JPH07248476A - Agent for contact lens - Google Patents

Abstract

PURPOSE:To obtain an agent for contact lens having proper viscosity to completely clean a contact lens in a short period of time, and moreover, having excellent stability of pH. CONSTITUTION:This agent for contact lens contains at least one kind of methylvinylether-maleic acid anhydride copolymers selected from methylvinylether-maleic acid anhydride copolymer, ring-opening product of methylvinylether-maleic acid anhydride copolymer, and salt of ring-opening product of methylvinylether-maleic acid anhydride copolymer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an agent for contact lenses. More specifically, it relates to a contact lens agent that can be suitably used as, for example, a cleaning agent for contact lenses, a preservative solution for contact lenses, and the like.

[0002]

2. Description of the Related Art Conventionally, as a component for imparting a builder effect for improving the cleaning efficiency of contact lenses and a cushioning effect for preventing damage to contact lenses, polyvinyl alcohol and hydroxyethyl cellulose have been used in contact lens agents. BACKGROUND ART Surfactants have been used as a component for removing thickeners such as methyl cellulose, sodium alginate, and sodium carboxymethyl cellulose, lipids attached to contact lenses, and proteins.

However, when the contact lens is washed or stored by using a contact lens cleaning and preserving solution to which a surfactant is added, and the surfactant is not completely removed, the conjunctiva is worn when the contact lens is worn. Disorders such as hyperemia of blood, cloudiness of the cornea, and peeling of the corneal epidermis may occur. In particular, when the contact lens cleaning preservative solution is used for a contact lens having a water absorbing property such as hydroxyethyl methacrylate as a main component, the cleaning preservative solution is impregnated into the contact lens, which may cause various problems. There is.

For the purpose of solving such a risk, Japanese Patent Laid-Open No.
JP-A-2-70812 proposes an agent for contact lenses to which an isobutylene-maleic anhydride copolymer is added. When such an agent for contact lenses is used, the contact lens can be thoroughly washed in a short time and has an appropriate viscosity, which is useful as a thickener.

However, since the isobutylene-maleic anhydride copolymer is usually insoluble in water having a pH below neutral and having a low pH, an aqueous solution of sodium hydroxide, aqueous ammonia or the like is used for dissolution at about 90 ° C. Had to heat up. Further, some isobutylene-maleic anhydride copolymers have been given water solubility by previously subjecting them to an alkali treatment or the like, but when such a compound is used, the pH after dissolution in water is gradually increased. The pH stability was not sufficient.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art and has an appropriate viscosity for completely cleaning a contact lens in a short time, and has a stable pH. It is intended to provide an excellent agent for contact lenses.

[0007]

DISCLOSURE OF THE INVENTION The present invention is directed to a methyl vinyl ether-maleic anhydride copolymer, a methyl vinyl ether-maleic anhydride copolymer ring-opening product and a methyl vinyl ether-maleic anhydride copolymer ring-opening product. The present invention relates to an agent for contact lenses, which comprises at least one methyl vinyl ether-maleic anhydride copolymer of the product salt.

[0008]

ACTIONS AND EXAMPLES As described above, the contact lens agent of the present invention comprises a methyl vinyl ether-maleic anhydride copolymer, a methyl vinyl ether-maleic anhydride copolymer ring-opening product and a methyl vinyl ether-
It contains at least one methyl vinyl ether-maleic anhydride copolymer of a salt of a ring-opening product of a maleic anhydride copolymer, and has an appropriate viscosity for cleaning a contact lens, that is, a viscosity of 1 to 50,000 cP (2
(5 ° C.), it is easily dissolved in water over a wide pH range, and has excellent pH stability over a long period of time. In addition, in the present invention, the viscosity of the agent for contact lens is 1 to 1000 cP, especially 1 to 1000 cP.
It is preferably 100 cP (25 ° C.).

The methyl vinyl ether-maleic anhydride copolymer has the formula:

[0010]

[Chemical 1]

The repeating unit represented by the formula:

[0012]

[Chemical 2]

It is a copolymer having a repeating unit represented by:

If the ratio of methyl vinyl ether and maleic anhydride constituting the methyl vinyl ether-maleic anhydride copolymer (methyl vinyl ether / maleic anhydride: molar ratio) is too high, the ratio of methyl vinyl ether is too large. However, it tends to be difficult to obtain a contact lens agent having a desired cleaning property, and maleic anhydride does not polymerize alone, and the proportion of methyl vinyl ether is 50 mol% or more. 1,
Especially preferred is 5/5 to 7/3.

The ring-opened product of the methyl vinyl ether-maleic anhydride copolymer is obtained by ring-opening the acid anhydride group of the methyl vinyl ether-maleic anhydride copolymer, and has the formula:

[0016]

[Chemical 3]

The repeating unit represented by the formula:

[0018]

[Chemical 4]

(Wherein R ¹ and R ² each independently represents a hydroxyl group, an amino group or an alkoxyl group) is a copolymer having a repeating unit. The alkoxyl group represented by R ¹ and R ² preferably has 1 to 4 carbon atoms.

The salt of the ring-opened product of the methyl vinyl ether-maleic anhydride copolymer is a salt obtained by ring-opening of the acid anhydride group of the methyl vinyl ether-maleic anhydride copolymer. formula:

[0021]

[Chemical 5]

A repeating unit represented by the formula:

[0023]

[Chemical 6]

(Wherein, X ¹ and X ² each independently represent an alkali metal atom, an ammonium group or a quaternary ammonium group) is a copolymer having a repeating unit. Typical examples of the alkali metal atom include sodium atom and potassium atom. Representative examples of the quaternary ammonium group include a dimethyldiphenylammonium group, a tetramethylammonium group, a triethylphenylammonium group and the like.

The ring-opened product of the above-mentioned methyl vinyl ether-maleic anhydride copolymer can be usually obtained by dissolving the methyl vinyl ether-maleic anhydride copolymer in, for example, water or alcohol. The salt of the ring-opened product can be obtained, for example, by neutralizing the ring-opened product with an alkali or the like. Therefore, depending on the solvent and liquid used, methyl vinyl ether-
The maleic anhydride-based copolymer can exist in various states in the formulation using a contact lens agent.

If the weight average molecular weight of the methyl vinyl ether-maleic anhydride type copolymer is too low, the viscosity tends to be small and the slipperiness may not be sufficiently exhibited. 10
It is preferably 000 or more, and when it is too high, the solubility in water tends to decrease, and it tends to become cloudy without being completely dissolved. Therefore, it should be 500,000 or less, especially 100,000 or less. Is preferred.

The content of the methyl vinyl ether-maleic anhydride copolymer in the agent for contact lenses depends on the type and molecular weight of the methyl vinyl ether-maleic anhydride copolymer used, but is too low. On the other hand, the viscosity is not sufficiently imparted, and the slipperiness and detergency tend not to be sufficiently exhibited.
It is desirable that the content is 005% by weight or more, preferably 0.01% by weight or more, and when it is too much, the resulting contact lens agent causes gelation, fluidity is lowered, and detergency is lowered. In addition, the filterability tends to decrease as well, so it is desirable that the content be 35% by weight or less, preferably 10% by weight or less, and more preferably 5% by weight or less.

If necessary, the agent for contact lenses of the present invention contains at least one compounding agent selected from a surfactant, a buffer, an isotonicity agent, a thickener, a chelating agent and a preservative. May be included.

The surfactant has a property of enhancing the cleaning effect of the contact lens agent.

Examples of the surfactants include anionic surfactants, nonionic surfactants, and anionic and nonionic surfactants. In the present invention, any of these surfactants can be used. A surfactant may be used.

Typical examples of the anionic surfactant include:
For example, sodium alkylsulfate, sodium alkylbenzenesulfonate, sodium alkyloylmethyltaurine, sodium alkyloylsarcosine, sodium α-olefinsulfonate, sodium polyoxyethylene alkyl ether phosphate, sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl. Examples thereof include sodium phenyl ether sulfate and sodium di (polyoxyethylene alkyl ether) phosphate. Among these, sodium alkyl sulfate, sodium alkylbenzenesulfonate, sodium α-olefinsulfonate, sodium polyoxyethylene alkyl ether sulfate, Sodium polyoxyethylene alkyl phenyl ether sodium sulfate shows excellent cleaning effect, When used in combination with a surface-active agent, an effective cleaning effect can be obtained by a short-time immersion storage.

The content of the anionic surfactant in the agent for contact lenses is 0.01% by weight or more, especially 0.0 in order to give a sufficient cleaning effect.
It is preferably 2% by weight or more. If the content of such an anionic surfactant is too high, the cleaning effect may not be so high, which may cause rough hands, so the content is 10% by weight or less, especially 5% by weight or less. Preferably.

Typical examples of the nonionic surfactants include higher alkylamine polyethylene glycol adducts, higher fatty acid amide polyethylene glycol adducts, higher fatty acid polyglycerin esters, higher fatty acid polyethylene glycol esters, and higher fatty acids. Polyalkylene glycol, polyethylene glycol copolymer ester, polyhydric alcohol ester of higher fatty acid polyethylene glycol, higher alcohol polyethylene glycol ether, higher alcohol polyglycerin ether, alkylphenol polyethylene glycol ether, alkylenephenol polyethylene glycol ether Formaldehyde condensate, polypropylene glycol-polyethylene glycol copolymer, Esters, castor oil, hydrogenated castor oil, polyethylene glycol sorbitan alkyl esters, polyethylene glycol adducts of sterols and the like. Of these, polyethylene glycol ethers of higher alcohols, polyethylene glycol esters of higher fatty acids, polyglycerin esters of higher fatty acids, polyethylene glycol ethers of alkylphenols, and polyethylene glycol sorbitan alkyl esters are preferable because they exhibit excellent cleaning effects.

The content of the nonionic surfactant in the contact lens preparation is 0.01% by weight or more, especially 0.0 in order to give a sufficient cleaning effect.
It is preferably 2% by weight or more. If the content of such a nonionic surfactant is too high, the cleaning effect will not be so high, which may cause rough hands, so the content is 10% by weight or less, especially 5% by weight or less. Preferably.

When the anionic surfactant and the nonionic surfactant are used in combination, the contents of the anionic surfactant and the nonionic surfactant are within the above-mentioned ranges and the total amount is 0. 0.02 to 20% by weight,
It is particularly preferably 0.05 to 10% by weight.

The buffering agent maintains the pH of the obtained contact lens agent within a range of 5.0 to 9.0, which is close to that of tear fluid, and suppresses the pH change due to external factors when washing or storing. It has the property of protecting the shape and optical properties of the contact lens.

Typical examples of the buffering agent include boric acid and its sodium salt, phosphoric acid and its sodium salt,
Examples thereof include ophthalmophysiologically acceptable buffers such as citric acid and its sodium salt, lactic acid and its sodium salt, amino acids such as glycine and glutamic acid and its sodium salt, and malic acid and its sodium salt.

The content of the buffer in the contact lens preparation is 0.01 mol / l or more, particularly 0.05 mol / l in order to give a sufficient buffering effect.
It is preferably 1 or more. If the content of such a buffering agent is too high, the buffering effect will not be so high and the shape of the contact lens will be affected, such as increasing the osmotic pressure.
It is preferably 1 or less, especially 0.15 mol / l or less.

The isotonicity agent is used to adjust the osmotic pressure of the obtained contact lens agent to that of tear fluid (280 to 300 mOs).
/ Kg), and has the property of maintaining the shape of the contact lens when washed and stored.

Representative examples of the tonicity agent include ophthalmophysiologically acceptable inorganic salts such as sodium chloride, potassium chloride and calcium chloride, and the buffering agent.

The content of the isotonicity agent in the agent for contact lenses is 0.01 mol / l or more, especially 0.05 mol / l in order to impart a sufficient osmotic pressure.
It is preferably 1 or more. If the content of such isotonicity agent is too high, the osmotic pressure will be high, which will affect the shape of the contact lens, so 0.5 mol / l or less, especially 0.15 Mol /
It is preferably 1 or less.

The above-mentioned thickening agent has a property of providing a good feeling during washing and protecting the contact lens from the external physical force during washing or storage.

Typical examples of the above-mentioned thickeners include polyvinyl alcohol, poly-N-vinylpyrrolidone, polyacrylamide and its hydrolysates, polyacrylic acid, xanthan gum, hydroxyethyl cellulose, carboxymethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxy. Propyl cellulose, methyl cellulose, sodium alginate, polyethylene glycol, gelatin, sodium chondroitin sulfate,
Ophthalmophysiologically acceptable viscous bases such as gum arabic and gar gum are mentioned.

The content of the above-mentioned thickening agent in the agent for contact lenses is 0.01% by weight or more, in order to sufficiently protect the contact lens applied during washing or storage of the contact lens from external stress. 0.
It is preferably set to 02% by weight or more. If the content of such a thickening agent is too high, the obtained contact lens agent tends to gel and the washability and storability tend to deteriorate, so that the content is 10% by weight or less, especially 5% by weight. The following is preferable.

The chelating agent has a property of preventing deposition of contact lens agent or calcium contained in the attached tear fluid on the contact lens.

Typical examples of the chelating agent include ethylenediaminetetraacetic acid and its sodium salt,
Examples include phytic acid and citric acid.

The content of the chelating agent in the agent for contact lenses is 0.001 mol / l or more, especially 0.0015 mol / l or more in order to sufficiently prevent calcium and the like from depositing on the contact lens. Is preferred. When the content of the chelating agent is too large, the improvement of the effect due to the inclusion of more than that is small, which is uneconomical.
It is preferably 0.1 mol / l or less, especially 0.05 mol / l or less.

The preservative has the property of preventing the contact lens preparation from being contaminated with bacteria, and preventing the contact lens from being contaminated with bacteria during washing or storage.

Typical examples of the above preservatives include phenylmercury-based preservatives such as phenylmercuric nitrate and phenylmercuric acetate; benzalkonium chloride, pyridinium bromide,
Surfactant-based preservatives such as chlorohexidine and polyhexamethylene biguanide; alcohol-based preservatives such as chlorobutanol; thimerosal; methylparaben, propylparaben, bronopol, dimethyloldimethylhydantoin, imidazolium urea and the like.

The content of the above-mentioned preservative in the contact lens preparation is 0.00001% by weight or more, in particular, in order to sufficiently prevent the contact lens from being contaminated by bacteria during washing or storage. 000
It is preferably set to 03% by weight or more. If the content of such an antiseptic is too large, it may cause damage to the eyes if such an antiseptic enters the eyes directly, or depending on the type of antiseptic. Since there is a tendency that the specifications and properties of the contact lens may be adversely affected, it is preferably 0.5% by weight or less, particularly 0.3% by weight or less.

The surfactants, buffers, tonicity agents, thickeners, chelating agents and preservatives may be used alone or in admixture of two or more.

The agent for contact lenses of the present invention can be prepared, for example, in the form of an aqueous solution or granules.

For example, in the case of an aqueous solution, a methyl vinyl ether-maleic anhydride copolymer is added to a predetermined amount of purified water, and if necessary, a surfactant, a buffer, an isotonicity agent, a thickener, It can be obtained by adding at least one compounding agent selected from chelating agents and preservatives, thoroughly mixing and stirring to dissolve, and filtering.

In the case of granules, each of the above-mentioned components is made into a fine powder, mixed and stirred in purified water, and further, if necessary, an excipient is added and kneaded. Next, it is obtained by passing through a mesh and then heating and drying. At the time of use, the granules are dissolved in a predetermined amount of purified water before use and used as an aqueous solution.

Further, the agent for contact lenses of the present invention includes
In addition to the above, guanidine, an aqueous bond breaking agent such as urea,
Salts exhibiting a salt-dissolving effect such as sodium thiocyanate may be added.

Next, the contact lens agent of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1 0.5 g of a methyl vinyl ether-maleic anhydride copolymer (weight average molecular weight: about 40,000) was added to about 50 m of purified water.
1 and dispersed at room temperature for about 2 hours to obtain a homogeneous solution. The pH of the obtained solution was adjusted to about 7 by adding a 0.1 N sodium hydroxide aqueous solution, and sodium alkylbenzenesulfonate 0.5 was added as an anionic surfactant.
g was added to bring the total volume to 100 ml.

The viscosity (25 ° C.) of the prepared solution was measured with a B type viscometer, and the solution was allowed to stand at 40 ° C. for 1 month,
The pH before and after that was measured with a glass electrode type pH meter (HORI
BApH METER F-13 (manufactured by Horiba Ltd.) was used to measure the change. The results are shown in Table 1.

In addition, the above solution was used to randomly select 1
0 men and women were asked to wash the contact lens (manufactured by Menicon Co., Ltd., trade name Menicon EX) for 30 seconds, and the washability was evaluated. As a result, all 10 persons evaluated that the cleanability was good.

Further, using the above-mentioned solution, the detergency of the contact lens having artificial eye oil adhered thereto was examined as follows.

Sorbitan monooleate 6% by weight, castor oil 16% by weight, lanolin 35% by weight, oleic acid 5% by weight, sorbitan trioleate 4% by weight, cetyl alcohol 2% by weight, cholesterol 2% by weight and cholesterol acetate 30% by weight. % Of artificial eye oil was dissolved in a mixed solvent of ethanol and hexane (weight ratio 1: 1) to prepare a 2.5% artificial eye oil solution. 3 μl of this 2.5% artificial eye oil solution was adhered to the surface of a contact lens (manufactured by Menicon Co., Ltd., trade name Menicon EX) and then dried to prepare a dirty contact lens.

Ten pieces of the soiled contact lenses were washed with the above solution for 30 seconds, and the washing power was evaluated. As a result, the stains were completely removed from all the 10 soiled contact lenses, and the cleaning power of such a solution against eye oil was large.

As described above, it was found that the above-mentioned solution can easily and completely clean the contact lens in a short time.

Example 2 5.0 g of methyl vinyl ether-maleic anhydride copolymer (weight average molecular weight: about 20000) was dispersed in about 60 ml of 0.5N sodium hydroxide aqueous solution and heated in a water bath at 90 ° C. until dissolved. Then, it was dissolved in about 15 minutes, and a homogeneous solution could be obtained. To the obtained solution, 0.5 g of sodium α-olefinsulfonate as an anionic surfactant was added, about 30 ml of purified water was added, and the pH was adjusted to about 7 with 0.5N aqueous sodium hydroxide solution. Purified water was added to bring the total volume to 100 ml.

The viscosity (25 ° C.) of the resulting solution and the change in pH of the solution were examined in the same manner as in Example 1.
The results are shown in Table 1.

Further, using the above-mentioned solution, the detergency of 10 men and women and the detergency against eye oil were examined in the same manner as in Example 1. As a result, all 10 persons evaluated that the cleanability was good, and the stains were completely removed from all the 10 soiled contact lenses, and the cleansing power of the solution against eye oil was large. . As described above, it was found that the solution can easily clean the contact lens in a short time and completely.

Example 3 0.5 g of methyl vinyl ether-maleic anhydride copolymer (weight average molecular weight: about 20,000) was dispersed in about 60 ml of 0.05N aqueous sodium hydroxide solution, and heated in a water bath at 90 ° C. until dissolved. Then, it was dissolved in about 10 minutes. 0.5% of polyoxyethylene alkylphenyl ether sulfate as an anionic surfactant was added to the obtained solution.
g, 0.5 g of polyoxyethylene (20) sorbitan monooleate as a nonionic surfactant and about 30 ml of purified water were added and dissolved, and the pH was adjusted to about 7 using 0.05N sodium hydroxide aqueous solution. Then, purified water was added to bring the total volume to 100 ml, and a homogeneous washing liquid was obtained.

The viscosity (25 ° C.) of the obtained solution and the change in pH of the solution were examined in the same manner as in Example 1.
The results are shown in Table 1.

Further, using the above solution, the detergency and the detergency against eye oil by 10 men and women were examined in the same manner as in Example 1. As a result, all 10 persons evaluated that the cleanability was good, and the stains were completely removed from all the 10 soiled contact lenses, and the cleansing power of the solution against eye oil was large. . As described above, it was found that the solution can easily clean the contact lens in a short time and completely.

Example 4 0.5 g of methyl vinyl ether-maleic anhydride copolymer (weight average molecular weight: about 20,000) was added to about 50 m of purified water.
1 and dispersed at room temperature for about 3 hours to obtain a homogeneous solution. The pH of the obtained solution was adjusted to about 7 by adding a 0.1 N sodium hydroxide aqueous solution, and sodium alkylbenzenesulfonate 0.5 was added as an anionic surfactant.
g, ethylenediaminetetraacetic acid as a chelating agent 0.1
g and 0.01 g of methylparaben as a preservative were added and dissolved to make the total amount 100 ml.

The viscosity (25 ° C.) of the obtained solution and the change in pH of the solution were examined in the same manner as in Example 1.
The results are shown in Table 1.

Further, using the above-mentioned solution, the detergency of 10 men and women and the detergency against eye oil were examined in the same manner as in Example 1. As a result, all 10 persons evaluated that the cleanability was good, and the stains were completely removed from all the 10 soiled contact lenses, and the cleansing power of the solution against eye oil was large. . As described above, it was found that the solution can easily clean the contact lens in a short time and completely.

Example 5 5.0 g of a methyl vinyl ether-maleic anhydride copolymer (weight average molecular weight: about 20,000) and 2.0 g of polyvinyl alcohol as a thickener were dispersed in about 60 ml of a 0.5N sodium hydroxide aqueous solution, When heated in a water bath at 90 ° C. until dissolved, it was dissolved in about 15 minutes, and a homogeneous solution could be obtained. To the obtained solution, 0.5 g of sodium α-olefinsulfonate as an anionic surfactant and 0.5 g of boric acid as a buffer were added,
About 30 ml of purified water was added, the pH was adjusted to about 7 with 0.5N aqueous sodium hydroxide solution, and then purified water was added to make the total amount 100 ml.

The viscosity (25 ° C.) of the resulting solution and the change in pH of the solution were examined in the same manner as in Example 1.
The results are shown in Table 1.

Further, using the above solution, the detergency and the detergency against eye oil by 10 men and women were examined in the same manner as in Example 1. As a result, all 10 persons evaluated that the cleanability was good, and the stains were completely removed from all the 10 soiled contact lenses, and the cleansing power of the solution against eye oil was large. . As described above, it was found that the solution can easily clean the contact lens in a short time and completely.

Comparative Example 1 0.5 g of isobutylene-maleic anhydride copolymer (weight average molecular weight: about 180,000) was dispersed in 100 ml of purified water and heated in a water bath at 90 ° C. until dissolved.
It did not dissolve.

Comparative Example 2 0.5 g of isobutylene-maleic anhydride copolymer (weight average molecular weight: about 180,000) was dispersed in about 60 ml of 0.05N aqueous sodium hydroxide solution, and the mixture was allowed to stand at room temperature for about 3 hours, but it was dissolved. There wasn't.

Comparative Example 3 0.5 g of a water-soluble type of isobutylene-maleic anhydride copolymer (weight average molecular weight: about 200,000) was dispersed in about 60 ml of purified water and heated in a water bath at 90 ° C. until dissolved. However, it dissolved homogeneously in about 20 minutes. After dissolution, 0.5 g of polyoxyethylene alkylphenyl ether sulfate as an anionic surfactant, 0.5 g of polyoxyethylene (20) sorbitan monooleate as a nonionic surfactant and about 30 ml of purified water were added and dissolved. Then, adjust the pH to about 7 with 0.05N aqueous sodium hydroxide and add purified water to bring the total volume to 1
It was set to 00 ml.

The viscosity (25 ° C.) of the resulting solution and the change in pH of the solution were examined in the same manner as in Example 1.
The results are shown in Table 1.

In addition, Table 1 also shows the time required for dissolution as the solubility and the difference between the pH immediately after the preparation of the solution and the pH after the solution was left at 40 ° C. for 1 month.

[0081]

[Table 1]

From the results shown in Table 1, in Examples 1 to 5, the contact lens preparation can be rapidly prepared, and the obtained contact lens preparation has a viscosity of about 4 to 30 cP. It can be seen that the change in pH is extremely small even when it is stored for a long period (one month).

[0083]

The agent for contact lenses of the present invention has an appropriate viscosity for completely cleaning contact lenses in a short time, and has excellent pH stability.

When the agent for contact lenses of the present invention contains a surfactant, such an agent for contact lenses has appropriate viscosity and slipperiness, so that the contact lens can be easily and quickly produced. And it can be completely washed.

Claims (4)

[Claims] 1. At least one salt of a methyl vinyl ether-maleic anhydride copolymer, a ring-opening product of a methyl vinyl ether-maleic anhydride copolymer and a ring-opening product of a methyl vinyl ether-maleic anhydride copolymer. An agent for contact lenses, which comprises the methyl vinyl ether-maleic anhydride copolymer. 2. The agent for contact lenses according to claim 1, wherein the content of the methyl vinyl ether-maleic anhydride copolymer is 0.005 to 35% by weight. 3. The agent for contact lenses according to claim 1, wherein the content of the methyl vinyl ether-maleic anhydride copolymer is 0.01 to 5% by weight. 4. The composition according to claim 1, 2 or 3 containing at least one compounding agent selected from a surfactant, a buffer, an isotonicity agent, a thickener, a chelating agent and an antiseptic. Agent for contact lenses.