Hard Gas Permeable Contact Lenses are a rigid type of contacts which allow oxygen to pass through to the eyes. Initially developed in the late 1970's and improved upon through the 1990's, hard gas permeable contacts are a vast improvement over prior hard contacts, which restricted oxygen flow to the eyes.
Available with a range of options, including Colored or Clear, hard gas permable contact lenses can assist with conditions like single-vision, farsightedness, nearsightedness and presbyopia (see bifocal contact lenses for more information). Especially helpful in the case of astigmatism is the ability of hard gas permeable contact lenses to replace the natural shape of the cornea, providing the eye with a new, consistent refracting surface.