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:
“They work, and age, and put off men
By being unattractive, or too shy,
Or having morals anyhow, none give in:
Some of them go quite rigid with disgust
At anything but marriage....”
—Philip Larkin (1922–1986)
“Droning a drowsy syncopated tune,
Rocking back and forth to a mellow croon,
I heard a Negro play.
Down on Lenox Avenue the other night
By the pale dull pallor of an old gas light”
—Langston Hughes (1902–1967)