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US 5,635,998 AGranted
Translating multifocal contact lens
OwnerThomas K. Baughinventor
Life of this patent
Estimating the term…
Abstract
A multifocal contact lens is made of hard or soft lens material in an ellipsoidal shape with a base-down prismatic cross section. Lens geometry improves translation characteristics and maintains rotational stability of the lens. Near- and distance-correcting zones of the lens are separated by an arcuate junction which is convex upward.
Claims4
An improved multi-focal contact lens for correcting astigmatism and presbyopia in a human eye, comprising:
- a) said lens having an ellipsoidal shape,
- b) a long axis of said ellipsoidal shape being horizontal,
- c) said lens having a cross section in the shape of a prism, with
- d) a base portion of said prism being in a downward position when the lens is in place on a human eye, so that said base portion rests on a lower eyelid,
- e) said ellipsoidal shape and said base portion of said prism in combination producing an elongated zone of contact between said base portion of the prism and the lower eyelid,
- f) two or more vision-correcting zones each having an optical center,
- g) an arcuate junction between said vision-correcting zones, said junction being convex upward, and
- h) a chamfered edge.
5 more elements
Dependencies are inferred from the claim text.