylmethacrylate (PMMA) was discovered and used as a replacement for glass. By 1971, when the first soft contact lenses appeared, all lenses were made of this type of material. PMMA has excellent properties, with high resistance to breakage and scratches, and is easy to work with. However, the downside of this material was that it was impermeable to oxygen and generally to various gases, whereas the eye needs a significant amount of oxygen.
However, in the meantime, gas-permeable lenses have been developed that include silicone, making them more flexible than hard PMMA lenses. Silicone allows oxygen to pass through the hard lens to keep the cornea healthy. In fact, many modern hard lenses allow more oxygen to reach the cornea than most soft contact lenses. Unlike rigid PMMA lenses, which had to be smaller in size and with edges away from the eye to allow oxygen to penetrate, hard contacts can be any size and can be fitted closer to the surface of the eye without any problem, providing the necessary amount of oxygen. They're also easier to fit so they're securely held to the eye while doing sports or other activities.
So RPG contacts offer better vision, durability, resistance to deposits, allow the eyes to breathe, provide the clearest vision throughout wear, are ideal for all types of activities including sports, can slow the progression of myopia and are water-free. However, whatever contact lenses you wear, good lens care is also necessary.
To take care of them, hard lenses need their own specific care solutions. For example, you can keep your hard contact lenses fresh, free of bacteria and protein traces, with the help of detergents or hard contact lens disinfecting solutions. These solutions for hard contacts keep your eyes healthy throughout wear, protecting them from infection, and provide comfortable contact lens wear.
In addition to these, there are also daily or weekly multi-purpose solutions or solutions for cleaning, disinfecting or moisturising hard contact lenses. Some of the most popular brands include Boston, Delta, Menicon with MeniCare Plus and MeniCare Pure and Menicon Progent. All of these combat dry eyes and any discomfort that lenses can create.