Bifocal corneal contact lens and method of making same

Claim 2

A bifocal corneal contact lens to be worn on the cornea of a human eye, comprising a thin circular lens body having a near viewing segment fused in the center of one surface thereof and a surrounding distance viewing portion, the near viewing segment and the distance viewing portion having the same principal optical axis, the lens having a thickness within the range of 0.1016 mm to 0.7721 mm, said near viewing segment made of a plastic material having an index of refraction greater than the distance viewing portion and a near focal point spaced rearwardly of the lens, the distance viewing portion having an index of refraction less than the near viewing segment and a distance focal point spaced rearwardly of the near focal point, the near viewing segment having a diameter within the range of 0.1 to 0.3 mm less than the near point pupil size of the eye under an active state of near accommodation and the near viewing segment having a very long depth of focus, said near viewing segment further having a power equal to the exact refractive add of the eye and being uncorrected for the tear layer of the eye on which the lens is to be worn, the focal points of the distance viewing portion of the lens and the near viewing segment being closely adjAcent one to the other, the far limit of the near viewing segment spaced farther from the lens than the near limit of the distance viewing portion with the near focal point and the distance focal point overlapping and coacting one with the other, the image rays uninterruptedly focused by the lens throughout the distance from the near limit of the near viewing segment to the far limit of the distance viewing portion, and there being clear uninterrupted vision throughout the entire focal range of the lens.

Claim 3

A plastic bifocal corneal contact lens to be worn on the cornea of a human eye, wherein the lens comprises a thin, circular, plastic lens body with a concave posterior surface and a convex anterior surface, a plastic near viewing segment fused in the center of the posterior surface, an annular distance viewing portion surrounding the near viewing segment, the near viewing segment and the distance viewing portion having the same principal optical axis, the thickness of the lens at the center thereof, including the near viewing segment and the adjacent part of the lens is 0.15 mm, the index of refraction of said plastic near viewing segment is greater than the index of refraction of the plastic distance viewing portion and the near viewing segment has a near focal point with a near limit and a far limit and spaced rearwardly of the lens, the distance viewing portion has a distance focal point with a near limit and a far limit and spaced rearwardly of the near focal point, the diameter of the near viewing segment is 2.6 mm and is less than the near point pupil size of the eye under an active state of near accommodation and the near viewing segment has a substantial depth of focus, the power of said near viewing segment is equal to the exact refractive add of the eye for near vision and thus eliminates correcting for the tear layer of the eye on which the lens is to be worn, said lens has a near point power less than three times as great as the distance viewing power, the far limit of the near viewing segment spaced farther from the lens than the near limit of the distance viewing portion, the near focal point and the distance focal point overlapping at a minor portion of adjacent ends thereof and coacting one with the other to define a single, composite focal area including the overlapped part, the image rays uninterruptedly focused by the lens throughout the single, composite focal area from the near limit of the near viewing segment to the far limit of the distance viewing portion.

Claim 4

A plastic bifocal corneal contact lens to be worn on the cornea of a human eye, wherein the lens comprises a thin, circular, plastic lens body with a concave posterior surface and a convex anterior surface, a plastic near viewing segment fused in the center of the posterior surface, an annular distance viewing portion surrounding the near viewing segment, the near viewing segment and the distance viewing portion having the same principal optical axis, the thickness of the lens at the center thereof, including the near viewing segment and the adjacent part of the lens is 0.15 mm, the index of refraction of said plastic near viewing segment is greater than the index of refraction of the plastic distance viewing portion and the near viewing segment has a near focal point with a near limit and a far limit and spaced rearwardly of the lens, the distance viewing portion has a distance focal point with a near limit and a far limit and spaced rearwardly of the near focal point, the diameter of the near viewing segment is 2.6 mm and is less than the near point pupil size of the eye under an active state of near accommodation and the near viewing segment has a substantial depth of focus, the power of said near viewing segment is equal to the exact refractive add of the eye for near vision and thus eliminates correcting for the tear layer of the eye on which the lens is to be worn, said lens has a near point power less than three times as great as the distance viewing power, the far limit of the near viewing segment spaced farther from the lens than the near limit of the distance viewing portion, the near focal point and the distance focal point overlapping at a minor portion of adjacent ends thereof and coacting one with the other to define a single, composite focal area including the overlapped part, the image rays uninterruptedly focused by the lens throughout the single, composite focal area from the near limit of the near viewing segment to the far limit of the distance viewing portion.

Claim 5

A plastic bifocal corneal contact lens to be worn on the cornea of a human eye, wherein, the lens comprises a thin, circular plastic lens body and a concave posterior surface and a convex anterior surface, a circular plastic near viewing segment fused in the center of the posterior surface, an annular distance viewing portion surrounding the near viewing segment, the near viewing segment and the distance viewing portion having the same principal optical axis, the thickness of the lens at the center thereof at the near viewing segment is 0.15 mm, the index of refraction of said near viewing plastic segment is about 1.57 and the index of refraction of said distance viewing portion is about 1.49, the diameter of said near viewing segment is 2.6 mm and is less than the near point pupil size of the eye under an active state of near accommodation and said near viewing segment has a very long depth of focus, the power of said near viewing segment is equal to the exact refractive add of the eye for near vision and thus eliminates correcting for the tear layer of the eye on which the lens is to be worn, said lens has a near point power which is no more than two and a half times as great as the distance viewing power, said near viewing segment has a near focal point with a near limit and a far limit and spaced rearwardly of the lens, the distance viewing portion has a distance focal point with a near limit and a far limit and spaced rearwardly of the near focal point, the far limit of the near viewing segment spaced farther from the lens than the near limit of the distance viewing portion with the near focal point and the distance focal point overlapping at a minor portion of adjacent ends thereof and coacting one with the other to define a single, composite focal area including the overlapped part, the image rays uninterruptedly focused by the lens throughout the single, composite focal area from the near limit of the near viewing segment to the far limit of the distance viewing portion, and there being clear, uninterrupted vision at both near and distant vision and intermediate vision and throughout the entire focal range of the lens.

Claim 6

A plastic bifocal corneal contact lens to be worn on the cornea of a human eye, wherein, the lens comprises a thin, circular plastic lens body and a concave posterior surface and a convex anterior surface, a circular plastic near viewing segment fused in the center of the posterior surface, an annular distance viewing portion surrounding the near viewing segment, the near viewing segment and the distance viewing portion having the same principal optical axis, the thickness of the lens at the center thereof at the near viewing segment is 0.15 mm, the index of refraction of said near viewing plastic segment is about 1.57 and the index of refraction of said distance viewing portion is about 1.49, the diameter of said near viewing segment is 2.6 mm and is less than the near point pupil size of the eye under an active state of near accommodation and said near viewing segment has a very long depth of focus, the power of said near viewing segment is equal to the exact refractive add of the eye for near vision and thus eliminates correcting for the tear layer of the eye on which the lens is to be worn, said lens has a near point power which is no more than two and a half times as great as the distance viewing power, said near viewing segment has a near focal point with a near limit and a far limit and spaced rearwardly of the lens, the distance viewing portion has a distance focal point with a near limit and a far limit and spaced rearwardly of the near focal point, the far limit of the near viewing segment spaced farther from the lens than the near limit of the distance viewing portion with the near focal point and the distance focal point overlapping at a minor portion of adjacent ends thereof and coacting one with the other to define a single, composite focal area including the overlapped part, the image rays uninterruptedly focused by the lens throughout the single, composite focal area from the near limit of the near viewing segment to the far limit of the distance viewing portion, and there being clear, uninterrupted vision at both near and distant vision and intermediate vision and throughout the entire focal range of the lens.

Claim 7

A plastic bifocal corneal contact lens to be worn on the cornea of a human eye, wherein the lens comprises a thin, circular, plastic lens body with a concave posterior surface and a convex anterior surface, a plastic near viewing segment fused in the center of the posterior surface, an annular distance viewing portion surrounding the near viewing segment, the near viewing segment and the distance viewing portion having the same principal optical axis, the thickness of the lens at the center thereof, including the near viewing segment and the adjacent part of the lens is from 0.1016 mm to 0.7721 mm, the index of refraction of said plastic near viewing segment is greater than the index of refraction of the plastic distance viewing portion and the near viewing segment has a near focal point with a near limit and a far limit and spaced rearwardly of the lens, the distance viewing portion has a distance focal point with a near limit and a far limit and spaced rearwardly of the near focal point, the diameter of the near viewing segment is 0.10 mm to 0.30 mm less than the near point pupil size of the eye under an active state of near accommodation and the near viewing segment has a substantial depth of focus, the power of said near viewing segment is equal to the exact refractive add of the eye for near vision and thus eliminates correcting for the tear layer of the eye on which the lens is to be worn, said lens has a near point power less than three times as great as the distance viewing power, the far limit of the near viewing segment spaced farther from the lens than the near limit of the distance viewing portion, the near focal point and the distance focal point overlapping at a minor portion of adjacent ends thereof and coacting one with the other to define a single, composite focal area including the overlapped part, the image rays uninterruptedly focused by the lens throughout the single, composite focal area from the near limit of the near viewing segment to the far limit of the distance viewing portion.

Claim 8

A plastic bifocal corneal contact lens to be worn on the cornea of a human eye, wherein the lens comprises a thin, circular, plastic lens body with a concave posterior surface and a convex anterior surface, a plastic near viewing segment fused in the center of the posterior surface, an annular distance viewing portion surrounding the near viewing segment, the near viewing segment and the distance viewing portion having the same principal optical axis, the thickness of the lens at the center thereof, including the near viewing segment and the adjacent part of the lens is from 0.1016 mm to 0.7721 mm, the index of refraction of said plastic near viewing segment is greater than the index of refraction of the plastic distance viewing portion and the near viewing segment has a near focal point with a near limit and a far limit and spaced rearwardly of the lens, the distance viewing portion has a distance focal point with a near limit and a far limit and spaced rearwardly of the near focal point, the diameter of the near viewing segment is 0.10 mm to 0.30 mm less than the near point pupil size of the eye under an active state of near accommodation and the near viewing segment has a substantial depth of focus, the power of said near viewing segment is equal to the exact refractive add of the eye for near vision and thus eliminates correcting for the tear layer of the eye on which the lens is to be worn, said lens has a near point power less than three times as great as the distance viewing power, the far limit of the near viewing segment spaced farther from the lens than the near limit of the distance viewing portion, the near focal point and the distance focal point overlapping at a minor portion of adjacent ends thereof and coacting one with the other to define a single, composite focal area including the overlapped part, the image rays uninterruptedly focused by the lens throughout the single, composite focal area from the near limit of the near viewing segment to the far limit of the distance viewing portion.