Mindblown: a blog about philosophy.
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Extended wear contact lens
A contact lens made of materials that permit permeation of gas (i.e., oxygen) so that there is less chance for corneal irritation.
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Disposable contact lens
A soft contact lens worn for a week or two and then discarded.
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Cylindrical lens
A segment of a cylinder parallel to its axis, used in correcting astigmatism.
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Corneal contact lens
A type of contact lens that adheres to and covers only the cornea.
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Convex spherical lens
A lens formed of prisms with their bases together, which is, therefore, thick at the center and thin at the edge. This type of lens is used in hyperopia.
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Convexo-concave lens
A lens with a convex surface on one side and a concave surface on the opposite side.
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Concave spherical Iens
A lens formed of prisms with their apices together, which is, therefore, thin at the center and thick at the edge. This type of lens is used in myopia.
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Bifocal contact lens
A contact lens that contains two corrections in the same lens.
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Biconvex lens
A lens that has a convex surface on each side.
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Biconcave lens
A lens that has a concave surface on each side.
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