Contact lens manufacturing methods

Abstract

This invention provides a method for manufacturing contact lenses. [Solution] The present invention provides a method for manufacturing a contact lens, comprising the steps of: providing a dry lens; performing a hydration process on the dry lens to obtain a wet lens; and performing a sterilization process on the wet lens to obtain a contact lens. A first polymer is used in at least one of the hydration process and the sterilization process, and a second polymer is used in at least one of the hydration process and the sterilization process, thereby the contact lens includes an outer shell layer, the outer shell layer includes the first polymer and the second polymer. The first polymer contains polyvinyl alcohol, and the second polymer contains polyvinylpyrrolidone.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing contact lenses, and particularly to a manufacturing method for imparting appropriate smoothness to the surface of contact lenses.

Background Art

[0002] The material of soft contact lenses began to be introduced in the 1960s. Due to the soft material, the discomfort that often existed when wearing conventional rigid gas-permeable (RGP) contact lenses was eliminated. Therefore, users who were originally not adapted to hard contact lenses could switch to using soft contact lenses. Thus, soft contact lenses have become the main choice for current contact lens users.

[0003] Soft contact lenses are softer and more comfortable than hard contact lenses, but still, many users report feeling a foreign object in their eyes when wearing soft contact lenses. This has become a reason for these users to abandon the use of contact lenses. The main cause of this problem is the frictional force on the surface of the contact lens. Therefore, when blinking, the lens moves on the eyeball and rubs against the eyeball, so the user feels that there is something in their eyes. To solve this problem, it is necessary to increase the smoothness of the lens surface.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Many studies have been conducted to obtain a surface lubrication effect by coating the lens surface with polyacrylic acid (PAA). However, PAA is an anionic polymer, which tends to carry a negative charge, and its properties are easily affected by the pH of tears. Therefore, irritation may occur during wear. Subsequent research has proposed using a cationic polymer to neutralize the charge of PAA in order to improve the stability of the above-mentioned technology. However, it has become clear that such methods involve significant control costs in the process, and the product cannot stably maintain its lubrication effect during prolonged wear.

[0005] In light of the above-mentioned challenges and technological advancements, the present invention proposes a method for manufacturing contact lenses that can effectively improve the smoothness of the contact lens surface. This method does not require complex process control, maintains its effect for a long period of time, improves the quality of contact lenses, and provides a cost-competitive technical solution.

[0006] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by a person of ordinary skill in the art to which the invention pertains. Generally, the terms and experimental procedures used herein are well known and widely used in the art. These procedures employ prior art methods, such as those provided in the art and various general references. Where a term is provided in the singular form, the inventors have also considered the plural form of that term. The terms and experimental procedures used herein and described below are well known and widely used in the art. Where used throughout this disclosure, unless otherwise stated, the following terms are understood to have the following meanings. [Means for solving the problem]

[0007] A dry lens refers to a contact lens that has completed the curing process but has not yet undergone hydration during the manufacturing process.

[0008] A wet lens refers to a contact lens that has completed the hydration process during the manufacturing process.

[0009] A contact lens packaging solution refers to an aqueous solution that undergoes a sterilization process along with the wet lens during the contact lens manufacturing process. Furthermore, since contact lenses formed after the sterilization process are usually stored in this aqueous solution, it is also called a contact lens packaging solution. This aqueous solution generally possesses a buffering function, i.e., it has a pH value and osmotic pressure within a certain range. Therefore, in this specification, the buffer may also be referred to as the contact lens packaging solution. The contact lens packaging solution used in the present invention may contain a first polymer and / or a second polymer. In one embodiment of the present invention, for contact lenses that have not undergone the sterilization process, the contact lens packaging solution has also not undergone the sterilization process.

[0010] Hydration, or the hydration process, refers to the process by which a hardened, dry lens begins to come into contact with a liquid. The liquid is, for example, water or an aqueous solution, preferably an aqueous solution, but the present invention is not limited to the type of liquid. The aqueous solution may contain any organic solvent that helps to clean any monomers remaining in the (hardened) dry lens. For example, organic solvents commonly used in the hydration process of contact lenses include ethanol or isopropyl alcohol. The aqueous solution may also contain any surfactant that helps to clean any monomers remaining in the (hardened) dry lens. For example, surfactants commonly used in the hydration process of contact lenses include Pluronic F-127 (also known as Poloxamer 407), Pluronic F-68 (also known as Poloxamer 188), or Tween 80 (also known as Polysorbate 80). Furthermore, the aqueous solution may contain any salts that promote the ionization of lens components during the hydration process, accelerate lens expansion, and stabilize the lens size. For example, salts commonly used in the hydration process of contact lenses include sodium chloride, sodium carbonate, sodium bicarbonate, sodium hydroxide, disodium hydrogen phosphate, sodium dihydrogen phosphate, boric acid, and sodium tetraborate.

[0011] In some specific contact lens manufacturing situations, before placing the wet lens in a container that is the minimum sterile unit of the contact lens, such as a container made of polypropylene (PP) (also referred to herein as a "PP cup") or a glass bottle, and bringing it into contact with the contact lens storage solution, it may be chosen to contact or immerse the wet lens in an aqueous solution similar to or identical to the components of the contact lens storage solution. Typically, this process is performed to reduce variability in the liquid components of the contact lens storage solution. To avoid any misunderstanding in this specification, the scope of the hydration process is further defined as follows: The process prior to "placing the wet lens in a container that is the minimum sterile unit of the contact lens, such as a PP cup or a glass bottle, and bringing the wet lens into contact with the contact lens storage solution" also includes any process of contacting the lens, whether dry or wet, with any liquid, and is classified as a hydration process in this specification.

[0012] The sterilization process, in the contact lens manufacturing process, refers to the process of sterilizing a wet lens, which has already completed the hydration process and is immersed in contact lens storage solution, for at least 20 to 30 minutes at a temperature of at least 120 to 122 degrees Celsius, for example, by autoclave. In one embodiment of the present invention, the wet lens and contact lens storage solution are stored in a container of a minimal sterilization unit for contact lenses, such as a PP cup sealed with aluminum foil or a glass bottle sealed with an aluminum lid.

[0013] In one embodiment of the present invention, a first polymer may be added during the hydration process, or a second polymer may be added, or both the first and second polymers may be added. Furthermore, by controlling the proportion, time, and order of adding the first or second polymer during the hydration process, and the combination with other components in the hydration process, it is possible to manufacture contact lenses with hydrophilicity and smoothness.

[0014] In one embodiment of the present invention, the first polymer may be added during the hydration process, or the second polymer may be added, or both the first and second polymers may be added. Furthermore, the first polymer or the second polymer, or both the first and second polymers, may be added to the contact lens storage solution during the sterilization process, thereby enabling the production of contact lenses with hydrophilicity and smoothness, but the present invention is not limited thereto.

[0015] The lens core body refers to the component of a lens formed from a contact lens formulation by curing. In this specification, the lens core body may be a dry lens or a wet lens. Some of the samples listed in this invention do not have a shell layer.

[0016] The shell layer refers to the surface of the lens core that is formed after the lens core body has been formed and hardened through other processes, but it is not part of the original structure of the lens core body. Furthermore, by forming a stable structure similar to an interpenetrating polymer network structure, the shell layer can stably exist on the surface of the lens core body.

[0017] Interpenetrating polymer networks (IPNs), in general theory, refer to polymer networks that contain two or more polymers, of which at least one polymer is a crosslinked polymer network structure, and where at least two or more polymers partially intersect in terms of size but do not form covalent bonds with each other. For example, if polymer A itself is a crosslinked polymer network structure, and polymer B partially intersects with polymer A, but no covalent bonds are formed between polymer A and polymer B, then polymer A and polymer B can be said to form an interpenetrating polymer network structure. Considering the complexity in the fields of polymers and chemistry, the interpenetrating polymer network structures used in the present invention allow for the occurrence of covalent bonds between different polymers in the formation process and as a result. For example, the disclosed examples of the present invention do not exclude the covalent bonding of a small amount (less than 0.1 wt%) of the first polymer with the polymer of the lens core body. For convenience of expression, the inventors still refer to the partially intersected polymer network formed by the first polymer and the polymer of the lens core body on the surface of the lens core body as an interpenetrating polymer network structure. Furthermore, the polymer structure formed by the entanglement of the first and second polymers within the outer shell layer can be described as a stable structure similar to a reciprocal polymer network structure. In this polymer structure, no clear crosslinking is observed between the polymeric chains of the first polymer itself, nor between the polymeric chains of the second polymer itself. Instead, very strong hydrogen bonds are observed only between the polymeric chains of the first polymer and between the polymeric chains of the first and second polymers, thus forming a stable structure similar to a reciprocal polymer network structure. Therefore, in order to get as close as possible to the general theoretical definition, the network structure formed by the first and second polymers in the outer shell layer is not directly called a reciprocal polymer network structure in this invention.

[0018] A semi-interpenetrating polymer network (Semi-IPN), in a general theoretical definition, specifically refers to an interpenetrating polymer network structure in which at least one polymer is a linear polymer. The interpenetrating polymer network structure of the present invention includes a semi-interpenetrating polymer network structure.

[0019] A simultaneously interpenetrating polymer network (Simultaneous-IPNs, SINs) is, in a general theoretical definition, a structure that interpenetrates polymers when two or more polymer component units undergo their respective polymerization reactions. For example, in the case of an interpenetrating polymer network structure consisting of polymer A and polymer B, polymer A is formed by the polymerization reaction of monomer a, and polymer B is formed by the polymerization reaction of monomer b. If monomer a and monomer b are mixed and then the mixture is polymerized, the resulting interpenetrating polymer network structure of polymers A and B may be a simultaneously interpenetrating polymer network structure. The interpenetrating polymer network structure according to the present invention does not include, for example, a simultaneously interpenetrating polymer network structure.

[0020] The present invention provides a method for manufacturing a contact lens, comprising the steps of: providing a dry lens; performing a hydration process on the dry lens to obtain a wet lens; and performing a sterilization process on the wet lens to obtain a contact lens. A first polymer is used in at least one of the hydration process and the sterilization process, and a second polymer is used in at least one of the hydration process and the sterilization process, thereby the contact lens comprising an outer shell layer, the outer shell layer comprising the first polymer and the second polymer. The first polymer comprises polyvinyl alcohol, and the second polymer comprises polyvinylpyrrolidone.

[0021] In one embodiment of the present invention, the first polymer is used in the hydration process, and the second polymer is used in the sterilization process.

[0022] In one embodiment of the present invention, the first polymer is used in both the hydration process and the sterilization process, and the second polymer is used in the sterilization process.

[0023] The first polymer is used in both the hydration process and the sterilization process, and the second polymer is used in both the hydration process and the sterilization process.

[0024] In one embodiment of the present invention, both the first polymer and the second polymer are used in the hydration process.

[0025] In one embodiment of the present invention, both the first polymer and the second polymer are used in the sterilization process.

[0026] In one embodiment of the present invention, the contact lens contains MAA (methacrylic acid).

[0027] In one embodiment of the present invention, sodium carbonate, sodium tetraborate, sodium hydroxide, or disodium hydrogen phosphate is used in the hydration process.

[0028] In one embodiment of the present invention, the contact lens is immersed in 10 ml of a standard buffered saline solution or RO water, and the solution is exchanged once every hour for 3 repetitions. After that, the immersed contact lens is dried, and the nitrogen element can be measured by elemental analysis using a scanning electron microscope.

[0029] The first polymer used in the present invention is a polymer containing a polyvinyl alcohol structure. The first polymer may be polyvinyl alcohol, a copolymer of polyvinyl alcohol and polyvinyl acetate (PVA-PVAc copolymer), or a mixture thereof. The first polymer may be crosslinkable or non-crosslinkable. The copolymer of polyvinyl alcohol and polyvinyl acetate may be a block copolymer, an alternate copolymer, a random copolymer, or a graft copolymer. The polyvinyl alcohol may be crosslinkable or non-crosslinkable. The polyvinyl alcohol may be fully hydrolyzed, i.e., fully hydrolyzed polyvinyl alcohol (PVA), or partially hydrolyzed, i.e., partially hydrolyzed polyvinyl alcohol (PVA). Partially hydrolyzed polyvinyl alcohol is preferred. From a classification standpoint, partially hydrolyzed polyvinyl alcohol can also be understood as a type of copolymer of polyvinyl alcohol and polyvinyl acetate (PVA-PVAc copolymer). This is because its polymer segment contains both vinyl alcohol and vinyl acetate units simultaneously. Furthermore, fully hydrolyzed polyvinyl alcohol is polyvinyl alcohol whose composition is 100% vinyl alcohol units. Also, partially hydrolyzed polyvinyl alcohol, for example, partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 80%, means that it contains 80% vinyl alcohol units and 20% unhydrolyzed vinyl acetate units. In the terminology of this invention, the two terms, partially hydrolyzed polyvinyl alcohol and copolymer of polyvinyl alcohol and polyvinyl acetate, can refer to the same subject and can be used interchangeably.

[0030] In the present invention, the first polymer is preferably partially hydrolyzed polyvinyl alcohol. The preferred range of the degree of hydrolysis of the partially hydrolyzed polyvinyl alcohol is 70% to 99%, more preferably 80% to 98%, and still more preferably 88% to 95%. The present invention shows that an appropriate degree of hydrolysis of polyvinyl alcohol improves the stability of forming an interpenetrating polymer network structure with the polymer on the surface of the lens core body, and at the same time, can also improve the stability of the first polymer that forms an interpenetrating polymer network structure with the second polymer in the outer shell layer. The reason why the effect of the partially hydrolyzed polyvinyl alcohol is superior to that of the completely hydrolyzed polyvinyl alcohol is that the intramolecular hydrogen bond of the completely hydrolyzed polyvinyl alcohol is strong, so the completely hydrolyzed polyvinyl alcohol is difficult to penetrate into the surface structure of the lens core body (polymer), and it is difficult to form an interpenetrating polymer network structure with the lens core body (polymer). Similarly, because the intramolecular hydrogen bond of the completely hydrolyzed polyvinyl alcohol is strong, it is difficult to form an intermolecular hydrogen bond with the second polymer containing polyvinylpyrrolidone. Therefore, compared with the partially hydrolyzed polyvinyl alcohol, the completely hydrolyzed polyvinyl alcohol is difficult to form a similar interpenetrating polymer network structure with the second polymer.

[0031] The preferred range of the molecular weight (Mw) of the first polymer is 5,000 to 300,000 Da, more preferably 10,000 to 200,000 Da, still more preferably 15,000 to 150,000 Da, and most preferably 25,000 to 100,000 Da.

[0032] The second polymer used in the present invention is a polymer containing a polyvinyl pyrrolidone structure. The second polymer may be polyvinyl pyrrolidone, a copolymer containing polyvinyl pyrrolidone, or a mixture thereof. The second polymer may be crosslinkable or non-crosslinkable. The copolymer containing polyvinyl pyrrolidone may be a copolymer of vinylpyrrolidone and dimethylaminoethyl methacrylate {(vinylpyrrolidone)-co-(dimethylaminoethylmethacrylate)}, and specific examples include Copolymer 845, Copolymer 937, and Copolymer 958 sold by Ashland Inc. The molecular weight of the copolymer of vinylpyrrolidone and dimethylaminoethyl methacrylate is, for example, 100,000 Da or more, more preferably 1,000,000 Da or more.

[0033] The preferred molecular weight (Mw) of the second polymer is 8,000 Da or greater, more preferably 100,000 Da or greater, even more preferably 160,000 Da or greater, and most preferably 360,000 Da or greater. The molecular weight range of the second polymer allows for the formation of an effective outer shell layer. If the molecular weight of the second polymer is insufficient, it is difficult to form an effective outer shell layer together with the first polymer. If the molecular weight of the second polymer is not sufficiently large, it is difficult to form an effective outer shell layer with the first polymer. This is because, even if the molecular weight of the second polymer is not sufficiently large, it is still possible to form a similar interpenetrating polymer network structure together with the first polymer, but because the molecular weight of the second polymer is small, migration is more likely to occur within the structure, resulting in insufficient stability of the outer shell layer.

[0034] At the boundary between the lens core body and the outer shell layer, the polymer structures of the first polymer and the lens core body form an interpenetrating polymer network structure. In most of the outer shell layer, a stable structure similar to the interpenetrating polymer network structure is formed between the first polymer and the second polymer.

[0035] At the boundary between the lens core body and the outer shell layer, the polymer structure of the first polymer and the polymer structure of the lens core body form an interpenetrating polymer network structure. Within this interpenetrating polymer network structure, some of the first polymers are freely movable polymers, and stable bonds are formed between other portions of the first polymers, and these bonds stabilize the interpenetrating polymer network structure. The formation of these bonds is mainly due to the generation of stable hydrogen bonds between polyvinyl alcohols under high temperature and pressure during the autoclave process of contact lenses. Therefore, the portion of the outer shell layer in contact with the lens core body is mainly composed of the first polymer, and the portion of the outer shell layer away from the lens core body is mainly composed of the second polymer. In most of the outer shell layer, a stable structure similar to an interpenetrating polymer network structure is formed between the first polymer and the second polymer. Within this structure, some of the first polymers are freely movable polymers, some of the second polymers are also freely movable polymers, and stable bonds are formed between portions of the first polymers, and these bonds stabilize the similar interpenetrating polymer network structure. The formation of the aforementioned bond is primarily due to the creation of stable hydrogen bonds between polyvinyl alcohols during the contact lens sterilization process. Simultaneously, stable hydrogen bonds can also be formed between polyvinyl alcohol and polyvinylpyrrolidone, mainly due to the hydroxyl groups of polyvinyl alcohol and the oxygen atoms of polyvinylpyrrolidone. Therefore, the overall structure of the outer layer becomes relatively stable, maintaining comfort for the wearer.

[0036] To elaborate further, controlling the proportion of vinyl acetate in the first polymer (i.e., the degree of hydrolysis of partially hydrolyzed polyvinyl alcohol) can significantly affect the formation effect of the outer shell layer. Because the polyvinyl alcohol structure itself has strong crystallinity, if the crystallinity of the first polymer is too strong, the first polymer cannot effectively penetrate the surface structure of the lens core before forming the outer shell layer, and the first polymer cannot form a semi-interpenetrating polymer network structure together with the surface structure of the lens core. As a result, a more stable interpenetrating polymer network structure cannot be formed in the subsequent sterilization process. Similarly, if the crystallinity of the first polymer is too strong, the oxygen atoms of polyvinylpyrrolidone in the second polymer will have difficulty forming hydrogen bonds with the hydroxyl groups of polyvinyl alcohol in the first polymer. This makes it difficult for sufficient entanglement to occur between the first and second polymers, affecting the effect of the first and second polymers in forming a similar interpenetrating polymer network structure, and consequently affecting the stability of the outer shell layer. Furthermore, a portion of the vinyl acetate in the first polymer can react with some of the vinyl alcohol during sterilization, forming an action similar to a cross-linking reaction, which can further stabilize the structure of the outer shell layer and simultaneously help the outer shell layer fix and cover the lens core body.

[0037] One of the key factors in the formation of the stable outer shell layer referred to in this invention is that the first polymer can form a mutually penetrating polymer network structure with the lens core body, and at the same time, the first polymer can also form a mutually penetrating polymer network structure with the second polymer. The sterilization process is a key factor in the formation of this stable mutually penetrating polymer network structure. The high temperature and pressure during sterilization generate stable hydrogen bonds between the polyvinyl alcohols in the first polymer. Simultaneously, some of the vinyl acetate in the first polymer can react with some of the vinyl alcohols during sterilization, forming an action similar to a crosslinking reaction. This transforms the semi-mutually penetrating polymer network structure originally formed by the surface structure of the first polymer and the lens core body into a more stable mutually penetrating polymer network structure. Similarly, while the first and second polymers in the outer shell layer initially only exhibited simple physical adsorption and minor entanglement, the high temperature and pressure during sterilization induce the formation of hydrogen bonds and crosslinking-like reactions between the first polymers, as well as strengthening the hydrogen bonds between the first and second polymers, further enhancing the strength of the entanglement. Therefore, the sterilization process not only helps the outer shell layer stably coat the lens core body, but also helps to enhance the stability of the outer shell layer itself.

[0038] The first polymer used in the present invention does not necessarily have to contain positively charged polymer segments (cationic polymeric segments) and does not necessarily have to contain negatively charged polymer segments (anionic polymeric segments).

[0039] The first polymer used in the present invention may include positively charged polymer segments, but these positively charged polymer segments must not have an inhibitory effect on the formation of an interpenetrating polymer network structure between the first polymer and the polymer of the lens core body. Nor must they have an inhibitory effect on the formation of a stable entanglement between the first polymer and the second polymer. Similarly, the first polymer used in the present invention may include negatively charged polymer segments, but these negatively charged polymer segments must not have an inhibitory effect on the formation of an interpenetrating polymer network structure between the first polymer and the polymer of the lens core body. Nor must they have an inhibitory effect on the formation of a stable entanglement between the first polymer and the second polymer.

[0040] The second polymer used in the present invention does not necessarily have to contain positively charged polymer segments (cationic polymeric segments) and does not necessarily have to contain negatively charged polymer segments (anionic polymeric segments).

[0041] The second polymer used in the present invention may include positively charged polymer segments, but these positively charged polymer segments must not have an inhibitory effect on the formation of a mutually penetrating polymer network structure between the first polymer and the polymer of the lens core body. Furthermore, they must not have an inhibitory effect on the formation of a stable entanglement between the second polymer and the first polymer. Similarly, the second polymer used in the present invention may include negatively charged polymer segments, but these negatively charged polymer segments must not have an inhibitory effect on the formation of a mutually penetrating polymer network structure between the first polymer and the polymer of the lens core body. Furthermore, they must not have an inhibitory effect on the formation of a stable entanglement between the second polymer and the first polymer.

[0042] In one embodiment of the present invention, the outer shell layer of the contact lens is composed of a first polymer and a second polymer in the contact lens storage solution, and the outer shell layer can be formed during the sterilization process.

[0043] In one embodiment of the present invention, the relative ratio of the first polymer and the second polymer in the contact lens storage solution in weight percent may be in the range of 2:1 to 1:15, more preferably in the range of 1:2 to 1:10, and even more preferably in the range of 1:4 to 1:8. Within the selected range of relative ratios of the first polymer and the second polymer, the outer shell layer is formed more stably and is less likely to disappear over time after formation.

[0044] In one embodiment of the present invention, the relative ratio of the first polymer and the second polymer in the contact lens storage solution in weight percent is related to the molecular weight of the second polymer, and a more stable outer shell layer can be formed when the combination of the two is within a certain range. A more preferred combination is when the relative ratio of the first polymer and the second polymer in the contact lens storage solution in weight percent is in the range of 1:2 to 1:10, and at the same time the molecular weight of the second polymer is 160,000 Da or more. An even more preferred combination is when the relative ratio of the first polymer and the second polymer in the contact lens storage solution in weight percent is in the range of 1:4 to 1:8, and at the same time the molecular weight of the second polymer is 360,000 Da or more.

[0045] In one embodiment of the present invention, the relative ratio of the first polymer and the second polymer in the contact lens storage solution in weight percent is related to the degree of hydrolysis of the first polymer, and a more stable outer shell layer can be formed when the combination of the two is within a certain range. A more preferred combination is when the relative ratio of the first polymer and the second polymer in the contact lens storage solution in weight percent is in the range of 1:2 to 1:10, and at the same time the first polymer is a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 80% to 98%. A still preferred combination is when the relative ratio of the first polymer and the second polymer in the contact lens storage solution in weight percent is in the range of 1:4 to 1:8, and at the same time the first polymer is a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 88% to 95%.

[0046] In one embodiment of the present invention, the pH value of the contact lens storage solution is in the range of 6.0 to 8.0, and the osmotic pressure is in the range of 200 to 400 mOsm / (kgH2O).

[0047] To facilitate reader understanding, a detailed theoretical explanation is provided here regarding the structural relationship and principle between the first polymer and the lens core body, as well as the structural relationship and principle between the first polymer and the second polymer. However, this theoretical explanation should not be derived or interpreted in a way that limits the scope of the patent rights of this invention.

[0048] As shown in the examples, the lens core of the contact lens provided by the present invention is mainly composed of HEMA (2-hydroxyethyl methacrylate), meaning that the HEMA content may be 85% or more, or 90% or more, or even 95% or more. The composition and percentage calculations described herein do not include the diluent. This type of contact lens is generally called a hydrogel contact lens.

[0049] As shown in the examples, the lens core of the contact lens provided by the present invention may be a contact lens containing a silicone-containing component. The silicone-containing component may be a silicone monomer or a silicone macromer, and may also contain a silicone-containing crosslinker. This type of contact lens is generally called a silicone hydrogel contact lens. [Brief explanation of the drawing]

[0050] [Figure 1] This is a flowchart showing a method for manufacturing contact lenses according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of a contact lens in one embodiment of the present invention. [Figure 3] This is a schematic enlarged view of circle A in Figure 2. [Figure 4] This is a schematic cross-sectional view of a contact lens placed inside a package according to one embodiment of the present invention. [Modes for carrying out the invention]

[0051] The present invention now provides a detailed reference to embodiments of the present invention, describing one or more such embodiments. Each embodiment is provided for illustrative purposes only, and not to limit the present invention. In practice, it will be obvious to a person with ordinary skill in the art to which the present invention belongs that various modifications and changes can be made to the present invention without departing from the spirit of the invention. For example, features disclosed or described as part of one embodiment can be used in another embodiment to generate a new embodiment. Thus, the present invention is intended to include such modifications and changes that fall within the scope of the appended claims and their equivalents. Other objects, features, and directions of the present invention are disclosed in the following detailed description or will become apparent from the following detailed description. A person with ordinary skill in the art to which the present invention belongs should understand that the present discussion is merely a description of exemplary embodiments and is not intended to limit broader aspects of the present invention.

[0052] Figure 1 is a flowchart of a method for manufacturing a contact lens according to one embodiment of the present invention. Referring to Figure 1, the present invention provides a method for manufacturing a contact lens, which includes steps S100 to S300 and will be described in detail below. In step S100, a dry lens is provided, which refers to a lens that has already been cured in the contact lens manufacturing process but has not yet been hydrated. Next, in step S200, a hydration process is performed on the dry lens to obtain a wet lens. Furthermore, in step S300, a sterilization process is performed on the wet lens to obtain a contact lens.

[0053] Referring to Figures 1, 2, and 3, in one embodiment of the present invention, the first polymer 121 is used in at least one of the hydration process and the sterilization process, and the second polymer 122 is used in at least one of the hydration process and the sterilization process. As a result, the contact lens 100 includes an outer shell layer 120, and the outer shell layer 120 includes the first polymer 121 and the second polymer 122. The first polymer 121 includes polyvinyl alcohol, and the second polymer 122 includes polyvinylpyrrolidone. Specifically, the contact lens 100 in one embodiment of the present invention includes, for example, a lens core body 110 and an outer shell layer 120, and the outer shell layer 120 covers, for example, the lens core body 110. It should be noted that the lens core body 110 in one embodiment of the present invention may be either a dry lens or a wet lens. In the embodiment shown in Figures 2 to 4, the lens core body 110 is, for example, a wet lens. In one embodiment in which the contact lens 100 includes an outer shell layer 120, the first polymer 121 covers, for example, the lens core body 110, and the second polymer 122 covers, for example, the first polymer 121.

[0054] Referring to Figure 4, in one embodiment of the present invention, the contact lens 100 is placed, for example, in a contact lens package 300, which is filled with a contact lens storage solution 200, and the contact lens 100 is immersed in the contact lens storage solution 200. The contact lens package 300 in this embodiment includes, for example, aluminum foil 310 and a container 320, the container 320 having a cavity for containing the contact lens 100 and the contact lens storage solution 200, and the container 320 is sealed with, for example, aluminum foil 310, but the present invention is not limited thereto. In one embodiment of the present invention, the container 320 is, for example, a PP cup, but the present invention is not limited thereto.

[0055] Abbreviations and descriptions of the compounds used in lens formulations: [Table 1]

[0056] Sample 1-1 (EX1-1): A dry lens of Hydrogel-1 was prepared, with the lens composition shown in Table 2. The process from lens formulation to dry lens production is well-known in this art, and a mold-based manufacturing method can be selected. For the hardening method of the contact lens, either photocuring or thermal curing can be selected, and photocuring was selected for this sample. The dry lens was hydrated in hot water at 70±5 degrees Celsius (reverse osmosis water (RO water) was used) for 60 minutes to wash away the monomers, crosslinking agents, initiators, and fillers remaining from the hardening reaction to obtain a wet lens. The obtained wet lens was immersed in an aqueous solution containing 0.2 g / L of PVA-PVAc copolymer for 120 minutes. The purpose of this immersion process is to allow the PVA-PVAc copolymer to penetrate the surface of the lens core by mass transfer. The PVA-PVAc copolymer used here is designated PVA-PVAc-1, with a molecular weight of 31,000 Da and containing 88% PVA, i.e., a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 88%. After completing these steps, the wet lens was removed from the aqueous solution of the PVA-PVAc copolymer and placed in a polypropylene (PP) cup, and Buffer-1 was added dropwise to the PP cup. The level of the buffer solution must be higher than the wet lens, ensuring that all of the buffer solution completely covers the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized in an autoclave. The sterilization conditions were to heat the temperature to 122 degrees Celsius and maintain it at 122 degrees Celsius and 2 atmospheres for 30 minutes. As a result, a contact lens was obtained in which the lens core body has a water content of approximately 38% and is mainly composed of HEMA, the outer shell layer is mainly composed of PVA-PVAc copolymer and PVP, and the lens core body and PVP are bonded by the PVA-PVAc copolymer.Approximately 12 hours after the wet lens came into contact with the buffer solution (including the sterilization process), the aluminum foil was opened, the buffer solution was extracted, and its pH was measured to be 7.2. The osmotic pressure was 313 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of the standard buffer solution was used per contact lens, and the buffer solution was changed every hour. This process was repeated three times, after which the smoothness of the contact lens surface was evaluated. The mixing ratio of Buffer-1 and Standard buffer is shown in Table 3. [Table 2] Footnote: Diluents (including glycerin, 1-hexanol, and DEGBE) in Table 2 are not included in the calculation of the lens's total composition (SUM). The SUM is added as the denominator to 100%. For example, the composition of Hydrogel-1 is HEMA 98.5g, MAA 0.1g, EGDMA 1.0g, and Irgracure819 0.4g, with a total weight of 100g. In this case, glycerin 15.0g is added separately as a diluent. [Table 3] Footnote: The numerical units in Table 3 are grams (g). PVP360K is PVP with a molecular weight of 360,000 Da, PVP8K is PVP with a molecular weight of 8,000 Da, PVA-PVAc-1 is a PVA-PVAc copolymer with a molecular weight of 31,000 Da in which PVA accounts for 88% of the total, PVA-PVAc-2 is a PVA-PVAc copolymer with a molecular weight of 205,000 Da in which PVA accounts for 88% of the total, and PVA-PVAc-3 is a PVA-PVAc copolymer with a molecular weight of 27,000 Da in which PVA accounts for 98% of the total.

[0057] Sample 1-2 (EX1-2): Prepared using the same method as Sample 1-1, but instead of heat-sealing the aluminum foil and PP cup and then sterilizing it in an autoclave, the wet lens was simply immersed in Buffer-1 within the heat-sealed aluminum foil PP cup. Approximately 12 hours after the wet lens began contact with the buffer (including the sterilization process), the aluminum foil was opened, the buffer was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 318 mOsm / (kg H2O). Simultaneously, the contact lens was removed and placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, after which the smoothness of the contact lens surface was measured.

[0058] Sample 2-1 (EX2-1): A hydrogel-2 dry lens was prepared, and the lens composition is shown in Table 2. The process from lens formulation to dry lens production is well known in this art, and a mold-based manufacturing method can be selected. For the hardening method of the contact lens, either photocuring or thermal curing can be selected, and photocuring was selected for this sample. The purpose of immersing the dry lens in a 0.5 wt% sodium carbonate aqueous solution for 20 minutes is to rapidly ionize the MAA in the dry lens, causing it to expand and improving cleaning efficiency. Subsequently, it is hydrated with RO water at room temperature (20-30 degrees Celsius) for 40 minutes to wash away the monomers, crosslinking agents, initiators, and fillers remaining from the hardening reaction from the dry lens, obtaining a wet lens. The obtained wet lens is immersed in an aqueous solution containing 0.2 g / L of PVA-PVAc copolymer for 120 minutes. The purpose of this immersion process is to allow the PVA-PVAc copolymer to penetrate the surface of the lens core by mass transfer. The PVA-PVAc copolymer used here is designated PVA-PVAc-1, with a molecular weight of 31,000 Da and containing 88% PVA, i.e., a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 88%. After completing these steps, the wet lens was removed from the aqueous solution of the PVA-PVAc copolymer and placed in a PP cup, and Buffer-1 was added dropwise to the PP cup. The level of the buffer solution must be higher than the wet lens, ensuring that all of the buffer solution completely covers the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized in an autoclave. The sterilization conditions were to heat the temperature to 122 degrees Celsius and maintain it at 122 degrees Celsius and 2 atmospheres for 30 minutes. As a result, a contact lens was obtained in which the lens core body has a water content of approximately 55% and is mainly composed of HEMA, the outer shell layer is mainly composed of PVA-PVAc copolymer and PVP, and the lens core body and PVP are bonded by the PVA-PVAc copolymer.Approximately 12 hours after the wet lenses came into contact with the buffer (including the sterilization process), the aluminum foil was opened, the contact lenses were removed, and they were placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, with the buffer replaced every hour. This process was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0059] Sample 2-2 (EX2-2): Prepared using the same method as Sample 2-1, but instead of heat-sealing the aluminum foil and PP cup and then sterilizing it in an autoclave, the wet lens was simply immersed in Buffer-1 within the heat-sealed aluminum foil PP cup. Approximately 12 hours after the wet lens began contact with the buffer (including the sterilization process), the aluminum foil was opened, the contact lens was removed, and it was placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, and then the smoothness of the contact lens surface was evaluated.

[0060] Sample 3-1 (EX3-1): A dry lens made of silicone hydrogel was manufactured, and the lens composition is shown in Table 2. The process from lens compounding to the manufacture of the dry lens is a well-known technique in this art, and a manufacturing method using a mold can be selected. For the curing method of the contact lens, either photocuring or thermal curing can be selected, and photocuring was selected for this sample. First, the dry lens was immersed in an aqueous solution containing 50 wt% isopropyl alcohol (IPA) for 60 minutes. This rapidly expands the dry lens and improves cleaning efficiency. Furthermore, by utilizing the principle that IPA has a high affinity for the silicone-containing components TRIS and MPDMS, any TRIS and MPDMS that did not react completely during the curing stage, as well as any remaining other monomers, crosslinking agents, initiators, and fillers, were thoroughly washed away. Subsequently, a wet lens was obtained by immersing the lens in RO water at room temperature (20-30 degrees Celsius) four times for 30 minutes each time, replacing the RO water with fresh water each time to completely rinse away the IPA. The resulting wet lens was immersed for 120 minutes in an aqueous solution containing 0.2 g / L of PVA-PVAc copolymer. The purpose of this immersion process is to allow the PVA-PVAc copolymer to permeate the surface of the lens core by mass transfer. The PVA-PVAc copolymer used here is PVA-PVAc-1, with a molecular weight of 31,000 Da, and is a PVA-PVAc copolymer in which PVA accounts for 88% of the total, i.e., a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 88%. After completing these steps, the wet lens was removed from the aqueous solution of PVA-PVAc copolymer and placed in a PP cup, and Buffer-1 was added dropwise to the PP cup. The level of the buffer solution must be higher than the wet lens, and all of the buffer solution must completely cover the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized in an autoclave. The sterilization conditions involve continuously heating to 122 degrees Celsius, maintaining that temperature at 122 degrees Celsius and 2 atmospheres of pressure for 30 minutes.As a result, a contact lens was obtained in which the lens core body was made of silicone hydrogel, the outer shell layer was mainly composed of PVA-PVAc copolymer and PVP, and the lens core body and PVP were bonded by the PVA-PVAc copolymer. Approximately 12 hours after the wet lens came into contact with the buffer (including the sterilization process), the aluminum foil was opened, the buffer was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 307 mOsm / (kg H2O). At the same time, the contact lens was removed and placed in a standard buffer solution to equilibrate, and 10 ml of the standard buffer solution was used per contact lens, with the buffer being changed every hour, and this was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0061] Sample 3-2 (EX3-2): Prepared using the same method as Sample 3-1, but instead of heat-sealing the aluminum foil and PP cup and then sterilizing it in an autoclave, the wet lens was simply immersed in Buffer-1 within the heat-sealed aluminum foil PP cup. Approximately 12 hours after the wet lens began contact with the buffer (including the sterilization process), the aluminum foil was opened, the contact lens was removed, and it was placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, and then the smoothness of the contact lens surface was evaluated.

[0062] Sample 4-1 (EX4-1): A dry lens of Hydrogel-2 was prepared, with the lens composition referred to in Table 2. The process from lens formulation to dry lens production is well-known in this art, and a mold-based manufacturing method can be selected. For the hardening method of the contact lens, either photocuring or thermal curing can be selected, and photocuring was selected for this sample. The reason for immersing the dry lens in a 0.5 wt% sodium carbonate aqueous solution for 20 minutes is to rapidly ionize the MAA in the dry lens, causing it to expand and improving cleaning efficiency. Subsequently, it is hydrated with RO water at room temperature (20-30 degrees Celsius) for 40 minutes to wash away any monomers, crosslinking agents, initiators, and fillers remaining from the hardening reaction from the dry lens, thereby obtaining a wet lens. The obtained wet lens was placed in a pp cup, and Buffer-3 was added dropwise to the pp cup. The level of the buffer must be higher than the wet lens, ensuring that all of the buffer completely covers the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat-sealing method and sterilized in an autoclave. The sterilization conditions were to continuously heat the temperature to 122 degrees Celsius and maintain 122 degrees Celsius at 2 atmospheres for 30 minutes. As a result, a contact lens was obtained in which the lens core body had a water content of approximately 55% and was mainly composed of HEMA, while the outer shell layer was mainly composed of PVA-PVAc copolymer and PVP, and the lens core body and PVP were bonded by the PVA-PVAc copolymer. Approximately 12 hours after the wet lens came into contact with the buffer (including the sterilization process), the aluminum foil was opened, the buffer was extracted, and the pH value was measured to be 7.3. The osmotic pressure was 321 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of the standard buffer solution was used per contact lens, with the buffer replaced every hour. This process was repeated three times, after which the surface smoothness of the contact lenses was evaluated. The composition ratio of Buffer-3 is shown in Table 3.

[0063] Sample 4-2 (EX4-2): A hydrogel-2 dry lens was manufactured, and the lens composition is shown in Table 2. The process from lens compounding to dry lens manufacturing is well known in this art, and a mold-based manufacturing method can be selected. For the hardening method of the contact lens, either photocuring or thermal curing can be selected, and photocuring was selected for this sample. The reason for immersing the dry lens in a 0.5 wt% sodium carbonate aqueous solution for 20 minutes is to rapidly ionize the MAA in the dry lens, causing the dry lens to expand and improving cleaning efficiency. After that, it is hydrated in RO water at room temperature (20-30 degrees Celsius) for 40 minutes to wash away the monomers, crosslinking agents, initiators, and fillers remaining from the hardening reaction from the dry lens to obtain a wet lens. The obtained wet lens was immersed in a 0.6 g / L PVP aqueous solution for 120 minutes. The purpose of this immersion process is to allow PVP to penetrate the surface of the lens core body by mass transfer. The PVP used here is PVP360, which has a molecular weight of 360,000 Da. After completing these steps, the wet lens was removed from the PVP aqueous solution and placed in a PP cup, and Buffer-2 was added dropwise to the PP cup. The level of the buffer solution must be higher than the wet lens, and all of the buffer solution must completely cover the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized in an autoclave. The sterilization conditions were to heat the temperature to 122 degrees Celsius and maintain it at 122 degrees Celsius and 2 atmospheres for 30 minutes. Approximately 12 hours after the wet lens came into contact with the buffer solution (including the sterilization process), the aluminum foil was opened, the buffer solution was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 320 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of the standard buffer solution was used per contact lens, with the buffer replaced every hour. This process was repeated three times, after which the smoothness of the contact lens surface was evaluated. The mixing ratios for Buffer-2 are shown in Table 3.

[0064] Sample 5-1 (EX5-1): Prepared using the same method as Sample 4-1, but with the substitution of PVP in the buffer with Copolymer 845 (the molecular weight of this polymer is approximately 1,000,000 Da). Approximately 12 hours after the wet lens began contact with the buffer (including the sterilization process), the aluminum foil was opened, the buffer was extracted, and the pH value was measured to be 7.4. The osmotic pressure was 288 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0065] Sample 5-2 (EX5-2): A hydrogel-2 dry lens was prepared, with the lens composition shown in Table 2. The process from lens formulation to dry lens production is well-known in this art, and a mold-based manufacturing method can be selected. For the hardening method of the contact lens, either photocuring or thermal curing can be selected, and photocuring was selected for this sample. The reason for immersing the dry lens in a 0.5 wt% sodium carbonate aqueous solution for 20 minutes is to rapidly ionize the MAA in the dry lens, causing it to expand and improving cleaning efficiency. Subsequently, it is hydrated with RO water at room temperature (20-30 degrees Celsius) for 40 minutes to wash away any monomers, crosslinking agents, initiators, and fillers remaining from the hardening reaction to obtain a wet lens. The obtained wet lens was placed in a pp cup, and Buffer-2 was added dropwise to the pp cup. The level of the buffer must be higher than the wet lens, ensuring that all of the buffer completely covers the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized in an autoclave. The sterilization conditions were to continuously heat the temperature to 122 degrees Celsius and maintain 122 degrees Celsius and 2 atmospheres for 30 minutes. After the sterilization was completed, the aluminum foil was opened, the buffer solution was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 315 mOsm / (kg H2O). At the same time, the contact lens was removed and placed in a new PP cup, and Buffer-1 was added dropwise to the PP cup. The level of the buffer solution must be higher than the wet lens, and all of the buffer solution must completely cover the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized a second time in an autoclave. The sterilization conditions were to continuously heat the temperature to 122 degrees Celsius and maintain 122 degrees Celsius and 2 atmospheres for 30 minutes.After completion, the aluminum foil was opened, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of the standard buffer solution was used per contact lens, with the buffer replaced every hour. This process was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0066] Sample 6-1 (EX6-1): Prepared using the same method as Sample 4-1, but with the substitution of Buffer-3 with Buffer-4. The mixing ratio of Buffer-4 is shown in Table 3. After sterilization was complete, approximately 12 hours (including the sterilization process) had elapsed since the wet lens began contact with the buffer. The aluminum foil was then opened, the buffer was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 307 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0067] Sample 7-1 (EX7-1): Prepared using the same method as Sample 4-1, but with the substitution of Buffer-3 with Buffer-5. The mixing ratio of Buffer-5 is shown in Table 3. After sterilization was complete, approximately 12 hours (including the sterilization process) had elapsed since the wet lens began contact with the buffer. The aluminum foil was then opened, the buffer was extracted, and the pH value was measured to be 7.3. The osmotic pressure was 311 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0068] Sample 8-1 (EX8-1): Prepared using the same method as Sample 4-1, but with the substitution of Buffer-3 with Buffer-6. The mixing ratio of Buffer-6 is shown in Table 3. After sterilization was complete, approximately 12 hours (including the sterilization process) had elapsed since the wet lens began contact with the buffer. The aluminum foil was then opened, the buffer was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 313 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was replaced every hour. This process was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0069] Sample 9-1 (EX9-1): A hydrogel-2 dry lens was prepared, and the lens composition is shown in Table 2. The process from lens formulation to dry lens production is well known in this art, and a mold-based manufacturing method can be selected. For the hardening method of the contact lens, photocuring or thermal curing can be selected, and photocuring was selected for this sample. The reason for immersing the dry lens in a 0.5 wt% sodium carbonate aqueous solution for 20 minutes is to rapidly ionize the MAA in the dry lens, causing the dry lens to expand and improving cleaning efficiency. After that, it is hydrated with RO water at room temperature (20-30 degrees Celsius) for 40 minutes to wash away the monomers, crosslinking agents, initiators, and fillers remaining from the hardening reaction from the dry lens to obtain a wet lens. The obtained wet lens was immersed in a 0.2 g / L PVA (molecular weight 145,000 Da, degree of hydrolysis 99%) aqueous solution and heated at 70 ± 5 degrees Celsius for 120 minutes. Subsequently, the wet lens was immersed in a 0.6 g / L aqueous solution of PVP (molecular weight 360,000 Da) and heated at 70 ± 5 degrees Celsius for 120 minutes. The resulting wet lens was placed in a PP cup, and a standard buffer salt solution was added dropwise to the PP cup. The level of the buffer solution must be higher than the wet lens, ensuring that all of the buffer solution completely covered the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and then sterilized in an autoclave. The sterilization conditions were to heat the temperature to 122 degrees Celsius and maintain it at 122 degrees Celsius and 2 atmospheres for 30 minutes. Approximately 12 hours after the wet lens came into contact with the buffer solution (including the sterilization process), the aluminum foil was opened, the buffer solution was extracted, and the pH value was measured to be 7.4. The osmotic pressure was 320 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of the standard buffer solution was used per contact lens, with the buffer replaced every hour. This process was repeated three times, after which the surface smoothness of the contact lenses was evaluated. The mixing ratios for the standard buffer solution are shown in Table 3.

[0070] Sample 6-2 (EX6-2): Prepared using the same method as Sample 9-1, but instead of heat-sealing the aluminum foil and PP cup and then sterilizing it in an autoclave, the wet lens was simply immersed in a standard buffer solution within the heat-sealed aluminum foil PP cup. Approximately 12 hours after the wet lens began contact with the buffer solution (including the sterilization process), the aluminum foil was opened, the buffer solution was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 310 mOsm / (kg H2O). Simultaneously, the contact lens was removed and placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer solution was changed every hour. This was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0071] Sample 7-2 (EX7-2): Prepared using the same method as Sample 4-1, but with the substitution of Buffer-3 with Buffer-1. The mixing ratio of Buffer-1 is shown in Table 3. After sterilization was complete, approximately 12 hours (including the sterilization process) had elapsed since the wet lens began contact with the buffer. The aluminum foil was then opened, the buffer was extracted, and the pH value was measured to be 7.2. The osmotic pressure was 320 mOsm / (kg H2O). Simultaneously, the contact lenses were removed and placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was replaced every hour. This process was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0072] Sample 8-2 (EX8-2): Prepared using the same method as Sample 7-2, but before evaluating the smoothness of the contact lens surface, the aluminum foil was opened, the contact lens was removed, and it was placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0073] Sample 9-2 (EX9-2): Prepared using the same method as Sample 4-1, but with the substitution of Buffer-3 with Buffer-2. The mixing ratio of Buffer-2 is shown in Table 3. After sterilization was complete, approximately 12 hours (including the sterilization process) had elapsed since the wet lens began contact with the buffer. Then, the aluminum foil was opened, the contact lens was removed, and it was placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, and the buffer was changed every hour. This was repeated three times, after which the smoothness of the contact lens surface was evaluated.

[0074] The surface lubricity score of contact lenses is evaluated. The surface lubricity of contact lenses is evaluated on a scale of 1 to 4. A higher score indicates a smoother contact lens. A score of 1 indicates a contact lens that is not smooth at all, as felt when rubbed with the hand. A score of 2 indicates a contact lens that is slightly smooth, as felt when rubbed with the hand, and is equivalent in evaluation to the commercially available contact lens product Acuvue Oasys 1 day. A score of 3 indicates a contact lens that is moderately smooth. A score of 4 indicates a contact lens that is very smooth, and is equivalent in evaluation to the commercially available contact lens product Dailies Total 1. It should be explained that while some contact lens users rate the wearing comfort of Dailies Total 1 as very good, the contact lenses are too slippery, making it very difficult to remove them from the eye after use, which affects their willingness to continue using that brand of contact lens. Therefore, a higher smoothness score is not always better. In the evaluation of this invention, the optimal smoothness score is 3.

[0075] Surface Smoothness Evaluation Test Method: Five subjects are selected, and each subject simultaneously rubs two products, Acuvue Oasys 1 day and Dailies Total 1. The perceived smoothness when rubbing Acuvue Oasys 1 day is assigned a score of 2, and the perceived smoothness when rubbing Dailies Total 1 is assigned a score of 4. If four out of the five subjects rate the smoothness of the test sample as clearly lower than that of Acuvue Oasys 1 day, the smoothness score of the test sample is assigned a score of 1. If three subjects rate the smoothness of the test sample as lower than that of Acuvue Oasys 1 day, and two subjects rate the difference as unclear, the score is assigned a score of 1-2. If four or more subjects judge the smoothness of the test sample to be equivalent to that of Acuvue Oasys 1 day, the score is assigned a score of 2. If three or more people rate the smoothness of the sample being tested as clearly superior to that of Acuvue Oasys 1 day, and two more rate it as equivalent to that of Acuvue Oasys 1 day, the score will be 2-3 points. If four or more people rate the smoothness of the sample being tested as clearly superior to that of Acuvue Oasys 1 day, the score will be 3 points.

[0076] Table 4 shows the evaluation of surface smoothness in this sample. [Table 4]

[0077] The data in Table 4 shows that the technical features proposed by the present invention (samples EX1-1, 2-1, 3-1, 4-1, 5-1, 6-1, 7-1, 8-1, and 9-1) effectively improve surface smoothness and allow for control within an appropriate range. The main difference between sample 1-1 (EX1-1) and sample 1-2 (EX1-2) is the presence or absence of sterilization. Sample 1-1, which underwent sterilization, has a higher surface smoothness score of 3. Similarly, the surface smoothness score of sample 2-1 (EX2-1) is higher than that of sample 2-2 (EX2-2). The surface smoothness score of sample 3-1 (EX3-1) is also higher than that of sample 3-2 (EX3-2), but the reason is similar to that of sample 1-1 (EX1-1), and a detailed explanation is omitted here. Samples 4-1 (EX4-1) and 4-2 (EX4-2) are similar, but the main difference between them is the timing of contact between the first and second polymers with the lens core. In Sample 4-1 (EX4-1), the lens core is immersed in a buffer containing both the first and second polymers, allowing the first polymer to effectively form an interpenetrating polymer network structure with the surface structure of the lens core, thus affecting the smoothness of the final contact lens surface. The main difference between Sample 5-1 (EX5-1) and Sample 5-2 (EX5-2) is that Sample 5-2 undergoes two sterilization steps. First, it is immersed in Buffer-2 containing PVA and then sterilized once, and then immersed in Buffer-1 containing PVP and then sterilized a second time. Looking at the surface smoothness scores, Sample 5-1 scores higher than Sample 5-2. The reason for this is thought to be that, during the first sterilization of sample 5-2, strong hydrogen bonding and crosslinking reactions first formed between some of the polyvinyl alcohols in the first polymer, which may prevent the second polymer from forming an outer layer together with the first polymer during the second sterilization. As a result, the outer layer may become unstable, potentially leading to a lower surface smoothness score.Comparing sample 9-1 (EX9-1) and sample 6-2 (EX6-2), sample 9-1 has a higher surface smoothness score because it has undergone sterilization. Samples 4-1 (EX4-1) and 7-2 (EX7-2) are similar, but the main difference is that Buffer-3 in which sample 4-1 is immersed contains not only the second polymer but also the first polymer. This allows the second polymer to stably exist on the surface of the lens core body with the help of the first polymer. Therefore, sample 4-1 has a higher surface smoothness score. Similarly, sample 4-1 (EX4-1) has a higher surface smoothness score than sample 8-2 (EX8-2), but a detailed explanation of this is omitted here. Comparing Sample 4-1 (EX4-1) and Sample 9-2 (EX9-2), Sample 4-1 receives a higher surface smoothness score than Sample 9-2 because the Buffer-3 in which it is immersed contains not only the first polymer but also the second polymer, which helps in the formation of an outer layer that improves the smoothness of the contact lens surface.

[0078] Contact lenses from samples 4-1 and 7-2 were rinsed three times with RO water to remove components that can be removed by RO water (including buffer salts NaCl, NaH2PO4, and Na2HPO4) from the surface of the contact lenses. The contact lenses were then dried at 105°C for at least 8 hours to remove moisture and obtain dry lenses. The surface components of the dry lenses were then analyzed using the elemental analysis function of a scanning electron microscope (Energy-dispersive X-ray spectroscopy with Scanning Electron Microscope, SEM-EDX). Elemental analysis data showed that the surface of the dried lens from sample 4-1 contained 4.39% nitrogen, indicating that the secondary polymer (PVP) remained stable on the surface of the lens core even after rinsing with RO water. However, no nitrogen was detected on the surface of the dried lens from sample 7-2, indicating that the secondary polymer (PVP) originally present on the surface of the lens core was washed away after rinsing with RO water. Therefore, by using the SEM-EDX analysis method, it can be further explained that the lens core body of the contact lens in one embodiment of the present invention is covered with an outer shell layer containing a second polymer (PVP).

[0079] Samples 10-15 (EX10-EX15): Prepared using the same method as Sample 4-1, but with the substitution of Buffer-3 with Buffer-7-12 (Buffer-7-Buffer-12). The composition of the buffers is shown in Table 5. Specifically, Buffer-7 was used instead of Buffer-3 in Sample 10, Buffer-8 was used instead of Buffer-3 in Sample 11, Buffer-9 was used instead of Buffer-3 in Sample 12, Buffer-10 was used instead of Buffer-3 in Sample 13, Buffer-11 was used instead of Buffer-3 in Sample 14, and Buffer-12 was used instead of Buffer-3 in Sample 15. After sterilization was complete, approximately 12 hours (including the sterilization process) had elapsed since the wet lens began contact with the buffer before the aluminum foil was opened, the buffer was extracted, and the pH value and osmotic pressure were measured. The pH values ​​of Samples 10-15 were in the range of 6.9-7.6, and the osmotic pressure was in the range of 288-337 mOsm / (kg H2O). The surface smoothness of samples 10-15 was evaluated using the same method as for sample 4-1, and the surface smoothness evaluation is shown in Table 6. [Table 5]

[0080] Footnote: The numerical units in Table 5 are grams (g). PVP360K is PVP with a molecular weight of 360,000 Da, PVP8K is PVP with a molecular weight of 8,000 Da, PVA-PVAc-1 is a PVA-PVAc copolymer with a molecular weight of 31,000 Da in which PVA accounts for 88% of the total, PVA-PVAc-2 is a PVA-PVAc copolymer with a molecular weight of 205,000 Da in which PVA accounts for 88% of the total, and PVA-PVAc-3 is a PVA-PVAc copolymer with a molecular weight of 27,000 Da in which PVA accounts for 98% of the total. [Table 6]

[0081] Sample 16 (EX16): Prepared using the same method as Sample 1-1, but instead of immediately placing the wet lens in a PP cup and contacting it with buffer after removing it from the PVA-PVAc copolymer aqueous solution, the wet lens was first placed in a 0.6 g / L PVP360 aqueous solution and heated at 80 degrees Celsius for 2 hours. After that, the wet lens was placed in the PP cup, and then a standard buffer solution was added dropwise into the PP cup. The buffer level had to be higher than the wet lens, and it was ensured that all of the buffer completely covered the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized in an autoclave. The sterilization conditions were to heat the temperature to 122 degrees Celsius and maintain it at 122 degrees Celsius and 2 atmospheres for 30 minutes.

[0082] Sample 17 (EX17): Prepared using the same method as Sample 2-1, but instead of immediately placing the wet lens in a PP cup and contacting it with buffer after removing it from the PVA-PVAc copolymer aqueous solution, the wet lens was first placed in a 0.6 g / L PVP360 aqueous solution and heated at 80 degrees Celsius for 2 hours. After that, the wet lens was placed in the PP cup, and then a standard buffer solution was added dropwise to the PP cup. The buffer level had to be higher than the wet lens, and it was ensured that all of the buffer completely covered the wet lens. After completion, the aluminum foil and PP cup were sealed using a heat seal method and sterilized in an autoclave. The sterilization conditions were to heat the temperature to 122 degrees Celsius and maintain it at 122 degrees Celsius and 2 atmospheres for 30 minutes.

[0083] Sample 18 (EX18): Prepared using the same method as Sample 17, but with the sodium carbonate used in the hydration process replaced with sodium tetraborate. The rest of the production process is the same.

[0084] Sample 19 (EX19): Prepared using the same method as Sample 16, but with the buffer replaced by Buffer-3. The other production processes are the same.

[0085] Sample 20 (EX20): Prepared using the same method as Sample 17, but with the buffer replaced by Buffer-3. The rest of the production process is the same.

[0086] Sample 21 (EX21): Prepared using the same method as Sample 2-1, but with the buffer replaced by Buffer-3. The other production processes are the same.

[0087] The surface smoothness of samples 16-21 was evaluated: Approximately 12 hours after the wet lenses came into contact with the buffer (including the sterilization process), the aluminum foil was opened, the contact lenses were removed, and they were placed in a standard buffer solution to equilibrate. 10 ml of standard buffer solution was used per contact lens, with the buffer replaced every hour, and this was repeated three times. The surface smoothness of the contact lenses was then evaluated, and the results are shown in Table 7. A comparison of EX16, EX17 with EX1-1 and EX2-1 (see Table 4) revealed that the surface smoothness score was lower only when the contact lenses came into contact with the first and second polymers during the hydration process. The sterilization temperature (122 degrees Celsius) is higher than the hydration temperature (20 degrees Celsius to 80 degrees Celsius), which is presumed to be favorable for the formation of the outer shell layer of the contact lenses. Furthermore, a comparison of EX19 and EX20 revealed that EX20 scored higher in surface smoothness. This is presumed to be because the higher proportion of MAA in the lens core body is advantageous for the adsorption of the first polymer to the surface of the wet lens, resulting in a more complete formation of the outer shell layer. EX20 also scored higher in surface smoothness than EX4-1 (see Table 4). This is presumed to be because the lens core body comes into contact with the first and second polymers not only during sterilization but also during the hydration process. [Table 7]

[0088] Based on the data analysis and explanation described above, it can be demonstrated that the technical features proposed by the present invention can effectively provide contact lenses with an appropriate surface smoothness, thereby improving comfort during contact lens wear.

[0089] Although the present invention has been disclosed above using examples, the present invention is not limited thereto. Those skilled in the art can make several modifications without departing from the spirit of the invention. Accordingly, the scope of protection of the present invention is limited by the appended claims. [Explanation of symbols]

[0090] 100: Contact lenses 110: Lens core body 120: Outer layer 121: First Polymer 122: Second Polymer 200: Contact lens storage solution 300: Contact lens packaging 310: Aluminum foil 320: Container S100, S200, S300: Step A: Yen

Claims

1. The process of providing dry lenses, The process involves performing a hydration process on the dry lens to obtain a wet lens, A method for manufacturing a contact lens, comprising the steps of performing a sterilization process on the wet lens to obtain a contact lens, The contact lens includes an outer shell layer, wherein the outer shell layer comprises the first polymer and the second polymer, and the first polymer is used in at least one of the hydration process and the sterilization process, A method for manufacturing contact lenses, characterized in that the first polymer contains polyvinyl alcohol and the second polymer contains polyvinylpyrrolidone.

2. A method for manufacturing a contact lens according to claim 1, characterized in that the first polymer is used in the hydration process and the second polymer is used in the sterilization process.

3. The method for manufacturing a contact lens according to claim 1, characterized in that the first polymer is used in both the hydration process and the sterilization process, and the second polymer is used in the sterilization process.

4. The method for manufacturing a contact lens according to claim 1, characterized in that the first polymer is used in both the hydration process and the sterilization process, and the second polymer is used in both the hydration process and the sterilization process.

5. The method for manufacturing a contact lens according to claim 4, wherein the step of performing the sterilization process on the wet lens includes a step of sterilizing the wet lens when it is immersed in a contact lens storage solution, the contact lens storage solution contains the first polymer and the second polymer, and the relative ratio of the first polymer and the second polymer in weight percent is 2:1 to 1:

15.

6. The method for manufacturing a contact lens according to claim 5, characterized in that the relative ratio of the first polymer and the second polymer in weight percent is 1:2 to 1:

10.

7. The method for manufacturing a contact lens according to claim 5, characterized in that the relative ratio of the first polymer and the second polymer in weight percent is 1:4 to 1:

8.

8. The pH range of the contact lens storage solution is 6.0 to 8.0, and the osmotic pressure range of the contact lens storage solution is 200 to 400 mOsm / (kgH). ２ A method for manufacturing a contact lens according to claim 5, characterized in that (O).

9. A method for manufacturing a contact lens according to claim 1, characterized in that both the first polymer and the second polymer are used in the hydration process.

10. A method for manufacturing a contact lens according to claim 1, characterized in that both the first polymer and the second polymer are used in the sterilization process.

11. The method for producing a contact lens according to claim 1, wherein the first polymer is a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 70% to 99%.

12. The method for producing a contact lens according to claim 1, wherein the first polymer is a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 80% to 98%.

13. The method for producing a contact lens according to claim 1, wherein the first polymer is a partially hydrolyzed polyvinyl alcohol with a degree of hydrolysis of 88% to 95%.

14. The method for manufacturing a contact lens according to claim 1, wherein the molecular weight of the second polymer is 8,000 Da or more.

15. The method for manufacturing a contact lens according to claim 1, wherein the molecular weight of the second polymer is 160,000 Da or more.

16. The method for manufacturing a contact lens according to claim 1, wherein the molecular weight of the second polymer is 360,000 Da or more.

17. The method for producing a contact lens according to claim 1, characterized in that the second polymer is a copolymer containing polyvinylpyrrolidone.

18. The method for producing a contact lens according to claim 17, characterized in that the copolymer containing polyvinylpyrrolidone is a copolymer of vinylpyrrolidone and dimethylaminoethyl methacrylate.

19. The method for manufacturing a contact lens according to claim 18, wherein the molecular weight of the second polymer is 100,000 Da or more.

20. A method for manufacturing a contact lens according to claim 18, characterized in that the molecular weight of the second polymer is 1,000,000 Da or more.

21. A method for manufacturing a contact lens according to claim 1, characterized in that the contact lens contains MAA (methacrylic acid).

22. A method for manufacturing a contact lens according to claim 1, characterized in that sodium carbonate, sodium tetraborate, sodium hydroxide, or disodium hydrogen phosphate is used in the hydration process.

23. The method for manufacturing a contact lens according to claim 1, characterized in that the contact lens manufactured by the above method for manufacturing a contact lens is immersed in 10 ml of a standard buffer salt solution or RO water, and the solution is changed once every hour for three times, the immersed contact lens is dried, and the nitrogen element can be measured by elemental analysis using a scanning electron microscope.

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