Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
  • A61L27/52—Hydrogels or hydrocolloids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/14—Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes
  • A61F2/16—Intraocular lenses
  • A61F2/1613—Intraocular lenses 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
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/14—Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes
  • A61F2/16—Intraocular lenses
  • A61F2/1613—Intraocular lenses 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
  • A61F2/1624—Intraocular lenses 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 having adjustable focus; power activated variable focus means, e.g. mechanically or electrically by the ciliary muscle or from the outside
  • A61F2/1627—Intraocular lenses 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 having adjustable focus; power activated variable focus means, e.g. mechanically or electrically by the ciliary muscle or from the outside for changing index of refraction, e.g. by external means or by tilting
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
  • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
  • A61F2/02—Prostheses implantable into the body
  • A61F2/14—Eye parts, e.g. lenses, corneal implants; Implanting instruments specially adapted therefor; Artificial eyes
  • A61F2/16—Intraocular lenses
  • A61F2/1613—Intraocular lenses 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
  • A61F2/1659—Intraocular lenses 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 having variable absorption coefficient for electromagnetic radiation, e.g. photochromic lenses
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
  • A61L27/14—Macromolecular materials
  • A61L27/16—Macromolecular materials obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/13—Phenols; Phenolates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/15—Heterocyclic compounds having oxygen in the ring
  • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
  • C08K5/1545—Six-membered rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/17—Amines; Quaternary ammonium compounds
  • C08K5/18—Amines; Quaternary ammonium compounds with aromatically bound amino groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/08—Homopolymers or copolymers of acrylic acid esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
  • C08L33/04—Homopolymers or copolymers of esters
  • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
  • C08L33/10—Homopolymers or copolymers of methacrylic acid esters
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2430/00—Materials or treatment for tissue regeneration
  • A61L2430/16—Materials or treatment for tissue regeneration for reconstruction of eye parts, e.g. intraocular lens, cornea

Definitions

• This invention relates to a hydrogel implantable ophthalmic lens whose optical parameters can be optimized and/or customized by a controlled absorption of electromagnetic radiation, such as laser radiation in the visible and/or near-IR region, and more particularly radiation emitted in pulses shorter than one nanosecond (so called Femtosecond Laser, FSL) resulting in a change of the refractive index of the irradiated hydrogel.
• electromagnetic radiation such as laser radiation in the visible and/or near-IR region
• FSL Femtosecond Laser
• Intra ocular lenses are surgically implantable lenses which replace or supplement optical function of the NCL.
• So called “posterior chamber intraocular lens”, or PC IOLs replace the NCL in the case of cataract or, more recently, in the case of presbyopia by so called “clear lens exchange”, or CLE.
• Other implantable lenses are placed into the anterior chamber of the eye (AC IOLs), into the cornea (corneal or intrastromal implants) or between the NCL and iris (so called “implantable contact lens” or ICL). So far, most of these IOLs were designed to replace or to supplement the basic optical function of the NCL only. It should be appreciated that an NCL in a human eye, depicted in the Fig.
• the main eye parts include the cornea 101; the iris 102; the NCL 103; the posterior capsule 104; the cilliary muscle 105; the zonules 106; the vitreous body 107; and the retina 108.
• the basic optical function of the NCL 103 consists in helping the cornea 101 to focus the incoming light so that a distant object can be projected on the retina 108.
• the other important optical function is accommodation - adjustment of optical power of the lens in such a way that objects at various distances can be projected onto the retina 108.
• accommodation mechanism See for example L. Werner et al, Physiology of Accommodation and Presbyopia, ARQ. BRAS. OFTALMOL. 63(6),
• the NCL 103 is essentially spherical.
• a spherical lens is not exactly monofocal, instead it demonstrates so called "spherical aberration" wherein rays incoming through the center are bent into a focal point that is slightly further from the lens than rays incoming through the lens periphery. Therefore, a spherical lens is somewhat more refractive in its periphery than in its center. This change is continuous: such a lens does not have a single focal point, but many focal points in a short interval of distances (focal range) between the longest and shortest focal distance.
• a spherical lens is negatively polyfocal (its focal distance decreases from the center to the periphery).
• Lenses with elliptical rather than spherical surfaces have even more distinct spherical aberration and are, therefore, even more negatively polyfocal than spherical lens.
• Some artificial intraocular lenses include hyperbolic surfaces alongside with other surfaces of second order, such as spheric or even elliptic surfaces that have negative polyfocality and very opposite optical effect. More importantly, the prior art generally combines second order (or conic section) surfaces with meniscoid surfaces that are poorly defined and merely approximate second order surfaces with positive spherical aberration (although never surfaces with hyperbolic aberration).
• Wichterle in US Pat. No. 4,971,732 claims the meniscoid surfaces to approximate a flat ellipsoid while Stoy in US Pat. No. 5,674,283 considers meniscoid surfaces an approximation of a spherical surface, both having negative polyfocality. A combination of surfaces with positive and negative polyfocality diminishes or negates advantages of the former.
• Wichterle '732 describes a manufacturing method of the intraocular lens where a monomer solidifies in an open mold, one (posterior) side of the lens having the shape of the mold cavity while the anterior side has a shape of a solidified liquid meniscus
• the mold cavity has the shape of a second order surface that may include a hyperbolic surface.
• each of the optical surfaces is created differently - one by solidification of a polymer precursor against a solid surface while the other by solidification on the liquid-gas interface. It is known to those skilled in the art that the surface quality of the two optical surfaces formed under such different circumstances may differ profoundly in both optical and biological respects.
• Wichterle in US Pat. No. 4,846,832 describes another manufacturing method of the intraocular lens where the posterior side of the lens has the shape of the solidified liquid meniscus (presumably approximating a flat ellipsoid shape with negative polyfocality) while the anterior side is formed as an imprint of the solid mold shaped as a second order surface that may implicitly include also a hyperbolic surface.
• each of the optical surfaces is created differently - one by solidification of a polymer precursor against a solid surface while the other by solidification on the liquid-gas interface.
• Stoy '283 discloses modifying the method described by Wichterle '732 using a two part mold, one part being similar to the Wichterle' s mold while the other being used to form a modified meniscoid of a smaller diameter on the anterior lens surface.
• the meniscoid optical surface is of the same character as the meniscoid resulting from Wichterle '732, albeit of a smaller diameter and, therefore, probably closer to a spherical surface than an ellipsoid surface. In any case, such a surface has negative polyfocality.
• the posterior side is formed as an imprint of the solid mold shaped as a second order surface that may include a hyperbolic surface while the other optical surface is formed by solidification of the liquid polymer precursor on the liquid-gas interface.
• Michalek and Vacik in PCT/CZ2005/000093 describe an IOL manufacturing method using a spin-casting method in open molds. Molds filled with monomer mixture spin along their vertical axis while polymerization proceeds. One of the optical surfaces is created as the imprint of a solid mold surface while the other is formed by the mold rotation. The imprinted surface has the shape formed by rotation of the conic section along the vertical axis (which may include hyperboloid shape). The other surface is shaped as a meniscoid modified by the centrifugal force that will transfer some of the liquid precursor from the center toward the periphery.
• the centrifugal force will flatten the center and create a steeper curvature in the periphery, i.e. increase the spherical aberration of the surface.
• the centrifugal force will create a meniscus with smaller central radius and modify the surface to approximate something between spheric and parabolic shape.
• the hyperbolic aberration cannot be achieved for either a convex or concave meniscoid surface.
• Sulc et al. in US Pat. Nos. 4,994,083 and 4,955,903 discloses an intraocular lens with its anterior face protruding forward in order to be in permanent contact with the iris that will center the lens. Both posterior and anterior surfaces may have the shape obtained by rotation of a conical section around of the optical axis (sphere, parabola, hyperbole, ellipse).
• the iris- contacting part of the lens is a hydrogel with very high water content (at least 70% and advantageously over 90% of water) that is inherently soft and deformable.
• the optical surface deformed by the contact with iris cannot be exactly a conic section surface, but a surface with a variable shape that will depend on the pupil diameter, probably close to a sphere with a somewhat smaller central radius. Namely, this situation is similar to the lens from another reference that achieves decrease in the central diameter by pressing a deformable gel-filled lens against a pupil-like aperture in an iris-like artificial element (Nun in US Pat. No. 7,220,279). Nun '279 does not mention or imply use of hyperboloid optical surfaces. Cummings in US Pat. Publ. Nos. 2007/0129800 and 2008/0269887 discloses a hydraulic accommodating IOL in which a liquid is forced into the internal IOL chamber by action of cilliary apparatus causing thus change of the optical surface and accommodation.
• Hong et al. in US Pat. No. 7,350,916 and US Pat. Publ. No. 2006/0244904 disclose an aspheric intraocular lens with at least one optical surface having a spherical aberration in order to compensate the positive spherical aberration of the cornea.
• the negative spherical aberration is achieved by hyperbolic shape of the optical surface.
• Hong et al. in US Pat. Publ. No. 2006/0227286 discloses optimal IOL shape factors for human eyes and defines the optimum lens by a certain range of "shape factors" from -0.5 to +4 (the shape factor being defined by Hong as the ratio of sum of anterior and posterior curvatures to their difference), and at least one of the optical surfaces is advantageously aspherical with conic constant between -76 and -27.
• the present invention provides an artificial lens implantable into the posterior chamber of human eye for replacement of the natural crystalline lens, the lens (referring to the Fig. 3) having a main optical axis 1 A ; the central optical part 2 and the peripheral supporting part 3; the overall shape of the implant being defined by its anterior surface 4, posterior surface 5 and the transition surface 6 between the upper boundaries of the anterior and posterior surfaces 7A and 7B of the implant; having the central anterior optical surface 8 A with boundary 9 A and anterior apex 10A; the central posterior optical surface 8B with boundary 9B and posterior apex 10B; and anterior peripheral supporting surface 11 A and posterior peripheral supporting surface 1 IB.
• the artificial lens according to at least one embodiment of the invention has at least the posterior surface approximating the shape and size of the posterior surface of the natural lens in order to achieve substantially complete contact with the posterior capsule of the eye.
• the term "substantially” can mean that either at least about 90% of the posterior BAIOL surface is in contact with the posterior capsule, or at least about 75% of the posterior capsule (that has diameter larger that the lens) is in contact with the posterior surface of the lens.
• At least the part of the artificial lens according to the invention that is contacting the posterior capsule is made from a transparent flexible hydrogel material approximating the optical, hydrophilic and electrochemical character of tissue forming the natural lens.
• the anterior side is designed to avoid a permanent contact with iris.
• the anterior surface is shaped to avoid a permanent contact with the iris with the anterior peripheral supporting surface 11 A being concave.
• the artificial lens according to the invention has at least the major parts of its anterior and posterior surfaces, including both optical surfaces, defined by rotation of one or more conic sections along the optical axis and formed by solidification of a liquid polymer precursor in contact with a solid wall of a mold, preferably a hydrophobic plastic mold.
• One aspect of the invention is directed to a hydrogel comprising UV-absorbing dopant moieties and activator moieties that are negatively charged at physiological pH, where exposure of the fully hydrated hydrogel to electromagnetic radiation results in two-photon absorption which causes one or more structural changes in the hydrogel and a change in the refractive index.
• the hydrogel is a covalently crosslinked hydrogel.
• the structural change is achieved without substantially changing the volume of the treated hydrogel segment after it gets into equilibrium with the liquid medium around the lens.
• One convenient method to determine the volume change can consist in the following procedure: several equal zones in the hydrogel (e.g., 50 x 50 microns) are treated with various laser settings to achieve different phase shift in different zones.
• the hydrogel comprises a polymer comprising monomer units of (meth)acrylic acid derivatives and/or (meth)acrylic acid.
• the dopant moieties and activator moieties are pendant groups on a polyacrylate or polymethacrylate polymer.
• the dopant moiety is a UV-absorbing compound that does not strongly absorb light of about 400 nm wavelength.
• the dopant moiety is a compound selected from the group consisting of rhodamines, benzophenones, coumarins, fluoresceins, benzotriazoles, and derivatives thereof.
• the UV absorbent moiety contains a carbonyl group conjugated with an aromatic system, a phenolic hydroxyl group conjugated with an aromatic system, or advantageously both carbonyl and phenolic hydroxyl groups conjugated with an aromatic system.
• the activator moiety is a compound comprising a carboxylate group, sulfonate group, sulfate group, phenolate group or phosphate group.
• the one or more structural changes comprise partial depolymerization of the hydrogel. In one embodiment the partial
• the depolymerization forms an aqueous-filled void in the hydrogel.
• the change in the refractive index is a negative change.
• the depth of the partial depolymerization of the hydrogel depends on the cumulative energy absorbed in a given location of the hydrogel.
• the hydrogel comprises a polymer comprising monomer units selected from the group consisting of acrylic acid derivatives, methacrylic acid derivatives, acrylic acid, methacrylic acid, and mixtures of two or more thereof.
• Another aspect of the invention is directed to an ophthalmic implant comprising the above hydrogel.
• Yet another aspect of the invention is directed to an in szYw-adjustable hydrogel ophthalmic implant comprising an acrylate or methacrylate copolymer hydrogel where the copolymer comprises at least four co-monomers: a) an acrylate or methacrylate ester containing at least one pendant hydroxyl group; b) a polyol acrylate ester or polyol methacrylate ester or amide with at least 2 acrylate or methacrylate groups per polyol ester or amide; c) a derivative of acrylic or methacrylic acid having at least one pendant carboxyl group; and d) a vinyl, acrylic or methacrylic monomer having a pendant UV-absorbing group; where the refractive properties of the implant are adjusted by a controlled absorption of targeted electromagnetic radiation by the hydrogel resulting in a change of refractive index in selected locations of the implant.
• the ester of component a) carries at least one pendant hydroxyl group on the alcohol portion of the ester.
• the copolymer is covalently crosslinked.
• the implant has anterior and posterior refractive surfaces forming a lens with positive or negative refractive power.
• the lens is an intrastromal lens.
• the lens is an anterior chamber lens.
• the lens is a phakic lens for location between the iris and the natural crystalline lens.
• the lens is a posterior chamber lens for at least partial replacement of the natural crystalline lens.
• at least one of the refractive surfaces is an aspheric surface with negative spherical aberration.
• the monomer containing the pendant UV-absorbing group is present in a concentration between 0.2 molar % and 2.5 molar % based on all monomer units of the co-polymer.
• the pendant UV-absorbing group contains a carbonyl group conjugated to an aromatic group; in one embodiment the monomer containing the pendant UV-absorbing group is present in a concentration between 0.1 molar % and 5 molar % based on all monomer units of the co-polymer.
• At least one of the UV-absorbing pendant groups is selected from the group consisting of derivatives of benzophenone, derivatives of benzotriazole, derivatives of coumarin and derivatives of fluorescein.
• the pendant carboxyl groups and pendant UV- absorbing groups are present in a molar ratio between about 0.25 and 5; in another embodiment the pendant UV-absorbing groups are present in a molar ratio between about 0.5 and about 3.5.
• the copolymer contains at least two different comonomers containing different UV-absorbing groups; in one embodiment at least one of the UV-absorbing groups is a benzophenone.
• the pendant carboxyl group is ionized, and the molar ratio of ionized pendant carboxyl groups to UV-absorbing pendant groups is from about 0.5 to about 3.5.
• at least the major portion of the polymer of the hydrogel is a derivative of methacrylic acid; in one embodiment at least the major portion of the methacrylic acid derivative is a hydrophilic derivative of methacrylic acid.
• the hydrophilic methacrylic acid derivative is a glycol ester of methacrylic acid.
• the covalently crosslinked hydrogel contains more than 30% by weight of liquid under equilibrium physiological conditions.
• the covalently crosslinked hydrogel contains less than 55% by weight of liquid under equilibrium physiological conditions. In another embodiment the covalently crosslinked hydrogel contains between 35% and 47.5% by weight of liquid under equilibrium physiological conditions.
• the ophthalmic lens at least the posterior optical surface contributes refraction with negative spherical aberration. In another embodiment the posterior optical surface contributes refraction with negative spherical aberration between -0.1 microns and -2 microns. In a further embodiment the negative spherical aberration is between -0.5 microns and -1.5 microns. Alternatively the negative spherical aberration is between -0.75 microns and -1.25 microns.
• ophthalmic lens comprises both UV-absorbing pendant groups containing carbonyl groups conjugated to an aromatic system as well as UV-absorbing groups containing a benzotriazole structure.
• the UV-absorbing pendant groups containing carbonyl groups conjugated to an aromatic system and the UV-absorbing groups containing a benzotriazole structure are located in separate layers of the ophthalmic lens.
• the ophthalmic lens is implanted into a cornea.
• the lens is implanted into the anterior chamber of an eye between the cornea and iris.
• the lens is a phakic lens implanted between the iris and the natural crystalline lens.
• the lens is implanted into the posterior chamber of eye, at least partially replacing the natural crystalline lens.
• Another aspect of the invention is directed to a method of adjusting the refractive properties of a fully hydrated hydrogel of the invention, where the method comprises the step of focused irradiation of the hydrogel with electromagnetic radiation such that two-photon absorption occurs, and the polymer component of the hydrogel undergoes partial
• An additional aspect of the invention is directed to a method of in situ adjusting the optical parameters of a hydrogel ophthalmic implant, the method comprising the steps of: a) providing an eye containing a hydrogel ophthalmic implant according to claim 13; and b) irradiating a portion of the hydrogel ophthalmic implant with electromagnetic radiation using a femtosecond laser, whereby part of the copolymer of the hydrogel is depolymerized and/or ablated; where the optical parameters of the implant are adjusted.
• the optical parameters include the refractive index.
• the irradiation produces elongated cavities or voxels inside the hydrogel ophthalmic implant.
• the voxel depth is up to 20-30 microns or more. In one embodiment increasing the depth of the voxels increases the phase shift while the refractive index remains approximately constant; in one embodiment the refractive index is >1.3335. In some embodiments of the method the phase shift is up to 3 wavelengths of green light. In other embodiments of the method the depolymerized matter ablated by irradiation comprises soluble, easily diffusible compounds of low toxicity. Since the procedure releases only very low concentrations of depolymerized compounds into the intraocular space, the low toxicity of the method is also evident. In one embodiment of the method the modified optical properties are provided by forming in the hydrogel a pattern of elongated voxels of varying depth while keeping the modified refractive index approximately constant. In one
• phase shift is controlled by varying voxel depth rather than by varying their refractive index.
• Fig. 2 illustrates distribution of refractive power in a lens with one hyperbolic surface.
• Fig. 3 A is a cross-sectional view of a bioanalogic intraocular lens according to an exemplary embodiment of the invention.
• Fig. 3B is a top view of the lens of Fig. 3 A.
• Fig. 4A is a top view of another exemplary embodiment of a lens with a circular optical part and elliptical support part.
• Fig. 4B is a top view of another exemplary embodiment of a lens with a circular support part truncated by a single straight cut.
• Fig. 4C is a top view of another exemplary embodiment of a lens with a circular support part truncated by two symmetric crescent cuts.
• Fig. 4D is a top view of another exemplary embodiment of a lens with a circular support part truncated by one straight and two crescent cuts.
• Fig. 4E is a top view of another exemplary embodiment of a lens with a circular support part truncated by four symmetric crescent cuts.
• Fig. 4F is a top view of another exemplary embodiment of a lens with a circular support part truncated by two straight parallel cuts and the cylindrical lens with cylinder axis IB in the angle a with regard to the cuts direction.
• Figs. 5 A, 5B and 5C illustrate top views of exemplary lenses with the optical surfaces divided into two or more optical zones.
• Figs. 6A, 6B and 6C are cross-sectional views of alterative lens in accordance with the invention composed from two or more materials.
• Figs. 7A, 7B and 7C are expanded views illustrating alternative profiles of the supporting peripheral part of the exemplary lenses.
• Fig. 8 illustrates the schematic arrangement of the mold for production of a lens in accordance with an exemplary embodiment of the invention.
• Fig. 9 A shows a comparison of the Raman spectra of a representative hydrogel of the invention before and after two photon absorption (TP A) using a femtosecond laser.
• Figs. 9B and 9C show graphs of relevant parameters of the Raman spectrum.
• (meth)acrylate denotes either acrylic/acrylate or methacrylic/methacrylate moieties.
• the polymers comprise acrylic/acrylate moieties.
• the polymers comprise methacrylic/methacrylate moieties.
• the polymers comprise both acrylic/acrylate and methacrylic/methacrylate moieties.
• the polymers comprise methacrylic/methacrylate moieties.
• ablation refers to removal of a section of the polymeric structural support of a hydrogel, preferably by decomposition of the polymer to diffusible, low-molecular fragments.
• depolymerization constitutes a special type of ablation where the fragments are monomers.
• implantable ophthalmic lenses used in various locations in the eye, from corneal stroma through anterior chamber to posterior chamber.
• One of the problems with implantable lenses is the complicated selection of the correct refractive properties (so called biometry) and difficulty to replace them or correct them if the biometry turned out to be wrong or if the optical requirements of eye change over time. This inspires the effort of the industry to develop implantable lenses whose optical parameters could be adjusted non-invasively and post-operatively. Change of the optical properties of an artificial lens, either pre-operatively or post-operatively, can be achieved by changing refractive index of the lens material.
• the wavelength of the laser beam is usually in the range of near infrared radiation, about 800 nm to 1300 nm, or more typically in the range of visible and near infrared radiation from about 660 nm to about 1100 nm. The use of higher wavelengths is usually preferred because of safety concerns.
• One method of changing the refractive index of the lens material, by means of a femtosecond laser ("FSL procedure" for short) can, in principle, achieve many changes of refractive properties, such as spherical refractive power, cylindrical refractive power, spherical aberration, etc.
• the procedure can selectively change any of the coefficients in the Zernike polynomial ("Zernike Coefficients") repeatedly even in the implanted lens. This has been demonstrated by Gustavo A. Gandara-Montano et al
• ETAFILCON® contact lens hydrogel when treated by femtosecond laser at 800 nm.
• the FSL procedure can be performed both on hydrophilic (where the refractive index RI is usually increased) and hydrophobic IOL materials (where the RI is usually decreased).
• the FSL procedure can be more advantageously performed on hydrogel ophthalmic lenses, particularly on implantable lenses of various types, since the refractive change even in the currently available hydrogels is higher than in the hydrophobic materials.
• FSL procedure in hydrophobic acrylates could lead, at least in theory, to so-called
• hydrogels micromachining by femtosecond lasers.
• the sensitivity of hydrogels can be increased by various "dopants" designed to respond to various wavelengths of electromagnetic radiation.
• dopants A number of dopants have been described so far in the patent and scientific literature. All presently known dopants are single compounds capable of UV absorption, but no known dopants are capable of single-photon absorption at the wavelength used for the FSL procedure.
• TPA activators e.g. co-monomers containing negatively charged pendant groups, particularly organic carboxylic acid salts.
• Both the dopant and its activator can be advantageously covalently bound to polymer chains, more advantageously to the chains forming the polymer network of the hydrogel.
• Both the dopant and its activator may be bound to the same polymer chain or to different polymer chains.
• the inventive hydrogels contain a combination dopant in the form of a minor part of a pendant UV-absorbing structure that does not significantly absorb visible light, with a minor part of the activator in the form of pendant groups comprising an ionized salt of an acid, with a major part of methacrylate neutral hydrophilic derivative, particularly glycol or glycerol esters of methacrylic acid and a minor part of a polyol with at least two of the hydroxyl groups esterified by acrylic or methacrylic acid.
• These hydrogels are materials particularly suitable for adjustment of refractive index by absorption of femtosecond pulses of visible or near infrared radiation (femtosecond laser (FSL) treatment).
• the absorption of electromagnetic energy causes controlled degradation and depolymerization of the polymeric component of such hydrogels thereby forming domains with lower refractive index. Thanks to the activator, such domains can be formed even if the hydrogel is irradiated by a femtosecond laser with pulses of relatively low energy and at a very high "writing speed" or "scanning velocity".
• bioanalogic covalently crosslinked acrylic and methacrylic hydrogels containing negatively charged groups, particularly carboxylate groups, and containing also monomers with pendant UV-absorbent groups, such as, for example, methacryloyloxybenzophenone (MOBP).
• MOBP methacryloyloxybenzophenone
• a method to depolymerize such polymers by absorption of electromagnetic radiation in order to adjust optical properties of the implantable hydrogel using femtosecond laser to depolymerize parts of the hydrogel and to form internal cavities that would form new refractive members, such as toric lenses.
• the UV-absorbent group used in the hydrogel acts as a "dopant” increasing the depolymerization rate, while the negatively charged group acts as an “activator” for the dopant, increasing the dopant's efficacy still further.
• the activator acting as a quencher protects the material from undesirable "charring” or “burning” that may happen over a certain amount of absorbed energy per time. This allows one to lower the overall amount of energy needed to achieve a certain refractive change, and therefore to use safely the more energetic visible light rather than less energetic near infrared (NIR) radiation.
• NIR near infrared
• the diameter of a voxel is much smaller than its depth thanks to the self-focusing of the laser beam in the case of TPA or MP A, and is typically around 500 nm.
• the voxel depth is much larger and grows with deposited energy.
• the reported maximum voxel depth is about 6 microns in currently known materials.
• the dopant If the radiation of a certain wavelength is absorbed via TPA or MP A, then the dopant accumulates excitation energy equivalent to a single-photon absorption of the wavelength of incident light divided by the number of the absorbed photons.
• laser light at 400 nm absorbed via TPA by the dopant will correspond to 200 nm light absorbed via SPA.
• Light of 200 nm wavelength is a hard UV light (UVC Band) that is sufficiently energetic to cause a breakage of chemical bonds and a deep structural rearrangement.
• UVC Band hard UV light
• 3 photon absorption or 4 photon absorption although much less probable than TPA, would accumulate even higher energy concentration.
• the excited state with high accumulated energy is shortlived since the energy dissipates quickly via one of several possible pathways, the most usual being conversion into thermal energy.
• the usual effect of femtosecond laser treatment of tissues or synthetic hydrogels involves local increase of temperature that may cause - depending on the amount of the energy absorbed - effects starting with conversion of the matter into a plasma (e.g., via laser ablation) through heating sufficient for charring, to more subtle additional crosslinking via various mechanisms such as re-esterification,
• the presence of the activator (pendant negatively charged groups, particularly carboxylate groups), changes the mechanism of this process. We believe that this is caused by certain cooperation of the activator groups with dopants. In this cooperation, activation of dopants further facilitates TPA absorption and increases its effect.
• the activator such as the carboxylic acid group of methacrylic acid or a salt thereof, is apparently in an interaction with the dopant because its presence causes a change of the dopant's UV/Vis spectrum (namely, a subtle shift from the UV toward the visible region). This may increase the dopant's "TPA cross-section" and increase the absorption efficacy of the dopant.
• the main role of the activator may be in channeling the absorbed energy of the two (or more for MP A) absorbed photons from the dopant to the main polymer chain to cause breakage of the covalent bond in the main chain. It is understood from the general character of this process, and from the known depolymerization kinetics of methacrylate polymers, that this cleavage is homopolar and produces free radicals that start the
• This free radical mechanism may vastly increase the quantum yield of the photodegradation and helps to explain why even a relatively low concentration (on molar basis) of the dopant can cause profound changes in the local composition and structure, and consequently a substantial change in the local refractive index.
• the activator groups help to divert the absorbed energy from the dopant to quench the excited state and “consume” this energy for the breakage of covalent bonds.
• This "energy conduit” function of the activator prevents excessive heat accumulation in the vicinity of the dopant moiety, helping thus to "recycle” the dopant molecule and preserve it for the future TPA cycle. It also helps to protect the polymer structure from burning and charring and helps to increase the efficacy of the whole absorption process.
• this proposed mechanism can explain the fact that in the absence of the activator, TPA in hydrogels with only the dopant proceeds via a different mechanism and achieves the opposite result: while in presence of the activator the refractive index decreases, in its absence the refractive index increases.
• One possible reason for the increased refractive index seems to be an additional crosslinking leading to decreased water content and, consequently, increased refractive index since water has the lowest refractive index of all hydrogel constituents.
• the mechanism stipulated in the present invention involves exchange of a certain part of the polymer mass for water, with a low net volume change, if any.
• the depolymerization of the hydrogels covered by the present invention yields low toxicity monomers and/or their fragments, primarily 2-hydroxy ethyl methacrylate, methacrylic acid and ethylene glycol. All these decomposition products are well soluble in water and capable of diffusing through the surrounding intact hydrogel network, to be dissipated from the implant over some time in very low concentrations.
• the proposed mechanism may explain very large phase shift achievable in hydrogels according to this invention.
• the phase shift is determined by the change in the refractive index and the length of light path through material with changed refractive index, in other words, the voxel depth.
• Refractive index in hydrogels cannot be practically lower than refractive index of water, or about 1.3335 since the lowest conceivable index can be achieved in a cavity filled with aqueous liquid.
• the cavity in a hydrophilic polymer matrix cannot be filled with a gas for certain basic thermodynamic reasons, and there is no known or readily conceivable mechanism of creating a hydrophobic cavity within the hydrogel.
• phase shifts (more than one wavelength) will require formation of voxels with large depth. It is usually assumed that the voxel depths can reach at most about 5 to 6 microns. However, if the refractive index in the focal volume decreases, then the elongated voxel would act as a light-guide that channels additional light pulses to be absorbed in the voxel bottom. Consequently, the depth of the voxel can gradually increase with increasing number of pulses, and so does then the phase shift even though the refractive index remains approximately constant and equal to or higher than 1.3335.
• the newly created refractive or diffractive structures form a system of parallel waveguides (i.e., elongated voxels with refractive index lower than the surrounding hydrogel) of different length, whereby the phase shift is controlled by the varying voxel depth rather than their varying refractive index.
• An additional feature of the invention is creation of a gradient of refractive index in the vicinity of individual voxels.
• the monomers and other fragments released by the depolymerization inside the voxel migrate radially by diffusion through the surrounding hydrogel.
• the temperature decreases below the ceiling temperature (around 200°C in the case of methacrylates) at least part of the released monomers and/or fragments may re- polymerize and create a denser network structure with a higher refractive index than the parent hydrogel.
• This mechanism has two beneficial consequences: first, it reduces the amount of compounds that diffuse outside of the implant to be metabolized, and second, the gradient of refractive index thus formed improves the light-guiding properties of the voxel.
• monomers released by depolymerization may not all diffuse out of the hydrogel, but may partly re-polymerize in the voxel vicinity.
• the present method is somewhat similar to FS laser ablation in that that both remove some polymer mass and retain water instead, although the term "ablation" frequently denotes a process of
• hydrogel copolymerization of the hydrogel copolymer is believed to be the primary mechanism involved in the presently disclosed process, it may be supplemented by other decomposition reactions that form small, water-soluble fragments, such as hydrolysis of the (meth)acrylate pendant groups, or oxidation.
• Dopant concentration in hydrogels according to the invention varies from about 0.05 %-mol to about 5%-mol, advantageously from about 0.1 %-mol to about 2.5 %-mol.
• the different optimum dopant concentration can be used for various dopants, e,g, 0.25 to 0.55 molar % for benzophenone derivatives, or 0.1 to 0.2 molar % for
• benzotriazole derivatives are UV absorbers with low absorbance for visible light, i.e. above a wavelength of about 390 nm.
• suitable dopants are vinyl, acrylate or methacrylate derivatives of benzophenone, benzotriazole and coumarin, although those skilled in the art can certainly identify other suitable UV absorbers that work as dopants in the sense of the invention.
• the activating groups are present in concentration from about 0.25 %-mol to about 5
• the preferred molar concentration of methacrylic acid is between 1 and 1.25 % molar.
• the preferred activator groups are derivatives of acrylic or methacrylic acid containing a pendant acidic group including carboxylate group, sulphate group, sulfonate group and phosphate group. Such acidic groups are preferably neutralized by suitable organic or inorganic cations.
• the activator to dopant group molar ratio should be about 0.75 to 10, advantageously from about 1 to about 5 . Alternatively the different optimum molar ratio activator/dopant are different for different dopant.
• the optimum ratio for benzophenone derivatives is from about 2 and 4 and for benzotriazol derivatives between about 5 and about 7.
• the preferred composition of a hydrogel according to the invention comprises a major fraction of a methacrylate monomer with pendant neutral hydrophilic groups.
• major fraction is meant at least 50%-mol of all monomer units in the hydrogel.
• the molar fraction of the hydrophilic methacrylate monomer is between 90%- mol and 99.5%-mol, and in many cases between 97.5%-mol and 99%-mol.
• Such hydrophilic methacrylate monomers can be esters of polyol aliphatic compounds, such as glycols, glycol ethers, glycerol and sugars.
• esters comprise amides of methacrylic acid, such as methacrylamide, N-isopropyl methacrylamide or N-(2- hydroxyethyl) methacrylamide.
• This major fraction of the hydrogel polymer may also comprise a mixture of such hydrophilic monomers.
• a minor portion of the methacrylate monomers (but not more than 25%-mol) can be replaced by analogous acrylic acid derivatives. In some embodiments 0.5 %-mol to 5%-mol can be replaced by acrylate monomers.
• a minor part of the monomer units is formed by the above mentioned activator monomers with a pendant negatively charged group, and still another minor part is formed by the above mentioned dopant monomers.
• the polymer is advantageously covalently crosslinked.
• the crosslinking can be achieved by any of the methods known to those skilled in the art, such as radiation crosslinking, crosslinking by formation of ether links between pendant OH groups, etc.
• the preferred crosslinking method is copolymerization with a minor fraction of methacrylate or acrylate crosslinking diesters or triesters of polyols, such as, for example, triethylenglycol dimethacrylate.
• Refractive index of the hydrogel according to the invention is between about 1.38 and about 1.48, preferably between about 1.40 and about 1.45. In some embodiments the RI is about 1.40, or about 1.41, or about 1.42, or about 1.43, or about 1.44, or about 1.45.
• the preferred hydrogel according to the invention contains between about 25%-wt and about 85%-wt liquid in equilibrium with live intraocular environment.
• the more advantageous equilibrium liquid concentration is between 35 %-wt and 50 %-wt, and more particularly between 40% and 47%-wt.
• the equilibrium water content is 41%-wt ⁇ 0.75%, or 42.5 ⁇ l%-wt, or 44.5 ⁇ 1% by weight. It is understood by those skilled in the art that equilibrium liquid content in hydrogels is subject to many variables, such as body temperature, composition of body fluids or pressure exerted by surrounding tissues or body structures.
• hydrophobic acrylates or methacrylates such as
• Typical concentration of such added methacrylates or acrylates is up to about 40% molar. In some embodiments the concentration of added hydrophobic monomers is between about 5%-molar and 25%-molar.
• the dopant group and activating group may be located on the same polymer chain, or on different polymer chains that are in an intimate contact e.g. in a polymer blend, or being on two different segments of polymer network.
• One or other may be on a graft, or one can be on a graft and the other on the basic chain.
• the dopant group and activating group may be on a single molecule in a suitable steric relationship allowing their mutual interaction.
• Such a "dopant-activator complex" may be then covalently bound to a polymer chain, or admixed into the polymer, or become part of the main polymer chain.
• Negatively charged activator groups have some additional advantages for intraocular implants, such as improved biocompatibility, resistance to adsorption of proteins, resistance to formation of biofilms, resistance to calcification, and resistance to adhesion and spreading of cells (which translates into resistance to sclerotization of posterior capsule and resistance to posterior capsule opacification).
• the hydrogel implant according to the invention can be placed in various locations within the eye along the optical path. It may have the form of a "blank" in which a refractive or diffractive lens is created, or it may have the form of a refractive or diffractive lens which optical properties are modified by the refractive index change within selected locations of the implant.
• Implantable Contact Lens Another type of implantable ophthalmic lens is so called “Implantable Contact Lens”.
• ICL is a phakic lens placed between iris and the natural crystalline lens. It is described in several patents, e.g., Fedorov , et al. Intraocular lens for correcting moderate to severe hypermetropia, US 5,766,245; Feingold V., Intraocular contact lens and method of implantation, UP 5,913,898; Intraocular refractive correction lens, US 6,106,553; each of which is incorporated herein by reference.
• These implantable lenses are made from hydrogels that incorporate a biological component, usually collagen.
• a biological component usually collagen.
• Collamers are described in various patents, such as Feingold, et al., Biocompatible, optically transparent, ultraviolet light absorbing, polymeric material based upon collagen and method of making, US 5,910,537; Feingold, et al. Biocompatible optically transparent polymeric material based upon collagen and method of making, US 5,654,349, US 5,654,388 and US 5,661,218; Fedorov, et al., Biocompatible polymeric materials, methods of preparing such materials and uses thereof, US 5,993,796; Method of preparing a biological material for use in ophthalmology; each of which is incorporated herein by reference.
• intrastromal implants are designed for post-operative adjustment of optical power by laser, as described by Peyman, Gholam A. in Intrastromal corneal modification via laser, US 2001/0027314; in Adjustable ablatable inlay, US 2002/0138069 and 2002/0138070;
• All such ophthalmic lens types can be manufactured from the hydrogels according to the present disclosure and then modified by using a femtosecond laser treatment.
• hydrogels and methods replace part of the hydrogel-forming copolymer with water or aqueous fluid, rather than decreasing the water content of the hydrogel by modifying the copolymer properties (such as by polymer crosslinking).
• the NCL has a very complicated structure that develops over time.
• One of the structural features is asphericity of posterior and anterior surfaces of the NCL 103.
• E.L.Markwell et al MRI study of the change in crystalline lens shape with accommodation and aging in humans, Journal of Vision (20110 11(3); 19, 1-16; M.Dubbelman et al, Change in shape of the aging human crystalline lens with
• Y - Yo X A 2/ ⁇ Ro*(l+l-h*(X/Ro) A 2) A 0.5 ⁇ equation 1 where Y is the coordinate in the direction of the main optical axis 1 A, X is the distance from the main optical axis 1 A, Yo is the apex position on the main optical axis 1 A, Ro is the central radius of curvature and h is the conic constant (or the shape parameter).
• the anterior surface is more hyperbolic than the posterior surface, that hyperbolicity increases significantly with accommodation, and that the human lens grows with age and its hyperbolicity decreases so that an old NCL may become approximately spherical.
• a typical human lens anterior central radius ranges from about 5 to 13 mm and the average anterior conic parameter is about -4 (ranging from about -22 to +6).
• the posterior central radius ranges from about 4 to 8 mm and the average posterior conic parameter is about -3 (ranging from about -14 to +3).
• the central thickness of a young, relaxed NCL ranges typically from about 3.2 mm to about 4.2 mm, increasing with age and/or with the near-focus adjustment to a thickness from about 3.5 mm to about 5.4 mm.
• the posterior part depth of the NCL is typically the same as, or larger than the anterior part depth. Therefore, the sagittal depth of the posterior lens surface is typically from about 1.75 mm to about 2.75 mm on equatorial diameter from about 8.4 mm to about 10 mm. This defines the basic dimensions of the posterior capsule in its "natural" state.
• Lenses with at least one hyperbolic surface demonstrate a "hyperbolic aberration" that is opposite of the spherical aberration: rays incoming through the center are bent into a focal point that is closest to the lens, and the focal point becomes progressively further from the lens for rays incoming in increasing distance from the lens center toward the lens periphery.
• the eye helps to focus on near objects by narrowing the pupil. This so called
• spherical or elliptical (e.g., meniscoid) lens becomes weaker lens with lower refractive power by the near myosis rather than a stronger lens that is needed for near focus.
• An artificial lens according to the invention is a hydrogel device implantable into the posterior chamber of human eye for replacement of the natural crystalline lens. It is designed to mimic or replicate essential physiological and optical functions of natural lens without creating problems that earlier attempts could cause in some situations. It is important to recognize that this is achieved by a novel thoughtful combination of features that might have been individually, or in different combinations, applied previously with a lesser success.
• the natural lens also achieves its function due to its balanced combination of features rather than to a single feature.
• the implant has a main optical axis 1 A with a central optical part 2 and a peripheral supporting part 3.
• the overall shape of the implant is defined by its anterior surface 4, posterior surface 5 and the transition surface 6 between the upper boundaries 7A and 7B of the anterior and posterior faces, respectively.
• Each face is composed of two or more surfaces.
• the anterior central optical surface 8A has boundary 9A and central posterior optical surface 8B has boundary 9B.
• Each of the surfaces may be divided into two or more zones with the boundary between them (denoted 13 A and 13B in Figs. 5 A to 5C) being circles, straight lines or otherwise defined shapes.
• the apexes of the central anterior optical surface 10A and central posterior optical surface 10B are positioned on the main optical axis 1 A.
• the anterior peripheral supporting surface is 11 A and the posterior peripheral supporting surface is 1 IB.
• any layer or structure in the optical path may be formed by the hydrogel according to the present invention.
• the preferred layer may be the layer closest to the cornea, i.e. the one forming the anterior optical surface of the lens.
• Optical structures formed by the hydrogel optical modification may be refractive structures, diffractive structures, Fresnel lenses shown in the Fig. 6B, refractive index gradient lenses or similarly. Such structures can be formed within the hydrogel, or on its surface, preferably on the anterior optical surface.
• the boundaries 7 A and 7B are distinguishable as a discontinuity on the top of the anterior and posterior surfaces 4 and 5, respectively. Such a discontinuity lay in the inflexion point of the surface in the direction of the optical axis, or a in a point of discontinuity of the second derivative of the surface in the direction of the optical axis.
• the boundary can be rounded and continuous, but advantageously it is formed by a sharp rim or edge. The advantage of the sharp edge is in forming the obstacle to migration of cells such as fibroblasts along the capsule surface (the usual reason for posterior capsule opacification).
• the overall lens diameter is defined as the larger diameter of the boundaries 7 A and 7B.
• the lens optical zone diameter is defined as the smallest diameter of the boundaries 9A and 9B.
• the posterior sagittal depth is the vertical distance between the posterior apex 10B and the plane defining the posterior boundary 7B. Central thickness is the distance between apexes 10A and 10B.
• Anterior depth is the vertical distance between the anterior apex 10A and the plane defining the anterior boundary 7A.
• the main optical axis 1 A may be the axis of symmetry in the case that boundaries 7A and 7B, as well as boundaries 9A and 9B, are defined by circles in the plane perpendicular to the optical axis, and if the central optical part 2 is symmetrical and e.g., does not have any cylindrical component.
• Such implant with symmetric circular footprint is shown in Fig. 3B.
• the rims and boundaries may have other than circular footprint, e.g. elliptical as shown in Fig. 4A, or may have the footprint shaped as a truncated circle in Figs. 4B to 4E with single, double, triple or quadruple truncating cuts 12A to 12D.
• These truncated footprint shapes serve several purposes:
• the optics has a cylindrical component
• the cylinder axis IB will be positioned in a defined way with respect to the asymmetry of the outside rim, e.g. be in the angle a to the truncating cuts 12A and 12B as shown in the Fig. 4F.
• the truncating cuts 12A to 12D may not be necessarily straight cuts, but may be suitably formed to e.g. a crescent shape, and their number may be even higher than 4.
• the truncating cuts may not be of the same length or positioned symmetrically.
• the footprint with truncated rim will facilitate folding of the implant and its insertion through a small surgical incision.
• the asymmetric rim footprint will prevent the implant rotation once the capsule settles around it. This is particularly important for toric lenses with a cylindrical component designed to compensate for astigmatism.
• the posterior surface 5 is shaped and sized to approximate the shape and size of the posterior surface of the natural lens and to achieve contact with at least the major part of the posterior capsule of the eye. This is important for several reasons:
• the implant will keep the posterior capsule in its natural shape, unwrinkled and smooth for the optimum optical performance
• the implant will occupy the space vacated by the posterior side of the natural lens and keep thus vitreous body from advancing forward and prevent thus the decrease of the pressure of vitreous body against retina (which could facilitate retinal detachment and/or cystoic macular edema).
• the intimate contact between the implant and posterior capsule is beneficial particularly if the contacting surface of the implant is hydrophilic and carrying fixed negative charge in order to prevent capsular fibrosis and its consequent stiffening, opacification and contraction that would interfere with the implant function (or could even dislocate it), as will be described hereinafter.
• the major part of the posterior surface 5 is formed by a generally smooth convex surface formed by rotation of conic sections around the optical axis, or a combination of such surfaces.
• the peripheral part is preferably formed by a conic surface or a hyperboloid surface, while the central optical surface is preferably hyperboloid, paraboloid or spherical surface (or a combination thereof).
• the sagittal depth of the posterior surface i.e. the vertical distance between the posterior central optical surface apex 10B and the boundary of the posterior surface 7B, measured on the main optical axis 1A
• the posterior sagittal depth should be larger than 1.25 mm, advantageously larger than 1.75 mm and preferably larger than 2 mm, but in any case less than about 2.75 mm.
• the overall outer diameter of the implant is important for its centricity, position stability and capsule-filling capability.
• the outer diameter of the posterior surface 5, i.e. the largest dimension of the posterior outer boundary 7B (in the plane perpendicular to the main axis 1 A) should be larger than 8.4 mm, desirably at least 8.9 mm and preferably at least 9.2 mm.
• the largest outer diameter permissible is about 11 mm, but desirably should be lower than 10.75 mm and preferably at smaller than 10.5 mm.
• the considerable flexibility in the outer dimensions is allowed by several factors - flexibility of the lens, and particularly flexibility of the outer peripheral supporting part 3 that can accommodate various capsule sizes and capsule contraction without deforming the central optical part 2.
• the central optical surfaces may consist of one or more zones with different geometry.
• the zones may be concentric, in which case the posterior boundary 13B between them in the Fig. 5 A will be circular. Zones may also be divided by straight boundaries, in which case the zones may have crescent or wedge footprint.
• Figs. 5A to 5C The zones may be on the anterior or posterior optical surface.
• Fig. 5A shows the posterior optical surface is divided by the boundary 13B into two concentric optical zones - the central optical zone 8B1 and the outer optical zone 8B2.
• the posterior optical surface of the central optical zone 8B1 may be a spherical or parabolic zone used for the sharp near vision, while the hyperbolic outer zone serves for intermediate and far distance vision.
• both zones may have hyperboloid surfaces with different central radii Ro and/or different conic constants.
• Each optical surface may be also divided into more than two zones.
• the example in Fig. 5B shows the top view of the lens which anterior optical surface 8 A is divided by a straight boundary 13 A into two optical zones of equal area 8A1 and 8A2. Each of those zones has different shape with different optical parameters.
• the example in Fig. 5C shows a top view of a lens with anterior optical surface 8A divided by two straight boundaries 13 A and 13B into four paired optical zones 8A1 and 8A2, each having a different area and different optical parameters.
• 8A1 may have higher refractive power that 8A2 and serve for near focus.
• One of the zones may have a cylindrical component.
• Both optical surfaces are surfaces formed by rotation of a conical section along the optical axis, or by a combination thereof.
• One or both optical surfaces may contain one or more spherical optical zones.
• at least one of the optical surfaces comprises at least one hyperbolic surface, preferably in the outer optical zone.
• both optical surfaces comprise at least one hyperbolic zone each.
• Such hyperbolic surface resembles the surfaces of the NCL and mimics some of its beneficial optical properties.
• both posterior and anterior optical surfaces are hyperbolic surfaces or a combination of two or more concentric hyperbolic zones.
• Lenses with at least one hyperbolic surface have so called hyperbolic aberration, the very opposite of spherical aberration of lenses with spherical, ellipsoid or meniscoid surfaces.
• the lenses with hyperbolic aberration have highest refraction in the center and gradually decreasing with distance from the optical axis. (In lenses with spherical aberration the refractive power increases with distance from the optical axis.)
• the hyperbolic aberration helps the eye to accommodate through several mechanisms described above. It should be understood that hyperbolic aberration can be created not only by the exactly hyperbolic surfaces in the geometry sense, but also by similar surfaces where surface steepness generally decreases with the distance from the optical axis. Therefore, by “hyperbolic surfaces” are meant also other hyperbole-like surfaces approximating this property.
• the negative spherical aberration of hyperboloid-like surfaces increases in absolute value (i.e., gets more negative).
• the spherical aberration can be expressed in various alternative ways, such as a deviation of wave-front in microns, or as steepness of decrease of local refractive power from the optical axis, or by decrease of the refractive power with increasing aperture, or by the value of conic constant or shape parameter corresponding to such optical profiles.
• Those skilled in the art can readily convert one of such values into the corresponding value expressed in a different way.
• the implant according to the present invention can have originally any spherical aberration, since its value can be adjusted post-operatively using the method of this invention.
• the spherical aberration in the final implanted state (i.e., after the hydrogel modification by a laser) will be generally between about -0.1 microns and -2 microns on aperture 4.5 mm.
• the final spherical aberration will be between about -0.5 microns and -1.5 microns on aperture 4.5 mm, and even more advantageously the spherical aberration will be between about -0.75 microns and -1.25 microns on the aperture 4.5 mm.
• conical constants of the anterior and posterior optical surfaces are selected so that the refractive power of the central optical part 2 generally decreases from the highest value at the optical axis to the lowest value at the periphery of the central optical part 2.
• the steepness of the refractive power decrease with the distance from optical axis is dependent on the shape parameter (conic constant) of the hyperbolic surface.
• the conic parameter should be selected that the average decrease of the refractive power is between - 0.25 Dpt/mm and -3 Dpt/mm, advantageously between -0.5 Dpt/mm and -2.5 Dpt/mm and preferably between about -1 Dpt/mm and -2 Dpt/mm.
• the posterior central radius of curvature (at the point where the optical axis intersects the posterior apex) is advantageously from 2.5 to 8 mm, and preferably from about 3.0 to 5 mm.
• the conic constant of the posterior surface is advantageously selected from the range of about +3 to about -14 reported for NCL, preferably from about -1 to -8.
• the central radius Ro of the anterior optical surface 8A is selected to be either larger than about +3 mm or smaller than about -3 mm, and preferably larger than from about +5 mm or smaller than about -5 mm.
• the conical constant of the anterior optical surface 8 A is selected from the range from
• +6 to -22 reported from human NCL, preferably from the range between about -1 to -8 mm.
• the anterior optical surface 8A may be formed partly or fully by a spherical surface or a parabolic surface.
• the central posterior optical surface 8B should be preferably hyperbolic with the conic parameter selected in such a range so that the whole lens has hyperbolic aberration.
• the anterior optical surface 8 A is a hyperboloid surface, particularly the outer optical zone.
• the central optical zone of the anterior optical surface having diameter between about 1.5 to 4 mm, advantageously between about 2 and 3.5 mm, can be formed by parabolic or spherical surface in order to further improve the near focus resolution.
• Fig. 2 shows schematically one example of the preferred optical profile of the lens according to the invention. It should be appreciated that different eyes require different refractive power of the implanted lens.
• IOLs are not bioanalogic since they are designed to simulate just the basic optical function of NCL, i.e. to provide the basic refractive power needed to focus a distant object on retina.
• the basic refractive power is usually between 15 and 30 Dpt, with some deviations on either side. This requirement can be met by an approximately monofocal (usually spherical) rigid lens located somewhere near of the principal plane of the NCL.
• Small size of optics has its disadvantages, however. IOL edges may reflect light at large pupil opening (e.g., during night driving) and cause glare, halos and other adverse effects. Besides, a small optic cannot project all peripheral and off-axis rays that NCL does, particularly at a large pupil opening. Lastly, a small size optics interferes with clear visibility of retinal periphery that is sometimes needed for diagnostics and treatment. For those reasons, the large optics similar in size to NCL is preferable over a smaller one that is used in most of the current IOLs. Importantly, the whole large optical zone has to have well defined geometry to be optically useful. Lenses with meniscoid optical surfaces have poorly defined shape particularly in the peripheral region. This may cause unexpected and disturbing optical phenomena.
• IOLs are designed to simulate to some extent the accommodation or pseudoaccomodation of the NCL (i.e. allowing the eye to focus on both far and near objects).
• Various IOLs use different means to achieve this goal: some are using bifocal, multifocal or polyfocal optics; others are using designs allowing anterior-posterior shift of the IOL optics with respect to the eye; or allow change of optical power by changing mutual position between two lenses.
• Some lenses even change the refractive power due to liquid transfer within the lens driven by pressure of cilliary muscles and/or vitreous body, change of head position or by a miniature pump.
• these lenses are using optics of a small diameter, typically 4.5 to 6 mm, with slender, flexible "haptics" to position the optics in the center of the optical path.
• deformable materials are used to allow folding or rolling for implantation through a small incision.
• the surface properties of such IOLs are sometimes modified to achieve better biocompatibility (e.g., A. M Domschke in the US Pat. Publ. No. 2012/0147323, J. Salamone et al in the US Pat. Publ. No. 2008/0003259).
• the small optics with diameter 6 mm or less may not fully replace the crystalline lens of diameter 9 to 10.5 mm if eye aperture is large due to poor light conditions (causing night glare, halos, limited peripheral vision etc.) or if the IOL becomes decentered (causing the "sunset syndrome" or other problems);
• the IOL with optics suspended in the relatively vacant space by means of relatively fragile haptics may be sensitive to damage and/or dislocation in case of an accidental impact (fall on a slippery surface, car collision, a punch, etc.).
• Implantation of a large, bulky IOL in a highly deformed shape that allow implantation through a reasonably small incision and fills a significant part of the capsule.
• This approach was tried with hydrophobic memory polymers that can be "frozen” in a highly deformed shape for implantation, and returns into the original functional shape upon heating to body temperature (Gupta in US Pat. No. 4,834,750 and US Pat. No. RE 36, 150).
• the hydrophobic memory polymer is very foreign material and causes similar problems like the materials used to fill the capsule.
• hydrogels used in these lenses lacked the fixed negative charge, and such hydrogels have tendency to calcify sometime after their implantation.
• Some other capsule-filling lenses (Sulc et al. '083 and '903) had anterior protrusions touching the iris and stabilizing thus the lens in the approximately central position but causing various problems such as blockage of the liquid flow, deformation of lens optics and iris erosion.
• Such implants filling essentially the whole capsule of the original crystalline lens have also some problems: Unless made from extremely biocompatible materials with similar hydration and negative charge as NCL, the anterior face of the IOL may touch the iris and cause its erosion, depigmentation, bleeding or inflammation.
• An NCL is composed of an intricate natural hydrogel structure comprising water, salts, and polymeric component containing collagenous proteins, polysaccharides and proteoglycans.
• the polymeric components contain a considerable concentration of acidic ionizable groups, such as carboxylates or sulfates. These groups provide the lens material with a fixed negative charge. The hydration and the negative charge influence the interaction between the NCL and proteins in the intraocular fluids. Furthermore, its surface properties affect the interaction between the lens and cells.
• Carboxylate groups may be uniformly dispersed in the hydrogel, or concentrated mainly on the surface forming a gradient of swelling and charge density, as described e.g. in Stoy '208 and Sulc et al. US Pat. No. 5, 158,832.
• the NCL material contains, on average, about 66% by weight of water.
• the NCL is structured with denser core and more hydrated jacket and the NCL hydration changes with age and from individual to individual. Therefore, one cannot assign a single water content value to the NCL other than average.
• the ERI increases with accommodation by about 0.0013 - 0.0015 per Diopter. See M.Dubbelman et al, "Change In Shape Of The Aging Human Crystalline Lens With Accommodation", Vision Research 45 (2005), 117-132Ref pp. 127-128.
• a synthetic hydrogel containing 66% by wt of water would typically have a refractive index of about 1.395 rather than 1.42 that would be expected with hydrogel containing closer to 50% of water.
• Example 1 of this reference shows an IOL with water content 88.5 %
• Example 2 shows the IOL with water content 81%
• Example 4 shows the lens with water content 91 ). No water content is given for Example 3.
• Hydrogel character of the NCL material has some possible, less obvious but potentially important consequences: its water content is dependent on the pressure against the lens. Consequently, the NCL adjusted to the far distance may have a different water content, and therefore a different refractive index, than the relaxed lens adjusted to the near objects. Since the stress in the NCL adjusted for far distance is not distributed evenly, a gradient of swelling and gradient of refractive index may result. This will create subtle changes in the optical properties, in addition to the polyfocality of the NCL surfaces. These subtle changes may be important for vision, and it will be difficult to replicate them otherwise rather than by using a hydrogel of similar physical-chemical and optical properties, as well as geometry similar to that of an NCL.
• the hydrogel of the NCL substitute should have a similar refractive index and capability to change water content by an external stress that can be reasonably expected to act on an NCL. Therefore, the hydrogel used in a bioanalogic IOL should have a hydraulic flow capability for water.
• At least the part of the implant contacting the posterior capsule is made from a transparent flexible hydrogel material approximating the optical, hydrophilic and electrochemical character of tissue forming the natural lens.
• the anterior part of the IOL may interfere with, or even block the flow of the vitreous humor causing thus increase of IOP and ultimately glaucoma. This design often requires a preemptive iridectomy.
• the central optical part 2 is made of a deformable, elastic material, such as a hydrogel with equilibrium water content between about 35 and 65%, advantageously between about 38% and 55% and preferably between about 40% and 50% (all % are weight percent and equilibrium water content is water content in equilibrium with intraocular fluid, unless stated otherwise).
• a deformable, elastic material such as a hydrogel with equilibrium water content between about 35 and 65%, advantageously between about 38% and 55% and preferably between about 40% and 50% (all % are weight percent and equilibrium water content is water content in equilibrium with intraocular fluid, unless stated otherwise).
• the optical part may be constructed as a hydrogel shell with a core composed from a liquid or a soft gel, as shown in the Fig. 6A.
• Fig. 6 A shows a cross-sectional view of a lens with the posterior hydrogel jacket 14, the softer core 15 and the anterior shell 16.
• the posterior hydrogel jacket 14 is advantageously integral with the peripheral supporting part 3 of the lens and contains the fixed negative charge at least on its posterior surface.
• the core 15 can be advantageously made from a hydrophobic liquid, such as mineral oil or silicone oil, or from a soft silicone or acrylic slightly cross linked gel that can be easily designed and created by those skilled in the art.
• the core can be made or a hydrophilic fluid or a soft hydrogel.
• the anterior shell 16 can be made from the same or different material as the posterior hydrogel jacket 14.
• the hydrogel jacket and the soft core 15 have essentially the same refractive index so that the major part of the refraction takes place on the outer optical surfaces of the lens rather than on its internal interfaces.
• This can be achieved e.g. by making the core from a silicone liquid or a silicone gel having refractive index around 1.42, and making the jacket from a hydrogel with water content between about 41 and 45% of water.
• the core and the jacket can have different refractive indices so that part of the refraction takes place on the internal interfaces between materials.
• Fig. 6B a cross-sectional view of a lens with an internal interface between the core 15 and adjacent optical medium 16 that is shaped to form a compound lens, e.g. a Fresnel lens.
• the materials of core 15 and the optical medium 16 have different refractive indices, and one of them is advantageously a fluid that can improve both deformability and refraction.
• the zone 15 or 16 (the one with the lower refractive index) can be created by the modification of a hydrogel according to the present invention using a laser.
• the hydrogel modification can be carried out either preoperatively or postoperatively.
• Advantage of this arrangement is the possibility to use hydrogels with high water content and low refractive index as the basic construction material, and yet achieve relatively low central thickness of the lens that allows implantation through a small incision.
• Fig. 6C shows an alternative design of the lens comprising two different materials.
• Material on the posterior side 14 is a hydrogel with high hydration rate and containing negatively charged groups. It is the same for the optical and supporting part.
• the anterior side material of core 15 is a material with lower water content and higher refractive index. The interface between the two materials is refractive.
• Both central optical anterior surface 8 A and central posterior optical surface 8B have a diameter larger than about 5.6 mm, advantageously larger than about 6.5 mm and preferably larger than about 7.2 mm.
• Optimum diameter of the larger of the two optical surfaces is larger than about 7.5 mm, advantageously about 8 mm to approximate the size of the NCL optics.
• Such a large optic is usually suitable for convex-concave or plano-convex central optical part 2.
• the anterior optical diameter is usually selected smaller in order to minimize the central thickness of the optical part.
• the diameter of the anterior optical surface 8A is advantageously not larger than the diameter of the central posterior optical surface 8B.
• the central optical surfaces 8A and 8B are surrounded by boundaries 9A and 9B that are not necessarily circular.
• the boundaries 9A and/or 9B may be also elliptical or have a shape of a truncated circle, in order to facilitate the lens folding and implantation through a small incision.
• Non-circular optical surfaces are particularly suitable for lenses with a cylindrical component.
• the posterior peripheral supporting surface 1 IB is formed by a convex surface, advantageously a hyperbolic or conical surface with the axis identical with the main optical axis 1 A.
• This surface is highly hydrophilic and carrying a fixed negative charge due to a content of acidic groups such as carboxylate, sulfo, sulphate or phosphate groups.
• This combination of hydration and negative charge prevents a permanent adhesion to the capsule, prevents migration of cells, particularly fibroblasts, along the interface between the lens and the capsule, decreases irreversible protein adsorption, and discourages capsular fibrosis and opacification.
• the posterior peripheral surface is advantageously limited by a sharp edge 7B that further discourages cell migration toward the optical zone.
• the anterior peripheral supporting surface 11 A is a concave surface with its apex located on the optical axis and it is preferably symmetrical along the axis 1 A.
• it is a conical or hyperbolic surface with its axis coinciding with the main optical axis 1 A.
• the surface is advantageously highly hydrophilic and carrying fixed negative charge in order to discourage cell adhesion and migration and anterior capsular fibrosis.
• the anterior peripheral surface is advantageously limited by a sharp edge 7A that further discourages cell migration.
• the anterior and posterior peripheral supporting surfaces 11 A and 1 IB together with the connecting surface 6 define the shape of the peripheral supporting part 3.
• the peripheral supporting part is convex on the posterior side and concave on the anterior side, the average distance between the two surfaces ranging from about 0.05 to 1 mm, advantageously from about 0.1 to 0.6 mm and preferably from about 0.15 to 0.35 mm. The optimum distance depends on the stiffness of the material that is dependent on water content, negative charge density, crosslinking density and other parameters.
• the peripheral supporting part 3 will have even thickness.
• the arrangement shown in Fig. 7A has the advantage to be readily deformable and adjustable to various sizes of the capsule, and two sharp edges 7A and 7B preventing migration of fibroblasts toward the optical zone.
• the peripheral supporting part 3 can be also made less or more deformable by increasing or decreasing its thickness from the rim toward the center, as shown in Figs. 7B and 7C, respectively. These figures also show various alternative arrangements of edges 7A and 7B.
• the anterior surface 4 of the implant is shaped to avoid any permanent contact with iris that could cause iris erosion, pupilar block, iris pigment transfer to the implant and other problems. Such a contact could also interfere with the flow of the intraocular fluid causing thus adverse changes of the intraocular pressure. It could also interfere with the contraction of the pupil as to prevent so called near myosis that helps the near focus both by the natural lens and by the implant according to the invention. Therefore, the anterior central optical surface 8A part is partially sunk due to the anterior peripheral supporting surface 11 A concavity and due to positioning the boundary 9A under the plane defined by the anterior boundary 7A.
• the central anterior surface 8A is a plane, a convex surface or a concave surface with its anterior apex 10A not exceeding the uppermost point of the lens (the higher of 7 A and 7B) by more than about 0.25 mm, advantageously not exceeding the upper rim at all and preferably having the anterior apex 10A bellow the uppermost point 7A by at least 0.1 mm.
• At least the major part (including the central optical surfaces 8 A and 8B) of both anterior and posterior surfaces 4 and 5 are defined by rotation of one or more conic sections around the main optical axis 1 A. wherein the term "conic section" includes a segment of a line for purpose of this application.
• the surfaces defined by the rotation will include a plane perpendicular to the axis and conical surface symmetrical by the main optical axis 1 A.
• the peripheral supporting part is convex on the posterior side and concave on the anterior side, the average distance between the two surfaces ranging from about 0.05 to 1 mm,
• the lens according to the invention is manufactured by solidification of liquid polymer precursors.
• the solidification takes place in contact with a solid mold, particularly a mold made of a hydrophobic plastic. It can be appreciated that the surface microstructure of a polymer depends on the
• the surface microstructure will be different if the solidification occurs on the solid liquid interface that if it takes place on the liquid-liquid or liquid-gas interface.
• at least all optical surfaces are created by solidification of the precursor on a solid interface.
• whole surface of the implant is formed by solidification of a liquid precursor against a solid surface, particularly a hydrophobic plastic surface.
• Preferred plastic for the mold is a polyolefin, and particularly preferred plastic is polypropylene.
• the polyolefin has low polarity and has low interaction with highly polar monomers that are used as hydrogel precursors.
• the hydrogel formed by the liquid precursor solidification has very low adhesion to the mold surface and can be cleanly detached without even a microscopic surface damage. This is important for both optical properties and for long-term biocompatibility of the implant.
• the mold depicted in Fig. 8 is composed from two parts 18A and 18B, the part 18A being used for molding the anterior surface 4 and the part 18B for molding the posterior surface 5.
• the shaping surface 19B of the part 18B has a shape needed to form the posterior optical surface 8B of the lens.
• the peripheral part 22B of the molding surface has a diameter larger than the diameter of the lens and advantageously a hyperboloid or conical shape
• the part 18A has the shaping surface 19A that is divided into the central part 21 A shaping the anterior optical surface 8 A of the lens, and the peripheral part 22 A of the diameter larger than the diameter of the lens.
• the peripheral part 22A has advantageously a hyperboloid or conical shape.
• the peripheral surface 22A is substantially parallel to the corresponding surface 22B of the part 18B.
• the diameter of the molding the mold parts 18A and 18B are larger than diameter of the lens and advantageously they are the same.
• One of the surfaces for 22A or 22B is equipped with a relatively thin and deformable barrier 20 with inner surface corresponding to the geometry of the surface 6 of the lens.
• the height of the part 20 is typically between about 0.05 mm and 1.3 mm, and its thickness is lesser than its height.
• the profile of the part 20 is advantageously wedge-like or triangular. At least one of its surfaces is advantageously parallel to the optical axis 1A.
• the barrier 20 may be separate from the parts 18A and 18B, but advantageously it is an integral part of one of them.
• this part 20 is located on the concave surface 22B.
• the liquid precursor is filled into the concave mold part 18B in a slight excess to reach over the barrier 20, and then it is covered with the part 18 A.
• the mold is constructed in such a way that the only contact between parts 18A and 18B is via the part 20.
• the solidification of the precursor generates its contraction and the consequent decrease of the pressure in the mold cavity.
• the additional liquid precursor is pulled into the mold cavity. Once the gel- point is reached due to the crosslinking, the precursor cannot flow anymore.
• the decreased pressure will cause deformation of the part 20 and decrease of the distance between parts 18A and 18B and the consequent decrease of the molding cavity volume.
• the two-part mold for the IOL according to the invention is preferably made by injection molding from a polyolefin, advantageously from polypropylene.
• the preferred liquid precursor for the invention is a mixture of acrylic and/or methacrylic monomers with crosslinkers, initiators and other components known well to those skilled in the art.
• the preferred precursor composition comprises a mixture of acrylic and/or methacrylic monoesters and diesters of glycols where monoesters are hydrophilic components and diesters are crosslinkers.
• the preferred precursor also comprises acrylic and/or methacrylic acid or its salts. It advantageously comprises also a UV absorbing molecule with a polymerizable double bond, such as methacryloyloxybenzophenone
• ionizable groups bearing a negative charge such as carboxylate, sulfate, phosphate or sulfonate pendant groups. They may be introduced by copolymerization with appropriate monomers bearing such groups, such as methacrylic or acrylic acid. In this case, the ionogenic functionality will be uniformly dispersed in the hydrogel. Particularly advantageous are hydrogels with ionogenic groups concentrated mainly on the surface with the consequent gradient of swelling and charge density. Such gradients can be created by after-treatment of molded lenses, e.g. by methods described in Stoy '208 and Sulc et al. US Pat. Nos. 5,080683 and 5, 158,832.
• Other methods include, e.g. grafting of monomers comprising ionogenic groups on the lens surface. It is understood that only a part of the lens surface may be treated to contain high concentration of ionogenic groups, or that different parts of the surface may be treated by different methods.
• the lens according to the invention can be implanted in the deformed and partly dehydrated state.
• the controlled partial dehydration can be achieved by contacting lens with a suitably hypertonic aqueous solution of physiologically acceptable salts, such as chlorides, sulfates or phosphates magnesium or monovalent ions, such as sodium or potassium. Salt concentration can be adjusted to achieve hydration between about 15% and 25% by weight of the liquid.
• physiologically acceptable salts such as chlorides, sulfates or phosphates magnesium or monovalent ions, such as sodium or potassium.
• Salt concentration can be adjusted to achieve hydration between about 15% and 25% by weight of the liquid.
• the lens in the hypertonic solution can be advantageously sterilized by autoclaving.
• Another method for preparing the hydrogel lens for implantation through an incision with reduced size is plastification of the hydrogel by a non-toxic organic water-miscible solvent, such as glycerol or dimethylsulfoxide, in such a way that the plasticized hydrogel has softening temperature above ambient but lower than eye temperature.
• a non-toxic organic water-miscible solvent such as glycerol or dimethylsulfoxide
• the lens according to at least one embodiment of the invention is advantageously implanted in the state of the osmotic non-equilibrium to adhere to the tissue temporarily.
• the osmotic non-equilibrium allows the lens centering by adhering it against the posterior capsule while the capsule shrinks around it. Once the lens is enveloped by the capsule, its position is stabilized.
• the osmotic non-equilibrium can be achieved in various ways: soaking the lens prior to the implantation in a hypertonic salt solution, e.g. in a solution of 10% to 22% by wt.
• NaCl advantageously 15% to 19% by wt.; replacing water prior to the implantation by a smaller concentration of a water-miscible solvent, such as glycerol or dimethylsulfoxide; or implanting the lens in the state in which the iogenic groups are not fully ionized, i.e. in the acidic state prior to the neutralization, and letting the neutralization proceed spontaneously in situ by positive ions from the body fluids.
• the lens achieves its osmotic equilibrium spontaneously in hours to days after the implantation.
• the lens shape is being formed preferably by crosslinking copolymerization of methacrylic and/or acrylic esters and salts in the closed two-part mold.
• the shape of the lens can be adjusted after the molding by removing some part of the lens, e.g. by cutting off part of the supporting part, by drilling the lens outside the optical zone etc.
• the shape adjustment can be made in the hydrogel or the xerogel (i.e. non-hydrated) state.
• the negatively charged hydrogel material even allows use of methods developed primarily for living tissues (incl. NCR), such as ultrasonic
• phacoemulsification, cauterization or femtosecond laser treatment allow shape adjustment even in the fully hydrated hydrogel state.
• the femtosecond laser may be used even for formation of cavities inside the hydrogel lens that can be used to form new refractive members in the lens, for instance as a refractive cylindrical lens for astigmatism compensation.
• the matter removed by the shape adjustment e.g., by a laser treatment
• the composition of the hydrogel in at least the treated part of the lens should be advantageously based on esters of polymethacrylic acid.
• polymers are capable of depolymerization to their parent monomers (such as 2-hydroxyethyl methacrylate or methacrylic acid) that are well soluble, easily diffusible compounds of low toxicity.
• parent monomers such as 2-hydroxyethyl methacrylate or methacrylic acid
• Other polymers such as polyacrylates, polyvinyl compounds or polyurethanes do not have this advantage.
• the following monomer mixture was prepared: 98 weight parts of 2-hydroxyethyl methacrylate (HEMA), 0.5 wt% of triethyleneglycol dimethacrylate (TEGDMA), 1 wt% of methacryloyloxybenzophenone (MOBP), 1 wt% of methacrylic acid, 0.25 wt% of camphorcquinone (CQ) and 0.05 wt% of trieathanolamine (TEA).
• HEMA 2-hydroxyethyl methacrylate
• TEGDMA triethyleneglycol dimethacrylate
• MOBP methacryloyloxybenzophenone
• CQ camphorcquinone
• TAA trieathanolamine
• the mixture was de-aired using by carbon dioxide and filled into two-part plastic molds shown schematically in Fig. 8 where 18B is the part of the mold for molding the a posterior lens surface, 18A is the part of the mold to shape the anterior part of the surface of the lens.
• Both parts are injection molded from polypropylene (PP).
• the shaping surface 19B of the part 18B has shape formed by two concentric hyperboloids.
• the central part of the surface has the diameter 3 mm, central radius of 3.25 mm and conic constant -3.76 while the peripheral is hyperboloid with central radius of 3.25 mm and conic constant -6.26.
• the molding surface is equipped with a protruding circular barrier 20 on diameter 8.5 mm that has asymmetric triangular profile, height 0.2 mm. This lip is designed to shape the connecting surface 6 in Fig. 3 A.
• the part 18A has the shaping surface 19A that is divided into the central part 21 of diameter 6.8 mm and the peripheral part 22A of the diameter 13 mm.
• the peripheral part is formed by a hyperboloid with the central radius 3.25 mm and the conic constant -6.26.
• the peripheral hyperbolic surface is parallel to the corresponding surface of the part 18B.
• the mold design is particularly suitable for production of relatively bulky IOLs from materials with high polymerization contraction that achieves gel-point at a relatively low conversion.
• the following monomer mixture was prepared: 94 weight parts of 2-hydroxyethyl methacrylate (HEMA), 0.5 wt% of triethyleneglycol dimethacrylate (TEGDMA), 4.5 wt% of methacryloyloxybenzophenone (MOBP), 1 wt% of methacrylic acid and 0.25 wt% of dibenzoylperoxide.
• HEMA 2-hydroxyethyl methacrylate
• TEGDMA triethyleneglycol dimethacrylate
• MOBP methacryloyloxybenzophenone
• the central part of the surface has the diameter 3 mm, central radius of 3.00 mm and conic constant 1 while the peripheral section is a hyperboloid with central radius of 3.25 mm and conic constant -6.26.
• the molding surface is equipped with a protruding circular barrier 20 on diameter 8.8 mm that has asymmetric triangular profile, height 0.15 mm.
• the inner side of the barrier 20 is designed to shape the connecting surface 6 in Fig. 3 A.
• the part 18A has the shaping surface 19A that is divided into the central part 21 of diameter 7.1 mm and the peripheral part 22A of the diameter 13 mm.
• the peripheral part is formed by a hyperboloid with the central radius 3.25 mm and the conic constant -6.26.
• the peripheral hyperbolic surface is parallel to the corresponding surface of the part 18B.
• the central portion of the part 18A is a plane perpendicular to the optical axis 1 A.
• the mold parts are separated and the xerogel lens, the exact copy of the mold cavity, is neutralized by solution of sodium bicarbonate and extracted 3 times with ethyl alcohol and 5 times with isotonic solution.
• the lens was yellow with complete absorption of UV light and part of the blue visible light.
• the linear expansion factor between the xerogel and hydrogel lens is 1.13. After evaluation of optical properties the lens was immersed in the 15% by weight aqueous solution of NaCl in a sealed blister package and sterilized by autoclaving.
• EXAMPLE 3 EXAMPLE 3 :
• the following monomer mixture was prepared: 94.5 weight parts of 2-hydroxyethyl methacrylate (HEMA), 0.5 wt% of triethyleneglycol dimethacrylate (TEGDMA), 5 wt% of methacryloyloxybenzophenone (MOBP) and 0.25 wt% of dibenzoylperoxide.
• HEMA 2-hydroxyethyl methacrylate
• TEGDMA triethyleneglycol dimethacrylate
• MOBP methacryloyloxybenzophenone
• dibenzoylperoxide 0.25 wt% of dibenzoylperoxide.
• the shaping surface 19B of the part 18B has a shape formed by two concentric surfaces.
• the central part of the surface has the diameter 6.5 mm, central radius of 4.5 mm and conic constant 0 while the peripheral section is a hyperboloid with central radius of 4.25 mm and conic constant -8.
• the molding surface is equipped with a protruding circular barrier 20 on diameter 9.3 mm that has asymmetric triangular profile, height 0.35 mm.
• the inner side of the barrier 20 is designed to shape the connecting surface 6 in Fig. 3 A.
• the part 18A has the shaping surface 19A that is divided into the central part 21 of diameter 6.4 mm and the peripheral part 22A of the diameter 13 mm.
• the peripheral part is formed by a hyperboloid with the central radius 4.25 mm and the conic constant -8.
• the peripheral hyperbolic surface is parallel to the corresponding surface of the part 18B.
• the central portion of the part 18A is a surface of diameter 6.4 mm, central radius -3.75 mm and conic constant -6.
• the mold parts are separated and the xerogel lens, the exact copy of the mold cavity, is extracted.
• the lens is then treated by a quaternary base as described in the reference Stoy '208.
• the z lens from the clear, electroneutral crosslinked hydrophilic polymer has a surface created by a gradiented layer with high hydration and negative charge density.
• the lens was neutralized by solution of sodium bicarbonate and extracted 3 times with ethyl alcohol and 5 times with isotonic solution.
• the lens was clear with complete absorption of UV light.
• the linear expansion factor between the xerogel and hydrogel lens is about 1.12. After evaluation of optical properties the lens was immersed in the isotonic aqueous solution of NaCl in a sealed blister package and sterilized by autoclaving.
• EXAMPLE 4 EXAMPLE 4:
• Raman spectra of the hydrogels of the invention show a significant difference between the original hydrogel and the same hydrogel subjected to TP A by exposure to the focused beam of a femtosecond laser. Namely, there is a significant difference in the ratio of the signal at 3420 cm “1 corresponding to water, and at 2945 cm “1 corresponding to the CH 2 group from the polymer backbone (see Fig. 9A). The ratio between the intensities of the two peaks is proportional to the phase-shift (in number of wavelengths) of the test laser beam between the modified and unmodified material (see Fig 9B). The Raman scan across the modified strip within the hydrogel showed increased water content in the treated area (see Fig 9C). On the other hand, the Raman spectrum of the region below 2000 cm "1 showed no indication of new chemical groups. This is consistent with replacement of part of the polymer mass for an aqueous liquid through a mechanism such as depolymerization.

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