US-12619103-B2 - Diffractive multifocal small aperture ophthalmic lens

US12619103B2US 12619103 B2US12619103 B2US 12619103B2US-12619103-B2

Abstract

A transmissive ophthalmic lens has a first surface opposite a second surface. The first surface includes a centrally disposed diffractive multifocal zone surrounded by a peripherally disposed refractive non-multifocal zone. The second surface is a refractive non-multifocal surface. The refractive non-multifocal zone forms the far focus. The diffractive multifocal zone is no more than 2.5 millimeters in diameter to produce a far focus and an Add focus and no less than 1.5 mm in diameter for Multipeak performance. A first groove and a second groove of the diffractive multifocal zone may be the only two grooves. At least 20% of light is directed within the diffractive multifocal zone to one of the far and the Add focus. The diffractive multifocal zone may have a base curve that together with a peripheral zone is bi-sign aspheric around far focus and aspheric grooves configured for minimum spherical aberration at the Add focus.

Inventors

Valdemar Portney
F. Richard Christ

Assignees

Valdemar Portney
F. Richard Christ

Dates

Publication Date: 20260505
Application Date: 20230328

Claims (14)

1 . A transmissive ophthalmic lens, comprising: a first surface opposite a second surface; the first surface comprising a centrally disposed diffractive multifocal zone surrounded by a peripherally disposed refractive non-multifocal zone; the second surface being a refractive non-multifocal surface; wherein the diffractive multifocal zone is no more than 2.5 millimeters configured to mitigate halos and no less than 1.5 mm diameters configured for the transmissive ophthalmic lens to manifest multipeak performance with a far focus and an Add focus; wherein at least 20% of light directed within the diffractive multifocal zone of the transmissive ophthalmic lens is to one of the far and the Add focus; wherein the refractive non-multifocal zone is configured to form the far focus; and wherein a smoothened transition is disposed between two consecutive grooves, wherein the smoothened transition includes a refractive segment connected to each groove by a step.
2 . The lens of claim 1 , wherein a first groove and a second groove of the diffractive multifocal zone are the only two grooves.
3 . The lens of claim 2 , wherein a transition is disposed between the first groove and the second groove, wherein the transition includes a refractive segment connected to each groove by a step.
4 . The lens of claim 1 , wherein the non-multifocal refractive surface of the second surface is spherical, aspheric or cylinder.
5 . The lens of claim 1 , wherein the transmissive ophthalmic lens is an intra-ocular lens.
6 . The lens of claim 1 , wherein the transmissive ophthalmic lens is an implantable contact lens.
7 . The lens of claim 1 , wherein the transmissive ophthalmic lens is a corneal inlay lens.
8 . The lens of claim 1 , wherein the transmissive ophthalmic lens is a contact lens.
9 . The lens of claim 1 , wherein the diffractive multifocal zone comprises a base curve together with the refractive non-multifocal zone that is bi-sign aspheric.
10 . The lens of claim 1 , wherein the diffractive multifocal zone includes high periodicity structure and low periodicity structure synchronized with each other that each width of low periodicity structure includes two widths of high periodicity structure.
11 . The lens of claim 1 , wherein the diffractive multifocal zone includes not more than two grooves of low periodicity structure each consisting of two widths of high periodicity structure.
12 . The lens of claim 1 , wherein the diffractive multifocal zone is configured to manifest a multipeak performance with the Add power of 1.75±0.5 D.
13 . A transmissive ophthalmic lens, comprising: a first surface opposite a second surface; the first surface comprising a centrally disposed diffractive multifocal zone surrounded by a peripherally disposed refractive non-multifocal zone; the second surface being a refractive non-multifocal surface; wherein the diffractive multifocal zone is no more than 2.5 millimeters configured to mitigate halos and no less than 1.5 mm diameters configured for the transmissive ophthalmic lens to manifest multipeak performance with a far focus and an Add focus; wherein a first groove and a second groove of the diffractive multifocal zone are the only two grooves; wherein at least 20% of light directed within the diffractive multifocal zone is to one of the far and the Add focus; including a smoothened transition disposed between the first groove and the second groove that includes a refractive segment connected to each groove by a step; and wherein the refractive non-multifocal zone is configured to form the far focus.
14 . A transmissive ophthalmic lens, comprising: a first surface opposite a second surface; the first surface comprising a centrally disposed diffractive multifocal zone surrounded by a peripherally disposed refractive non-multifocal zone; the second surface being a refractive non-multifocal surface; wherein the diffractive multifocal zone is no more than 2.5 millimeters configured to mitigate halos and no less than 1.5 mm diameters configured for the transmissive ophthalmic lens to manifest multipeak performance with a far focus and an Add focus; wherein at least 20% of light directed within the diffractive multifocal zone is to one of the far and the Add focus; wherein the diffractive multifocal zone includes not more than two grooves of low periodicity structure each consisting of two widths of high periodicity structure; and wherein the refractive non-multifocal zone is configured to form the far focus.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This utility patent application claims priority from U.S. Provisional patent applications: Ser. No. 63/362,387 filed Apr. 1, 2022, Ser. No. 63/371,501 filed Aug. 15, 2022 and Ser. No. 63/376,086 filed on Sep. 17, 2022, the entire contents of which all three applications are fully incorporated into the present application with these references. DESCRIPTION Field of the Invention The present invention relates generally to a multifocal ophthalmic lens of extended depth-of-focus (DOF) performance over a monofocal lens of the same shape and material. More particularly, it relates to an extended DOF diffractive multifocal small aperture intra-ocular lens (phakic intra-ocular lens, implantable contact lens and aphakic intra-ocular lens), corneal inlay and contact lens. Background of the Invention Ophthalmic lenses disclosed in this application refer to phakic or aphetic intraocular lens (IOL) including implantable contact lens (ICL) that is installed inside the eye, to a corneal inlay (CI) of the eye that is installed within the eye cornea and to a contact lens (CL) that is installed over the front surface of the eye. In describing the present invention, we shall provide the definitions of terms used. A monofocal lens is a fixed single power lens that provides good quality of vision but only within a small range of viewing distances that is usually significantly narrower than the range required from near or intermediate to far vision where far vision is usually defined at a distance of about 6 feet from the eye (around 2 meters) and beyond, near at about 2 feet (around 50 centimeters) and closer to the eye and intermediate is between far and near. Usually, it is said that a monofocal ophthalmic lens manifests a far power, far focus, and forms a far image of an object located at far distance. A monofocal lens may include a cylinder power to correct for ocular astigmatism which is referenced to in this application as non-multifocal lens; i.e., a monofocal lens that may also include cylinder. There is a significant effort to develop a lens for presbyopia correction in a form of refractive or diffractive type lenses where image forming refractive, diffractive or their combination is placed within a lens surface within so called clear aperture. This type of the lens provides a number of powers, so called bifocal or multifocal lens. Reference to bifocal or multifocal terminology is used herein interchangeably. A multifocal ophthalmic lens can provide refractive powers, diffractive powers or a combination of both and an additional power to far power called Add power (AP), additional focus to far focus called Add focus and additional image to far image called Add image formed by an object located at a distance other than far distance. A multifocal lens may include a cylinder power to correct for ocular astigmatism and a reference to multifocal lens throughout of this application also includes a cylinder. A multifocal ophthalmic lens includes multifocal surface to provide Add power and opposite refractive surface. The opposite surface means the refractive surface of the multifocal lens which is opposite to the multifocal surface with light passing the clear aperture of the lens through both surfaces. A diffractive lens generally consists of a number of annular surface zones of equal area over an imaginable surface called base curve, they are called diffractive grooves or just grooves. In a simple paraxial form, the grooves, echelettes or surface-relieve profiles can be expressed by the formula rj2=j⁢m⁢λ⁢f, the focal length (f) of m-order diffraction (m=±1, ±2, etc.) for the design wavelength (λ) can be closely approximated by the following formula: fm=rj2j⁢m⁢λ(1) In the paraxial approximation the blaze material thickness of blaze shape grooves also called diffractive optical step or just step (h), produces 100% efficiency at m-order is: hm=m⁢λ(n-n′)(2) Where n=refractive index of the lens material and n′=refractive index of the surrounding medium. Blaze shape is the most effective shape of diffractive multifocal lens and most used for multifocal ophthalmic lenses. Half of the step (h) in the formula (2) is used to produce bifocal diffractive lens with 40.5% of light directed to zero-order allocated to far focus and (−1)-order allocated to Add focus, i.e., m=−1. A trifocal diffractive lens manifests more complicated shape and it was described in the U.S. Pat. No. 8,500,805 by Kobayashi et al. (which is incorporated herein in full with this reference) as a superposition of two blaze surfaces where each diffractive order groove of the blaze surface of lower Add power coincides with every other groove of the blaze surface of higher Add power, 1st order coincides with 2nd, 2nd with 4th and do on. Both types of lenses are commonly referred to as diffractive multifocal lenses. If step sizes are zero or randomly sized or groove areas are randomly sized, the lens becomes a refractive type, i.