Orthokeratology lens and method for making orthokeratology lenses
AssigneeEyebright Medical Technology (Beijing) Co., Ltd.
InventorsZhao Wang, Jiangbing Xie
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Abstract
The present disclosure relates to an orthokeratology lens which may comprise an inner surface facing a cornea of a human eye when the orthokeratology lens is worn and an outer surface opposite the inner surface, the inner surface comprising a centrally located base are zone, wherein the base arc zone is configured for pressing and shaping an anterior surface of the cornea to have a shape that conforms to the base are zone, wherein the base arc zone comprises two or more regions, at least two of the two or more regions having different radii of curvature. The present disclosure also relates to a method for making orthokeratology lenses.
Claims34
An orthokeratology lens comprising an inner surface facing a cornea of a human eye when the orthokeratology lens is worn and an outer surface opposite the inner surface, the inner surface comprising a centrally located base arc zone, wherein the base arc zone is configured for pressing and shaping an anterior surface of the cornea to have a shape that conforms to the base arc zone, wherein the base arc zone comprises two or more regions, at least two of the two or more regions having different radii of curvature,
- wherein ΔT calculated from the following equation is from +0.5 D to +5.0 D, preferably from +0.75 D to +3.5 D, and more preferably from +1.0 D to +3.0 D:
- Δ
-
-
- T
- =
- 1000
- *
- (
- n
- -
- 1
- )
-
- (
- 1
- R
- 2
- -
- 1
- R
- 1
- )
- where R1 is the maximum radius of curvature of the base arc zone in millimeters, R2 is the minimum radius of curvature of the base arc zone in millimeters, n is the refractive index of the cornea with a value of 1.3375.
A method for making an orthokeratology lens comprising an inner surface facing a cornea of a human eye when the orthokeratology lens is worn and an outer surface opposite the inner surface, the inner surface comprising a centrally located base arc zone, the method comprising the steps of:
- (a) determining the maximum radius of curvature of the base arc zone;
- (b) determining an amount of presbyopia correction required by the wearer;
- (c) determining the minimum radius of curvature of the base arc zone using the following equation:
- 1000
- *
- (
- n
- -
- 1
- )
- R
-
-
- 1
- +
- Δ
-
-
- T
- =
- 1000
- *
- (
- n
- -
- 1
- )
- R
-
-
- 2
- where n is a refractive index of the cornea, R1 is the maximum radius of curvature of the base arc zone in millimeters, ΔT is the determined amount of presbyopia correction required by the wearer in D (diopter), R2 is the minimum radius of curvature of the base arc zone in millimeters;
- and
- (d) making an orthokeratology lens such that the base arc zone comprises two or more regions, and such that a first region of the two or more regions has the maximum radius of curvature and a second region of the two or more regions has the minimum radius of curvature.
An orthokeratology lens comprising an inner surface facing a cornea of a human eye when the orthokeratology lens is worn and an outer surface opposite the inner surface, the inner surface comprising a centrally located base arc zone, wherein the base arc zone comprises a centrally located circular first region, a circular ring shaped second region surrounding the first region, and a third region surrounding the second region, wherein a radius of curvature of the second region is smaller than a radius of curvature of the first region, and the radius of curvature of the second region is smaller than a radius of curvature of the third region,
- wherein the radii of curvature of the first region and the second region satisfy the following relationship:
- 0.5
- ≤
- 337.5
- *
- (
- 1
- R
- B
- -
- 1
- R
- A
- )
- ≤
- 6.0
- where RA is the radius of curvature of the first region in millimeters and RB is the radius of curvature of the second region in millimeters.
Dependencies are inferred from the claim text.