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EP-4110230-B1 - INTRAOCULAR LENS WITH FOCAL PERFORMANCE TAILORED TO PUPIL SIZE DEPLOYING REFRACTIVE POWER MODIFICATION ALONG SPIRAL TRACKS

EP4110230B1EP 4110230 B1EP4110230 B1EP 4110230B1EP-4110230-B1

Inventors

  • DE ABREU, Rodrigo
  • FERRAZ COSTA, Diogo
  • DE ALMEIDA GUSMÃO LYRA, João Marcelo

Dates

Publication Date
20260506
Application Date
20210302

Claims (14)

  1. An intraocular lens comprising: a transparent body with an anterior surface (20) and a posterior surface (40) having an optical axis (14) intersecting the centers of the anterior and the posterior surfaces; a base refractive power ( Φ IOL ) range defined by the base topologies of the anterior and posterior surfaces combined, as defined by the equation Φ IOL = n IOL − n aq R ant + n vit − n IOL R pos − n IOL − n aq R ant . n vit − n IOL R pos ⋅ t IOL n IOL ; characterized in that the intraocular lens comprises an additional power distribution along spiral tracks (24) wherein at least one surface has a spiral grid from which the surface is shifted axially in a step-like helicoidal pattern following the internal and external edges of the spiral tracks, wherein in said step-like helicoidal pattern a transition region (52, 54) is introduced between shifted zones, said transition region occupies part of the spiral track to which it transitions in the radial direction, or occupies the full width of said track.
  2. The intraocular lens of claim 1, wherein the transition function ( z step ) introduced between shifted zones is described by a Taylor series, a Fourier series, Bessel functions, Jacobi polynomials or Lagrange polynomials or by a smooth truncated sinusoidal function.
  3. The intraocular lens according to claim 1 or 2, wherein the step height, is constant or varies along the spiral track.
  4. The intraocular lens according to any one of claims 1 to 3, wherein the step height of one spiral track is equal to that of another spiral track defined on the same surface; or the step height is different to that of another spiral track defined on the same surface.
  5. The intraocular lens according to any one of claims 1 to 4, wherein the radial position (r) of the spiral tracks of the spiral pattern is described by equation r = a ∗ θ β + b , which depends on the azimuthal angle ( θ ), the parameter β can vary from -2 to 2; or wherein the radial position (r) of the spiral pattern described by a Logarithmic spiral follows equation r = a ∗ e β ∗ θ + b , which depends on the azimuthal angle ( θ ) and the parameter β , which varies from -2 to 2.
  6. The intraocular lens according to any one of claims 1 to 5, wherein the spiral patterns have a number of spiral tracks in the range of 1 to 200, and are contiguous, sparse or juxtaposed.
  7. The intraocular lens according to any one of claims 1 to 6, wherein the spiral pattern having the number of turns in the range of 1 to 200 include complete or incomplete turns.
  8. The intraocular lens according to any one of claim 1 to 7, wherein the spiral pattern starts at an outer edge of a central zone (22) on the base surface, or at a center of the base surface, and ending in a predefined circular region (28) with a radius equal to or smaller than the lens radius.
  9. The intraocular lens according to any one of claims 1 to 8, wherein the power variation along spiral tracks are deployed on the anterior, posterior or both surfaces.
  10. The intraocular lens according to any one of claims 1 to 9, wherein the anterior and/or posterior surfaces are convex, concave or flat.
  11. The intraocular lens according to claim 10, wherein the anterior base surface, posterior base surface or both base surfaces, are simple aspheric, spherical, toric, or have a base refractive power range changed by a multi-aspheric function (Z(r)) described by equation Z r = c . r 2 1 + 1 − 1 + k r c 2 r 2 , which depends on the radial position (r) and the conic function (k(r)); said multi-aspheric function formulated dividing the lens radius in N radial segments, with N being an integer in the range of 1 to 10,000 (ten thousand), and K 1 to K N+1 defining the conic values at the beginning and the end of each segment which can assume any real number in the range of from -1,000 (minus one thousand) to 1,000 (one thousand), and a transition function connecting two adjacent segments.
  12. The intraocular lens according to claim 11, wherein a transition function connects two adjacent segments of the multi-aspheric base ( k n ( r )), the transition function is defined by a Taylor series, a Fourier series, Bessel functions, Jacobi polynomials or Lagrange polynomials; or the transition function connecting two adjacent segments of the multi-aspheric base ( k n ( r )) is defined by k n r = K n + 1 − K n Δ r − n − 1 Δ + K n , where the radial position (r) varies from Δ · (n - 1) to Δ · n; or the transition function connecting two adjacent segments of the multi-aspheric base ( k n ( r )) is defined by k n r = β n K n + 1 − β n K n + 1 , where β n = 1 + sin π r − n − 1 Δ Δ + π Δ 2 and the radial position (r) varies from Δ · (n - 1) to Δ · n.
  13. The intraocular lens according to any one of claims 1 to 12, wherein the lens comprises multifocal, enhanced monofocal or extended-depth-of-focus characteristics that are maintained or morphed across different pupil sizes.
  14. A method of manufacturing the intraocular lens according to any one of claims 1 to 13, comprising using diamond turning, casting, hot stamping, injection molding or lithographic pattern wet and dry etching, and variations or combinations thereof; wherein said method relies on RIS (Refractive-Index Shaping) by a femtosecond laser, or a Laser Induced Refractive Index Change (LIRIC) to generate refractive power variations along spiral tracks; and wherein said lens is manufactured using materials that are rigid or foldable, hydrophobic or hydrophilic, methacrylate-based or silicone, such as PMMA, collamers, macromers, hydrogels, and acrylates.

Description

FIELD OF INVENTION The present invention relates to an ophthalmic intraocular lens, phakic or pseudophakic, meant to have its focal performance tailored to different pupil sizes, ensuring acceptable contrast of the retinal image and visual preferences and needs of the patient. The lens deploys refractive power variation along spiral tracks to achieve this goal. BACKGROUND OF THE INVENTION An intraocular lens is used in addition to or to replace the natural lens of the eye (crystalline lens), mostly when the latter is affected by cataract. In cataract surgery, the crystalline lens is removed, often preserving the capsular bag where the intraocular lens is inserted. This artificial lens can be developed to provide a good visual acuity for a single object distance, called monofocal lens, or for several object distances, thus referred to as multifocal. The simplest monofocal lens is the one with spherical surfaces. In these lenses the amount of spherical aberration becomes increasingly more detrimental to the image contrast in a distant focal point as the pupil is dilated. This issue can be mitigated by deploying at least one aspheric surface to the lens, which imparts a smooth reduction of the curvature radius from the center to the border, therefore reducing the contribution of spherical aberration. This aspheric surface can also be designed to compensate for some or all the spherical aberration present in the cornea. Both spherical and aspheric monofocal lenses provide a single focal distance, generally to favor far vision. Objects closer to the eye then have its optimal image projected on a plane off the retina. The focal spot, Point-Spread Function (PSF), of a point object distant from the eye features a minimum spot dimension at the exact focal plane of the system for distant vision. This plane is often the retina. The spot size is larger on longitudinally adjacent planes along the optical axis. However, there is a maximum spot size deviation from that of the optimal focal spot that is still perceived as yielding good resolution. The distance of the plane, on which this acceptable enlarged spot is projected, to the focal plane, is referred to as depth of focus. Spherical lenses, despite the worse quality of the focal spot on the focal plane, are known to feature larger depths of focus than their aspheric counterparts. The latter, on the other hand, offer better and smaller focal spots, thus higher contrast, and therefore better resolution. The pupil size naturally changes for different illumination conditions and, for both spherical and aspheric lenses, the depth of focus and contrast change as the pupil diameter varies. Since intraocular lenses do not usually feature the accommodation mechanism present in the crystalline lens, which partly compensates the pupil size variations, their contrast and depth of focus are often not in tune with the functional needs of the patients throughout the full range of pupil diameters. A person with an implanted aspheric monofocal lens might benefit from high-contrast and reasonable field range for distant vision under photopic light conditions (bright scene), but this individual still suffers from a poorer vision and limited field range under mesopic and scotopic conditions (medium lit to dark scenes). The same patient would have poor contrast for objects ranging from intermediate to close distances, regardless the pupil size. Unlike monofocal lenses, which are designed for good visual acuity for distant objects, the multifocal lenses are designed for a good visual acuity for objects at different distances. Objects at different distances yield their images overlapped on the retina in a process called simultaneous vision. This intraocular rivalry is partly sorted out by neural processes, such as neural adaptation or neural resignation, which allows the patient to privilege the image of the object of interest at any particular moment. Multifocal lenses usually have the optical zone partitioned into specific areas, resulting in different optical powers to yield more than one focal plane. A bifocal lens often creates a focal plane for far vision and another for near vision, while a trifocal lens has one more focal plane, often for intermediate vision. In most cases, multifocal lenses have a refractive central area with the reference optical power and at least one other area with an additional positive optical power which can be refractive, diffractive or a combination of both. The diffractive pattern in the periphery delays and bends the light propagation in such a way that the constructive and destructive interference orders are used to create a focal point other than the central one. In these lenses there tends to be intermediate distances along which the visual acuity is far lower than that on the designed target distances or foci. Multifocal lenses, in addition to the contrast reduction of the main focus, can have some positive dysphotopsia drawbacks such as halos, ring