Multifocal contact lens with aspheric surface

• US 6,808,262 B2
• Filed: 06/14/2001
• Issued: 10/26/2004
• Est. Priority Date: 12/16/1998
• Status: Expired due to Term

• Current Assignee: Alcon Incorporated
• Original Assignee: Novartis Ag
• Inventors: Chapoy, L. Lawrence, Lett, John B. W., Rovani, William
• Primary Examiner(s): Sugarman, Scott J.
• Assistant Examiner(s): Collins, Darryl J.
• Application Number:
  US09/881,548
• Publication Number:
  US 20020036748A1
• Time in Patent Office: 1,230 Days
• Field of Search: 351/161
• US Class Current: 351/161
• CPC Class Codes: G02C 7/042 Simultaneous type
• CPC Class Codes: G02C 7/044 Annular configuration, e.g. pupil tuned
• CPC Class Codes: G02C 7/048 Means for stabilising the orientation of lenses in the eye

Abstract

A contact lens is disclosed having a front surface and a back surface. The lens contains a continuously varying aspheric surface on one or more of these surfaces.

Claims

1. A contact lens comprising:

a front surface and a back surface, one of the front surface and the back surface being an aspheric surface having an equatorial angle φ

wherein an eccentricity of the aspheric surface varies continuously as a function only of the angle φ

,

wherein the eccentricity varies according to the following equation;

2. The contact lens of claim 1 wherein the aspheric surface is the front surface.

3. The contact lens of claim 2 wherein the aspheric surface is the back surface.

4. A contact lens comprising:

a top portion and a bottom portion having an equatorial angle φ

, the top portion having a constant eccentricity as a function of the angle φ

, the bottom portion having an eccentricity that varies continuously as a function only of the angle φ

.

5. The contact lens of claim 4 wherein the top portion has an eccentricity to provide a distance correction power and the bottom portion has an eccentricity to provide, in part, a near correction power.

6. The contact lens of claim 5 wherein the near correction power has a maximum correction power where the angle φ

is in the range 225°

-315°

.

7. The contact lens of claim 6 wherein the near correction power has a maximum correction power where the angle φ

is 270°

.

8. The contact lens of claim 7 wherein the eccentricity of the bottom portion varies by the function:

9. The contact lens of claim 8 wherein the top portion and the bottom portion are on a back surface.

10. The contact lens of claim 8 wherein the top portion and the bottom portion are on a front surface.

11. The contact lens of claim 8 wherein the lens includes a ballast.

12. A contact lens comprising:

a top portion and a bottom portion, and two opposite side portions, the top portion having a first eccentricity along a selected arc, the bottom portion having a second eccentricity different from the first eccentricity a long the selected arc and the side portions having an equatorial angle φ and

an eccentricity that that varies continuously as a function of the angle φ

along the selected arc.

13. The contact lens of claim 12 wherein the top portion has an eccentricity that provides a distance correction power and the bottom portion has an eccentricity that provides a near correction power.

14. The contact lens of claim 13 wherein the first side portion is found at φ

=150°

to 210° and

the second side portion is found at φ

=330°

to 360° and

0°

to 30°

.

15. The contact lens of claim 14 wherein the eccentricity of the side portion varies according to the following equations:

16. The contact lens of claim 15 wherein the top portion and the bottom portion are on a front surface.

17. The contact lens of claim 16 wherein the lens includes a prism ballast.

18. A contact lens comprising:

a front surface and a back surface, one of the front surface and the back surface being an aspheric surface having an equatorial angle φ

wherein an eccentricity of the aspheric surface varies continuously as a function of the angle φ

, wherein a near correction power is located between 30°

-150° and

a distance correction power is located between 210°

-330°

.