MXPA00006436A - Programmable corrective lens - Google Patents

Abstract

The invention provides an ophthalmic lens, which uses a volume HOE to provide an optical power. The ophthalmic lens is produced by a highly flexible production process such that a variety of different ametropic conditions can be accommodated.

Description

PROGRAMMABLE CORRECTIVE LENS The present invention relates to a corrective optical lens containing a holographic element in volume. More specifically, the present invention relates to a corrective optical lens having a holographic element that provides an optical power. Optical lenses for correcting ametropia and other adverse vision conditions, which use refractive power of optically transparent polymers, are widely available. Ametropia is the term that indicates a condition of visual refractive error of the eye, including nearsightedness, farsightedness, presbyopia, and astigmatism. Commonly used corrective optical lenses include eyeglass lenses and ophthalmic lenses. Ophthalmic lenses to correct ametropia include contact lenses and intraocular lenses. Because each ametropic condition requires a specific corrective power, there needs to be a large number of different designs for ophthalmic lenses, in order to accommodate many different visual defects of the eye. For example, in order to accommodate different levels of myopic conditions with contact lenses, a range of different spherical power contact lenses are produced which have from 0 to -10 diopters or even less, usually in one-quarter increments. diopter. The difficulty of accommodation is particularly severe to correct astigmatic conditions, because astigmatic conditions require not only adjustment of powers, but also adjustments of the cylindrical axis. In addition, a corrective lens for astigmatism must have a stabilization mechanism, for example, a prism or plate ballast, to properly align the lens axis on the eye. Consequently, many different design criteria must be considered to produce a toric lens that appropriately accommodates the ametropic condition and that can be used comfortably. There remains a need for a corrective lens that is simple to design and produce through a simpler production process than conventional ophthalmic lens production processes. The present invention provides an ophthalmic lens having a holographic element in transmission volume, and the holographic element in volume has a grating structure that provides an optical power. An ophthalmic lens is also provided to correct astigmatism. The corrective lens for astigmatism has a holographic element in volume that provides a cylindrical corrective power. Suitable ophthalmic lenses having the holographic element in volume include contact lenses and intraocular lenses.

The ophthalmic lens is produced by a highly flexible production method, because the power or corrective powers of the lens are provided by programming adequate powers in the lens, without the need to change the dimensions of the lens. Accordingly, a wide range of different corrective powers can be provided, and the ophthalmic lenses can be designed to promote the comfort of the lens user without the optical limitations of the prior art lens design. Figure 1 illustrates a corrective ophthalmic lens of the present invention. Figure 2 illustrates a method for producing a volume holographic optical element of the present invention. Figure 3 illustrates a method for producing an ophthalmic lens of a toric holographic optical element. Figure 4 illustrates an ophthalmic lens of the present invention. Figure 5 illustrates an ophthalmic lens of the present invention. Figure 6 illustrates an ophthalmic lens of the present invention. Figures 7-7B illustrate a holographic optical element in combination. The ophthalmic lens of the present invention can be Program to provide a wide variety of different optical powers and configurations, and therefore, the lens is highly suitable to correct different ametropic conditions. The ametropic conditions of example that can be corrected with the present lens include myopia, hyperopia, presbyopia, regular and irregular astigmatisms, and combinations thereof. The ophthalmic lens uses the diffraction property of a holographic optical element (HOE), more particularly an optical holographic element in transmission volume, to provide an optical power. The holographic optical element in volume of the present invention contains patterns of interference fringes, ie, a grid structure in volume, which are programmed or recorded as a periodic variation in the refractive index of the optical material- The grating structure in volume, it diffracts the light entering the holographic optical element, and the path of the light is modified and redirected to a desired direction. Figure 1 illustrates an exemplary holographic optical element 10 which is suitable for the present invention, which has a convergent or positive optical power. The holographic optical element lens 10 has a grid structure 12 in volume, and the grid structure 12 directs the light 14, which enters the lens 10 from one side, to focus on a focal point 16, which is located on the other side of the lens 10.

Preferably, the input light 14 is diffracted by more than one interference band 12, and redirected to the focal point 16, so that a high diffraction efficiency is achieved. Figure 2 illustrates a process for producing or programming a holographic optical element in volume, which provides a converging power. The holographic optical elements suitable for the present invention can be produced, for example, from polymerizable or reticleable optical materials, and from photographic hologram recording means. Suitable optical materials are discussed further below. Hereinafter, for purposes of illustration, the term "polymerizable materials" is used to indicate both polymerizable materials and crosslinkable materials, unless otherwise indicated. The point source light (first light) 20 and the collimated light (second light) 24, are projected simultaneously towards a photopolymerizable optical material (ie, a photopolymerizable holographic optical element) 22, such that the electromagnetic waves of the first light 20 and second light 24 form patterns of interference fringes, which are recorded in the polymerizable optical material, as the optical material is polymerized. The photopolymerizable holographic optical element 22 is a photopolymerizable material that is polymerized by both the first light and the second light. From Preferably, the first light and the second light are produced from a collimated light source, using a beam splitter, such that the first light and the second light are coherent. As two divided portions of the light are projected towards the holographic optical element 22, the path of the first portion of the divided light is modified to form a point source light 20. The first point source light 20 is provided, for example, by placing a conventional convex optical lens at some distance from the polymerizable holographic optical element 22, such that a portion of the divided light is focused at a desirable distance from the holographic optical element 22, i.e. the spot light source 20 of Figure 2. The first light and the second light coherently enters the holographic optical element 22, and they record a pattern of inference stripes (ie, the grid structure in volume 26). The fully recorded and polymerized holographic optical element has a focal point, which corresponds to the origin position of the point source light 20, when the light enters the holographic optical element from the side opposite the focal point. According to the present invention, the power of the ophthalmic lens can be changed, for example, by changing the distance and position of the first light 20. According to the present invention, a preferred light source for the first and second lights, is a laser source, more preferably a Ultraviolet laser source. Although the appropriate wavelength of the light source depends on the type of holographic optical element employed, the preferred wavelength ranges are between 300 nanometers and 600 nanometers. As can be appreciated, holographic optical elements having a corrective power divergent with the production establishment of the holographic optical element described above can also be produced, with some modifications. For example, a first convergent light which forms a focal point on the other side of the holographic optical element from the light source, can be used in place of the first point source light, to produce a holographic optical element having a power negative corrective Turning to Figure 3, an example process is provided for programming a cylindrical power that is suitable for correcting an astigmatic visual condition. A grid structure programming facility similar to the process discussed above can be used to produce a holographic optical element having a convergent corrective power, except that the first point source light is replaced by a first line bridge light. The first line source light is provided by modifying the collimated light 32 with the cylindrical optical lens 34, which is placed vertically at some distance from a polymerizable optical material 38. The cylindrical lens 34 does not modify the path of light 32 in the vertical direction (i.e., the axis meridian) with respect to cylindrical lens 34, while significantly modifying the path of light 32 in the horizontal direction (i.e., the power meridian), to Focus the light on a focal point. Again, the first lumen 32 and the second lumen 36 are simultaneously directed towards the polymerizable optical material 38 to register a grid structure in volume, thereby forming a holographic optical element lens with a cylindrical optic optical power. The location of the focal point, which is provided by the cylindrical lens 34, can be changed to provide different convergent and divergent optical powers. For example, when designing a holographic optical element lens programmed to receive visual light from the opposite side of the programming light sources, and designed to provide a convergent power at the power meridian, the path of the first light it must be modified to focus on a point that is located in front of the polymerizable optical material 38 during the programming process. In addition, the rotational orientation of the cylindrical lens 34 with respect to the polymerizable optical material 38 can be changed to impart a wide variety of cylindrical power orientations. According to the above, the production process to produce the toric holographic optical element lens, is a highly flexible process, which can produce a wide variety of toric lenses. Although Figure 3 illustrates a process for producing a toric holographic optical element lens for regular astigmatism, the process can be easily modified to produce a corrective lens for irregular astigmatism. A corrective lens for irregular astigmatism can be produced by using an irregular cylindrical lens to modify the path of the first light, instead of the regular cylindrical lens 34. For example, a cylindrical lens that provides an acute or obtuse angle between the axis of the meridian of power and the axis of the axis meridian produces a toric holographic optical element lens for irregular astigmatism. The toric holographic optical element lens is highly convenient over conventional toric ophthalmic lenses, for example toric contact lenses. Unlike a conventional toric contact lens, the holographic optical element lens does not have to change its dimensions to accommodate different corrective needs of different astigmatism conditions, for example, the cylindrical orientation, the power requirement, and the position of the mechanism of stabilization. The toric holographic optical element lens can be designed to optimize user comfort, because the corrective power of the lens is flexibly programmed into the lens, and is not produced by the geometric shape of the lens. the Corrective power of the holographic optical element lens does not rest on the geometric shape of the lens, the geometric shape of the lens can be used to provide additional optical power, or to supplement the programmed optical power. For example, the lens shape can be designed to provide additional refractive power, for example, more or less spherical power. Figure 4 illustrates a holographic optical element lens design of the present invention. In this embodiment, a bifocal active lens of holographic optical element 40 is produced from an optical material that forms a holographic optical element. The programmed volume grid structure of the holographic optical element lens provides an optical power, and as discussed above, the combination of the holographic optical element lens shape and the refractive index of the holographic optical element material can provide a complementary or additional optical power. This type of holographic optical element lens is particularly suitable when the material of the holographic optical element used is a biocompatible material, and therefore, does not interact adversely with body tissues. The term "biocompatible material", as used herein, refers to a polymeric material that does not appreciably deteriorate, and that does not induce a significant immune response or reaction. damaging tissue, for example, a toxic reaction or significant irritation, over time, when implanted into, or placed adjacent to, the biological tissue of a subject. Preferably, a biocompatible material does not deteriorate or cause an immune response or a damaging tissue reaction for at least 6 months, more preferably at least 1 year, and most preferably at least 10 years. Suitable biocompatible optical materials are highly photocrosslinkable or photopolymerizable optical materials. Suitable biocompatible materials include derivatives and copolymers of a polyvinyl alcohol, polyethyleneimine, or polyvinylamine. Exemplary biocompatible materials that are particularly suitable for producing the holographic optical element of the present invention are disclosed in U.S. Patent No. 5,508,317 to Müller, and in International Patent Application PCT / EP96 / 00246 to Mühlebach, whose patent and patent application are incorporated herein by reference, and are discussed further below. The ophthalmic lens of holographic optical element 40 may have a stabilizing mechanism (not shown), especially when the lens 40 is designed as a contact lens to correct astigmatism. For example, a prism ballast can be added to the bottom of the lens, provided an offset plate on the top of the lens, or an upper and lower double offset plate design is used, to properly and stably guide the cylindrical shaft of the toric lens, to match the astigmatic condition of an eye. In addition, as discussed above, the lens shape 40 and the inherent refractive index of the holographic optical element material can provide additional optical power. Another embodiment of lens design is illustrated in Figure 5. The composite lens 50 has a holographic optical element 52 recessed or encapsulated in a first optical material 54, preferably a biocompatible optical material. This composite lens mode is particularly suitable when the holographic optical element 52 is made of an optical material that is not suitably biocompatible. Another embodiment is illustrated in Figure 6. The composite holographic optical element lens 60 has a first optical lens 62, and a holographic optical element lens 64, which is placed adjacently on the first optical lens 62. Alternatively, the holographic optical element lens 64 can be a size that covers only the pupil of the eye, and the placement of the first optical lens 62 and the holographic optical element lens 64 can be interchanged. The first optical lens 62 of a first optical material, and the holographic optical element lens 64 of a holographic optical element material, it they can be manufactured separately and joined, for example, adhesively or thermally. In an alternative way, the first optical lens 62 and the holographic optical element lens 64 can be manufactured in sequence or simultaneously one above the other, such that a composite lens is produced. This sequential or simultaneous approach is particularly suitable when the first optical lens and the holographic optical element lens are produced from a basic material, or from two chemically compatible materials. In accordance with the present invention, suitable holographic optical elements can be produced from polymerizable and crosslinkable optical materials, which can be light-cured or photo-reticularized in a relatively fast manner, especially a fluid optical material. Hereinafter, for purposes of illustration, the term "polymerizable material" 1 is used to indicate both polymerizable and crosslinkable materials, unless otherwise indicated. An optical material that can polymerize rapidly, allows to create a periodic variation in the refractive index within the optical material, thus forming a grid structure in volume, while the optical material is being polymerized, to form a solid optical material . When a fluid polymerizable optical material is used to produce the holographic optical element, the light source transforms the optical material fluid in a non-fluid or solid holographic optical element, while forming the grid structure in volume. The term "fluid", as used herein, indicates that a material can flow as a liquid. Preferably, suitable polymerizable and crosslinkable optical materials are selected from biocompatible optical materials, and preferably, suitable optical materials are selected from fluid biocompatible optical materials that are crosslinked or polymerized to form a solidified non-fluid optical element, having a defined shape equal to, or less than, 5 minutes, more preferably equal to, or less than, 3 minutes, still more preferably equal to, or less than, one minute, and most preferably equal to, or less than , 30 seconds, for example, between 5 and 30 seconds. The duration of the crosslinking or polymerization is determined by placing a crosslinkable or polymerizable optical material between two quartz plates, having the dimensions of a microscope slide, and separated by 100 microns with separators. A sufficient amount of the optical material is applied on the first quartz plate, to form a circular droplet having a diameter of about 14 millimeters, and a second plate is placed on the optical material. Alternatively, a spacer may be used to provide the cylindrical space between the plates for the optical material. The optical material between the plates is irradiated with a mercury arc lamp of medium pressure of 200 watts, which is placed, 18_ centimeters above the top quartz plate. An exemplary group of biocompatible polymerizable optical materials suitable for the present invention is disclosed in U.S. Patent No. 5,508,317 to Müller. A preferred group of polymerizable optical materials, as described in U.S. Patent No. 5,508,317, are those having a basic structure of 1,3-diol, wherein a certain percentage of the 1,3-diol units they have been modified to 1,3-dioxane which has, in position 2, a radical that can be polymerized, but not polymerized. The polymerizable optical material is preferably a polyvinyl alcohol derivative having a weight-average molecular weight, Mw, of at least about 2,000, which, based on the number of polyvinyl alcohol hydroxyl groups, is about 0.5 percent by weight. approximately 80 percent of units of formula I: (i) wherein: R is lower alkylene having up to 8 carbon atoms, R is hydrogen or lower alkyl, and 2 R is an olefinically unsaturated copolymerizable electron attracting radical, preferably having 2 to 25 carbon atoms. R is, for example, an olefinically unsaturated acyl radical of the formula R -CO-, wherein: R is an olefinically unsaturated copolymerizable radical having from 2 to 24 carbon atoms, preferably from 2 to 8 carbon atoms, especially preferably from 2 to 4 carbon atoms. Exemplary olefinically unsaturated copolymerizable radicals include ethenyl, 2-propenyl, 3-propenyl, 2-butenyl, hexenyl, octenyl, and dodecanyl. As a desirable embodiment, the radical R2 is a radical of the formula II: [-CO-NH- (R 4 -NH-CO-0) g-R 5-0] P-CO-R 3 (II) wherein: p is zero or one, preferably zero; q is zero or one, preferably zero; R and R are each independently lower alkylene having from 2 to 8 carbon atoms, arylene having from 6 to 12 carbon atoms, a divalent cycloaliphatic group saturated having from 6 to 10 carbon atoms, arylenealkylene, alkylenearylene having from 7 to 14 carbon atoms, or arylene-nalkylenearylene having from 13 to 16 carbon atoms; and R3 is as defined above. R as lower alkylene preferably has up to 8 carbon atoms, and can be straight or branched chain. Suitable examples include octylene, hexylene, pentylene, butylene, propylene, ethylene, methylene, 2-propylene, 2-butylene, and 3 -pentylene. Preferably, R as lower alkylene has up to 6, and especially preferably up to 4 carbon atoms. Methylene and butylene are especially preferred. R1 is preferably hydrogen or lower alkyl having up to 7, especially up to 4 carbon atoms, especially hydrogen. As for R 4 and R 5, R 4 or R 5 as lower alkylene have preferably 2 to 6 carbon atoms, and are especially straight chain. Suitable examples include propylene, butylene, hexylene, dimethylethylene, and especially preferably ethylene. R 4 or R 5, as arylene, are preferably phenylene which is unsubstituted or substituted by lower alkyl or lower alkoxy, especially 1,3-phenylene or 1,4-phenylene or methyl-1, phenylene. R4 or R.5 as a saturated divalent cycloaliphatic group is preferably cyclohexylene or lower cyclohexylenealkylene, for example, cyclohexylenemethylene, which is unsubstituted or substituted by 1 or more methyl groups, such as, for example, trimethylcyclohexylenemethylene, for example the divalent isophorone radical. The arylene unit of R 4 or R 5 as alkylenearylene or arylenealkylene is preferably phenylene, unsubstituted or substituted by lower alkyl or lower alkoxy, and its alkylene unit is preferably lower alkylene, such as methylene or ethylene, especially methylene. These radicals R4 or R5, therefore, are preferably phenylenemethylene or methylenephenylene. R 4 or R 5 as arylenenalkylene arylene are preferably lower phenylene-alkylene-phenylene having up to 4 carbon atoms in the alkylene unit, for example phenylene-ethylene-phenylene. The radicals R4 and R5 are each independently preferably lower alkylene having from 2 to 6 carbon atoms, phenylene, unsubstituted or substituted by lower alkyl, cyclohexylene or lower cyclohexylenealkylene, unsubstituted or substituted by lower alkyl, lower phenylene alkylene, lower alkylene- phenylene, or phenylene-lower alkyl-phenylene. The polymerizable optical materials of the formula I are produced, for example, by the reaction of a polyvinyl alcohol with a compound of the formula III: wherein R, R1 and R2 are as defined above, and R 'and R "are each independently hydrogen, lower alkyl, or lower alkanoyl, such as acetyl or propionyl, preferably between about 0.5 and about 80 one hundred percent, more preferably between about 1 and about 50 percent, most preferably between about 2 and about 15 percent of the hydroxyl groups of the resulting polymerizable optical material, are replaced by compound III. Suitable polyvinyl alcohols for the present polyvinyl alcohol derivative have an average molecular weight in weight of between about 2,000 and about 1,000,000, preferably between 10,000 and 300,000, more preferably between 10,000 and 100,000, and most preferably between 10,000 and 50,000. Polyvinyl alcohols have less than about 50 percent, preferably less than about 20 percent by weight. of non-hydrolyzed vinyl acetate units. In addition, the polyvinyl alcohols can contain up to about 20 percent, preferably up to about 5 percent, of one or more copolymer units, such as ethylene, propylene, acrylamide, methacrylamide, dimethacrylamide, hydroxyethyl methacrylate, methyl methacrylate. , methyl acrylate, ethyl acrylate, vinylpyrrolidone, hydroxyethyl acrylate, allyl alcohol, and styrene.

The polyvinyl alcohol derivative is polymerized in a solvent by a photocrosslinking process, for example using an ultraviolet laser, to produce a holographic optical element. A suitable solvent is any solvent that dissolves polyvinyl alcohol and vinyl comonomers. Exemplary solvents include water, ethanol, methanol, propanol, dimethylformamide, dimethyl sulfoxide, and mixtures thereof. To facilitate the photocrosslinking polymerization process, it is desirable to add a photoinitiator, which can initiate radical crosslinking. Exemplary photoinitiators suitable for the present invention include benzoin methylether, 1-hydroxycyclohexylphenyl ketone, Durocure® 1173 photoinitiators and Irgacure®. Preferably, between about 0.3 and about 2.0 percent, based on the total weight of the polymerizable formulation, of a photoinitiator is used. In accordance with the present invention, suitable concentrations of the polyvinyl alcohol derivative in the solvent to produce the holographic optical element are preferably between about 3 and about 90 weight percent, more preferably between about 5 weight percent. one hundred and 60 percent, and most preferably between about 10 percent and about 50 percent, especially when the holographic optical element is designed to be used as an ophthalmic lens.

Other groups of exemplary biocompatible polymerizable optical materials suitable for the present invention are disclosed in U.S. Patent Application Serial Number 08 / 875,340 (International Patent Application Number PCT / EP96 / 00246 to Mühlebach. ). The description of the polymerizable optical materials of the United States of America Patent Application is hereby incorporated by reference. Suitable optical materials include derivatives containing an azalactone moiety of polyvinyl alcohol, polyethyleneimine, or polyvinylamine, containing from about 0.5 to about 80 percent, based on the number of hydroxyl groups of polyvinyl alcohol, or in the number of imine or amine groups of polyetiienimine or polyvinylamine, respectively, of units of formulas IV and V: wherein Ri and R2 are, independently of one another, hydrogen, an alkyl group of 1 to 8 carbon atoms, an aryl group, or a cyclohexyl group, wherein these groups are unsubstituted or substituted; R3 is hydrogen or an alkyl group of 1 to 8 carbon atoms, preferably it is methyl; and R is a bridge of -O- or -NH-, preferably it is -O-. Polyvinyl alcohols, polyethylene imines, and polyvinylamines, suitable for the present invention, have a number average molecular weight between about 2,000 and 1,000,000, preferably between 10,000 and 300,000, more preferably between 10,000 and 10,000,000. 100,000, and most preferably between 10,000 and 50,000. A particularly suitable polymerizable optical material is a water-soluble derivative of a polyvinyl alcohol having between about 0.5 and about 80 percent, preferably between about 1 and about 25 percent, more preferably between about 1.5 and about 12 percent, based on the number of hydroxyl groups in the polyvinyl alcohol, of formula IV, having methyl groups for Ri and R2, hydrogen for R3, -O- (ie, an ester bond) stop .

The polymerizable optical materials of formulas IV and 7 can be produced, for example, by the reaction of an azalactone of formula VI: wherein Ri, R2, and R3 are as defined above, with a polyvinyl alcohol, a polyetiienimine, or a polyvinylamine, at an elevated temperature, between about 55 ° C and 75 ° C, in a suitable organic solvent, optionally in the presence of a suitable catalyst. Suitable solvents are those which dissolve the base structure of the polymer, and include polar aprotic solvents, for example formamide, dimethylformamide, hexamethylphosphoric triamide, dimethyl sulfoxide, pyridine, nitromethane, acetonitrile, nitrobenzene, chlorobenzene, trichloromethane, and dioxane. The suitable catalyst includes tertiary amines, for example triethylamine, and organotin salts, for example dibutyltin dilaurate. In addition to the azalactone fraction, optical materials containing azalactone fraction may have other hydrophobic and hydrophilic vinyl comonomers, depending on the desired physical properties of the polymerized holographic optical element. Exemplary hydrophobic comonomers include alkyl acrylates and methacrylates of 1 to 18 carbon atoms, acrylamides and alkyl methacrylamides of 3 to 18 carbon atoms, T-acrylonitrile, methacrylonitrile, vinyl alkoxide of 1 to 18 carbon atoms, alkenes of 2 to 18 carbon atoms, styrene, vinyl alkyl ethers, perfluoroalkyl acrylates and methacrylates of 2 to 10 carbon atoms, perfluoroalkyl acrylates and methacrylates of 3 to 10 carbon atoms. at 12 carbon atoms - "ethylthiocarbonylaminoethyl, acryloxy- and methacryloxy-alkylsiloxane, N-vinylcarbazole, alkyl esters of 1 to 12 carbon atoms of maleic acid, fumaric acid, itaconic acid, and the like. Exemplary hydrophilic comonomers include hydroxyalkyl acrylates and methacrylates, acrylamide, methacrylamide, methoxylated methacrylates and acrylates, hydroxyalkyl amides and methacrylamides, N-vinylpyrrole, N-vinyl succinimide, N-vinylpyrrolidone, vinylpyridine, acrylic acid, methacrylic acid, and Similar. Optical materials containing azalactone fraction are polymerized in a solvent by a photoforming process, for example using an ultraviolet laser, to produce a holographic optical element. A suitable solvent is any solvent that dissolves the polymer base structure of the optical materials. Exemplary solvents include aprotic solvents disclosed above in conjunction with the modification of azalactone, water, ethanol, methanol, propanol, glycols, glycerols, dimethylformamide, dimethyl sulfoxide, mixtures thereof. To facilitate the polymerization process by photocrosslinking, it is desirable to add a photoinitiator, which can initiate radical crosslinking. Exemplary photoinitiators suitable for the present invention include benzoin methylether, 1-hydroxycyclohexylphenyl ketone, Durocure® 1173 photoinitiators and Irgacure®. Preferably, between about 0.3 and about 2.0 percent, based on the total weight of the polymerizable formulation, of a photoinitiator is used. In accordance with the present invention, suitable concentrations of the optical material containing azalactone fraction in the solvent to produce the holographic optical element are preferably between about 3 and about 90 weight percent, more preferably between about 5 percent and 60 percent, and most preferably between about 10 percent and about 50 percent, especially when the holographic optical element is designed to be used as an ophthalmic lens. Yet another group of biocompatible polymerizable optical materials suitable for the present invention is a functionalized copolymer of a vinyl lactam, and at least one additional vinyl monomer, a second vinyl monomer. The copolymer is functionalized with a reactive vinyl monomer. The vinyl lactam of the present invention is a lactam of 5-7 members of formula VII: wherein: Ra is an alkylene bridge having from 2 to 8 carbon atoms; Rb is hydrogen, alkyl, aryl, aralkyl, or alkaryl, preferably hydrogen, lower alkyl having up to 7 carbon atoms, aryl having up to 10 carbon atoms, or aralkyl or alkaryl having up to 14 carbon atoms; and R c is hydrogen or lower alkyl having up to 7 carbon atoms, preferably methyl, ethyl, or propyl. Exemplary vinyl lactams suitable for the invention include N-vinyl-2-pyrrolidone, N-vinyl-2-caprolactam, N-vinyl-3-methyl-2-pyrrolidone, N-vinyl-3-methyl-2-piperidone. , N-vinyl-3-methyl-2-caprolactam, N-vinyl-4-methyl-2-pyrrolidone, N-vinyl-4-methyl-2-caprolactam, N-vinyl-5-methyl-2-pyrrolidone, N -vinyl-5-methyl-2-piperidone, N-vinyl-5, 5-dimethyl-2-pyrrolidone, N-vinyl-3, 3, 5-trimethyl-2-pyrrolidone, N-vinyl-5-methyl-5 -ethyl-2-pyrrolidone, N-vinyl-3, 4, 5-trimethyl-3-ethyl-2-pyrrolidone, N-vinyl-6-methyl-2-piperidone, N-vinyl-6-ethyl-2-piperidone , N-vinyl-3, 5-dimethyl-2-piperidone, N-vinyl-4,4- dimethyl-2-piperidone, N-vinyl-7-methyl-2-caprolactam, N-vinyl-7-ethyl-2-caprolactam, N-vinyl-3,5-dimethyl-2-caprolactam, N-vinyl-4, 6-dimethyl-2-caprolactam, N-vinyl-3, 5, 7-trimethyl-2-caprolactam, and mixtures thereof. Preferred vinyl lactams are heterocyclic monomers of the formula VII containing from 4 to 6 carbon atoms in the heterocyclic ring. More preferred vinyl lactams have a heterocyclic monomer of formula VII, wherein the heterocyclic ring has 4 carbon atoms, and Rb and Rc are independently selected from the lower alkyl and hydrogen moieties. A highly suitable vinyl lactam is 2-N-vinylpyrrolidone. Suitable second vinyl monomers include functional vinyl monomers having, in addition to the vinyl group, a functional group, for example hydroxyl, amino, lower alkyl-substituted amino, carboxyl, esterified carboxyl, alkoxycarbonyl, epoxy, or sulfo (-S03H ). The functional group is retained when the vinyl group of the second vinyl monomer is reacted with the vinyl lactam to produce a polymer chain, and can be used to modify or functionalize the polymer. Suitable functional vinyl monomers include lower alkyl acrylates and methacrylates substituted by hydroxyl, ethoxylated acrylates and methacrylates, lower epoxyalkyl acrylates and methacrylates, acrylates and methacrylates of epoxycycloalkylalkyl lower, acrylamides and methacrylamides of lower alkyl substituted by hydroxyl, lower alkyl vinyl ethers substituted by hydroxyl, styrenes substituted by amino or hydroxyl, sodium ethylene sulfonate, sodium styrene sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid, methacrylic acid, lower aminoalkyl and lower alkylaminoalkyl acrylates and methacrylates, acryloxy- and methacryloxy-lower alkyl maleimides, and allyl alcohol. The term "lower alkyl", as used herein, refers to an alkyl radical having up to 7 carbon atoms, preferably up to 4 carbon atoms. Particularly suitable functional vinyl monomers include 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, acrylic acid, methacrylic acid, 4-aminostyrene, 3-methacryloxymethyl-7-oxa-bicyclo [4.1.0] heptane, N-methacryloxyethyl- maleimide, glycidyl methacrylate, ethylammonium methacrylate hydrochloride, and propylammonium methacrylate hydrochloride. A copolymer of the vinyl lactam and the second vinyl monomer is produced with or without a solvent, in a known manner. The copolymer can also be a statistical polymer. A process for producing a statistical polymer is disclosed, for example, in U.S. Patent No. 5,712,356. A suitable solvent dissolves, and is substantially inert towards, the monomers and the polymer produced from the monomers. Exemplary suitable solvents include water, alcohols, for example methanol, ethanol and propanol; amides of the carboxylic acid, for example dimethylformamide and dimethyl sulfoxide; ethers, for example diethyl ether, tetrahydrofuran and diglyme; and mixtures thereof. Suitable copolymers have a weight average molecular weight of between about 2,000 and about 1,000,000, preferably between 10,000 and 300,000, more preferably between 10,000 and 100,000, and most preferably between 10,000 and 50,000. The copolymer is further modified with a reactive vinyl monomer to produce a rapidly crosslinkable polymer. Suitable reactive vinyl monomers have, in addition to the vinyl group, a reactive moiety, which reacts with a functional group present in the copolymer, to form a covalent bond, while retaining the vinyl group of the monomer. Exemplary suitable reactive vinyl monomers include hydroxyl-substituted lower alkyl acrylates and methacrylates, hydroxyl-substituted lower alkyl acrylamides and methacrylamides, hydroxyl-substituted lower alkyl vinyl ether, 2-acrylamido-2-methylpropanesulfonic acid, acrylates and methacrylates. lower aminoalkyl and lower monoalkyl-lower aminoalkyl, allyl alcohol, lower epoxyalkyl acrylates and methacrylates, acrylates and methacrylates of lower isocyanatoalkyl, vinyl unsaturated carboxylic acids having from 3 to 7 carbon atoms, and acid chlorides and anhydrides thereof, styrenes substituted by amino, hydroxyl, or isocyanate, and lower epoxycycloalkyl acrylates and methacrylates. Preferred reactive vinyl monomers include hydroxyethyl acrylate and methacrylate, hydroxypropyl acrylate and methacrylate, isocyanatoethyl acrylate and methacrylate, acrylic and methacrylic acid chloride, and ethylammonium methacrylate hydrochloride, and propylammonium methacrylate hydrochloride. The functionalized copolymer is typically crosslinked or polymerized in a solvent by a photocrosslinking process, for example using an ultraviolet laser, to produce a holographic optical element, although the copolymer can be crosslinked or polymerized in the absence of a solvent. A suitable solvent is any solvent that dissolves the base structure of the polymer. Exemplary solvents include water; alcohols, for example methanol and ethanol; amides of the carboxylic acid, for example dimethylformamide and dimethyl sulfoxide; and mixtures thereof. The photocrosslinking process is facilitated by a photoinitiator, which can initiate radical crosslinking. Exemplary photoinitiators suitable for the present invention include benzoin methylether, 1-hydroxycyclohexylphenyl ketone, Durocure® 1173 and Irgacure® 2959. "Preferably, between about 0.3 and about 2.0 percent, based on the total weight of the polymerizable formulation, of a photoinitiator. In accordance with the present invention, suitable concentrations of the vinyl lactam copolymer functionalized in the solvent to produce the holographic optical element are preferably between about 3 percent and about 90 percent by weight, more preferably between about 5 percent and 60 percent, and most preferably between about 10 percent and about 50 percent, especially when the holographic optical element is designed to be used as an ophthalmic lens. Another group of holographic optical elements suitable for the present invention can be produced from conventional recording means and other means of recording holographic optical transmission element in volume. As with the polymerizable materials described above for holographic optical elements, the first light and the collimated reference light, are projected simultaneously on a recording medium of holographic optical element, in such a way that the electromagnetic waves of the object and reference light, form patterns of interference fringes. The patterns of interference fringes, that is, the grid structure in volume, are recorded in the holographic optical element means. When the holographic optical element registration means is completely exposed, the element means Registered holographic optic is disclosed in accordance with a known holographic optical element development method. Suitable volume transmission holographic optical element recording means include commercially available holographic photographic recording materials or plates, such as dichromatic gelatins. The holographic photograph registration materials are available from different manufacturers, including Polaroid Corp. Other holographic media suitable for the present invention are disclosed, for example, in International Patent Application Number PCT / US96 / 15600 to Polaroid, and in U.S. Patent Number 5,453,340 to Nippon Paint. When using photographic recording materials such as the holographic optical element, however, the toxicological effects of the materials on the ocular environment must be considered. Accordingly, when a conventional photographic holographic optical element material is used, it is preferred that the holographic optical element be encapsulated in a biocompatible optical material. As for the first optical material of the ophthalmic lens, an optical material suitable for a hard lens, a gas permeable lens, or a hydrogel lens can be used. Suitable polymeric materials for the first optical material include hydrogel materials, rigid gas permeable materials, and rigid materials known to be useful for produce ophthalmic lenses, for example contact lenses. Suitable hydrogel materials typically have a crosslinked hydrophilic network, and contain between about 35 percent and about 75 percent, based on the total weight of the hydrogel material, of water. Examples of materials suitable hydrogel include copolymers having methacrylate, 2-hydroxyethyl and one or more comonomers such as acrylate, 2-hydroxyl ethyl acrylate, methyl methacrylate, vinylpyrrolidone, N-vinyl acrylamide, hydroxypropyl methacrylate , isobutyl methacrylate, styrene, ethoxyethyl methacrylate, methoxy triethyleneglycol methacrylate, glycidyl methacrylate, diacetone acrylamide, vinyl acetate, acrylamide, ylene hidroxitrime methacrylate, methoxymethyl, acrylic acid, methacrylic acid, ethacrylate, and dimethylaminoethyl acrylate. Other suitable hydrogel materials include copolymers having methyl vinylcarbazole or dimethylaminoethyl methacrylate. Another group of suitable hydrogel include polymerizable materials such as polyvinyl alcohols, polyethyleneimines and polyvinylamines, modified, for example, disclosed in Patent United States Number 5,508,317, issued to Beat Müller and Application Patent Number PCT / EP96 / 01265. Still another group of highly suitable hydrogel materials include silicone copolymers, given to known in International Patent Application Number PCT / EP96 / 01265. Rigid gas-permeable materials suitable for the present invention include cross-linked siloxane polymers. The network of such polymers incorporates appropriate, crosslinkers such as N, N'-dimethyl bisacrylamide, ethylene glycol diacrylate, triacrylate trihydroxypropane, pentaerythritol tetra-acrylate, and other acrylates and methacrylates polyfunctional like, or vinyl compounds, for example N , m-ethylaminodivinylcarbazole. Suitable rigid materials include acrylates, methacrylates eg, diacrylates and dimethacrylates, pyrrolidone, styrenes, amides, acrylamides, carbonates, vinyl, acrylonitriles, nitriles, sulfones, and the like. Of the suitable materials, hydrogel materials are particularly suitable for the present invention. According to the present invention, the holographic optical elements of the present invention preferably have a diffraction efficiency of at least about 70 percent, more preferably at least about 80 percent, and most preferably at least 95 percent. percent, over all or substantially all wavelengths within the spectrum of visible light. The holographic optical elements especially suitable for the present invention have a diffraction efficiency of 100 percent over all the wavelengths of the spectrum of visible light, when the Bragg condition is satisfied. According to the foregoing, a holographic optical element and volume is particularly suitable for the present invention. However, holographic optical elements having a lower diffraction efficiency than that specified above can also be used for the present invention. The Bragg condition is well known in the optical art, and is defined, for example, in Conpl ed Wave Theory for Th-ir. fíol ngram Gratings. by H. Kogelni, The Bell System Technical Journal, Vol. 48, No. 9, pages 2909-2947 (Nov. 1969). The description of the Bragg condition disclosed therein is incorporated by reference. The condition of Bragg can be expressed as: cos (f -?) = K / 2B where K = 2p / ?,? = the period of the grid of the interference fringes,? is the incident angle of the input light, f is the inclined angle of the grid, and B is the average propagation constant, which can be expressed as B = 2pn / ?, where n is the average refractive index and? It is the wavelength of light. When the Bragg condition is satisfied, up to 100 percent of the input light can be coherently diffracted. The holographic optical elements suitable for present invention are preferably holographic optical elements in combination of multiple layers, having at least two layers of holographic optical elements, because layered thin holographic optical elements improves the diffraction efficiency and the optical quality of the holographic optical element, and makes it possible to reduce the thickness of the holographic optical element. As is known in the ophthalmic art, an ophthalmic lens must have a thin dimensional thickness to promote the comfort of the lens user. According to the above, a dimensionally thin holographic optical element is preferred for the present invention. However, in order to provide a holographic optical element having a high diffraction efficiency, the holographic optical element has to be optically thick, that is, the light is diffracted by more than one plane of the pattern of interference fringes. One way to provide an optically thick and dimensionally thin optical holographic optical element is to program the pattern of interference fringes in a direction that is inclined towards the length of the holographic optical element. This grid structure in inclined volume causes the holographic optical element to have a large angular deviation between the incident angle of the entrance light and the exit angle of the exit light. However, a holographic optical element having a large angular deviation may not be particularly suitable for a ophthalmic lens. For example, when a holographic optical element such as this is placed over the eye, the line of vision significantly doubles the normal line of vision of the eye. As a preferred embodiment of the present invention, this angular limitation in the design of a holographic optical element is solved using a holographic optical element in combination of multiple layers, especially a two-layer holographic optical element. Figure 7 illustrates a holographic optical element in combination of example 70 of the present invention. Two dimensionally thin holographic optical elements are fabricated having a large angular deviation, in a holographic optical element in combination, to provide a dimensionally thin holographic optical element having a small angular deviation. The multilayer holographic optical element 70 has a first dimensionally thin holographic optical element 72, and a second thin holographic optical element 74. The first holographic optical element 72 is programmed to diffract the input light, such that, when the light enters the holographic optical element at an alpha angle, the light exiting the holographic optical element 72 forms an acute output angle β, which is greater than the alpha incident angle, as shown in Figure 7A. Preferably, the first holographic optical element has a thickness of between about 10 microns and about 100 microns, more preferably of between about 20 microns and about 90 microns, and most preferably between about 30 microns and about 50 microns. The second holographic optical element 74, FIG. 7B, is programmed to have an incident activation angle β, which is coupled with the output angle β of the first holographic optical 72. In addition, the second holographic optical element 74 is programmed to focus the input light at a focal point 76, when the light enters the activation angle ß. Figure 7B illustrates the second holographic optical element 74. Preferably, the second holographic optical element has a thickness of between about 10 microns and about 100 microns, more preferably between about 20 microns and about 90 microns, and most preferably between about 30 microns and approximately 50 microns. When the first holographic optical element 72 is placed next to the second holographic optical element 74, and the input light enters the first holographic optical element 72 at an angle corresponding to the angle alpha, the path of the light exiting the holographic optical element 70 in combination, it is modified, and the light is focused on the focal point 76. By utilizing a holographic optical element in combination of multiple layers, a dimensionally thin holographic optical element having a high diffraction efficiency can be produced, and a small angled deviation. In In addition to the high diffraction efficiency, and the advantages of small angular deviation, the use of a multi-layer holographic optical element provides additional advantages, including the correction of dispersion aberration and chromatic aberration. A single holographic optical element can produce images that have scattering and chromatic aberrations, since the visual light consists of a spectrum of electromagnetic waves that have different wavelengths, and the differences in the wavelengths can make the electromagnetic waves difract in a different way by the holographic optical element. It has been found that a multi-layer holographic optical element, especially two layers, can counteract to correct these aberrations, which can be produced with a single-layer holographic optical element. According to the above, a holographic optical element in combination of multiple layers is preferred. The ophthalmic lens production method of the present invention is a highly flexible method, which can be used to produce ophthalmic lenses having a wide range of corrective potencies, and produce ophthalmic lenses that are designed to promote the comfort of the wearer of the lens. Unlike conventional ophthalmic lenses, the power or corrective powers of the present ophthalmic lens, provide the power or corrective powers through programming of adequate powers in the lens, without the need to change the dimensions of the lens. As discussed above, different corrective powers can be programmed in the ophthalmic lens, for example, by changing the distance, the pattern, and / or the configuration of the object light and the reference light. In accordance with the above, the production process of the lens is greatly simplified. Additional advantages include the fact that manufacturers of ophthalmic lenses do not need to have different equipment and lens manufacturing methods to produce a wide range of different lenses that have different corrective powers. It should be noted that, although the present invention is described in conjunction with ophthalmic lenses, corrective eyeglass lenses having a holographic optical element in volume can be produced in accordance with the present invention. For example, a dimensionally thin film of a holographic optical element can be laminated, which is programmed to provide a corrective power, on a flat eyeglass lens. These spectacle lenses, ie spectacle lenses, can be designed to promote user comfort without sacrificing the corrective efficacy of the lenses, because the corrective holographic optical element lens does not lean on the thickness of the lens to provide the corrective power, as discussed above. The present invention is further illustrated with The following examples. However, the examples should not be construed to limit the invention to them.

Examples Example 1 Approximately 0.06 milliliters of the Nelfilcon A monomer lens composition is deposited in the central portion of a female mold half, and a male mold half of coupling is placed on the female mold half, forming a lens mold assembly . The male mold half does not touch the female mold half, and they are separated by approximately 0.1 millimeters. The lens mold halves are made of quartz, and are masked with chrome, except for the circular central portion of the lens of approximately 15 millimeters in diameter. Briefly, Nelfilcon A is a product of a crosslinkable modified polyvinyl alcohol containing approximately 0.48 millimoles / gram of an acrylamide crosslinker. The polyvinyl alcohol has an acetate content of about 7.5 mole percent. Nelfilcon A has a solid content of approximately 31 percent, and contains approximately 0.1 percent of a photoinitiator, Durocure® 1173. The closed lens mold assembly is placed under a laser device. The laser apparatus provides two coherent collimated ultraviolet laser beams that have a wavelength of 351 nanometers, wherein a beam is passed through an optical convex lens, such that the focal point is formed 500 millimeters from the lens mold assembly. The focused light serves as a first point source light. The angle formed between the trajectories of the first light and the reference light is approximately 7 °. The apparatus provides a holographic optical element that has an aggregate corrective power of two diopters. The monomeric lens composition is exposed to laser beams having approximately 0.2 watts for about 2 minutes, to completely polymerize the composition, and to form a grid structure in volume. Since the lens mold is masked, except for the central portion, the lens monomer exposed in the circular center portion of the mold is subjected to the first light and the reference light, and polymerized. The mold assembly opens, leaving the lens attached to the male mold half. Again, approximately 0.06 milliliters of the Nelfilcon A monomer lens composition are deposited in the central portion of the female mold half, and the male mold half is placed with the lens formed on the female mold half. The male and female mold halves are separated by approximately 0.2 millimeters. The closed mold assembly is again exposed to the laser apparatus, except that the first convex optical lens is removed. light device. Again the monomeric composition is exposed to the laser beams for about 2 minutes, to completely polymerize the composition. The resulting composite lens has an optical power based on the shape of the lens and on the refractive index of the lens material, and an additional activatable corrective power of +2 diopters.

Example 2 Example 1 is repeated, except that the convex optical lens for the first light is replaced with a cylindrical lens. The cylindrical lens provides a line source light that is vertically oriented. The resulting composite lens has an optical power based on the shape of the lens and the refractive index of the lens material, and an additional cylindrical power of +2 diopters, with a cylindrical axis of 90 °. The composite lens is suitable for correcting an astigmatic condition.

Claims (20)

KF.TVTNnTCApTONES

1. An ophthalmic lens for correcting astigmatism, which comprises a holographic element in volume, wherein this holographic element has a grid structure in volume that provides one or more corrective powers comprising a cylindrical power.

2. The ophthalmic lens of claim 1, wherein this lens further provides a spherical power.

3. The ophthalmic lens of claim 2, wherein said spherical power is provided by the grid structure in volume.

4. The ophthalmic lens of claim 2, wherein the spherical power is a refractive power proportionally cloned by the contour of the ophthalmic lens.

5. The ophthalmic lens of claim 1, wherein the lens has a stabilizing mechanism.

6. The ophthalmic lens of claim 1, wherein the lens is a contact lens. The ophthalmic lens of claim 1, wherein the lens is an intraocular lens. The ophthalmic lens of claim 1, wherein the holographic element comprises a biocompatible optical material. 9. The ophthalmic lens of claim 8, in where the lens is a composite lens. 10. An ophthalmic lens comprising a holographic element in transmission volume, wherein this holographic element has a grid structure in volume that provides an optical power. 11. The ophthalmic lens of claim 10, wherein the holographic element is a biocompatible optical element. The ophthalmic lens of claim 10, wherein the lens is a composite lens. 13. The ophthalmic lens of claim 10 is a contact lens. 14. The ophthalmic lens of claim 10 is an intraocular lens. 15. A contact lens for correcting astigmatism, which comprises a holographic element in volume, wherein this holographic element has a grid structure in volume that is programmed to provide a cylindrical power. 16. The contact lens of claim 15, wherein the lens has a stabilizing mechanism. 1

7. The contact lens of claim 15, wherein the holographic element comprises a biocompatible optical element. 1

8. The contact lens of claim 15, in where the lens also provides a spherical power. 1

9. The contact lens of claim 18, wherein the spherical power is a negative power. 20. The contact lens of claim 18, wherein the spherical power is a positive power.