MULTIFOCAL OPHTHALMIC LENS

• US 20080198326A1
• Filed: 03/26/2008
• Published: 08/21/2008
• Est. Priority Date: 11/29/2002
• Status: Active Grant

• Current Assignee: Amo Groningen B. V.
• Original Assignee: Amo Groningen B. V.
• Inventors: Norrby, Sverker, Piers, Patricia Ann, Weeber, Hendrik A.
• Granted Patent: US 7,543,937 B2
• Time in Patent Office: Days
• US Class Current: 351/177
• CPC Class Codes: A61B 3/0025 characterised by electronic signal processing, e.g. eye models
• CPC Class Codes: A61F 2/1613 having special lens configurations, e.g. multipart lenses; having particular optical properties, e.g. pseudo-accommodative lenses, lenses having aberration corrections, diffractive lenses, lenses for variably absorbing electromagnetic radiation, lenses having variable focus
• CPC Class Codes: A61F 2/1618 Multifocal lenses
• CPC Class Codes: A61F 2/1637 Correcting aberrations caused by inhomogeneities; correcting intrinsic aberrations, e.g. of the cornea, of the surface of the natural lens, aspheric, cylindrical, toric lenses
• CPC Class Codes: A61F 2/164 Aspheric lenses
• CPC Class Codes: A61F 2/1654 Diffractive lenses
• CPC Class Codes: A61F 2002/1696 Having structure for blocking or reducing amount of light transmitted, e.g. glare reduction
• CPC Class Codes: A61F 2240/002 Designing or making customized prostheses
• CPC Class Codes: G01J 9/00 Measuring optical phase difference devices or arrangements for controlling the phase of light beams G02F1/01; Determining degree of coherence; Measuring optical wavelength spectrometry G01J3/00
• CPC Class Codes: G02C 2202/20 Diffractive and Fresnel lenses or lens portions
• CPC Class Codes: G02C 2202/22 Correction of higher order and chromatic aberrations, wave front measurement and calculation
• CPC Class Codes: G02C 7/027 considering wearer's parameters
• CPC Class Codes: G02C 7/028 Special mathematical design techniques
• CPC Class Codes: G02C 7/041 bifocal; multifocal
• CPC Class Codes: G02C 7/06 bifocal; multifocal ; progressive G02C7/041 takes precedence

Abstract

A method of designing a multifocal ophthalmic lens with one base focus and at least one additional focus, capable of reducing aberrations of the eye for at least one of the foci after its implantation, comprising the steps of: (i) characterizing at least one corneal surface as a mathematical model; (ii) calculating the resulting aberrations of said corneal surface(s) by employing said mathematical model; (iii) modelling the multifocal ophthalmic lens such that a wavefront arriving from an optical system comprising said lens and said at least one corneal surface obtains reduced aberrations for at least one of the foci. There is also disclosed a method of selecting a multifocal intraocular lens, a method of designing a multifocal ophthalmic lens based on corneal data from a group of patients, and a multifocal ophthalmic lens.

Claims

1. A method of designing a multifocal ophthalmic lens, comprising:

selecting a representative group of patients;

for the group, determining at least one of an average corneal shape and an average corneal spherical aberration;

modeling a lens comprising;

an anterior surface and an opposing posterior surface;

a diffractive pattern on one of the surfaces configured to generate multiple foci, the diffractive pattern characterized by a plurality of zones having predetermined diameters and the step heights; and

an aspheric shape on one of the surfaces, the aspheric surface being described by a radius of curvature and a conic constant; and

selecting the radius of curvature, the conic constant, the predetermined diameters, and the step heights to compensate for the average corneal spherical aberration and to reduce an averaged chromatic aberration for the group.

2. The method of claim 1, wherein the aspheric surface and the diffractive pattern are on a common surface.

3. The method of claim 1, wherein the diffraction pattern is configured to produce an apodization zone in which the step heights are selected to reduce towards the periphery of the lens.

4. The method of claim 1, wherein the diffractive pattern includes an apodization zone configured to gradually shift energy from a first focus of the multifocal lens to a second focus of the multifocal lens.

5. The method of claim 1, wherein a light distribution between the base focus and the additional focus is between 70%:

30% to 30%;

70%

6. Method according to claim 1, further comprising the steps of:

designing an average corneal model for the group of people from the calculated at least one mean corneal surface shape term or from the at least one mean corneal wavefront aberration term; and

checking that the designed multifocal ophthalmic lens compensates correctly for the at least one mean aberration term for at least one of the foci by measuring these specific aberration terms of a wavefront having traveled through the model average cornea and the lens and redesigning the multifocal lens if the at least one aberration term not has been sufficiently reduced in the measured wavefront.

7. The method of claim 1, further comprising selecting people in a specific age interval to constitute the group of people.

8. The method of claim 1, further comprising selecting people who will undergo a cataract surgery to constitute the group of people.

9. The method of claim 1, further comprising designing the lens specifically for a patient that has undergone corneal surgery and therefore selecting people who have undergone corneal surgery to constitute the group of people.

10. The method of claim 1, further comprising selecting people who have a specific ocular disease to constitute the group of people.

11. The method of claim 1, further comprising selecting people who have a specific ocular optical defect to constitute the group of people.

12. The method of claim 1, further comprising the steps of:

measuring the at least one wavefront aberration term of one specific patient'"'"'s cornea; and

determining if the selected group corresponding to this patient is representative for this specific patient and, if this is the case, implanting the multifocal lens designed from these average values and, if this is not the case, implanting a multifocal lens designed from average values from another group or designing an individual lens for this patient.

13. The method of claim 1, further comprising providing the multifocal lens with at least one non-spherical surface that reduces at least one positive spherical aberration term of an incoming non-spherical wavefront for at least one of the foci.

14. The method of claim 1, wherein the ophthalmic lens is an intraocular lens.