Gas permeable contact lenses

Gas permeable contact lenses are small, curved pieces of durable, slightly flexible plastic shaped to fit your eyes. They float on the tear film in front of the cornea (the clear outer layer on the front of the eyeball).The plastic used for gas permeable lenses allows oxygen to reach the cornea. Although gas permeable lenses are not the same as the hard lenses of the past, people sometimes still refer to gas permeable lenses as "hard" or "rigid" lenses. This is because they are harder and more durable than soft contact lenses.

Due to improvements in materials used to make them, gas permeable lenses have several advantages over soft lenses and are being prescribed more frequently again, particularly in the fields of Ortho-K and Bifocal contact lenses.