Contact lens treatment liquid and use thereof

Abstract

The present invention provides a contact lens treatment liquid of a single-liquid type, including: a hypochlorite; and water, wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae: 0.001≦X≦0.41; Y≦11.9; and Y≧2.28X+10.46; and use thereof.

Description

CONTACT LENS TREATMENT LIQUID AND USE THEREOFThe present invention relates to a contact lens treatment liquid, a method of treating a contact lens and / or a storage container therefor including using the contact lens treatment liquid, and a method of storing a contact lens.A protein, a lipid, and the like in a tear fluid or a secretion from, for example, a cornea or a conjunctiva may adhere as dirt to a contact lens to induce, for example, eye problems or a reduction in wearing comfort. Accordingly, it is important to remove such dirt from the contact lens after being worn.With regard to the removal of the dirt, in general, a contact lens may be subjected to treatment (daily care) including cleaning by digital rubbing or cleaning by soaking with a treatment liquid containing a surfactant, an enzyme, and the like every day or every time after wearing. However, with such cleaning by digital rubbing or cleaning by soaking, the dirt may not be sufficiently removed, and is hence particularly liable to cause a problem in a specialty contact lens having a special curve design such as a multi-stage curve on an inner surface thereof, such as a scleral lens or an orthokeratology lens. In addition, the dirt may accumulate in a storage container for the contact lens, leading to bacterial growth.To cope with such problems, in addition to the daily care, regular (e.g., once or twice a month) special treatment (special care) such as cleaning with a treatment liquid having an intensive cleaning effect may be performed (Non Patent Literature 1). According to the special care, the removal of the dirt, which is difficult to sufficiently remove by the daily care, can be suitably performed.Journal of Japan Contact Lens Society, 57: 270-273, 2015When the daily care (e.g., cleaning by soaking) is performed with the treatment liquid for the special care, an adverse effect (e.g., deterioration such as discoloration) may be caused on the contact lens. Accordingly, a primary object of the present invention is to provide a treatment liquid that enables long-time treatment or frequent treatment in which an adverse effect on the contact lens is suppressed.In addition, treatment liquids for the daily care and the special care are required to be separately managed, and hence management of a plurality of care articles and a plurality of cares with different treatment liquids are complicated. Accordingly, another object of the present invention may be to provide a contact lens treatment liquid of a single-liquid type (single-item care) that can unite the daily care and the special care, and, as a result, can improve the convenience of the care (treatment) of a contact lens. Further, most of the users of an orthokeratology lens are children, and the lens is used in a wearing cycle of being worn at night and removed at the time when the user wakes up. Accordingly, the orthokeratology lens may be cared by a child or at the time when the user wakes up. Accordingly, it is desired that the treatment liquid have high safety at the time of the care, and an operation, such as cleaning, neutralization, or rinsing, be simple. In addition, there is a demand for a reduction in treatment time. Accordingly, still another object of the present invention may be to provide a contact lens treatment liquid improved in treatability, safety, and / or operability.[1] According to one aspect of the present invention, there is provided a contact lens treatment liquid of a single-liquid type, including: a hypochlorite; and water, wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii).0.001≦X≦0.41 (i)Y≦11.9 (ii)Y≧2.28X+10.46 (iii)[2] In the contact lens treatment liquid according to the above-mentioned item [1], the X and the Y may further satisfy at least one, preferably two, more preferably three of the following formulae (v), (vi), and (vii).X≧0.006 (v)Y≦11.7 (vi)Y≧2.28X+10.73 (vii)[3] In the contact lens treatment liquid according to the above-mentioned item [1] or [2], the X may further satisfy the following formula (viii).X≧0.008 (viii)[4] In the contact lens treatment liquid according to any one of the above-mentioned items [1] to [3], the hypochlorite may include at least one kind selected from sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite.[5] The contact lens treatment liquid according to any one of the above-mentioned items [1] to [4] may further include a pH adjuster.[6] In the contact lens treatment liquid according to the above-mentioned item [5], the pH adjuster may contain a compound having a pKa of from 9 to 13.[7] In the contact lens treatment liquid according to the above-mentioned item [5] or [6], the pH adjuster may contain at least one kind selected from a carbonic acid buffering agent, a boric acid buffering agent, a phosphoric acid buffering agent, a citric acid buffering agent, an acetic acid buffering agent, an epsilon-aminocaproic acid buffering agent, an aspartic acid buffering agent, and a silicic acid buffering agent.[8] In the contact lens treatment liquid according to the above-mentioned item [7], the carbonic acid buffering agent may contain at least one kind selected from sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate.[9] In the contact lens treatment liquid according to any one of the above-mentioned items [5] to [8], the pH adjuster may contain at least one kind selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate.

[0010] The contact lens treatment liquid according to any one of the above-mentioned items [1] to [9] may be used for treating a hard contact lens.

[0011] The contact lens treatment liquid according to any one of the above-mentioned items [1] to

[0010] may be used for treating a contact lens containing an organic colorant.

[0012] In the contact lens treatment liquid according to the above-mentioned item

[0011] , the organic colorant may contain at least one kind selected from an anthraquinone-based dye, an azo-based dye, and a phthalocyanine-based dye.

[0013] The contact lens treatment liquid according to any one of the above-mentioned items [1] to

[0012] may be used for treating a specialty contact lens.

[0014] The contact lens treatment liquid according to any one of the above-mentioned items [1] to

[0012] may be used for treating an orthokeratology lens, a hard contact lens for keratoconus, or a scleral lens.

[0015] The contact lens treatment liquid according to any one of the above-mentioned items [1] to

[0014] may be used for performing daily care.

[0016] The contact lens treatment liquid according to any one of the above-mentioned items [1] to

[0015] may be substantially free of any other hypohalite than the hypochlorite.

[0017] According to another aspect of the present invention, there is provided a contact lens treatment liquid of a single-liquid type, including: a hypochlorite; and water, wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii), and wherein a color difference ΔE*ab of a contact lens before and after immersion in the contact lens treatment liquid at room temperature for 4 weeks is 5.0 or less.0.001≦X≦0.41 (i)Y≦11.9 (ii)Y≧2.28X+10.46 (iii)

[0018] According to another aspect of the present invention, there is provided a method of treating a contact lens and / or a storage container therefor, including bringing the contact lens treatment liquid of any one of the above-mentioned items [1] to

[0017] into contact with a contact lens and / or a storage container therefor.

[0019] The treatment method according to the above-mentioned item

[0018] may be performed as daily care of the contact lens and / or the storage container therefor.

[0020] The treatment method according to the above-mentioned item

[0018] or

[0019] may include bringing the contact lens and the contact lens treatment liquid into contact with each other in the storage container every time after wearing of the contact lens.

[0021] In the treatment method according to any one of the above-mentioned items

[0018] to

[0020] , the storage container may be a storage container for daily use.

[0022] In the treatment method according to any one of the above-mentioned items

[0018] to

[0021] , the contact lens treatment liquid and the contact lens and / or the storage container therefor may be brought into contact with each other for a time period of from 4 hours to 18 hours.

[0023] In the treatment method according to any one of the above-mentioned items

[0018] to

[0022] , the contact lens may be a hard contact lens.

[0024] In the treatment method according to any one of the above-mentioned items

[0018] to

[0023] , the contact lens may contain an organic colorant.

[0025] According to another aspect of the present invention, there is provided a method of treating a contact lens and / or a storage container therefor, including frequently treating a contact lens and / or a storage container therefor with a contact lens treatment liquid, wherein the contact lens treatment liquid is a contact lens treatment liquid of a single-liquid type, wherein the contact lens treatment liquid includes a hypochlorite and water, and wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii).0.001≦X≦0.41 (i)Y≦11.9 (ii)Y≧2.28X+10.46 (iii)

[0026] According to another aspect of the present invention, there is provided a method of storing a contact lens, including using the contact lens treatment liquid of any one of the above-mentioned items [1] to

[0017] .

[0027] According to another aspect of the present invention, there is provided a method of storing a contact lens, including immersing a contact lens in a contact lens treatment liquid for a long time period, wherein the contact lens treatment liquid is a contact lens treatment liquid of a single-liquid type, wherein the contact lens treatment liquid includes a hypochlorite and water, and wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii).0.001≦X≦0.41 (i)Y≦11.9 (ii)Y≧2.28X+10.46 (iii)According to the present invention, the contact lens treatment liquid of a single-liquid type that is excellent in convenience, and is also excellent in treatability, safety, and / or operability can be provided. In addition, when a contact lens and / or a storage container therefor is treated with the contact lens treatment liquid, the dirt that is difficult to sufficiently remove by daily care can be suitably removed.FIG. 1 is a graph showing results of a lens discoloration evaluation test 1.FIG. 2 is a set of micrographs of a contact lens in a dirt removal test 1.FIG. 3 is a graph showing a V / P value of the contact lens in the dirt removal test 1.FIG. 4 is a set of micrographs of a contact lens and a graph showing a V / P value thereof in a dirt removal test 2.Preferred embodiments of the present invention are described below. However, the present invention is not limited to these embodiments. The embodiments may be appropriately combined with each other. In this description, the expression "from … to …" representing a numerical range includes the upper limit and lower limit numerical values thereof.A. Contact Lens Treatment LiquidA contact lens treatment liquid (hereinafter sometimes simply referred to as "treatment liquid") according to one embodiment of the present invention includes a hypochlorite and water. The contact lens treatment liquid preferably further includes a pH adjuster, and may include any other additive as required.The contact lens treatment liquid according to the embodiment of the present invention is of a single-liquid type. Herein, the term "single-liquid type" means that an operation of preparing a treatment liquid by mixing two or more kinds of solutions before a contact lens is subjected to treatment (e.g., washing treatment) is not required. Accordingly, the contact lens treatment liquid according to the embodiment of the present invention enables treatment of a contact lens and / or a storage container therefor by being brought into contact therewith as it is, and hence can be excellent in convenience and operability as compared to those of a two-liquid type. In addition, the conversion of the two-liquid type into the single-liquid type leads to reduction of the usage amount of plastic and garbage, and hence contributes to improvements in environmental issues, such as ocean pollution and global warming. In other words, the invention of the present application is an invention corresponding to "12. Responsible production and consumption" of the 17 goals of Sustainable Development Goals (SDGs). In one embodiment, the contact lens treatment liquid may be subjected to continuous use every day, and may be used for daily care. Accordingly, the contact lens after the treatment may be kept immersed in the treatment liquid according to the embodiment of the present invention until being worn next time. Alternatively, the contact lens after the treatment may be stored by being immersed in another solution.In a contact lens treatment liquid according to a first embodiment of the present invention, when the concentration of the hypochlorite is represented by X w / v% and the pH (23°C) of the treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i), (ii), and (iii). The treatment liquid that satisfies the formula (i) can suitably exhibit a dirt-removing effect. In addition, even when part of the treatment liquid remains in the container at the time of replacement with another liquid after the treatment with the treatment liquid, safety at the time of wearing can be secured. The degree of basicity of the contact lens treatment liquid that satisfies the formula (ii) is suppressed to be relatively low, and hence safety at the time of treatment can be improved. According to the treatment liquid that satisfies the formula (iii), discoloration of the lens can be suitably suppressed. Accordingly, the treatment liquid that satisfies the formulae (i) to (iii) can achieve both of excellent treatability (e.g., a dirt-removing effect and a lens discoloration-suppressing effect) and a high degree of safety (specifically, safety at the time of wearing and at the time of treatment). According to the above-mentioned treatment liquid, lens discoloration can be suppressed even when long-term immersion (long-time treatment) or frequent treatment is performed.0.001≦X≦0.41 (i)Y≦11.9 (ii)Y≧2.28X+10.46 (iii)The pH (Y) of the contact lens treatment liquid according to the first embodiment may be preferably 11.7 or less, more preferably 11.5 or less. The contact lens treatment liquid having the above-mentioned pH may have higher safety at the time of treatment. The lower limit of the pH of the contact lens treatment liquid according to the first embodiment is, for example, 10.4 or more, preferably 10.5 or more, more preferably 10.6 or more, 10.7 or more, 10.8 or more, 10.9 or more, 11.0 or more, or 11.1 or more from the viewpoint of the dirt-removing effect.The contact lens treatment liquid according to the first embodiment preferably satisfies Y≧2.28X+10.48, more preferably satisfies Y≧2.28X+10.53, more preferably satisfies Y≧2.28X+10.6, still more preferably satisfies Y≧2.28X+10.7, and even still more satisfies Y≧2.28X+10.73. A treatment liquid that satisfies the above-mentioned requirements can more suitably suppress discoloration of the lens while achieving both of the dirt-removing effect and safety (specifically, safety at the time of wearing and at the time of treatment) at high levels.In a contact lens treatment liquid according to a second embodiment of the present invention, when the concentration of the hypochlorite is represented by X w / v% and the pH (23°C) of the treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) and (iv). The treatment liquid that satisfies the formula (i) can suitably exhibit a dirt-removing effect. In addition, even when part of the treatment liquid remains in the container at the time of replacement with another liquid after the treatment with the treatment liquid, safety at the time of wearing can be secured. According to the contact lens treatment liquid that satisfies the formula (iv), the dirt-removing effect is improved, and hence the treatment time period can be reduced. In addition, discoloration of the lens can be suppressed. Accordingly, the treatment liquid that satisfies the formulae (i) and (iv) can achieve both of excellent treatability (e.g., the dirt-removing effect in a short time period and the lens discoloration-suppressing effect) and safety at the time of wearing at high levels.0.001≦X≦0.41 (i)Y>11.9 (iv)The pH (Y) of the contact lens treatment liquid according to the second embodiment may be, for example, 12.4 or more or 13.1 or more. The contact lens treatment liquid having the above-mentioned pH may have a higher dirt-removing effect, and hence may enable treatment in a short time period (e.g., 1 minute or more and less than 30 minutes, less than 10 minutes, or 5 minutes or less). The upper limit of the pH of the contact lens treatment liquid according to the second embodiment may be, for example, 14.0 or less, 13.9 or less, 12.9 or less, or 12.2 or less. Accordingly, the pH of the contact lens treatment liquid according to the second embodiment may be, for example, from 11.9 to 12.2, from 12.4 to 12.9, or 13.1 or more.The concentration (X) of the hypochlorite in each of the contact lens treatment liquids of the first embodiment and the second embodiment (hereinafter simply referred to as "contact lens treatment liquid" or "treatment liquid" when the contact lens treatment liquids do not need to be distinguished from each other) is, for example, 0.001 w / v% or more, 0.002 w / v% or more, 0.003 w / v% or more, 0.004 w / v% or more, or 0.005 w / v% or more, preferably 0.006 w / v% or more, and may be 0.008 w / v% or more, or 0.01 w / v% or more. The concentration of the hypochlorite is, for example, 0.41 w / v% or less, 0.38 w / v% or less, 0.35 w / v% or less, 0.33 w / v% or less, or 0.3 w / v% or less, preferably 0.25 w / v% or less, and may be 0.2 w / v% or less, 0.15 w / v% or less, 0.1 w / v% or less, or 0.05 w / v% or less. When the concentration of the hypochlorite falls within such ranges, even in case that part of the treatment liquid remains in the container at the time of the replacement with another liquid after the treatment with the treatment liquid, safety at the time of wearing can be secured. In addition, high cleaning actions on protein dirt and lipid dirt can be exhibited by a synergistic effect between a hypochlorite ion and a hydroxide ion (OH-) in the treatment liquid. As a result, a sufficient cleaning effect can be obtained in a practical treatment time period. Further, a high disinfecting action can be exhibited. In addition, for example, when the daily care is performed with the contact lens treatment liquid of the present invention, the lens can be kept cleaner as compared to the regular special care of the related art, a foreign-body sensation and the risk of an epithelium disorder and a corneal infection in some cases caused by the dirt adhering to the contact lens can be alleviated. The concentration of the hypochlorite in the contact lens treatment liquid of the second embodiment may be, for example, 0.04 w / v% or less. The contact lens treatment liquid of the second embodiment having a concentration of the hypochlorite of 0.04 w / v% or less can achieve both of a high level of treatability that can remove the dirt in a short time period while suppressing discoloration and safety at the time of wearing, and can reduce costs. The term "concentration of the hypochlorite" means a weight ratio of the hypochlorite in the total (volume) of the contact lens treatment liquid including the hypochlorite.In one embodiment, the contact lens treatment liquid is substantially free of a water-soluble silicate. Specifically, the content ratio of the water-soluble silicate in the contact lens treatment liquid is, for example, 0.4 w / v% or less, preferably 0.1 w / v% or less. For example, the contact lens treatment liquid can maintain excellent treatability even when the liquid is substantially free of a water-soluble silicate, and, as a result, can achieve both of reduction of costs and excellent treatability.<Hypochlorite>For example, an alkali metal salt or an alkaline earth metal salt of hypochlorous acid may be used as the hypochlorite. Specifically, at least one kind selected from sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite may be preferably used. The hypochlorite preferably includes sodium hypochlorite. In one embodiment, the hypochlorite is sodium hypochlorite.<pH Adjuster>Any appropriate compound may be used as the pH adjuster as long as a hydrogen ion concentration in the treatment liquid can be changed in desired ranges and the effects of the present invention are obtained. Specific examples of the pH adjuster include: an inorganic acid, such as hydrochloric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, carbonic acid, or boric acid, or a salt thereof; an organic acid, such as acetic acid, propionic acid, oxalic acid, gluconic acid, fumaric acid, lactic acid, citric acid, tartaric acid, malic acid, succinic acid, epsilon-aminocaproic acid, aspartic acid, glutamic acid, or aminoethylsulfonic acid, or a salt thereof; a hydroxide, such as sodium hydroxide, potassium hydroxide, calcium hydroxide, or magnesium hydroxide; an organic base, such as monoethanolamine, triethanolamine, dipropanolamine, triisopropanolamine, or lysine; borax; and gluconolactone. The pH adjusters may be used alone or in combination thereof. For example, one kind or two or more kinds of the pH adjusters may be selected and used as a pH buffering agent so that an action of reducing a change in hydrogen ion concentration in the treatment liquid (buffering action) is exhibited.Specific examples of the pH buffering agent include a carbonic acid buffering agent, a boric acid buffering agent, a phosphoric acid buffering agent, a citric acid buffering agent, an acetic acid buffering agent, an epsilon-aminocaproic acid buffering agent, an aspartic acid buffering agent, and a silicic acid buffering agent. Of those, in consideration of a pH range in which a buffering action is obtained, a carbonic acid buffering agent, a boric acid buffering agent, and a phosphoric acid buffering agent are preferred, a carbonic acid buffering agent and a boric acid buffering agent are more preferred, and a carbonic acid buffering agent is still more preferred.Constituent components of the carbonic acid buffering agent include carbonic acid and a carbonate (e.g., sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate). The carbonate may be an anhydride or a hydrate. In one embodiment, the carbonic acid buffering agent contains at least one selected from sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate, and preferably contains sodium carbonate and sodium hydrogen carbonate.Constituent components of the boric acid buffering agent include boric acid and a borate (e.g., sodium borate and potassium borate).Constituent components of the phosphoric acid buffering agent include phosphoric acid and a phosphate (e.g., sodium phosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium phosphate, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate).In one embodiment, the pH adjuster contains a hydroxide (e.g., sodium hydroxide or potassium hydroxide) and / or a compound (e.g., a carbonate) having a pKa of from 9 to 13, preferably a pKa of from 10 to 12. For example, the pH adjuster contains at least one kind selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate, and may preferably contain at least one kind selected from sodium hydroxide and potassium hydroxide, and at least one kind selected from sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate. When such pH adjuster is used, a cleaning action and a disinfecting action of the hypochlorite ion and the hydroxide ion can be suitably obtained.The content ratio of the pH adjuster in the treatment liquid is not limited as long as the effects of the present invention are obtained, and may be, for example, 0.00001 w / v% or more, preferably 0.001 w / v% or more, more preferably 0.01 w / v% or more, still more preferably 0.1 w / v% or more, and may be, for example, 15 w / v% or less, preferably 10 w / v% or less, more preferably 5 w / v% or less, still more preferably 3 w / v% or less.<Water>Various kinds of purified water, such as distilled water, RO water, and ion-exchanged water, may each be preferably used as the water.<Additive>As the additive, a surfactant, a chelating agent, or the like may be used as required. The content of the additive in the contact lens treatment liquid is not limited as long as the effects of the present invention are obtained, and may be appropriately set in accordance with purposes.<Other Hypohalite>In one embodiment, the contact lens treatment liquid is substantially free of any other hypohalite (e.g., a hypobromite or a hypoiodite) than the hypochlorite. A hypochlorite having a predetermined concentration (as a result, a hypochlorite ion having a predetermined concentration) and a hydroxide ion are incorporated as main active components, and thus, even when the contact lens treatment liquid is substantially free of any other hypohalite (as a result, other hypohalite ion), an excellent dirt-removing effect can be exhibited, and the discoloration of the lens can be suitably suppressed. Herein, the phrase "substantially free of any other hypohalite" may encompass not only the case in which the contact lens treatment liquid is completely free of any other hypohalite (case in which the concentration of the other hypohalite is 0 w / v%) but also the case in which the concentration of the other hypohalite is, for example, less than 0.001 w / v% or 0.0005 w / v% or less. The term "concentration of the other hypohalite" means a weight ratio of the other hypohalite in the total (volume) of the contact lens treatment liquid including the other hypohalite.<Production Method>The contact lens treatment liquid may be produced by any appropriate production method. For example, the above-mentioned treatment liquid may be obtained by: dissolving the hypochlorite in water; adding the pH adjuster to the solution so that a desired concentration and a desired pH are achieved; and then diluting the resultant with water as required.<Contact Lens to be treated>The contact lens to be treated is not particularly limited, and may be a hard contact lens or a soft contact lens. In one embodiment, the contact lens to be treated is a hard contact lens. The contact lens may be a lens having a general spherical degree, or may be a lens (specialty contact lens) having a special shape. An example of the specialty contact lens may be a lens to be used as a myopia progression suppression lens or a lens for keratoconus, and specific examples thereof include an orthokeratology lens, a scleral lens, and a multi-stage curve lens. Those specialty contact lenses each have a special curve design such as a multi-stage curve on an inner surface thereof, and the dirt is liable to accumulate thereon, and hence the effects of the present invention can be more suitably obtained.The contact lens to be treated may contain a colorant. In one embodiment, the L*, a*, and b* values in the Lab color space of the contact lens containing a colorant may be 50≦L*<100, -60≦a*≦60, and -60≦b*≦60, preferably 80≦L*≦98, -20≦a*≦20, and -20≦b*≦20, more preferably 85≦L*≦95, -12≦a*≦10, and -12≦b*≦10, still more preferably 85≦L*≦95, -12≦a*≦5, and -12≦b*≦5.The colorant may be appropriately selected from known organic colorants and inorganic colorants in accordance with purposes. Of those, an organic colorant is preferred. When the organic colorant formed of an organic compound is subjected to decomposition by, for example, oxidization, an absorption wavelength may change, but according to the treatment liquid of the embodiment of the present invention, such change in absorption wavelength is suppressed, and hence a contact lens discoloration-suppressing effect can be suitably obtained. Examples of the organic colorant include an anthraquinone-based dye, an azo-based dye, a phthalocyanine-based dye, a nitro-based dye, a triphenylmethane-based dye, a nitroso-based dye, a xanthene-based dye, an azine-based dye, and a quinoline-based dye. Of those, an anthraquinone-based dye, an azo-based dye, and a phthalocyanine-based dye are preferred. The colorants may be used alone or in combination thereof.The color difference ΔE*ab of the contact lens (e.g., a contact lens containing the organic colorant) before and after immersion when the contact lens is immersed in the contact lens treatment liquid (room temperature such as about 23°C) according to the embodiment of the present invention for 4 weeks is, for example, 5.0 or less, preferably 4.0 or less, more preferably 3.0 or less, still more preferably 2.5 or less.B. Method of treating Contact Lens and / or Storage Container thereforAccording to another aspect of the present invention, there is provided a method of treating a contact lens and / or a storage container therefor. The treatment method according to the embodiment of the present invention includes bringing the contact lens treatment liquid described in the section A into contact with a contact lens and / or a storage container therefor. With this configuration, dirt on the contact lens and / or the storage container therefor can be removed, and hence the contact lens and / or the storage container therefor can be cleanly managed. In addition, for example, a storage container to be used for daily care can be kept clean with the contact lens treatment liquid of the present invention.As a method of bringing the treatment liquid and the contact lens and / or the storage container therefor into contact with each other, there are given, for example: a method including immersing the contact lens and / or the storage container therefor in the treatment liquid filled in a treatment container; and a method including applying or spraying the treatment liquid to the contact lens and / or the storage container therefor. For example, the treatment liquid is filled in the storage container for the contact lens used as the treatment container, and the contact lens may be immersed therein. According to such method, the contact lens and the storage container therefor are simultaneously treated, a cleaning effect can be obtained, and a disinfecting effect can be further obtained.The contact conditions are not particularly limited as long as the effects of the present invention are obtained. The contact time period may be set to, for example, 1 minute or more, preferably 10 minutes or more, more preferably 30 minutes or more, still more preferably 4 hours or more, 6 hours or more, 8 hours or more, or 10 hours or more, and may be set to, for example, 24 hours or less, preferably 20 hours or less, more preferably 18 hours or less. The temperature of the treatment liquid at the time of contact is, for example, from 0°C to 60°C, preferably from 5°C to 55°C, more preferably from 10°C to 50°C, or may be room temperature (23°C±5°C).The treatment method may include frequently treating the contact lens and / or the storage container therefor. Herein, the term "frequently treating (frequent treatment)" means that the number of times (frequency) of treatment is at least equal to or more than that of the special care of the related art. The frequent treatment may be treatment to be performed, for example, once a month or more, preferably once every 3 weeks or more, more preferably once every 2 weeks or more, still more preferably once a week or more (e.g., once every 2 days to 6 days or more or every day). The contact lens and / or the storage container therefor can be kept clean by the frequent treatment. Accordingly, the treatment method may be performed as the daily care of the contact lens and / or the storage container therefor. Specifically, the treatment as the daily care may be performed consecutively, such as every day or every time after wearing without the need of an interval for a predetermined period (e.g., a period of 3 days or more or 7 days or more). The storage container is, for example, a storage container for daily use. Herein, the term "storage container for daily use" means a storage container for storing the contact lens after being worn until being worn next time, and does not include a container dedicated to the special care. An interval after the contact lens is taken out from the "storage container for daily use" until the contact lens is stored in the "storage container for daily use" next time may be, for example, 48 hours or less, 24 hours or less, or 20 hours or less. As a material for forming the storage container, there are given, for example, resin materials, such as polypropylene, polystyrene, AS, ABS, acryl, and polycarbonate, and various commercially available products are available.In one embodiment, the treatment method includes bringing the contact lens and the contact lens treatment liquid into contact with each other in the storage container every time after wearing.The contact lens after the treatment may be worn, for example, after rinsing with a rinsing liquid. The rinsing liquid is not particularly limited, and, for example, a commercially available cleaning liquid and multipurpose solution (MPS) may be appropriately used as well as the tap water and saline. Alternatively, the contact lens after the treatment may be stored in the storage container filled with a solution different from the above-mentioned treatment liquid (e.g., commercially available preservation solution, MPS). Cleaning by digital rubbing may be performed before and after the contact with the treatment liquid as required.According to the treatment method, dirt, such as a protein or a lipid adhering to the contact lens and / or the storage container therefor, can be suitably removed by a simple operation. In addition, discoloration during treatment can be suppressed in a colored contact lens.C. Method of storing Contact LensAccording to another aspect of the present invention, there is provided a method of storing a contact lens using the contact lens treatment liquid described in the section A. In the method of storing a contact lens according to the embodiment of the present invention, the contact lens is typically stored in the contact lens treatment liquid described in the section A. Specifically, the storage of the contact lens may be performed in a state in which the contact lens is immersed in the treatment liquid filled in the storage container. The contact lens to be stored and the storage container are as described in the section B. The storage temperature is, for example, from 0°C to 60°C, preferably from 5°C to 55°C, and more preferably from 10°C to 50°C, or may be room temperature (23°C±5°C). The storage period may be set to, for example, 1 minute or more, preferably 10 minutes or more, still more preferably 30 minutes or more, even still more preferably 4 hours or more, 6 hours or more, 8 hours or more, or 10 hours or more, or may be set to, for example, 24 hours or less, preferably 20 hours or less, more preferably 18 hours or less. However, the storage period is not particularly limited to the above-mentioned period. For example, the storage period may be more than 24 hours, more than 48 hours, more than 72 hours, or more than 7 days, and the contact lens can be stored by being immersed in the treatment liquid for a long time period of 1 month, 3 months, 6 months, 1 year, or about 3 years.ExamplesThe present invention is specifically described below by way of Examples. However, the present invention is by no means limited to these Examples.<<Test Example 1: Preparation of Contact Lens Treatment Liquid>>Sodium hypochlorite was added to purified water in various addition amounts, and a pH adjuster (sodium hydroxide, sodium hydrogen carbonate, and / or sodium carbonate) was added thereto as required. Thus, contact lens treatment liquids having various pHs and sodium hypochlorite concentrations (w / v%) shown in Table 1 were obtained. The pHs were each measured with a pH meter (manufactured by Horiba, Ltd., F-15 or F-73) at about 22°C.<<Test Example 2: Lens Discoloration Evaluation Test 1>>10 Milliliters of each of the contact lens treatment liquids prepared in Test Example 1 was filled into a contact lens storage container (manufactured by Menicon Co., Ltd., "Progent vial"), and then a contact lens to be described below was immersed in the liquid and stored at about 22°C for 4 weeks under a state in which the container was lidded. During the storage, the contact lens treatment liquid was replaced with a fresh one once every 2 weeks. Color spaces (L*, a*, b*) of the lens were measured before and after the immersion treatment for 4 weeks, and a color difference ΔE*ab thereof before and after the treatment was calculated from the measured values. The results are shown in FIG. 1. In FIG. 1, the marks "○", "◇", and "□" indicate that the color difference ΔE*ab is 4.0 or less, more than 4.0 and 5.0 or less, and more than 5.0, respectively.<Contact Lens>Name: Lens (L) for left eye of Menicon Ortho-K (containing an anthraquinone-based dye, and having a color space before the immersion treatment of L*=86.36±0.99, a*=-9.91±0.97, and b*=-4.00±0.76)Specification: F.K. / T.P. / B.C. / Power / Dia. / =40.25D / -3.00D / 9.25 mm / +0.75D / 11.00 mm<Method of measuring Color Space>The color space of the lens was measured with a non-contact imaging spectrophotometer (X-Rite, Incorporated, "MetaVue VS3200"). Specifically, the lens serving as a measurement object was placed on White Backing Card (PantoneLIVE) so that a BC surface was arranged on an upper side. The resultant was set at the center of the non-contact imaging spectrophotometer. A sample stage of the non-contact imaging spectrophotometer was adjusted to a height of 0 mm, and the measurement was performed at a measurement diameter of 2 mm.As shown in FIG. 1, the color difference ΔE*ab of the contact lens treated with the following contact lens treatment liquid was 5.0 or less: when the concentration of a hypochlorite was represented by X w / v% and the pH of the treatment liquid was represented by Y, the X and the Y satisfied the relationship of Y≧2.28X+10.46. Further, the color difference ΔE*ab of the contact lens treated with the contact lens treatment liquid in which the X and the Y satisfied the relationship of Y≧2.28X+10.73 was 4.0 or less, and thus discoloration of the lens was suitably suppressed. The color difference ΔE*ab=5.0 is such a level that the colors are recognizable to be substantially the same when compared over time.<<Test Example 3: Lens Discoloration Evaluation Test 2>>Sodium hypochlorite and potassium bromide were added to purified water in various addition amounts, and a pH adjuster (sodium hydroxide, sodium hydrogen carbonate, and / or sodium carbonate) was added thereto as required. Thus, contact lens treatment liquids (Comparative Examples 1 and 2) having pHs and sodium hypobromite concentrations (w / v%) shown in Table 2 were obtained.A reaction formula in each of the contact lens treatment liquids is as described below, a hypobromite ion (BrO-) and a hydroxide ion may function as main active components.NaClO+KBr → Na++ClO-+K++Br-→ Na++BrO-+K++Cl-The same immersion treatment for 4 weeks as that of Test Example 2 was performed except that the above-mentioned contact lens treatment liquids (Comparative Examples 1 and 2) and treatment liquids (Examples 1 and 2) obtained by adding potassium chloride to the treatment liquids of No. 2-2 and No. 5-5 of Test Example 2 in amounts equal to those of potassium chloride in Comparative Examples 1 and 2 were used, and the color difference ΔE*ab of the lens before and after the immersion treatment for 4 weeks was determined. The results are shown in Table 2. The treatment liquids of Example 1 and Comparative Example 1 have the same hypohalite concentration (in terms of sodium hypochlorite and sodium hypobromite) and pH, and the treatment liquids of Example 2 and Comparative Example 2 have the same hypohalite concentration (in terms of sodium hypochlorite and sodium hypobromite) and pH. A discoloration-suppressing effect was evaluated by the following criteria.<Evaluation Criteria for Discoloration-suppressing Effect>○: The color difference ΔE*ab is 5.0 or less.×: The color difference ΔE*ab is more than 5.0.As shown in Table 2, in the case where each of the hypohalite concentration and the pH was adjusted to the same value, discoloration of the lens was suppressed in the contact lens treatment liquid of a single-liquid type containing a hypochlorite ion as a main component than in the contact lens treatment liquid containing a hypobromite ion as a main component. In addition, it was recognized that potassium chloride was added to the treatment liquids of Examples 1 and 2 in amounts equal to those of potassium chloride in the treatment liquids of Comparative Examples 1 and 2 as described above, and hence potassium chloride did not have any influence on the above-mentioned results. The results were different from the prediction based on the common general technical knowledge that the oxidization action and bleaching action of the hypochlorite were stronger than those of the hypobromite. In addition, when the above-mentioned discoloration evaluation test 2 was performed while the hypohalite concentration and the pH were adjusted to the same values, that is, 0.14 w / v% and 11.7, respectively, a lens discoloration-suppressing effect obtained by the treatment with the contact lens treatment liquid having a hypochlorite ion as a main component was about three times as high as that obtained in the case of the treatment with the contact lens treatment liquid having a hypobromite ion as a main component (specifically, the color difference ΔE*ab was about 1 / 3).<<Test Example 4: Dirt Removal Test 1>>Contact lens treatment liquids having various sodium hypochlorite concentrations (0.005 w / v%, 0.006 w / v%, 0.007 w / v%, 0.008 w / v%, and 0.010 w / v%) and each having a pH of 10.5 were prepared in the same manner as in Test Example 1. The following dirt removal treatment was performed with the respective contact lens treatment liquids as test liquids. A lens after the treatment was observed with a stereoscopic microscope (Olympus, "SZX16"), and its image was picked up with a digital camera for a microscope (Olympus, "DP26"). The observed image is shown in FIG. 2.In addition, the observed image was processed with image processing software (Sweday, "JustTLC"), and a V / P value was calculated. Methods for the image processing and the calculation of the V / P value were all in accordance with the reference (Hiraoka et al. Japanese Journal of Ophthalmology, 65: 855-863 (2021)). The results are shown in FIG. 3. In FIG. 3, the V / P value of each of the test liquids is a relative value when the V / P value of an untreated dirt adhesion lens is set to 100. The V / P value is a brightness value per unit pixel. The V / P value may also include a flaw on the lens, but a high V / P value would mean a large dirt adhesion amount.<Dirt Removal Treatment>(1) Lysozyme, mucin, and lecithin were caused to artificially adhere to a Menicon Ortho-K lens in accordance with the reference (Sumide et al., Journal of Japan Contact Lens Society, 61: 18-21 (2019)) to prepare a dirt adhesion lens.(2) The dirt adhesion lens was immersed in 3 mL of each of the test liquids, and was left to stand still at about 22°C for 4 hours.(3) After the rinsing of the lens with distilled water, the lens was dried by removing water droplets with a blower.As shown in FIG. 2, the contact lens treatment liquid having a sodium hypochlorite concentration of 0.008 w / v% exhibited an excellent dirt-removing effect, and the contact lens treatment liquid having a sodium hypochlorite concentration of 0.010 w / v% exhibited an extremely excellent dirt-removing effect.In addition, as shown in FIG. 3, the contact lens treatment liquid having a sodium hypochlorite concentration of 0.008 w / v% had a V / P value reduced to less than 10%, and the dirt was almost completely removed. In addition, the contact lens treatment liquid having a sodium hypochlorite concentration of 0.010 w / v% had a V / P value reduced to 3.1, which is almost equivalent to that of a fresh lens, and exhibited a sufficient dirt-removing effect.<<Test Example 5: Dirt Removal Test 2>>Contact lens treatment liquids having various sodium hypochlorite concentrations (0.006 w / v% and 0.007 w / v%) and each having a pH of 10.5 were prepared in the same manner as in Test Example 1. Dirt removal treatment, pick-up of the observed image of a lens after the treatment, and calculation of a V / P value (n=2) were performed in the same manner as in the dirt removal test 1 except that: the resultant contact lens treatment liquid was used as a test liquid; and the immersion time period of the dirt adhesion lens in the test liquid was set to 16 hours. The results are shown in FIG. 4.As shown in FIG. 4, the contact lens treatment liquid having a sodium hypochlorite concentration of 0.006 w / v% or 0.007 w / v% exhibited an excellent dirt-removing effect. A lens treated with such treatment liquid had a V / P value reduced to less than 2%, and dirt was removed to the same level as a fresh lens.As can be seen from the above-mentioned results, according to the contact lens treatment liquid of the first embodiment of the present invention, an adverse effect on the contact lens (e.g., deterioration such as discoloration) due to long-time and frequent treatment is suppressed, and hence, for example, an effect in which there is no need to separately perform daily care and special care (as a result, a daily care article and a special care article can be united) or an effect in which there is no need to perform strict time management at the time of special care can be obtained. In addition, as a result of the foregoing, convenience of contact lens care can be improved.The contact lens treatment liquid according to one embodiment of the present invention can suppress discoloration, and is excellent in dirt-removing effect, and hence long-term immersion (storage) and frequent treatment can be performed on a contact lens. As described above, the daily care and the special care can be united, and hence the convenience of contact lens care can be improved. The contact lens treatment liquid of the present invention may be suitably used in treatment of the contact lens and the storage container therefor, such as cleaning treatment and disinfecting treatment, or storage thereof.

Claims

1. A contact lens treatment liquid of a single-liquid type, comprising: a hypochlorite; and water, wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii): 0.001≦X≦0.41 (i); Y≦11.9 (ii); and Y≧2.28X+10.46 (iii).

2. The contact lens treatment liquid according to claim 1, wherein the X and the Y further satisfy at least one of the following formulae (v), (vi), and (vii): X≧0.006 (v); Y≦11.7 (vi); and Y≧2.28X+10.73 (vii).

3. The contact lens treatment liquid according to claim 1, wherein the X further satisfies the following formula (viii): X≧0.008 (viii).

4. The contact lens treatment liquid according to claim 1, wherein the hypochlorite includes at least one kind selected from sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite.

5. The contact lens treatment liquid according to claim 1, further comprising a pH adjuster.

6. The contact lens treatment liquid according to claim 5, wherein the pH adjuster contains a compound having a pKa of from 9 to 13.

7. The contact lens treatment liquid according to claim 5, wherein the pH adjuster contains at least one kind selected from a carbonic acid buffering agent, a boric acid buffering agent, a phosphoric acid buffering agent, a citric acid buffering agent, an acetic acid buffering agent, an epsilon-aminocaproic acid buffering agent, an aspartic acid buffering agent, and a silicic acid buffering agent.

8. The contact lens treatment liquid according to claim 7, wherein the carbonic acid buffering agent contains at least one kind selected from sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate.

9. The contact lens treatment liquid according to claim 5, wherein the pH adjuster contains at least one kind selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate.

10. The contact lens treatment liquid according to claim 1, wherein the contact lens treatment liquid is used for treating a hard contact lens.

11. The contact lens treatment liquid according to claim 1, wherein the contact lens treatment liquid is used for treating a contact lens containing an organic colorant.

12. The contact lens treatment liquid according to claim 11, wherein the organic colorant contains at least one kind selected from an anthraquinone-based dye, an azo-based dye, and a phthalocyanine-based dye.

13. The contact lens treatment liquid according to claim 1, wherein the contact lens treatment liquid is used for treating a specialty contact lens.

14. The contact lens treatment liquid according to claim 1, wherein the contact lens treatment liquid is used for treating an orthokeratology lens, a hard contact lens for keratoconus, or a scleral lens.

15. The contact lens treatment liquid according to claim 1, wherein the contact lens treatment liquid is used for performing daily care.

16. The contact lens treatment liquid according to claim 1, wherein the contact lens treatment liquid is substantially free of any other hypohalite than the hypochlorite.

17. A contact lens treatment liquid of a single-liquid type, comprising: a hypochlorite; and water, wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii): 0.001≦X≦0.41 (i); Y≦11.9 (ii); and Y≧2.28X+10.46 (iii), and wherein a color difference ΔE*ab of a contact lens before and after immersion in the contact lens treatment liquid at room temperature for 4 weeks is 5.0 or less.

18. A method of treating a contact lens and / or a storage container therefor, comprising bringing the contact lens treatment liquid of any one of claims 1 to 17 into contact with a contact lens and / or a storage container therefor.

19. The method of treating a contact lens and / or a storage container therefor according to claim 18, wherein the method is performed as daily care of the contact lens and / or the storage container therefor.

20. The method of treating a contact lens and / or a storage container therefor according to claim 18, comprising bringing the contact lens and the contact lens treatment liquid into contact with each other in the storage container every time after wearing.

21. The method of treating a contact lens and / or a storage container therefor according to claim 18, wherein the storage container is a storage container for daily use.

22. The method of treating a contact lens and / or a storage container therefor according to claim 18, wherein the contact lens treatment liquid and the contact lens and / or the storage container therefor are brought into contact with each other for a time of from 4 hours to 18 hours.

23. The method of treating a contact lens and / or a storage container therefor according to claim 18, wherein the contact lens is a hard contact lens.

24. The method of treating a contact lens and / or a storage container therefor according to claim 18, wherein the contact lens contains an organic colorant.

25. A method of treating a contact lens and / or a storage container therefor, comprising frequently treating a contact lens and / or a storage container therefor with a contact lens treatment liquid, wherein the contact lens treatment liquid is a contact lens treatment liquid of a single-liquid type, wherein the contact lens treatment liquid includes a hypochlorite and water, and wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii): 0.001≦X≦0.41 (i); Y≦11.9 (ii); and Y≧2.28X+10.46 (iii).

26. A method of storing a contact lens, comprising using the contact lens treatment liquid of any one of claims 1 to 17.

27. A method of storing a contact lens, comprising immersing a contact lens in a contact lens treatment liquid for a long time period, wherein the contact lens treatment liquid is a contact lens treatment liquid of a single-liquid type, wherein the contact lens treatment liquid includes a hypochlorite and water, and wherein, when a concentration of the hypochlorite is represented by X w / v% and a pH of the contact lens treatment liquid is represented by Y, the X and the Y satisfy the following formulae (i) to (iii): 0.001≦X≦0.41 (i); Y≦11.9 (ii); and Y≧2.28X+10.46 (iii).

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