Rigid gas permeable lenses are rigid contact lenses made of oxygen-permeable polymers. Initially developed in the late 1970s, and through the 1980s and 1990s, they were an improvement over prior 'hard' lenses that restricted oxygen transmission to the eye.
Rigid lenses are able to replace the natural shape of the cornea with a new refracting surface. This means that a regular (spherical) rigid contact lens can provide good level of vision in people who have astigmatism or distorted corneal shapes as with keratoconus. However, they require a period of adaptation before full comfort is achieved.
Famous quotes containing the words rigid and/or gas:
“It is the custom of the Roman Church which I unworthily serve with the help of God, to tolerate some things, to turn a blind eye to some, following the spirit of discretion rather than the rigid letter of the law.”
—Pope Gregory VII (c. 1020–1085)
“one pale woman all alone,
The daylight kissing her wan hair,
Loitered beneath the gas lamps’ flare,
With lips of flame and heart of stone.”
—Oscar Wilde (1854–1900)