Bifocal soft contact lens

Claim 2

A multifocal contact lens comprising a lens body with a generally spherical, concave inner surface adapted to fit the cornea of a human eye, and a generally concave outer surface; said lens body having a central, horizontal axis defining a superior portion of the lens and an inferior portion; said lens body having a central vertical axis; the superior portion of said lens'body being substantially equiangularly truncated from points on either side of the vertical axis at the apex of the lens to points on each respective side proximal the horizontal axis; said lens including a first optical zone having at least a major portion thereof in the superior portion of the lens; said lens including a second optical zone having at least a major portion thereof in the inferior portion of the lens; the focal length of said second optical zone being shorter than that of said first optical zone.

Claim 3

A lens of Claim 1 wherein the optical center of the concave inner surface is at the geometric center of the lens.

Claim 4

or Claim 2 3. A lens of Claim 1/wherein the optical center of said first optical zone is on the vertical axis in the superior portion of the lens.

Claim 5

A lens of any one of Claims 1 to 3 wherein the optical center of said second optical zone is on the vertical axis in the inferior portion of the lens.

Claim 6

A lens of any one of Claims 1 to 4 wherein the optical center of said second optical zone is coincident with the optical center of said first optical zone.

Claim 7

A lens of any one of Claims 1 to 5 including a third optical zone positioned intermediate said first and said second optical zones and having a focal length intermediate that of said first and second optical zones.

Claim 8

A lens of any one of Claims 1 to 6 wherein the equiangular truncation of the superior portion of the lens extends from points spaced apart from about 2 mm to 8 mm at the apex of the lens.

Claim 9

A lens of any one of Claims 1 to 7 wherein the included angle of truncation is from about 45 degrees to 120 degrees.

Claim 10

A lens of any one of Claims 1 to 8 wherein said lens body includes base-down prism ballast.

Claim 11

A multifocal contact lens comprising a lens body with a generally spherical, concave inner surface adapted to fit the cornea of a human eye, and a generally concave outer surface; said lens body having a central, horizontal axis defining a superior portion of the lens and an inferior portion; said lens body having a central vertical axis and being symmetrical thereabout; the superior portion of said lens body being substantially equiangularly truncated from points at the apex of the lens spaced apart from about 3 to 5 mm to points on each respective side of the lens proximal the horizontal axis, the included angle of truncation being from about 65 to 80 degrees; said lens including a first optical zone having at least a major portion thereof in the superior portion of the lens; said lens including a second optical zone having at least a major portion thereof in the inferior portion of the lens; the focal length of said second optical zone being shorter than that of said first optical zone.

Claim 12

A multifocal contact lens comprising a lens body with a generally spherical, concave inner surface adapted to fit the cornea of a human eye, and a generally concave outer surface; said lens body having a central, horizontal axis defining a superior portion of the lens and an inferior portion; said lens body having a central vertical axis and being symmetrical thereabout; the superior portion of said lens body being substantially equiangularly truncated from points at the apex of the lens spaced apart from about 3 to 5 mm to points on each respective side of the lens proximal the horizontal axis, the included angle of truncation being from about 65 to 80 degrees; said lens including a first optical zone having at least a major portion thereof in the superior portion of the lens; said lens including a second optical zone having at least a major portion thereof in the inferior portion of the lens; the focal length of said second optical zone being shorter than that of said first optical zone.