Method for manufacturing a light-absorbing contact lens and light-absorbing contact lens prepared thereby

Abstract

The present invention provides a method for manufacturing a light-absorbing contact lens and a light-absorbing contact lens prepared thereby. The method comprises: (a) providing a mold assembly comprising a bottom surface and a front surface, the bottom surface and the front surface defining and enclosing a cavity therebetween, the cavity containing a reactive mixture, wherein the reactive mixture comprises at least one polymerizable monomer, a photoinitiator that absorbs at an activation wavelength, and a light-absorbing compound that exhibits absorbance at the activation wavelength; and (b) curing the reactive mixture by exposing the reactive mixture to radiation including the activation wavelength to form a light-absorbing contact lens, wherein the radiation is directed to both the bottom surface and the front surface of the mold assembly, and wherein the radiant energy of the radiation at the bottom surface is greater than the radiant energy of the radiation at the front surface.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Patent Application Serial No. 16 / 805,931, filed Mar. 2, 2020, and U.S. Provisional Patent Application Serial No. 62 / 825,050, filed Mar. 28, 2019, the entire contents of each of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present invention relates to contact lenses and methods of making the same. More particularly, the present invention relates to methods for making contact lenses that include light-absorbing compounds, such as high-energy visible (HEV) light-absorbing compounds or photochromic compounds. BACKGROUND OF THE INVENTION

[0004] Precision spectral filters absorb visible light radiation or UV radiation at specific wavelengths. This allows for the preparation of optical articles such as glasses that can be customized to block specific wavelengths of light for different uses, including protecting the cornea, lens, and retina from harmful or unwanted radiation wavelengths. For example, various sunglasses have been developed to protect the human eye from bright light, including photochromic glass, polarized glasses, and glasses for specific activities such as shooting and fishing. Photochromic glasses darken when exposed to certain wavelengths of light (typically ultraviolet (UV) light) and lighten when the UV light is removed. Typically, such photochromic glasses include a prescription for vision correction.

[0005] Adapting certain technologies, including photochromic technologies, to contact lenses is more difficult than adapting the same technologies to glasses. Additional factors must be considered, such as the oxygen permeability, comfort, and fit of the resulting lens. The manufacturing process for contact lenses is also more complex. Typically, contact lenses are formed by irradiating a photoinitiator in the presence of one or more polymerizable materials. In the case of photochromic contact lenses, it is desirable to include a photochromic dye in a reactive mixture that includes a photoinitiator and a polymerizable material that forms the contact lens when polymerized. Unfortunately, certain light-absorbing compounds, including photochromic dyes, can absorb the radiation needed to otherwise activate the photoinitiator and thus have the potential to interfere with the polymerization reaction.

[0006] A manufacturing method that allows for the effective and reproducible incorporation of light-absorbing compounds into contact lenses would be a significant advancement in the art. SUMMARY OF THE INVENTION

[0007] The present invention relates to a method for manufacturing a light-absorbing contact lens and a light-absorbing contact lens prepared by such a method. It has been found that contact lenses containing light-absorbing compounds can be effectively and reproducibly prepared by the manufacturing methods described herein. Contact lenses are typically manufactured by polymerizing a reactive monomer mixture within a lens-shaped mold. The polymerization can be initiated by various known techniques, such as UV or visible light initiation or thermal initiation. In typical UV or visible light initiation techniques, the reactive monomer mixture is exposed to activating radiation from one direction. However, in the present invention, the reactive monomer mixture is exposed to activating radiation from at least two directions. Additionally, the radiant energy of the activating radiation is different between the two directions, which is referred to herein as differential curing. Thus, the method of the present invention provides a light-absorbing contact lens in which the optical parameters of the contact lens have been improved compared to single-sided curing and non-differential double-sided curing, and the lens characteristics of the contact lens are less dependent on curing conditions such as time, temperature, and irradiation intensity and wavelength.

[0008] Accordingly, in one aspect, the present invention provides a method for manufacturing a light-absorbing contact lens. The method comprises: (a) providing a mold assembly comprising a bottom surface and a front surface, the bottom surface and the front surface defining and enclosing a cavity therebetween, the cavity containing a reactive mixture, wherein the reactive mixture comprises at least one polymerizable monomer, a photoinitiator that absorbs at an activating wavelength, and a light-absorbing compound that exhibits absorbance at the activating wavelength; and (b) curing the reactive mixture by exposing the reactive mixture to radiation comprising the activating wavelength to form a light-absorbing contact lens, wherein the radiation is directed at both the bottom surface and the front surface of the mold assembly, and wherein the radiant energy of the radiation at the bottom surface is greater than the radiant energy of the radiation at the front surface.

[0009] In another aspect, the present invention provides a light-absorbing contact lens prepared by the manufacturing method described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Shows the overlapping absorption spectra of a photoinitiator and a light-absorbing monomer within the emission bandwidth of an LED lamp.

[0011] Figure 2 Shows a schematic diagram of a two-zone curing tunnel.

[0012] Figure 3 Shows a scatter plot of RMS_65 data.

[0013] Figure 4 Shows a scatter plot of DMD data.

[0014] Figure 5 Shows a scatter plot of BCD data.

[0015] Figure 6 A scatter plot of RMS_65 data is shown, where the wavelengths of the top and bottom panels are 435 nm.

[0016] Figure 7 A scatter plot of RMS_65 data is shown, where the intensity ratio of the top and bottom panels is 1. Detailed Description

[0017] It should be understood that the present invention is not limited to the details of the construction or process steps set forth in the following description. With the teachings herein, the present invention is capable of other embodiments and of being practiced or carried out in various ways.

[0018] The following definitions are provided with respect to the terms used in the present disclosure.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Polymer definitions conform to those disclosed in Compendium of Polymer Terminology and Nomenclature, IUPAC Recommendations 2008, edited by Richard G. Jones, Jaroslav Kahovec, Robert Stepto, Edward S. Wilks, Michael Hess, Tatsuki Kitayama, and W. Val Metanomski, and recommended by IUPAC in 2008. All publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference.

[0020] The term “(meth)” means an optional methyl substitution. Thus, terms such as “(meth)acrylate” mean both methacrylate and acrylate.

[0021] The term “contact lens” refers to an ophthalmic device that can be placed on the cornea of an individual's eye. Contact lenses can provide corrective, cosmetic, or therapeutic benefits, including wound healing, drug or nutritional agent delivery, diagnostic evaluation or monitoring, ultraviolet light absorption, visible light or glare reduction, or any combination thereof. Contact lenses can be any suitable material known in the art and can be soft lenses, hard lenses, or hybrid lenses that include at least two different parts having different physical, mechanical, or optical properties such as modulus, water content, light transmission, or any combination thereof.

[0022] "Monomer" is a monofunctional molecule that is a repeating unit in a chemical structure capable of undergoing chain-growth polymerization (and specifically free-radical polymerization) to form a target macromolecule. As used in this specification, the term "monomer" encompasses small molecules, as well as larger molecules capable of chain growth under free-radical polymerization conditions, such as macromonomers, oligomers, and prepolymers. A "hydrophilic monomer" is a monomer that, when mixed with deionized water at a concentration of 5 wt% at 25 °C, produces a clear single-phase solution.

[0023] "Silicone-containing component" is a molecule (usually a monomer) having at least one silicon-oxygen bond, which is typically in the form of a silyloxy group, a siloxanyl group, a carbosiloxanyl group, and mixtures thereof.

[0024] "Initiator" is a molecule that can decompose into free radicals, which can then react with monomers to initiate a free-radical polymerization reaction. Depending on the temperature, thermal initiators decompose at a certain rate; typical examples are azo compounds such as 1,1'-azobisisobutyronitrile and 4,4'-azobis(4-cyanovaleric acid), peroxides such as benzoyl peroxide, tert-butyl peroxide, tert-butyl hydroperoxide, tert-butyl perbenzoate, dicumyl peroxide, and lauroyl peroxide, peracids such as peracetic acid and potassium persulfate, and various redox systems. Photoinitiators that decompose by photochemical methods; typical examples are benzil, benzoin, acetophenone, benzophenone, camphorquinone, and mixtures thereof, as well as derivatives of various monoacyl and diacyl phosphine oxides and combinations thereof.

[0025] The terms "reactive mixture" and "reactive monomer mixture" refer to a mixture of components (both reactive and non-reactive) that are mixed together and, when subjected to polymerization conditions, form a conventional or silicone hydrogel of the present invention and contact lenses made therefrom. The reactive monomer mixture can include reactive components such as monomers, crosslinkers, and initiators, additives such as wetting agents, release agents, polymers, dyes, light-absorbing compounds such as UV absorbers, pigments, dyes, and photochromic compounds (any of which can be reactive or non-reactive but capable of remaining in the resulting biocompatible device), as well as pharmaceutical and nutritional formulation compounds and any diluents. It should be understood that a wide range of additives can be added based on the contact lenses to be produced and their intended use. The concentration of the components of the reactive mixture is expressed as a weight percentage of all components in the reactive mixture (excluding diluents). When diluents are used, their concentration is expressed as a weight percentage based on the amount of all components in the reactive mixture and the diluents.

[0026] "Conventional hydrogel" refers to a polymer network made from components that do not contain any silyloxy, siloxane, or carbosilane groups. Conventional hydrogels are prepared from a reactive mixture containing hydrophilic monomers. Examples include 2-hydroxyethyl methacrylate ("HEMA"), N-vinylpyrrolidone ("NVP"), N,N-dimethylacrylamide ("DMA"), or vinyl acetate. U.S. Patent Nos. 4,436,887, 4,495,313, 4,889,664, 5,006,622, 5,039459, 5,236,969, 5,270,418, 5,298,533, 5,824,719, 6,420,453, 6,423,761, 6,767,979, 7,934,830, 8,138,290, and 8,389,597 disclose the formation of conventional hydrogels. Conventional hydrogels can also be formed from polyvinyl alcohol. Conventional hydrogel lenses can include a coating, and the coating can be the same or a different material from the substrate. Conventional hydrogels can contain additives such as polyvinylpyrrolidone, and comonomers including phosphorylcholine, methacrylic acid, etc. Commercially available conventional hydrogels include, but are not limited to, etafilcon, genfilcon, hilafilcon, lenifilcon, nesofilcon, omafilcon, polymacon, and verofilcon, including all their variants.

[0027] "Silicone hydrogel" refers to a polymer network made from at least one hydrophilic component and at least one silicone-containing component. Examples of suitable types of hydrophilic components that can be present in the reactive mixture include (meth)acrylates, styrenes, vinyl ethers, (meth)acrylamides, N-vinyl lactams, N-vinyl amides, N-vinyl imides, N-vinyl ureas, O-vinyl carbamates, O-vinyl carbonates, other hydrophilic vinyl compounds, and mixtures thereof. Silicone-containing components are well-known and have been widely described in the patent literature. For example, a silicone-containing component can contain at least one polymerizable group (e.g., (meth)acrylate, styryl, vinyl ether, (meth)acrylamide, N-vinyl lactam, N-vinyl amide, O-vinyl carbamate, O-vinyl carbonate, vinyl group, or a mixture of the above), at least one siloxane group, and one or more linking groups (which can be bonds) that link one or more polymerizable groups to one or more siloxane groups. A silicone-containing component can, for example, contain 1 to 220 siloxane repeat units. A silicone-containing component can also contain at least one fluorine atom. Silicone hydrogel lenses can include a coating, and the coating can be the same or a different material from the substrate.

[0028] Examples of silicone hydrogels include acquafilcon, asmofilcon, balafilcon, comfilcon, delefilcon, enfilcon, fanfilcon, formofilcon, galyfilcon, lotrafilcon, narafilcon, riofilcon, samfilcon, senofilcon, somofilcon, and stenfilcon, including all of their variants, as well as silicone hydrogels prepared as described in U.S. Patent Nos. 4,659,782, 4,659,783, 5,244,981, 5,314,960, 5,331,067, 5,371,147, 5,998,498, 6,087,415, 5,760,100, 5,776,999, 5,789,461, 5,849,811, 5,965,631, 6,367,929, 6,822,016, 6,867,245, 6,943,203, 7,247,692, 7,249,848, 7,553,880, 7,666,921, 7,786,185, 7,956,131, 8,022,158, 8,273,802, 8,399,538, 8,470,906, 8,450,387, 8,487,058, 8,507,577, 8,637,621, 8,703,891, 8,937,110, 8,937,111, 8,940,812, 9,056,878, 9,057,821, 9,125,808, 9,140,825, 9156,934, 9,170,349, 9,244,196, 9,244,197, 9,260,544, 9,297,928, 9,297,929, and WO 03 / 22321, WO 2008 / 061992, and US 2010 / 0048847. These patents are hereby incorporated by reference in their entireties.

[0029] As used in this specification, the term "radiant energy" refers to the energy of electromagnetic radiation used to activate a photoinitiator present in a reactive monomer mixture. In the present invention, the radiant energy is controlled by the intensity, wavelength, or both the intensity and wavelength of the radiation. The radiant energy is directly proportional to the intensity of the radiation and inversely proportional to the wavelength of the radiation (shorter wavelengths provide greater radiant energy).

[0030] As described above, the present invention provides methods for manufacturing light-absorbing contact lenses (e.g., contact lenses comprising a photochromic compound and / or a high-energy visible (HEV) light-absorbing compound). The contact lenses are made from a reactive mixture that comprises at least one polymerizable monomer, a photoinitiator that absorbs at an activation wavelength, and a light-absorbing compound that exhibits absorbance at the activation wavelength.

[0031] The presence of both a photoinitiator and a light-absorbing compound having overlapping light-absorbing characteristics in the same reactive mixture can pose problems for the controlled activation of the photoinitiator. Without being bound by any particular theory, it is believed that absorption of the light-absorbing compound in the same spectral region as the photoinitiator causes the light-absorbing compound to at least partially "shield" the photoinitiator. In the case where the light-absorbing compound is a photochromic compound, this absorption can occur when the photochromism is at least partially activated. It is believed that incomplete activation of the initiator caused by absorption by the light-absorbing compound can prevent curing and / or result in non-uniform or anisotropic curing, which leads to the formation of material defects and stresses within the lens. These defects adversely affect the mechanical and optical properties of the resulting contact lens. The present invention solves these problems by providing different curing methods, as further described below.

[0032] The present invention can be used to provide hard or soft contact lenses made from any known lens material or materials suitable for manufacturing such lenses. Preferably, the lenses of the present invention are soft contact lenses that can have a water content of from about 0% to about 90% or from about 20% to about 75% water. The contact lenses of the present invention can have a water content of at least about 25%. The lenses of the present invention can have other desired properties, such as a tensile modulus of less than about 200 psi or less than about 150 psi. The lenses can have an oxygen permeability of greater than about 50×10 -11 (cm 2 / sec)(ml O2 / ml×mmHg) or greater than about 75×10 -11 (cm 2 / sec)(ml O2 / ml×mmHg). It should be understood that combinations of the above properties are desirable and the above ranges can be combined in any combination.

[0033] The contact lenses of the present invention can be conventional hydrogels. The contact lenses of the present invention can be silicone hydrogels. The contact lenses can be made from hydrophilic monomers, silicone-containing components, and mixtures thereof to form polymers such as siloxanes, hydrogels, silicone hydrogels, and combinations thereof. The materials that can be used to form the lenses of the present invention can be prepared by reacting blends of macromonomers, monomers, polymers, and combinations thereof with additives such as polymerization initiators. Suitable materials include, but are not limited to, silicone hydrogels made from silicone macromonomers and hydrophilic monomers. Reactive mixtures of different polymerizable monomers can also be used to produce copolymers.

[0034] Reactive mixtures for preparing contact lenses are well known, and the components of such mixtures are commercially available or can be readily prepared by those skilled in the art. Exemplary polymers suitable for forming contact lenses include, but are not limited to, etafilcon A, genfilcon A, lenefilcon A, polymacon, balafilcon, acquafilcon, comfilcon, galyfilcon, senofilcon, narafilcon, and lotrafilcon. Contact lens formulations can include etafilcon, senofilcon, balafilcon, galyfilcon, lotrafilcon, comfilcon, filcon II 3, asmofilcon A, and silicone hydrogels, such as those prepared in the following patents: U.S. Patent 5,998,498; U.S. Patent Application 09 / 532,943, a partial continuation application of U.S. Patent Application 09 / 532,943 filed on August 30, 2000, and U.S. Patents 6,087,415, U.S. 6,087,415, U.S. 5,760,100, U.S. 5,776,999, U.S. 5,789,461, U.S. 5,849,811, U.S. 5,965,631, US7,553,880, WO2008 / 061992, US2010 / 048847. These patents are hereby incorporated by reference for the hydrogel components contained therein.

[0035] The reactive mixture of the present invention can be a HEMA-based hydrogel, such as etafilcon A. Etafilcon A, disclosed in U.S. Patents 4,680,336 and 4,495,313 (which are incorporated herein by reference in their entireties), is generally a formulation consisting mainly of HEMA and methacrylic acid (MAA) and various other additives such as crosslinking agents and visible colorants.

[0036] The reactive mixture of the present invention can be a silicone hydrogel made from at least one hydrophilic monomer and at least one silicone-containing component. Examples of silicone hydrogels include acquafilcon, asmofilcon, balafilcon, comfilcon, delefilcon, enfilcon, fanfilcon, formofilcon, galyfilcon, lotrafilcon, narafilcon, riofilcon, samfilcon, senofilcon, somofilcon, and stenfilcon, including all their variants.

[0037] The preferred reactive mixture can be based on hydrophilic monomers selected from N,N-dimethylacrylamide (DMA), HEMA, and mixtures thereof; a silicone-containing component selected from 2-hydroxy-3-[3-methyl-3,3-bis(trimethylsilyloxy)silylpropoxy]-propyl methacrylate (SiMAA), mono-methacryloxypropyl-capped mono-n-butyl-capped polydimethylsiloxane (mPDMS), mono-(2-hydroxy-3-methacryloxypropyl)-propyl ether-capped mono-n-butyl-capped polydimethylsiloxane (OH-mPDMS), and mixtures thereof. For the hydrophilic monomers, a mixture of DMA and HEMA is preferred. For the silicone-containing component, a mixture of SiMAA and mPDMS is preferred.

[0038] The preferred reactive mixture can be based on hydrophilic monomers comprising a mixture of DMA and HEMA; a silicone-containing component comprising a mixture of mono-(2-hydroxy-3-methacryloxypropoxy)-propyl-capped mono-n-butyl-capped polydimethylsiloxane (OH-mPDMS) having 2 to 20 repeating units (preferably a mixture of 4 and 15 repeating units).

[0039] The reactive mixture for the process of the present invention comprises a photoinitiator. The photoinitiator can absorb light of various wavelengths (and be activated by it), such as UV wavelengths and / or visible wavelengths. Preferably, the photoinitiator in the process of the present invention can absorb within the visible light range (from about 380 nm to about 780 nm) of the electromagnetic spectrum. Suitable visible light photoinitiators are known in the art and include, but are not limited to, aromatic α-hydroxy ketones, alkoxyoxybenezils, acetophenones, acylphosphine oxides, bisacylphosphine oxides, and tertiary amine plus diketones, mixtures thereof, etc. Illustrative examples of photoinitiators are 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide (DMBAPO), bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide (Irgacure 819), 2,4,6-trimethylbenzyl diphenyl phosphine oxide, and 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, benzoin methyl ether, and a combination of camphorquinone and ethyl 4-(N,N-dimethylamino)benzoate. Commercially available visible light photoinitiator systems include Irgacure 819, Irgacure 1700, Irgacure 1800, Irgacure 819, Irgacure 1850 (all from Ciba Specialty Chemicals) and Lucirin TPO initiator (purchased from BASF). These and other photoinitiators that can be used are disclosed in Voclume III, Photoinitiators for Free Radical Cationic & Anionic Photopolymerization, 2nd Edition by J.V. Crivello and K. Dietliker; edited by G. Bradley; John Wiley and Sons; New York; 1998. The initiator can be used in the reactive mixture in an effective amount to initiate the photopolymerization of the reactive mixture (e.g., from about 0.1 parts by weight to about 2 parts by weight per 100 parts of one or more reactive monomers).

[0040] Particularly preferred visible light photoinitiators include α-hydroxy ketones, such as those available from CIBA (such as Irgacure 1700 or 1800); various organic phosphine oxides, 2,2'-azobis(isobutyronitrile); diethoxyacetophenone; 1-hydroxycyclohexyl phenyl ketone; 2,2-dimethoxy-2-phenylacetophenone; phenothiazine; diisopropylxanthogen disulfide; benzoin or benzoin derivatives; etc. Preferably, the photoinitiator is activated at wavelengths included in the range of 200 nm to 600 nm, or 300 nm to 500 nm, or 350 nm to 450 nm, or 380 nm to 450 nm, or 400 nm to 450 nm, or 430 nm to 440 nm.

[0041] The photoabsorbing compounds present in the reactive mixture are generally compounds that absorb at least some of the activating radiation. For example, such compounds can absorb UV and / or visible light whose wavelength at least partially overlaps with the wavelength of the activating radiation required to initiate the photoinitiator. The photoabsorbing compound can be a static photoabsorbing compound, which means that its absorption profile does not change significantly upon exposure to radiation. Static photoabsorbing compounds are used, for example, in non-photochromic sunglasses. Examples include compounds that absorb UV and / or HEV light (e.g., blue light).

[0042] The photoabsorbing compound can be a photochromic dye. A photochromic dye is any compound capable of transitioning between a first “clear,” “bleached,” or “unactivated” ground state and a second “colored,” “darkened,” or “activated” state in response to the absorption of certain wavelengths of electromagnetic radiation (or “actinic radiation”). In one embodiment, the photochromic dye absorbs within the visible range (380 nm to 780 nm) of the electromagnetic spectrum when in the activated state. Examples of suitable photochromic dyes are known in the art and include, but are not limited to, materials of the following classes: chromenes, such as naphthopyrans, benzopyrans, indonaphthopyrans, and phenanthopyrans; spirooxazines, such as spiro(benzodihydroindolyl)naphthopyran, spiro(dihydroindolyl)benzopyran, spiro(dihydroindolyl)naphthopyran, spiro(dihydroindolyl)quinolinopyran, and spiro(dihydroindolyl)pyran; oxazines, such as spiro(dihydroindolyl)naphthoxazine, spiro(dihydroindolyl)pyridinobenzoxazine, spiro(benzodihydroindolyl)pyridinobenzoxazine, spiro(benzodihydroindolyl)naphthoxazine, and spiro(dihydroindolyl)benzoxazine; mercuric dithizonate, fulgides, fulgimides, and mixtures of such photochromic compounds.

[0043] Additional suitable photochromic dyes include, but are not limited to, organometallic dithiozonates, such as (arylazo)-thioformic acid arylhydrazonates, for example mercury dithizonate; and fulgides and fulgimides, naphthoxazines, spirobenzopyrans; polymerizable spirobenzopyrans and spirobenzopyrans; polymerizable fulgides; polymerizable bianthraquinodimethanes; polymerizable spirooxazines; and polymerizable polyalkoxylated naphthopyrans. The photochromic dyes may be used alone or in combination with one or more other photochromic dyes or static light absorbing compounds.

[0044] Other suitable photochromic compounds are disclosed in US 7,556,750, the disclosure of which is incorporated by reference. Non-limiting examples of suitable photochromic dyes include naphthopyrans, such as those shown in Table 1. The dyes may include polymerizable functional groups such that they copolymerize into the resulting contact lens. Examples of polymerizable functional groups include (meth)acrylates, (meth)acrylamides, vinyls, and the like. In one embodiment, the photochromic dye is selected such that when in the activated state, it absorbs throughout the visible spectrum, but when unactivated, it absorbs below about 430 nm and absorbs less than about 10% throughout the visible spectrum.

[0045] Other available photochromic dyes include indeno-fused naphthopyrans selected from indeno[2',3':3,4]naphtho[1,2-b]pyran and indeno[1',2':4,3]naphtho[2,1-b]pyran, which are more specifically disclosed in US 2009 / 0072206 and US 2006 / 0226401 and those cited in US 7,364,291, and combinations thereof. The preferred photochromic dye is 4-[4-[3,13-dihydro-6-methoxy-13,13-dimethyl-3-phenyl-7-(1-piperidinyl)benzo[3,4]fluoreno[2,1-b]pyran-3-yl]phenyl]-γ-oxo-,2-[(2-methyl-1-oxo-2-propen-1-yl)oxo]ethyl 1-piperazinebutanoate (registration number 1339922-40-5) shown in Formulation 1 below.

[0046]

[0047] The contact lens may contain a mixture of light absorbing compounds, for example a mixture of at least one photochromic compound with other static light absorbing compounds (including pigments, dyes, and UV and / or HEV absorbing compounds). Preferred UV and / or HEV absorbing compounds include the compounds of Formulation 2:

[0048]

[0049] Wherein:

[0050] m and n are independently 0, 1, 2, 3 or 4;

[0051] T is a chemical bond, O or NR;

[0052] X is O, S, NR, SO or SO2;

[0053] Y is a linking group;

[0054] P g is a polymerizable group;

[0055] R is independently H, C1-C6 alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or Y-P each time it appears g ;

[0056] When R 1 and R 2 are present, R 1 and R 2 are independently C1-C6 alkyl, C1-C6 alkoxy, C1-C6 thioalkyl, C3-C7 cycloalkyl, aryl, halogen, hydroxy, amino, NR 3 R 4 or benzyl, where R 3 and R 4 are independently H or C1-C6 alkyl, or two adjacent R 1 or R 2 groups together with the carbon atom to which they are attached form a cycloalkyl or aryl ring; and

[0057] EWG is an electron-withdrawing group.

[0058] Preferred compounds of Formulation 2 include those in which Y is independently alkylene, cycloalkylene, heterocycloalkylene, arylene, heteroarylene, oxaalkylene, alkylene-amide-alkylene, alkylene-amine-alkylene, or a combination thereof each time it appears.

[0059] Preferred compounds of Formulation 2 include those in which P g includes styryl, vinyl carbonate, vinyl ether, vinyl carbamate, N-vinyl lactam, N-vinyl amide, (meth)acrylate or (meth)acrylamide.

[0060] Preferred compounds of Formulation 2 include those in which X is O.

[0061] Preferred compounds of Formulation 2 include those in which X is S.

[0062] Preferred compounds of Formulation 2 include those in which EWG is cyano, amide, ester, ketone or aldehyde. More preferably, EWG is cyano.

[0063] Preferred compounds of Formulation 2 include those in which m and n are each zero.

[0064] Preferred compounds of Formulation 2 include the following, including mixtures of two or more of them:

[0065] 2-(2-Cyano-2-(9H-thioxanthen-9-ylidene)acetamido)ethyl methacrylate;

[0066] 2-(2-Cyano-2-(9H-thioxanthen-9-ylidene)acetamido)ethyl acrylate;

[0067] N-(2-(2-Cyano-2-(9H-thioxanthen-9-ylidene)acetamido)ethyl)methacrylamide;

[0068] N-(2-(2-Cyano-2-(9H-thioxanthen-9-ylidene)acetamido)ethyl)acrylamide;

[0069] 2-(2-Cyano-N-methyl-2-(9H-thioxanthen-9-ylidene)acetamido)ethyl methacrylate;

[0070] 2-Cyano-2-(9H-thioxanthen-9-ylidene)-N-(2-(N-vinylacetamido)ethyl)acetamide;

[0071] 2-(2-Cyano-2-(9H-xanthen-9-ylidene)acetamido)ethyl methacrylate;

[0072] 2-(2-Cyano-2-(9H-xanthen-9-ylidene)acetamido)ethyl acrylate;

[0073] N-(2-(2-Cyano-2-(9H-xanthen-9-ylidene)acetamido)ethyl)methacrylamide;

[0074] N-(2-(2-Cyano-2-(9H-xanthen-9-ylidene)acetamido)ethyl)acrylamide;

[0075] 2-(2-Cyano-N-methyl-2-(9H-xanthen-9-ylidene)acetamido)ethyl methacrylate;

[0076] 2-Cyano-N-(2-(N-vinylacetamido)ethyl)-2-(9H-xanthen-9-ylidene)acetamide;

[0077] 2-(2-(Acridin-9(10H)-ylidene)-2-cyanoacetamido)ethyl acrylate;

[0078] N-(2-(2-(Acridin-9(10H)-ylidene)-2-cyanoacetamido)ethyl)methacrylamide;

[0079] N-(2-(2-(Acridin-9(10H)-ylidene)-2-cyanoacetamido)ethyl)acrylamide;

[0080] 2-(2-(Acridin-9(10H)-ylidene)-2-cyano-N-methylethanamido)ethyl methacrylate;

[0081] 2-(Acridin-9(10H)-ylidene)-2-cyano-N-(2-(N-vinylacetamido)ethyl)acetamide;

[0082] 2-(2-Cyano-2-(9H-thioxanthen-9-ylidene)acetamido)-2-methylpropyl methacrylate;

[0083] 2-(2-Cyano-2-(9H-xanthen-9-ylidene)acetoxy)-2-methylpropyl acrylate;

[0084] (Z)-2-(2-Cyano-2-(3-hydroxyacridin-9(10H)-ylidene)acetamido)ethyl methacrylate;

[0085] 2-(2-Cyano-2-(10-methylacridin-9(10H)-ylidene)acetamido)ethyl methacrylate;

[0086] 2-(2-Cyano-2-(3,6-dihydroxyacridin-9(10H)-ylidene)acetamido)ethyl methacrylate;

[0087] (E)-2-(2-(7H-benzo[c]xanthen-7-ylidene)-2-cyanoacetamido)ethyl methacrylate;

[0088] (Z)-2-(2-Cyano-2-(3-methoxy-9H-xanthen-9-ylidene)acetamido)ethyl methacrylate;

[0089] 2-(2-Cyano-2-(3,6-dihydroxy-9H-xanthen-9-ylidene)acetamido)ethyl methacrylate;

[0090] (E)-2-(2-Cyano-2-(2-methyl-9H-xanthen-9-ylidene)acetamido)ethyl methacrylate;

[0091] (E)-2-(2-Cyano-2-(1-hydroxy-9H-xanthen-9-ylidene)acetamido)ethyl methacrylate;

[0092] (E)-2-(2-Cyano-2-(2,4-dichloro-9H-thioxanthen-9-ylidene)acetamido)ethyl methacrylate;

[0093] (E)-2-(2-(2-Chloro-9H-thioxanthen-9-ylidene)-2-cyanoacetamido)ethyl methacrylate;

[0094] (E)-2-(2-Cyano-2-(2-isopropyl-9H-thioxanthen-9-ylidene)acetamido)ethyl methacrylate;

[0095] (E)-2-(2-Cyano-2-(4-isopropyl-9H-thioxanthen-9-ylidene)acetamido)ethyl methacrylate;

[0096] 2-(3-Oxo-2-(9H-thioxanthen-9-ylidene)propanamido)ethyl methacrylate;

[0097] 2-(3-Oxo-2-(9H-thioxanthen-9-ylidene)butanamido)ethyl methacrylate;

[0098] 2-(3-Methoxy-3-oxo-2-(9H-thioxanthen-9-ylidene)propanamido)ethyl methacrylate;

[0099] 2-(3-Amino-3-oxo-2-(9H-thioxanthen-9-ylidene)propanamido)ethyl methacrylate;

[0100] 2-(2-Cyano-2-(10,10-dioxo-9H-thioxanthen-9-ylidene)acetamido)ethyl methacrylate;

[0101] N-(2-(2-Cyano-2-(10-methylacridin-9(10H)-ylidene)acetamido)ethyl)methacrylamide; or

[0102] 2-(2-Cyano-2-(9H-thioxanthen-9-ylidene)acetoxy)ethyl methacrylate.

[0103] The amount of the light-absorbing compound used will be an amount effective to achieve the desired reduction in percent transmission at the particular wavelength at which the selected light-absorbing compound is active. By way of example, based on the total weight of the reactive mixture (excluding diluent), the amount can range from 0.05 wt% to 10 wt%, or from 0.1 wt% to 5 wt%, or from 0.1 wt% to 3 wt%. In some embodiments, based on the total weight of the reactive mixture (excluding diluent), the amount is from 0.75 wt% to 1.25 wt%.

[0104] The reactive mixture can contain various other additives, which can be reactive or non-reactive. Examples of such additives include, but are not limited to, crosslinking agents, wetting agents, release agents, polymers, dyes, other light-absorbing compounds such as UV absorbers, pigments, pharmaceutical compounds, nutritional compounds, diluents, or combinations of any of the foregoing.

[0105] According to the present invention, a reactive mixture such as that described above is formed into a contact lens by dispensing the mixture into a mold assembly and then curing the mixture. The mold assembly consists of a bottom surface and a front surface. The bottom surface is the mold half for the back surface of the contact lens, and the front surface contacts the front surface. When the front surface and the bottom surface are joined together, they define and enclose a cavity therebetween, which, according to the present invention, houses the reactive mixture.

[0106] The mold parts (front surface and bottom surface) constituting the mold assembly used in the present invention can be made of various materials, including disposable or reusable materials. For example, the mold can be a thermoplastic optical mold made of any suitable material, including but not limited to polyethylene, polypropylene, other polyolefins (including homopolymers, copolymers, and terpolymers), polystyrene, polystyrene copolymers, polyesters such as poly(ethylene terephthalate) and poly(butylene terephthalate), polyamides, poly(vinyl alcohol) and its derivatives, hydrogenated styrene-butadiene block copolymers such as Tuftec, cycloolefin polymers such as Zeonor and Topas resins, and combinations thereof. The mold can be selected to be transparent or nearly transparent to the wavelength that will activate the photoinitiator, thereby allowing irradiation through the front surface and the bottom surface. The materials between the front surface and the bottom surface can be the same or different. Preferred materials for the front surface of the mold assembly are 90:10 (w / w) blends of cycloolefin polymers and hydrogenated styrene-butadiene block copolymers. Preferred materials for the bottom surface of the mold assembly are 90:10 (w / w) blends of cycloolefin polymers and polypropylene. Other exemplary materials include blends of Zeonor and Tuftec for either or both of the bottom surface and the front surface. The thickness of the bottom surface mold or the front surface mold can vary, but is typically between 100 microns and 1500 microns, preferably between 600 microns and 800 microns, as measured at the center of the optical zone of the target lens mold design.

[0107] The activation radiation source for initiating the photoinitiator includes, for example, a lamp that transmits light of a suitable wavelength for such initiation. A preferred activation radiation source is a light-emitting diode (LED) lamp. Preferably, the LED lamp transmits at the desired intensity and within a wavelength range of 200 nm to 600 nm, more preferably 300 nm to 500 nm, and most preferably 350 nm to 450 nm.

[0108] The curing step is carried out by exposing the reactive mixture to radiation including the activation wavelength (the wavelength required to activate the photoinitiator). In the present invention, the radiation is directed at both the bottom surface and the front surface of the mold assembly. In addition, the radiation energy at the bottom surface is greater than the radiation energy at the front surface.

[0109] The difference in radiant energy can be provided by using a higher intensity of radiation at the bottom surface than at the front surface. The intensity of radiation can be measured by various instruments. For example, as shown in the examples, a preferred instrument is the ILT-2400 from International Light Technologies.

[0110] The intensity of the radiation can generally be in the range of 0.1 mW / cm 2 to 25 mW / cm 2 , preferably 1 mW / cm 2 to 15 mW / cm 2 . As noted, the intensity of the radiation at the bottom surface can be greater than its intensity at the front surface. The intensity of the radiation at the bottom surface can be at least 1%, alternatively at least 5%, alternatively at least 10%, alternatively at least 15%, or alternatively at least 20% greater than the intensity of the radiation at the front surface. The intensity of the radiation at the bottom surface can be less than 350%, alternatively at most 300%, alternatively at most 250%, alternatively at most 200%, alternatively at most 150%, alternatively at most 100%, alternatively at most 90%, alternatively at most 80%, alternatively at most 70%, alternatively at most 60%, alternatively at most 50%, alternatively at most 45%, alternatively at most 40%, alternatively at most 35%, or alternatively at most 30% greater than the intensity at the front surface. For example, the intensity of the radiation at the bottom can be at least 1% and less than 350%, alternatively 1% to 300%, alternatively 1% to 250%, alternatively 1% to 250%, alternatively 1% to 200%, alternatively 1% to 150%, alternatively 1% to 100%, alternatively 5% to 300%, alternatively 5% to 250%, alternatively 5% to 200%, alternatively 5% to 150%, alternatively 5% to 100%, alternatively 10% to 300%, alternatively 10% to 200%, alternatively 10% to 150%, alternatively 10% to 100%, alternatively 20% to 300%, alternatively 20% to 250%, alternatively 20% to 200%, alternatively 20% to 150%, or alternatively 20% to 100% greater than the intensity of the radiation at the front surface. By way of additional examples, the intensity of the radiation at the base can be at least 5% and at most 100%, alternatively 5% to 80%, alternatively 10% to 66.7% greater than the intensity of the radiation at the front surface. As an illustration, if the intensity at the bottom surface is 10% greater than the intensity at the front surface, and then if the intensity at the bottom surface is about 3.3 mW / cm 2 , then the intensity of the radiation at the front surface will be about 3.0 mW / cm 2 . For further illustration, if the intensity at the bottom surface is 66.7% greater than the intensity at the front surface, and then if the intensity at the bottom surface is about 4.17 mW / cm 2, the intensity of the radiation at the front surface will be about 2.5 mW / cm 2 .

[0111] When the intensity of the radiation is used to provide a difference in radiant energy at the top and bottom surfaces, it is preferred that the wavelengths at the top and bottom surfaces are the same. For example, the wavelength can be in the range of 350 nm to 450 nm, or 380 nm to 450 nm, or 400 nm to 450 nm, or 430 nm to 440 nm.

[0112] The difference in radiant energy in the method of the present invention can be provided by using radiation of different wavelengths at the bottom and front surfaces. More specifically, the wavelength at the bottom surface can be shorter than the wavelength at the front surface. For example, the wavelength at the bottom surface can be at least 5 nm, or at least 10 nm, or at least 20 nm shorter than the wavelength at the front surface. Both wavelengths are capable of activating the photoinitiator. Both wavelengths can have the same intensity.

[0113] The difference in radiant energy in the method of the present invention can be provided by using radiation of different wavelengths and intensities at the bottom and front surfaces. For example, the difference can be provided by using radiation of a shorter wavelength and a higher intensity at the bottom surface than at the front surface.

[0114] As described above, the method of using radiant energy at the bottom surface of the activating radiation to be greater than that at the front surface has several advantages. For example, the method of the present invention provides a contact lens comprising a light-absorbing compound, and the optical parameters of the contact lens have been improved compared to single-sided curing or non-differential double-sided curing, and the lens characteristics of the contact lens are less dependent on curing conditions such as time, temperature, and irradiation intensity.

[0115] There are several ways to create a difference in radiant energy across the mold assembly. One method is to use two separate light sources having different intensities, wavelengths, or both intensity and wavelength. Another method is to use a single light source with a series of mirror or reflective tray features pointing at the bottom surface to redirect and / or reflect a portion of the illumination light, which now has a reduced intensity, to the front surface.

[0116] After curing, the lens can be extracted to remove unreacted components and release the lens from the lens mold. The extraction can be carried out using a conventional extraction liquid (such as an organic solvent (such as an alcohol)), or an aqueous solution extraction can be used.

[0117] An aqueous solution is a solution that contains water. The aqueous solution of the present invention may contain at least about 20% by weight of water, or at least about 50% by weight of water, or at least about 70% by weight of water, or at least about 95% by weight of water. The aqueous solution may also contain additional water-soluble compounds such as inorganic salts or mold release agents, wetting agents, lubricants, pharmaceutical and nutritional preparations, combinations thereof, and the like. A mold release agent is a compound or mixture of compounds that, when combined with water, shortens the time required to remove a contact lens from a mold compared to using an aqueous solution without a mold release agent.

[0118] Extraction can be achieved, for example, by immersing the lens in the aqueous solution or exposing it to a flowing aqueous solution. Extraction may also include, for example, one or more of the following: heating the aqueous solution; stirring the aqueous solution; increasing the content of the mold release aid in the aqueous solution to a level sufficient to release the lens; mechanically or ultrasonically agitating the lens; and incorporating at least one filtering or extraction aid into the aqueous solution until a level sufficient to promote the adequate removal of unreacted components from the lens is reached. The above operations can be carried out in a batch or continuous process, with heating, stirring, or both, or without.

[0119] It may be desirable to apply physical agitation to facilitate leaching and demolding. For example, the lens mold part with the lens adhered thereto can be vibrated or moved back and forth in the aqueous solution. Other methods may include ultrasonics through the aqueous solution.

[0120] The lens prepared as described above may exhibit the following quality characteristics. As measured using a 6.5 mm aperture, the lens may have a root mean square optical path wavefront deviation from the lens design target with spherical and cylindrical powers and coma removed, which is reduced compared to other identical lenses prepared under conditions of equal radiant energy at the back and front surfaces. As measured using a 6.5 mm aperture, the lens may have a root mean square optical path wavefront deviation from the lens design target with spherical and cylindrical powers and coma removed, which is reduced by at least 3% compared to other identical lenses prepared under conditions of equal radiant energy at the back and front surfaces. As measured using a 6.5 mm aperture, the lens may have a root mean square optical path wavefront deviation from the lens design target with spherical and cylindrical powers and coma removed, which is reduced by at least 0.0020 microns compared to other identical lenses prepared under conditions of equal radiant energy at the back and front surfaces.

[0121] The following clauses list non-limiting embodiments of the present disclosure:

[0122] 1. A method for manufacturing a light-absorbing contact lens, the method comprising:

[0123] (a) Provide a mold assembly, the mold assembly being composed of a bottom surface and a front surface, the bottom surface and the front surface defining and enclosing a cavity therebetween, the cavity accommodating a reactive mixture, wherein the reactive mixture comprises at least one polymerizable monomer, a photoinitiator that absorbs at an activation wavelength, and a light-absorbing compound that exhibits absorbance at the activation wavelength; and

[0124] (b) Cure the reactive mixture by exposing the reactive mixture to radiation including the activation wavelength to form the light-absorbing contact lens, wherein the radiation is directed to both the bottom surface and the front surface of the mold assembly, and wherein the intensity of the radiation at the bottom surface is greater than the intensity of the radiation at the front surface.

[0125] 2. The method according to clause 1, wherein the intensity of the radiation at the bottom surface is less than 350% greater than the intensity of the radiation at the front surface.

[0126] 3. The method according to any one of clauses 1 to 2, wherein the intensity of the radiation at the bottom surface is 1% to less than 350% greater than the intensity of the radiation at the front surface.

[0127] 4. The method according to any one of clauses 1 to 3, wherein the radiation is provided by a first light source adjacent to the bottom surface of the mold assembly and a second light source adjacent to the front surface of the mold assembly.

[0128] 5. The method according to clause 4, wherein the first light source is a light-emitting diode and the second light source is a light-emitting diode.

[0129] 6. The method according to any one of clauses 1 to 5, wherein the light-absorbing compound is a static light-absorbing compound.

[0130] 7. The method according to any one of clauses 1 to 6, wherein the light-absorbing compound is a high-energy visible light absorber.

[0131] 8. The method according to any one of clauses 1 to 5, wherein the light-absorbing compound is a photochromic compound.

[0132] 9. The method according to any one of clauses 1 to 8, wherein the bottom surface and the front surface of the mold assembly are composed of polyethylene, polypropylene, polystyrene, hydrogenated styrene-butadiene block copolymer, cycloolefin polymer, and combinations thereof.

[0133] 10. The method according to any one of clauses 1 to 9, wherein the wavelength of the radiation at the bottom surface is the same as the wavelength of the radiation at the front surface.

[0134] 11. The method according to any one of clauses 1 to 10, wherein the wavelength of the radiation at the bottom surface and the front surface is 350 nm to 450 nm.

[0135] 12. The method according to any one of clauses 1 to 11, wherein the wavelength of the radiation at the bottom surface and the front surface is 400 nm to 450 nm.

[0136] 13. A method for manufacturing a light-absorbing contact lens, the method comprising:

[0137] (a) providing a mold assembly composed of a bottom surface and a front surface, the bottom surface and the front surface defining and enclosing a cavity therebetween, the cavity accommodating a reactive mixture, wherein the reactive mixture comprises at least one polymerizable monomer, a photoinitiator that absorbs at an activation wavelength, and a light-absorbing compound that exhibits absorbency at the activation wavelength; and

[0138] (b) curing the reactive mixture by exposing the reactive mixture to radiation including the activation wavelength to form the light-absorbing contact lens, wherein the radiation is directed to both the bottom surface and the front surface of the mold assembly, and wherein the wavelength of the radiation at the bottom surface is shorter than the wavelength of the radiation at the front surface.

[0139] 14. The method according to any one of clause 13, wherein the wavelength at the bottom surface is at least about 10 nanometers shorter than the wavelength at the front surface.

[0140] 15. The method according to any one of clauses 13 to 14, wherein the radiation is provided by a first light source adjacent to the bottom surface of the mold assembly and a second light source adjacent to the front surface of the mold assembly.

[0141] 16. The method according to clause 15, wherein the first light source is a light-emitting diode, and the second light source is a light-emitting diode.

[0142] 17. The method according to any one of clauses 13 to 16, wherein the light-absorbing compound is a static light-absorbing compound.

[0143] 18. The method according to any one of clauses 13 to 17, wherein the light-absorbing compound is a high-energy visible light absorber.

[0144] 19. The method according to any one of clauses 13 to 18, wherein the light-absorbing compound is a photochromic compound.

[0145] 20. The method according to any one of clauses 13 to 19, wherein the bottom surface and the front surface of the mold assembly are made of polyethylene, polypropylene, polystyrene, hydrogenated styrene-butadiene block copolymer, cycloolefin polymer, and combinations thereof.

[0146] 21. The method according to any one of clauses 13 to 20, wherein the intensity of the radiation at the bottom surface is the same as the intensity of the radiation at the front surface.

[0147] 22. The method according to any one of clauses 13 to 21, wherein the wavelength of the radiation at the bottom surface and the front surface is 350 nm to 450 nm.

[0148] 23. The method according to any one of clauses 13 to 22, wherein the wavelength of the radiation at the bottom surface and the front surface is 400 nm to 450 nm.

[0149] 24. A light-absorbing contact lens, the light-absorbing contact lens being prepared by the method according to any one of clauses 1 to 12.

[0150] 25. The method according to any one of clauses 1 to 12 or the light-absorbing contact lens according to clause 24, as measured using a 6.5 mm aperture, the lens having a root mean square optical path wavefront deviation from the lens design target with spherical power, cylindrical power, and coma removed, the root mean square optical path wavefront deviation being reduced compared to other identical lenses prepared under the condition of equal radiant energy at the bottom surface and the front surface.

[0151] 26. The method or contact lens according to clause 25, wherein as measured using a 6.5 mm aperture, with spherical power, cylindrical power, and coma removed, the root mean square optical path wavefront deviation from the lens design target is reduced by at least 3% compared to other identical lenses prepared under the condition of equal radiant energy at the bottom surface and the front surface.

[0152] 27. The method or contact lens according to clause 25, wherein as measured using a 6.5 mm aperture, with spherical power, cylindrical power, and coma removed, the root mean square optical path wavefront deviation from the lens design target is reduced by at least 0.0020 microns compared to other identical lenses prepared under the condition of equal radiant energy at the bottom surface and the front surface.

[0153] 28. A light-absorbing contact lens, the light-absorbing contact lens being prepared by the method according to any one of clauses 13 to 23.

[0154] 29. The method according to any one of clauses 13 to 23 or the light-absorbing contact lens according to clause 28, as measured using a 6.5 mm aperture, has a root mean square optical path wavefront deviation from the lens design target with spherical and cylindrical powers and coma removed, and this root mean square optical path wavefront deviation has been reduced compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

[0155] 30. The method or contact lens according to clause 29, wherein, as measured using a 6.5 mm aperture, with spherical and cylindrical powers and coma removed, the root mean square optical path wavefront deviation from the lens design target has been reduced by at least 3% compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

[0156] 31. The method or contact lens according to clause 29, wherein, as measured using a 6.5 mm aperture, with spherical and cylindrical powers and coma removed, the root mean square optical path wavefront deviation from the lens design target has been reduced by at least 0.0020 micrometers compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

[0157] Some embodiments of the present invention will now be described in detail in the following examples.

[0158] Examples

[0159] Contact lens parameters in a wetting solution are measured using calibrated dual interferometry. These parameters include equivalent spherical power (diopters or D) at multiple apertures, cylindrical power (diopters or D) at multiple apertures, diameter (millimeters or mm), central thickness (millimeters or mm), sagittal height (millimeters or mm), and root mean square (RMS) optical path wavefront deviation from the lens design target (in micrometers (μm)), where spherical / cylindrical power and coma are removed as measured using a 6.5 mm aperture. The instrument consists of a custom propionic acid interferometer for measuring wavefront parameters and a Lumetrics II low coherence interferometer for measuring dimensional parameters such as sagittal height and central thickness. The combination of the two separate instruments is similar to Lumetrics Clearwave TM Plus, and the software is similar to Lumetrics OptiGauge Control Center v7.0 or higher. Using Clearwave TMPlus, the camera is used to find the edge of the lens and then calculate the lens center, which is then used to align the 1310 nm interferometer probe at the lens center for measuring the sagittal height and center thickness. A wavefront sensor (shack-Hartmann sensor) is also used in series to collect the transmitted wavefront. Multiple parameters of the transmitted wavefront from the contact lens are measured, and other parameters are calculated from those measurements.

[0160] Based on the collected data, difference terms are calculated by comparing the measured values with the targets. These include the root mean square optical path wavefront deviation from the lens design target in μm as measured using a 6.5 mm aperture (sphericity / cylindricity and coma are removed) (RMS_65), the second equivalent spherical deviation from the lens design target in diopters (D) as measured using a 5 mm aperture (PW2EQD), the deviation from the lens design target diameter in mm (DMD), the deviation from the lens design target base curve radius in mm (BCD) as calculated from the sagittal height and target lens diameter measured according to ISO 18369-3, and the deviation from the lens design target center thickness in mm (CTD). RMS_65, DMD, and BCD are used to develop the manufacturing process for the light-absorbing contact lens.

[0161] The present invention is now described in connection with the following examples. Before describing the various exemplary embodiments of the present invention, it should be understood that the present invention is not limited to the construction details and processes mentioned in the following description. The present invention can have other embodiments and can be practiced or implemented in various ways.

[0162] The following abbreviations will be used in the examples and have the following meanings:

[0163] PP: Polypropylene, i.e., the homopolymer of propylene

[0164] TT: Tuftec, i.e., hydrogenated styrene-butadiene block copolymer (Asahi Kasei Chemicals)

[0165] Z: Zeonor, i.e., polycycloolefin thermoplastic polymer (Nippon Zeon Co Ltd)

[0166] DMA: N,N-Dimethylacrylamide (Jarchem)

[0167] HEMA: 2-Hydroxyethyl methacrylate (Bimax)

[0168] mPDMS: Mono-n-butyl terminated mono-methacryloxypropyl terminated polydimethylsiloxane (M n = 600 daltons - 1500 daltons) (Gelest)

[0169] SiMAA: 2 - Acrylic acid, 2 - methyl - 2 - hydroxy - 3 - [3 - [1,3,3,3 - tetramethyl - 1 - [(trimethylsilyl)oxy]disiloxanyl]propoxy]propyl ester or 3 - (3 - (1,1,1,3,5,5,5 - heptamethyltrisiloxan - 3 - yl)propoxy)-2 - hydroxypropyl methacrylate (Toray)

[0170] Norbloc: 2 - (2′ - Hydroxy - 5 - methacryloyloxyethylphenyl)-2H - benzotriazole (Janssen)

[0171] Blue HEMA: 1 - Amino - 4 - [3 - (4 - (2 - methacryloyloxy - ethoxy)-6 - chlorotriazin - 2 - ylamino)-4 - sulfophenylamino]anthraquinone - 2 - sulfonic acid, as described in U.S. Patent No. 5,944,853

[0172] Formulation 1: 4 - [4 - [3,13 - Dihydro - 6 - methoxy - 13,13 - dimethyl - 3 - phenyl - 7 - (1 - piperidinyl)benzo[3,4]fluoreno[2,1 - b]pyran - 3 - yl]phenyl]-γ - oxo-, 2 - [(2 - methyl - 1 - oxo - 2 - propen - 1 - yl)oxy]ethyl 1 - piperazinebutyrate.

[0173] PVP K90: Poly(N - vinylpyrrolidone) (ISP Ashland)

[0174] Irgacure 1870: Blend of bis(2,6 - dimethoxybenzoyl)-2,4,4 - trimethyl - pentylphosphine oxide and 1 - hydroxy - cyclohexyl - phenyl - ketone (BASF or Ciba Specialty Chemicals)

[0175] D3O: 3,7 - Dimethyloctan - 3 - ol (Vigon)

[0176] LED: Light - emitting diode

[0177] Wetting (Packing or Packaging) solution formulation: Dissolve 18.52 g (300 mmol) of boric acid, 3.7 g (9.7 mmol) of sodium borate decahydrate, and 28 g (197 mmol) of sodium sulfate in sufficient deionized water to fill a 2 - liter volumetric flask.

[0178] Examples 1 - 36

[0179] Contact lenses are prepared on a pilot line consisting of a two - zone curing tunnel, where irradiation can be carried out from the top and bottom of the tunnel (see Figure 2)。A tray including eight mold components travels down the tunnel. The first zone uses 435 nm LED lights with an intensity of approximately 1.5 mW / cm as measured on the tray supporting the mold components. 2 The second zone uses the same lights but again has an intensity between approximately 5 mW / cm 2 and approximately 10 mW / cm 2 as measured on the tray supporting the mold components. At 65 °C, the temperature in both zones is kept constant. Nitrogen is also used to keep the atmosphere in both zones constant. The proportion of the total curing time spent in the low-intensity first zone is fixed at 62.5% of the total curing time. The intensity ratio (I t / I b ) varies in the two-zone curing tunnel, where I t is defined as the light intensity on the top or bottom curved surface side of the mold component as measured on the tray, and I b is defined as the light intensity on the bottom or front curved surface side of the mold component as measured on the tray. When the intensities of I t and I b are equal, the intensity ratio is equal to one (1). When I t is higher than I b , the intensity ratio is greater than one (>1). When I t is lower than I b , the intensity ratio is less than one (<1). An intensity ratio greater than one represents an experimental condition where the radiant energy at the bottom curved surface is greater than that at the front curved surface. For a given intensity ratio, the average intensity in the first zone (0.5*I t +0.5*I b ) is kept constant at approximately 1.5 mW / cm 2 . For a given intensity ratio, the average higher intensity in the second zone varies between approximately 5 mW / cm 2 and approximately 10 mW / cm 2 .

[0180] The curing light source used is an LED panel manufactured by Lumos Solutions Ltd with adjustable intensity and fixed emission wavelength. The wavelength specification of each panel is equal to the target wavelength ±1 nm. For each experimental setup, an NIST-traceable radiometer model ILT2400 equipped with an XRD340A sensor is used to set the panel light intensity, both of which are purchased from International Light Technologies Inc and calibrated by it. During the experimental setup, a holder is used to position the radiometer sensor, which places the radiometer sensor at the height of the top of the lens mold for upward measurement (top intensity), and places the radiometer sensor at the height of the bottom of the lens mold for downward measurement (bottom intensity).

[0181] The reactive monomer mixtures (batches 1 and 2) were prepared by combining a mixture of the components listed in Table 1 with a diluent (D3O). The mixture of reactive and non-reactive components accounted for 77 wt% of the final reactive monomer mixture, while the diluent D3O accounted for 23 wt% of the final reactive monomer mixture. The final reactive monomer was filtered through a 3-micron filter paper under pressure and then degassed under vacuum (about 40 mmHg). Approximately 100 μL of these reactive monomer mixtures were dispensed onto the front surface molds in trays. Subsequently, the bottom surface mold was placed on top of the front surface mold and mechanically fixed. The front surface mold was made by injection molding and consisted of a 90:10 (w / w) Zeonor and Tuftec blend; the bottom surface mold was also injection molded and consisted of a 90:10 (w / w) Zeonor and Tuftec blend. The molds were generally injection molded and used almost immediately. The molds could also be injection molded, stored, and then balanced in a nitrogen environment with a low fixed amount of oxygen for at least twelve hours before use. In the following examples, the molds used were not calibrated for any curing conditions and were designed to form spherical contact lenses with a power of -12 diopters. The curing conditions for Examples 1-36 are listed in Table 2.

[0182] The cured lenses were mechanically demolded, where most of the lenses adhered to the front surface mold, and were demolded by immersing the lenses in propylene glycol for about two or four hours, then washing a total of two times with deionized water for at least 90 minutes, and equilibrating with a borate buffer wetting solution. One of ordinary skill in the art recognizes that the exact lens demolding process can vary depending on the lens formulation, mold material, and demolding solvent / solution. The purpose of the lens demolding process is to demold all lenses without defects and to transform from a diluent-swollen network to a wetting solution-swollen hydrogel. The hydrated lenses were transferred to the primary packaging and then sterilized by autoclaving at 122 °C for 18 minutes. After sterilization, the contact lenses were equilibrated for at least 14 days before optical characterization.

[0183] For each example, RMS_65, DMD, and BCD were measured. The RMS_65 data are shown in Figure 3 ; the DMD data are shown in Figure 4 ; and the BCD data are shown in Figure 5 . The average values of RMS_65, DMD, and BCD are listed in Table 3.

[0184] As Figure 3 shown, the trend of the decrease in RMS_65 with increasing intensity ratio indicates that the optical quality of the lenses is improving. As Figures 4 - 5As shown, when the intensity ratio is greater than one, the sensitivity of DMD and BCD to changes in the total curing time is significantly reduced compared to when the intensity ratio is greater than one or less than one, thus achieving a more robust processing window. These results are unexpected because the design of the tray has reduced the amount of light reaching the mold assembly from the bottom LED lights. Using an intensity ratio greater than one further increases this light gradient applied to the mold assembly.

[0185] Table 1: Formulations

[0186]

[0187] Table 2: Curing Conditions

[0188]

[0189] Table 3: Lens Characterization

[0190]

[0191]

[0192] Examples 37 - 72

[0193] Another batch of materials with the same formulation listed in Table 1 was used to prepare contact lenses by the same experimental protocol as described in Examples 1 - 36, except that (1) the proportion of the total curing time spent in the low-intensity first zone was fixed at 50% of the total curing time, (2) the intensities in Zone 1 and Zone 2 were varied as shown in Table 4, and (3) after sterilization, the contact lenses were allowed to equilibrate for at least 14 days before optical characterization. The optical characterization, namely wavefront measurement and RMS_65 average value calculation, was based on a sample size of fifteen lenses for each experimental condition.

[0194] The curing light source used was an LED panel manufactured by Lumos Solutions Ltd with adjustable intensity and fixed emission wavelength. The wavelength specification for each panel was equal to the target wavelength ±1 nm. For each experimental setup, an NIST-traceable radiometer model ILT2400 equipped with an XRD340A sensor was used to set the panel light intensity, both of which were purchased from International Light Technologies Inc and calibrated by them. During the experimental setup, the radiometer sensor was positioned using a holder that placed the radiometer sensor at the height of the top of the lens mold for upward measurement (top intensity), and placed the radiometer sensor at the height of the bottom of the lens mold for downward measurement (bottom intensity).

[0195] As shown in Table 4 and Figure 6As shown, the trend that RMS_65 decreases with the increase of the intensity ratio indicates that the optical quality of the lens is improving.

[0196] Table 4: Curing Conditions and RMS_65 Data

[0197]

[0198]

[0199] Examples 73 - 96

[0200] Another batch of materials with the same formulation listed in Table 1 was used and contact lenses were prepared by the same experimental protocol as described in Examples 1 - 36, except that (1) the proportion of the total curing time spent in the low - intensity first zone was fixed at 50% of the total curing time, (2) the top and bottom intensities were equal within each of the two intensity zones (I t / I b = 1), as shown in Table 5, and (3) the peak emission wavelengths of the top and bottom LED panels were varied as listed in Table 5. Optical characterization, namely wavefront measurement and RMS_65 average value calculation, was based on a sample size of fifteen lenses for each experimental condition.

[0201] The wavelength ratio (λ t / λ b ) varied throughout the dual - zone curing tunnel, where λ t was defined as the peak emission wavelength of the top - side LED light panel or the bottom - curved surface side of the mold assembly, and λ b was defined as the peak emission wavelength of the bottom - side LED light panel or the front - curved surface side of the mold assembly. When λ t and λ b are equal, the wavelength ratio is equal to one (1). When λ t is longer than λ b , the wavelength ratio is greater than one (>1). When λ t is shorter than λ b , the wavelength ratio is less than one (<1). A wavelength ratio less than one represents an experimental condition where the radiant energy at the bottom - curved surface is greater than that at the front - curved surface.

[0202] The curing light source used is an LED panel manufactured by Lumos Solutions Ltd with adjustable intensity and a fixed emission wavelength. The wavelength specification for each panel is equal to the target wavelength ±1 nm. For each experimental setup, an NIST-traceable radiometer model ILT2400 equipped with an XRD340A sensor was used to set the panel light intensity, both of which were purchased from International Light Technologies Inc and calibrated by it. During the experimental setup, a holder was used to position the radiometer sensor, which placed the radiometer sensor at the height on top of the lens mold for upward measurement (top intensity), and placed the radiometer sensor at the height at the bottom of the lens mold for downward measurement (bottom intensity).

[0203] As shown in Table 6 and Figure 7 as shown, when the wavelength ratio is less than one, the average RMS_65 value is significantly less than the average RMS_65 value when the wavelength ratio is greater than one, indicating an improvement in the optical quality of the lens.

[0204] Table 5: Curing Conditions

[0205]

[0206] Table 6: RMS_65 Data

[0207]

Claims

1. A method for manufacturing a light-absorbing contact lens, the method comprising: (a) providing a mold assembly comprising a bottom surface and a front surface, the bottom surface and the front surface defining and enclosing a cavity therebetween, the cavity containing a reactive mixture, wherein the reactive mixture comprises at least one polymerizable monomer, a photoinitiator that absorbs at an activation wavelength, and a light-absorbing compound that exhibits absorbance at the activation wavelength; and (b) curing the reactive mixture by exposing the reactive mixture to radiation including the activation wavelength to form the light-absorbing contact lens, wherein the radiation is directed to both the bottom surface and the front surface of the mold assembly, and wherein the radiation energy at the bottom surface is greater than the radiation energy at the front surface; wherein the radiation energy is controlled by the intensity of the radiation, the intensity at the bottom surface being less than 350% greater than the intensity at the front surface, and the reactive mixture being exposed to greater radiation energy at the bottom surface than at the front surface.

2. The method according to claim 1, wherein the radiation energy is provided by a first light source adjacent to the bottom surface of the mold assembly and a second light source adjacent to the front surface of the mold assembly.

3. The method according to claim 2, wherein the first light source is a light-emitting diode and the second light source is a light-emitting diode.

4. The method according to any one of claims 1 to 3, wherein the light-absorbing compound is a static light-absorbing compound.

5. The method according to any one of claims 1 to 3, wherein the light-absorbing compound is a high-energy visible light absorber.

6. The method according to any one of claims 1 to 3, wherein the light-absorbing compound is a photochromic compound.

7. The method according to any one of claims 1 to 3, wherein the bottom surface and the front surface of the mold assembly are made of polyethylene, polypropylene, polystyrene, hydrogenated styrene-butadiene block copolymer, cycloolefin polymer, and combinations thereof.

8. The method according to any one of claims 1 to 3, wherein the radiation energy is controlled by the intensity of the radiation, the wavelength of the radiation, or a combination thereof.

9. The method according to claim 1, wherein the intensity at the bottom surface is greater than the intensity at the front surface.

10. The method according to claim 8, wherein the radiation energy is controlled by the wavelength of the radiation.

11. The method according to claim 10, wherein the wavelength at the bottom surface is shorter than the wavelength at the front surface.

12. The method according to any one of claims 10 to 11, wherein the wavelength at the bottom surface is at least 10 nanometers shorter than the wavelength at the front surface.

13. The method according to any one of claims 1 to 3, as measured using a 6.5 mm aperture, the lens has a root mean square optical path wavefront deviation from the lens design target when spherical power, cylindrical power, and coma are removed, and the root mean square optical path wavefront deviation has been reduced compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

14. The method according to claim 13, wherein as measured using a 6.5 mm aperture, when spherical power, cylindrical power, and coma are removed, the root mean square optical path wavefront deviation from the lens design target has been reduced by at least 3% compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

15. The method according to claim 13, wherein as measured using a 6.5 mm aperture, when spherical power, cylindrical power, and coma are removed, the root mean square optical path wavefront deviation from the lens design target has been reduced by at least 0.0020 microns compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

16. A light-absorbing contact lens, the light-absorbing contact lens being prepared by the method according to any one of claims 1 to 12.

17. The light-absorbing contact lens according to claim 16, as measured using a 6.5 mm aperture, the lens has a root mean square optical path wavefront deviation from the lens design target when spherical power, cylindrical power, and coma are removed, and the root mean square optical path wavefront deviation has been reduced compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

18. The contact lens according to claim 17, wherein as measured using a 6.5 mm aperture, when spherical power, cylindrical power, and coma are removed, the root mean square optical path wavefront deviation from the lens design target has been reduced by at least 3% compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

19. The contact lens according to claim 17, wherein as measured using a 6.5 mm aperture, when spherical power, cylindrical power, and coma are removed, the root mean square optical path wavefront deviation from the lens design target has been reduced by at least 0.0020 microns compared to other identical lenses prepared under the condition of equal radiant energy at the back surface and the front surface.

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