Multifocal ocular lens

• US 6,260,966 B1
• Filed: 12/29/1999
• Issued: 07/17/2001
• Est. Priority Date: 03/11/1998
• Status: Expired due to Fees

• Current Assignee: Menicon Company Limited
• Original Assignee: Menicon Company Limited
• Inventors: Ohyama, Hiroyuki, Gotou, Yuuzi, Kondou, Hideaki, Miyamura, Kazuya, Sawano, Tadashi
• Primary Examiner(s): Sugarman, Scott J.
• Application Number:
  US09/474,740
• Time in Patent Office: 566 Days
• Field of Search: 351/160.R, 351/160.H, 351/161, 351/162, 351/177
• US Class Current: 351/161
• CPC Class Codes: A61F 2/1618 Multifocal lenses
• CPC Class Codes: G02C 2202/04 Lenses comprising decentered structures
• CPC Class Codes: G02C 7/042 Simultaneous type
• CPC Class Codes: G02C 7/043 Translating 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 multifocal ocular lens having a vision correction area which includes a central and outer vision correction region, an intermediate region located between the central and outer regions, and an intermediate-distance vision correction region located radially outwardly of and adjacent to the outer region, and which has an optical axis with which centers of these regions are aligned, the central and outer vision correction regions having respective different first and second optical power values, wherein the optical power of the intermediate region located between the central and outer regions is represented by a combination of two different quadratic curves connected to each other at a point of inflection which corresponds to a desired third optical power between the first and second values, and wherein the intermediate-distance vision correction region located radially outwardly of the outer region includes radially inner and outer varying-power zones, the optical power in the radially inner varying-power zone continuously varying from the second value of the outer vision correction region to a predetermined fourth value which is between the first and second values, while the optical power in the radially outer varying-power zone continuously varying from the fourth value to the second value of the outer region.

Claims

1. A multifocal ocular lens having a vision correction area consisting of a plurality of vision correction regions having respective different values of optical power, said plurality of vision correction regions including a central vision correction region, an outer vision correction region, and an intermediate region located between said central and outer vision correction regions, said vision correction area having an optical axis with which centers of said central and outer vision correction regions are aligned, said intermediate region consisting of a radially inner transition section adjacent to said central vision correction region and a radially outer transition section adjacent to said outer vision correction region,

said central and outer vision correction regions having respectively determined first and second mutually different optical power values (Pa, Pc), said optical power of said intermediate region changing from said first value to said second value, such that a rate of change of said optical power of said radially inner transition section increases with an increase in a radial distance from said optical axis of said vision correction area of said lens, along a first quadratic curve, while a rate of change of said optical power of said radially outer transition section increases with an increase in a radial distance from a radially inner periphery of said outer vision correction region, along a second quadratic curve,

said first and second quadratic curves being connected to each other at a point of inflection which corresponds to a radial position of a boundary between said radially inner and outer transition sections, and which corresponds to a desired third optical power value (Pb) between said first and second values,

and wherein said optical axis of said vision correction area of said lens is offset from a geometric center axis of said lens in a lateral direction by a distance of not larger than 2.0 mm, and also in a vertical direction by a distance of not larger than 7.0 mm.

2. A multifocal ocular lens according to claim 1, wherein a value y1 of said optical power of said radially inner transition section at a radial point which is distant from said optical axis of said vision correction area of said lens by a radial distance x1 is represented by the following equation (1), while a value y2 of said optical power of said radially outer transition section at a radial point which is distant from said optical axis of said vision correction area by a radial distance x2 is represented by the following equation (2),

3. A multifocal ocular lens according to claim 2, wherein said radial distance Wb from said optical axis of said vision correction area to said boundary of said radially inner and outer transition sections is determined according to the following equation:

4. A multifocal ocular lens according to claim 2, wherein said central vision correction region constitutes a part of a central optical zone for correction of a near vision, while said outer vision correction region constitutes a part of a peripheral optical zone for correction of a distant vision, and values Pa, Pb, Pc, Wa, Wb and Wc in said equations (1) and (2) are determined as follows:

5. A multifocal ocular lens according to claim 2, wherein said central vision correction region constitutes a part of a central optical zone for correction of a distant vision, while said outer vision correction region constitutes a part of a peripheral optical zone for correction of a near vision, and values Pa, Pb, Pc, Wa, Wb and Wc in said equations (1) and (2) are determined as follows:

6. A multifocal ocular lens according to claim 1, wherein at least one of opposite surf aces of said lens has part-spherical portions corresponding to said central and outer vision correction regions.

7. A multifocal ocular lens having a vision correction area consisting of a plurality of vision correction regions having respective different values of optical power, said plurality of vision correction regions including a central vision correction region, an outer vision correction region, and an intermediate region located between said central and outer vision correction regions, said vision correction area having an optical axis with which centers of said central and outer vision correction regions are aligned, said intermediate region consisting of a radially inner transition section adjacent to said central vision correction region and a radially outer transition section adjacent to said outer vision correction region,

said central and outer vision correction regions having respectively determined first and second mutually different optical power values (Pa, Pc), said optical power of said intermediate region changing from said first value to said second value, such that a rate of change of said optical power of said radially inner transition section increases with an increase in a radial distance from said optical axis of said vision correction area of said lens, along a first quadratic curve, while a rate of change of said optical power of said radially outer transition section increases with an increase in a radial distance from a radially inner periphery of said outer vision correction region, along a second quadratic curve,

said first and second quadratic curves being connected to each other at a point of inflection which corresponds to a radial position of a boundary between said radially inner and outer transition sections, and which corresponds to a desired third optical power value (Pb) between said first and second values,

said vision correction area further including an intermediate-distance vision correction region located radially outwardly of and adjacent to said outer vision correction region and having a distribution of optical power between said first and second values (Pa, Pc) of said central and outer vision correction regions, respectively,

and wherein said intermediate-distance vision correction region comprises a radially inner varying-power zone and a radially outer varying-power zone, and

the optical power in said radially inner varying-power zone continuously varying in a radial direction of said lens from said second optical power value (Pc) of said outer vision correction region to a predetermined fourth optical power value (Pd) which is between said first and second optical power values (Pa, Pc) of said central and outer vision correction regions, while the optical power in said radially outer varying-power zone continuously varies in said radial direction from said fourth optical power value (Pd) to said second optical power value (Pc) of said outer vision correction region.

8. A multifocal ocular lens according to claim 7, wherein a value y3 of the optical power in said radially inner varying-power zone is represented by the following equation (20):

9. A multifocal ocular lens according to claim 7, wherein a value y4 of the optical power in said radially outer varying-power zone is represented by the following equation (21):

10. A multifocal ocular lens according to claim 7, wherein said intermediate-distance vision correction region consists of said radially inner and outer varying-power zones which are connected to and adjacent to each other, such that the optical power at said radially outer end of said radially inner varying-power zone and the optical power at said radially inner end of said radially outer varying-power zone are both equal to said fourth optical power value (Pd).

11. A multifocal ocular lens according to claim 7, wherein said intermediate-distance vision correction region consists of said radially inner and outer varying-power zones, and a constant-power zone interposed between said radially inner and outer varying-power zones and having a constant optical power which is equal to the optical powers at said radially outer end of said radially inner varying-power zone and said radially inner end of said radially outer varying-power zone and which is equal to said fourth optical power value (Pd), said constant optical power in said constant-power zone being represented by one algebraic equation of the zeroth order.

12. A multifocal ocular lens according to claim 7, wherein at least one of the optical powers in said radially inner and outer varying-power zones is represented by one polynomial of the second or higher order or a combination of two different polynomials of the second or higher order.

13. A multifocal ocular lens according to claim 7, wherein said central vision correction region is used as a distant vision correction region while said outer vision correction region is used as a near vision correction region, and said radial distance Wd is in the range of 1.0-4.0 mm and said intermediate-distance vision correction region has a radial dimension of 0.4-3.0 mm.

14. A multifocal ocular lens according to claim 7, wherein said central vision correction region is used as a near vision correction region while said outer vision correction region is used as a distant vision correction region, and said radial distance Wd is in the range of 0.6-3.0 mm and said intermediate-distance vision correction region has a radial dimension of 0.4-3.0 mm.

15. A multifocal ocular lens according to claim 7, wherein said vision correction area further includes an outermost vision correction region located radially outwardly of and adjacent to said intermediate-distance vision correction region and consisting of a constant-power zone having an optical power which is represented by one algebraic equation of the zeroth order and which is equal to said second optical power value (Pc) of said outer vision correction region.

16. A multifocal ocular lens according to claim 7, wherein said vision correction area further includes an outermost vision correction region located radially outwardly of and adjacent to said intermediate-distance vision correction region and consisting of a varying-power zone and a constant-power zone, said varying-power zone having an optical power which is represented by one polynomial equation of the second or higher order or a combination of two different polynomial equations of the second or higher order, so that the optical power in said varying-power zone continuously varies from said second optical power value (Pc) of said outer vision correction region to said first optical power value (Pa) of said central vision correction region, and said constant-power zone having an optical power which is represented by one algebraic equation of the zeroth order and which is equal to said first optical power value (Pa) of said central vision correction region.

17. A multifocal ocular lens according to claim 7, wherein at least one of opposite surfaces of said lens has part-spherical portions corresponding to said central and outer vision correction regions.