KR20010043298A - Plasma surface treatment of silicone hydrogel contact lenses - Google Patents

Abstract

The present invention is plasma treated, hydrated, and heated when viewed in a 50 × 50 micron square AFM image, the surface being adjusted to be a silicate containing film having a nitrogen-enriched, enclosed mosaic-like protrusion plate compared to the lens prior to plasma treatment. A process involving sterilization is performed on the lens surface to provide an optically transparent and hydrophilic coating on the silicone hydrogel lens.

Description

Plasma surface treatment method of silicon hydrogel contact lens {PLASMA SURFACE TREATMENT OF SILICONE HYDROGEL CONTACT LENSES}

Contact lenses made of silicon-containing materials have been studied for many years. Such materials can generally be divided into two main classes, hydrogels and non-hydrogels. Non-hydrogels do not absorb significant amounts of water, while hydrogels can absorb and contain water at equilibrium. Regardless of its water content, non-hydrogel and hydrogel silicone contact lenses tend to have relatively hydrophobic and non-wetting surfaces.

Those skilled in the art have long recognized the need to modify the surface of such silicon contact lenses to suit the eye. It is known that increased hydrophilicity of the contact lens surface improves the wettability of the contact lens. In other words, it is related to the improved wearing comfort of contact lenses. In addition, the surface of the lens can affect the ease of infection of the lens for deposition, especially for deposition of proteins and lipids from tears during lens wearing. Deposited deposits can cause discomfort or even inflammation. In the case of an extended wear lens, the surface is particularly important because it is designed to be very comfortable to wear for a long time without having to remove the lens every day before going to bed. Thus, the regimen of use of a continuous wearing lens will not require a day's time to recover the eye from any discomfort or possible side effects of wearing the lens.

Silicon lenses have been subjected to plasma surface treatment to improve the properties of their surfaces, for example providing modified properties such as improved hydrophilicity, deposition resistance, scratch resistance, and the like. Conventional published plasma surface treatments include inert gas or oxygen on the contact lens surface (see, eg, US Pat. Nos. 4,055,378; 4,122,942; and 4,214,014); Various hydrocarbon monomers (see, eg, US Pat. No. 4,143,949); And plasma treatments comprising combinations of water and oxidants such as ethanol and hydrocarbons (see, eg, WO 95/04609 and US Pat. No. 4,632,844). U.S. Patent No. 4,312,575 (Peyman et al.) Discloses an electrical incandescent light discharge (plasma) process performed by applying a hydrocarbon atmosphere to a lens and then adding oxygen to the lens during flow discharge to increase the hydrophilicity of the lens surface. A method of providing a barrier coating on a urethane lens is disclosed.

Although such surface treatments disclose methods of modifying the surface properties of silicone contact lenses, the results have been problematic and questionable for commercial use, which is undoubtedly the commercialization of silicone hydrogel contact lenses. It has been the cause of failure. For example, US Pat. No. 5,080,924 (Kamel et al.) Describes that such treatment is only temporary, although exposing the subject surface to plasma discharge with oxygen increases the wettability or hydrophilicity of such surface.

Although the prior art has attempted to show that surface treatment of contact lenses can be achieved in the non-hydrated state, there is little or no discussion about the possible effects on successive process or production steps in the surface treatment of lenses, There is no teaching or detail description of the surface properties of a fully processed hydrogel lens made for practical wear. Similarly, there is little or no published information.

Accordingly, there is a need to provide an optically transparent silicone hydrogel contact lens, a hydrophilic surface film that exhibits improved wettability as well as generally enables the use of the silicone hydrogel contact lens in the human eye for continuous periods of time. In the case of silicone hydrogel lenses for continuous wear, it would be highly desirable to provide a contact lens having a surface that exhibits high permeability to oxygen and water. Such treated lenses, when used in practice, are convenient to wear and allow continuous wearing of the lenses without irritation or other adverse effects on the cornea. It would be desirable if such a surface treated lens was a product with commercially viable commercial use.

The present invention relates to a surface treatment method of a silicone hydrogel contact lens. In particular, the present invention relates to a method of modifying the surface of a contact lens to increase the wettability of the lens and to reduce the ease of infection of proteins and lipids in use. The surface is treated to form a silicate containing surface film or coating having a mosaic-shaped protruding plate surrounded by spaces or gaps, where the surface is viewed as a 50x50 square micron AFM image: (i) the peak to valley distance in the gap is averaged. About 100 to 500 mm 3, (ii) plate protection is on average about 40% to 99%, and (iii) nitrogen element analysis results are about 6.0 to 10.0%, where nitrogen is measured by XPS analysis at a predetermined depth If at least 10% relative to the lens surface prior to the plasma treatment.

1 is a flowchart of a lens manufacturing production method having a lens coating according to the present invention.

Figure 2 is an atomic force microscope (AFM) topographical image (50x50 microns) showing a plasma treated lens prior to further processing of extraction, hydration and sterilization according to the present invention.

FIG. 3 is presented for comparison, atomic force microscopy (AFM) phase image (50 × 50 micron) showing a plasma treated lens (completely processed) hydrated and autoclaved after only 4 minutes or a lens made equivalent to the lens of FIG. Which represents a relatively smooth surface with a barely visible plate and about 20% surface protection.

4 is an atomic force microscope (AFM) phase image (50 × 50 microns) showing a plasma treated lens extracted with isopropanol and showing 50% surface protection prior to autoclaving.

FIG. 5 shows an atomic force microscope (AFM) showing a plasma treated lens (completely processed) hydrated and autoclaved according to the present invention, after about 8 minutes per surface, according to the conditions of Example 1 Phase image (50x50 microns). All AFM images are for dried samples.

Summary of the Invention

The present invention relates to a silicone hydrogel lens with a silicate containing surface film having a mosaic-shaped protruding plate surrounded by spaces or gaps, which, when viewed in a 50x50 square micron AFM (Atomic Force Microscopy) image, (i) peak to gap The distance (or average depth) of the valleys is about 100 to 500 mm on average, (ii) on average about 40% to 99% on plate protection, and (iii) about 6.0 to 10.0% on nitrogen element analysis, with nitrogen Is concentrated to at least 10% relative to the lens surface prior to plasma treatment when measured by XPS analysis at a predetermined depth. The present invention also relates to a method of modifying the surface of a contact lens in order to increase the wettability of the lens and to increase the resistance to deposition formation when worn. Surface films can be prepared by oxidizing plasma treatment of the lens under suitable plasma conditions following hydration and autoclaving.

Detailed description of the invention

As mentioned above, the present invention relates to a silicone hydrogel contact lens having a silicate containing coating and a method of making the lens, wherein the coating improves the hydrophilicity and lipid / protein resistance of the lens. Thus, the silicate containing coating allows the lens to be worn on the eye for more than 24 hours at a time for a continuous period of time, which may not be worn comfortably on the eye.

Although silicone hydrogel lenses can be plasma treated in a non-hydrated state, such lenses are swelled continuously by solvent extraction and hydration, unlike their non-hydrogel lenses, which substantially changes the dimensions of the lens after coating. You can. In fact, depending on the ultimate moisture content of the lens, hydration may cause the lens to swell up to about 10 to about 20% or more. In addition to swelling of the lens during solvent extraction and hydration, continuous autoclaving of the hydrated lens (a common form of sterile lens during packaged lens manufacture) has been found to substantially affect the lens surface modified with plasma. The present invention relates to a surface modified silicone hydrogel lens having a silicate containing coating that exhibits desirable coating properties even after extraction, hydration, and autoclaving.

Especially the surface of a silicone hydrogel contact lens containing from 5 to 50% by weight of bulk at least one silicone macromonomer, from 5 to 75% by weight of at least one polysiloxaneylalkyl (meth) acrylic monomer, and from 10 to 50% by weight of lactam containing monomer Provides a silicate containing coating that represents a mosaic-like relatively flat plate, surrounded by a relatively narrow space or gap, wherein (i) the plate provides an average of about 40% to 99% surface protection, and (ii ) The gap has an average peak to valley distance of about 100 to 500 mm 3, and (iii) the results of nitrogen element analysis are about 6.0 to 10.0%, which is measured on the lens surface before plasma treatment when measured by XPS analysis at a predetermined depth. At least 10% of the nitrogen is concentrated. These coating properties of the fully processed lens after surface treatment, hydration and sterilization can be viewed and observed by viewing the surface under an AFM (Atomic Force Microscopy) image in a 50x50 square micron image.

The present invention is applicable to a wide range of silicone hydrogel contact lens materials. Hydrogels are generally known types of materials, including hydrated and crosslinked polymer systems containing water at equilibrium. Silicone hydrogels generally have a water content of at least about 5% by weight, and more generally from about 10 to about 80% by weight. Such materials are generally prepared by polymerizing mixtures containing at least one silicon-containing monomer and at least one hydrophilic monomer. Typically, as a crosslinking agent (crosslinking agent is defined as a monomer having a multi-polymerizable functional group), one or a separate crosslinking agent of a silicon-containing monomer or a hydrophilic monomer functional group can be used. Applicable silicon-containing monomer units used in the formation of silicone hydrogels are known in the art and many embodiments are described in US Pat. Nos. 4,136,250, 4,153,641, 4,740,533, 5,034,461, 5,070,215, 5,260,000. 5,310,779 and 5,358,995.

Examples of applicable silicon-containing monomer units include large polysiloxaneylalkyl (meth) acrylic monomers. Examples of large polysiloxaneylalkyl (meth) acrylic monomers are represented by the following formula (1).

Where

X represents -O- or NR-;

R ₁₈ independently represents hydrogen or methyl;

R ₁₉ is independently lower alkyl radical, phenyl radical or Wherein each R _{19 '} independently represents lower alkyl or phenyl radicals;

h is 1 to 10.

Some preferred macromonomers are methacryloxypropyl tris (trimethyl-siloxy) silane or tris (trimethylsiloxy) silylpropyl methacrylate (sometimes called TRIS), and tris (trimethylsiloxy) silylpropyl vinyl carbamate ( Sometimes referred to as TRIS-VC).

Representative silicon-containing monomers of other kinds include 1,3-bis [4- (vinyloxycarbonyloxy) but-1-yl] tetramethyl-disiloxane; 3- (trimethylsilyl) propyl vinyl carbonate; 3 (vinyloxycarbonylthio) propyl- [tris (tributylsiloxy) silane]; 3- [tris (trimethylsiloxy) silyl] propyl vinyl carbamate; 3- [tris (trimethylsiloxy) silyl] propyl allyl carbamate. 3- [tris (trimethylsiloxy) silyl] propyl vinyl carbonate; t-butyldimethylsiloxyethyl vinyl carbonate; Trimethylsilylethyl vinyl carbonate; And silicon-containing vinyl carbonate or vinyl carbamate monomers such as trimethylsilylmethyl vinyl carbonate.

Silicon-containing vinyl carbonate or vinyl carbamate monomers are represented by formula (2).

Where

Y 'represents -O-, -S- or -NH-;

R ^Si is a silicon-containing organic radical;

R ₂₀ represents hydrogen or methyl;

d is 1,2,3 or 4; q is 0 or 1;

Suitable silicon-containing organic radicals R ^Si include the following formulas.

— (CH ₂ ) _{n ′} Si [(CH ₂ ) _{m ′} CH ₃ ] ₃ ;

— (CH ₂ ) _{n ′} Si [OSi (CH ₂ ) _{m ′} CH ₃ ] ₃ ;

; And

ego,

Where R ₂₁ is Wherein p 'is 1 to 6;

R ₂₂ is alkyl radical or fluoroalkyl radical having 1 to 6 carbon atoms;

e is 1 to 200; n 'is 1,2,3 or 4; m 'is 0,1,2,3,4 or 5.

Examples of certain kinds of formula II are represented by formula III.

Another kind of silicon-containing monomer is a polyurethane-polysiloxane macromonomer (also sometimes referred to as a prepolymer), which may have hard-soft-hard blocks such as conventional urethane elastomers. They may be end-capped with hydrophilic monomers such as HEMA. Examples of such silicone urethanes are disclosed in various documents, including Lai, Yu-Chin, "The Role of Bulky Polysiloxanylalkyl Methacryates in Polyurethane-Polysiloxane Hydrogels" Journal of Applied Polymer Science, Vol. 60, 1193-1199 (1996). . International Publication No. WO 96/31792 discloses examples of such monomers, which are hereby incorporated by reference in their entirety. Moreover, examples of silicone urethane monomers are represented by the formulas (IV) and (V).

E (* D * A * D * G) _a * D * A * D * E '; or

E (* D * G * D * A) _a * D * G '* D * E';

Where

D represents alkyl diradical, alkyl cycloalkyl diradical, cycloalkyl diradical, aryl diradical or alkylaryl radical, having 6 to 30 carbon atoms;

G is alkyl diradical, cycloalkyl diradical, alkyl cycloalkyl diradical, aryl diradical or alkylaryl diradical having 1 to 40 carbon atoms, which may include ether, thio or amine bonds in the main chain;

* Means a urethane or ureido bond;

a is at least 1;

A means the divalent polymerizable radical of formula VI:

Where

Each R _S independently represents an alkyl or fluoro-substituted alkyl group having 1 to 10 carbon atoms, wherein it may comprise an ether bond between the carbon atoms;

m 'is at least 1;

p is a number that provides between 400 and 10,000 moiety weights;

Each E and E 'independently represents a polymerizable unsaturated organic radical represented by Formula VII:

Where

R ₂₃ is hydrogen or methyl;

R ₂₄ is hydrogen, alkyl radicals having 1 to 6 carbon atoms or —CO—YR ₂₆ radicals, wherein Y is —O—, —S— or —NH—;

R ₂₅ is a divalent alkylene radical having 1 to 10 carbon atoms;

R ₂₆ is alkyl radicals having 1 to 12 carbon atoms;

X represents -CO- or -OCO-;

Z represents -O- or -NH-;

Ar represents an aromatic radical having 6 to 30 carbon atoms;

w is 0 to 6; x is 0 or 1; y is 0 or 1; And z is 0 or 1.

Examples of more specific silicon-containing urethane monomers are represented by the formula VIII.

Wherein m is at least 1 and preferably 3 or 4, a is at least 1 and preferably 1, p is a number providing from 400 to 10,000 part weight, preferably at least 30, and R ₂₇ is Diradical of diisocyanate after isocyanate group removal, such as diradical of isophorone diisocyanate, and each E " Is represented by.

As pointed out above, the silicone hydrogel material may comprise 5 to 50% by weight, preferably 10 to 25% by weight, at least one polysiloxaneylalkyl (meth) acryl at least one silicone macromonomer (in bulk, ie in the copolymerized monomer mixture). 5 to 75% by weight of monomers, preferably 30 to 60% by weight, and 10 to 50% by weight, preferably 20 to 40% by weight, of hydrophilic monomers which are lactam containing monomers such as vinyl lactams such as N-vinyl pyrrolidone %, Wherein% is based on the hydrogel polymer material. Lactam containing monomers are known to have a relatively low critical surface tension in hydrophilic monomers. While not wishing to be bound by theory, the relatively low critical surface tension of N-vinyl pyrrolidone and other lactams (relatively less different from silane monomers and macromonomers) results in a controlled amount of layer, resulting in a concentrated silicone It is believed that a layer is formed at the surface of the lens after casting, and a nitrogen-rich layer is formed at a sufficiently close distance to the surface, so that the nitrogen-rich layer is exposed after gap formation and autoclaving sterilization of the lens surface during manufacture. .

The exposed nitrogen enrichment layer is advantageous because it is believed not only because of the hydrophilicity that facilitates comfort, but also because the enrichment of nitrogen contributes to improved interfacial adhesion, which will contribute to the permanence of the silicate containing coatings.

However, additional hydrophilic monomers used in silicone hydrogels in lesser proportions have significantly higher critical surface tensions, including unsaturated carboxylic acids such as methacrylic acid and acrylic acid; Acrylic substituted alcohols such as 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate; Acrylamides such as methacrylamide and N, N-dimethylacrylamide; Vinyl carbonate or vinyl carbamate monomers as disclosed in US Pat. No. 5,070,215 and oxazolone monomers as disclosed in US Pat. No. 4,910,277. Other hydrophilic monomers will be apparent to those skilled in the art.

Generally silicone macromonomers are poly (organosiloxanes) capped with unsaturated groups at two or more ends of the molecule. In addition to the end groups in the above structural formula, US Pat. No. 4,153,641 (Deichert et al.) Discloses additional unsaturated groups including acryloxy or methacryloxy. Preferably the silane macromonomer is silicon-containing vinyl carbonate or vinyl carbamate or polyurethane-polysiloxane having at least one hard-soft-hard block and end capped with a hydrophilic monomer.

Preferably the lens material used in the present invention is not fluorinated or has relatively few fluorine atoms. Although it has been pointed out that fluorination of any monomer used in the formation of silicone hydrogels reduces deposit deposits on contact lenses made therefrom, heavily fluorinated materials are silicates according to the invention because of their unique chemical properties. It cannot be used to prepare a containing coating. The present invention is also not applicable to fumarate siloxane hydrogel compositions according to US Pat. No. 5,420,324. While not wishing to be bound by theory, it is believed that the surface silicon content of the fumaride siloxane lens is too high to form a sufficiently flexible silicate material, so that the silicate surface formed by the oxidizing plasma treatment becomes so glassy that it is assumed to be thin during the continuous process. . The silicon content of the surface layer to be treated may be the result of the bulk chemistry of the composition, including its hydrophobic and hydrophilic portions, and / or the surface layer formation phenomenon that results in a relatively concentrated layer for different monomers or elements.

While not wishing to be bound by theory, the necessary coatings (in coatings fully processed by the present invention) have sufficient silicate content to provide the necessary surface properties such as wettability and deposition resistance, and sufficient polymer content is sufficient during swelling. It is believed that sufficient interface is aggregated during heat sterilization to allow flexibility and to prevent thin layers. In addition, the relative balance of hydrophilic and hydrophobic portions in the coating can affect the coating's resistance to thin layers during thermal and hydrodynamic expansion or compression. In general, the hydrodynamic expansion of hydrogels in water is a function of the form and amount of hydrophilic polymer content; Thermal expansion is a function of the silicone polymer content. As the former increases, the latter decreases or vice versa.

Thus, the chemical function of the silicate containing coating or film in the final product is not completely silicate, and some of the raw material may remain in modified form. In general, however, in coatings formed by plasma treatment, the material's original polymeric properties are changed to more glass-like hard materials.

To determine the applicability of certain silicone hydrogel materials of the present invention, the lens can be processed under two broad reverse plasma conditions, firstly "low temperature low speed" plasma treatment and secondly "high temperature high speed" plasma treatment. According to the plasma treatment step, hydration, and heat sterilization (so-called "whole process"), the silicate coating can be obtained, so that some additional process condition adjustments can achieve the lens coating with the surface properties according to the invention. . In general, "low temperature slow" surface treatments tend to be relatively more effective for relatively higher silicon containing lenses; "High temperature high speed" surface treatment is relatively more effective for relatively lower silicon containing lenses. "Low temperature, low speed" surface treatment refers to conditions designed to relatively minimize the collapse of covalent bonds during relatively short, high pressure, low wattage, and substrate modifications, thus leaving more polymer at the coating interface with the lens material. . Exemplary "low temperature low speed" conditions of plasma treatment (plasma chambers, such as those used in the following examples) are performed in an air / water / peroxide atmosphere (bubbles gas through an 8% hydrogen peroxide solution in HPLC grade water). 100 to 300 sccm (standard cubic centimeters per minute) at 0.3 to 0.6 torr, 100 watts for 1 to 2 minutes per side. By “high temperature high speed” treatment is meant a condition designed to relatively maximize wattage, low pressure, long time, surface modification. Exemplary “hot high speed” conditions of plasma treatment are from 0.1 to 0.4 torr, 400 watts for 10 minutes per side, at 200 to 500 sccm under the above described atmosphere. The presence of the silicate containing coatings may be characterized by a perceptible or statistically significant change in surface roughness (RMS), a change in visibility in surface morphology as evidenced by AFM, such as the formation of a surface plate, or by a pre-treated lens with a fully processed lens. This can be demonstrated by showing statistically significant differences in the XPS data and apparent differences in oxygen and / or silicon content (including the shape of the silicate peaks) in comparison. In a preferred test of coating formation, the oxygen content of 1-5% changes with 95% confidence. As described above, if any silicate coating in a fully processed (after hydration and heat sterilization) lens can be formed by either "low temperature slow" processing conditions or "high temperature high speed" processing conditions, a continuous process without unnecessary experimentation Adjustments generally yield coatings according to the invention, which will be understood by those skilled in the art. It should be noted that the formation of silicate coatings following plasma treatment is not an applicability test, as a continuous thin layer may occur during heat sterilization so that no coating will be seen as a fully processed lens.

Manufacture of lens

The contact lenses according to the present invention can be made into any shape with the necessary rear and front lens surfaces using various conventional techniques. Spin casting methods are disclosed in US Pat. Nos. 3,408,429 and 3,660,545, preferred acid static casting methods are disclosed in US Pat. Nos. 4,113,224 and 4,197,266. Curing of the monomer mixture often follows processing operations to provide a contact lens with the required final placement. For example, US Pat. No. 4,555,732 discloses that an excess of monomer mixture is cured by spincasting in a mold to form some form of material having a relatively large thickness with the front lens surface. The backside of the cured spincast material is continuously lathed to provide a contact lens with the required thickness and lens backside. Further machining operations follow lathe cutting of the lens surface, for example edge finishing operations.

Figure 1 shows a series of manufacturing process steps for the static casting of a lens, the first step being cutting (1), which is based on a given lens design, and the metal cutting machine is a conventional machining and polishing It is assembled by operation. These metal cutters are then used in injection or compression casting to produce a number of thermoplastic molds that are used in turn to cast the required lenses from the polymerizable composition. Thus, a set of metal cutting machines can produce many thermoplastic molds. The thermoplastic mold may be arranged after molding of one lens. Thereafter, the metal mold assembled during cutting (1) is subjected to the front casting (2) and the back casting to produce the front mold portion for forming the required front lens surface and the rear lens mold portion for forming the required rear lens surface, respectively. It is used in (3), respectively. Subsequently during the casting 4 the monomer mixture 5 is injected into the front mold, and the back mold is pressed and joined at a predetermined pressure to form the required lens shape. The bonded mold can be cured by exposure to ultraviolet or other energy sources for a period of time, preferably by moving the mold through the curing chamber, after which the contactor is removed.

After preparing the lens with the required final shape, it is desirable to remove residual solvent from the lens before edge finishing. Organic diluents are usually included in the initial monomer mixture to minimize phase separation of the polymerization product produced by polymerization of the monomer mixture and to lower the glass transition temperature of the reaction polymerization mixture, which is acceptable for a more efficient curing process and ultimately more uniform. Poorly polymerized product. The sufficiently uniform initial monomer mixture and polymerization product is due to the inclusion of silicon-containing monomers which are particularly relevant for silicone hydrogels and which may tend to separate from the hydrophilic comonomer. Suitable organic diluents are, for example, C ₆ -C ₁₀ straight-chain lipid family monohydric alcohols such as n-hexanol and n-nonanol as monohydric alcohols; Diols such as ethylene glycol; Polyols such as glycerin; Ethers such as diethylene glycol monoethylene ether; Ketones such as methyl ethyl ketone; Esters such as methyl enanthate; And hydrocarbons such as toluene. Preferably the organic diluent is sufficiently volatile to facilitate removal from the material cured by evaporation at or about ambient pressure. Diluents are generally contained in 5 to 60% by weight of the monomer mixture, with 10 to 50% by weight being particularly preferred.

The cured lens is then solvent removed 6, which can be achieved by evaporation at or near ambient pressure or under vacuum. The temperature can be raised to reduce the time required to evaporate the diluent. The time, temperature and pressure conditions for the solvent removal step will depend on such factors as the diluent and volatility of the particular monomer component and can be readily determined by one skilled in the art. According to a preferred embodiment, the temperature used in the removal step is preferably at least 50 ° C, such as 60 to 80 ° C. A series of heating cycles in a linear oven under inert gas or vacuum can be used to optimize solvent removal efficiency. The cured material after the diluent removal step comprises 20 wt% or less, preferably 5 wt% or less of the diluent.

After removing the organic diluent, the lens is removed and suitably mechanically processed 7 according to the embodiment of FIG. 1. The mechanical processing step includes, for example, polishing and polishing the lens edges and / or surfaces. In general, such a mechanical machining process can be carried out before or after the article is separated from the mold. Preferably, the lens is dried from the mold by using vacuum tweezers to take the lens out of the mold, and then the rotating surface is used to move the lens to a second set of vacuum tweezers using mechanical tweezers and smooth the surface or edges. Lay about. The lens is then flipped over to process the opposite side of the lens.

Following the mold separation / machining operation 7, the lens is surface treated 8, preferably using an oxidized RF plasma treatment of the lens surface using an oxygen-containing gas. Plasma treatment includes passing electrical discharges through the gas at low pressure. Although microwaves and other frequencies may be used, electrical discharge is usually done at the radio frequency (typically 13.56 MHz). This electrical discharge is absorbed by atoms and molecules in the gaseous state to form a plasma that interacts with the surface of the contact lens.

In the prior art, oxidized plasmas such as O ₂ (oxygen gas), water, hydrogen peroxide, air and the like or mixtures thereof have been used to form radical and oxidative functional groups to etch the lens surface. Such oxidants are known to impart more hydrophilicity to the silicon lens surface, but the bulk of the silicon material may remain apparent on the lens surface and become apparent after a relatively short period of use. For example, if the oxidation is relatively surface area, the silicon chains adjacent to the lens surface can be moved and / or rotated, thus exposing hydrophobic groups to the outer surface even on a fully extracted polymer. Oxidized surfaces may also lose coating due to thin layers during additional process steps, including autoclaving. In contrast, the plasma conditions of the present invention are adjusted to achieve the required ablation and oxidation formulation of the surface material based on careful quality control of the coating result. A relatively thick coating is ultimately created as it is a permanent barrier between the underlying silicon material and the outer lens surface.

The plasma for surface modification of the lens is initiated by low energy discharge. Collisions between active free electrons present in the plasma cause ions, excited molecules, and free radical formation. Such species, once formed, react not only with themselves in the gas phase but also with the ground state molecules. Plasma treatment can be understood as an energy dependent process including active gas molecules. If a chemical reaction occurs on the surface of the lens, it requires the species (element or molecule) required in terms of charged state and particle energy. Radio frequency plasma typically provides a distribution of active species. Typically "particle energy" refers to the so-called Boltzmann type energy distribution on average for active species. In low density plasma, the electrical energy distribution can be related to the ratio of the electric tension (E / p) that sustains the plasma to the discharge pressure. The plasma power density P is a function of the amount of watts, the pressure, the gas flow rate, etc. and will be understood by those skilled in the art. Basic information on plasma technology is incorporated herein by reference, including: A.T. Bell Proc. Intl. Conf. Phenom. Ioniz. Gases, "Chemical Reaction in Nonequilibrium Plasmas", 19-33 (1977); J. M. Tibbitt, R. Jensen, A. T. Bell, M. Shen, Macromolecules, "A Model for the Kinetics of Plasma Polymerization", 3, 648-653 (1977); J. M. Tibbitt, M. Shen, A. T. Bell, J. Macromol. Sci.-Chem., "Structural Characterization of Plasma-Polymerized Hydrocarbons", A10, 1623-1648 (1076); C. P. Ho, H. Yasuda, J. Biomed, Mater. Res., "Ultrathin coating of plasma polymer of methane applied on the surface of silicone contact lenses", 22, 919-937 (1988); H. Kobayashi, A. T. Bell, M. Shen, Macromolecules, "Plasma Polymerization of Saturated and Unsaturated Hydrocarbons", 3, 277-283 (1974); R.Y. Chen, US Pat. No. 4,143,949, March 13, 1979. "Process for Putting a Hydrophilic Coating on a Hydrophobic Contact lens"; And H. Yasuda. H.C. Marsh, M.O.Bumgarner, N. Morosoff, J. of Appl.Poly.Sci., "Polymerization of Organic Compounds in an Electroless Glow Discharge.VI. Acetylene with Unusual Comonomers", 19, 2845-2858 (1975).

Based on the prior art in the field of plasma technology, it is possible to understand the effect of changing the pressure and discharge power according to the plasma reforming ratio. In general, the ratio decreases with increasing pressure. Thus, as the pressure increases the value of E / p, the ratio of the periodic tension holding the plasma to the gas pressure decreases and causes a decrease in the average electrical energy. The decrease in electrical energy in turn leads to a decrease in the proportional coefficient during the entire electron-molecular collision process. As a further consequence of the pressure increase, the electron density decreases. If the pressure is constant, the relationship between electron density and power should be linear.

In practice, the contact lens is placed in an electrical incandescent discharge reaction vessel (vacuum chamber) in a non-hydrated state for surface treatment. Such reaction vessels are commercially available. The lens may be supported in a container on an aluminum tray (acting as an electrode) or with another support device designed to fit the position of the lens. It is known in the art to use certain support devices that allow for both surface treatment of the lens and can be used in the present invention.

The gas used in the plasma treatment is suitably between 100 and 1000 watts, preferably between 200 and 800 watts, more preferably between 300 and 500 watts, for example at an electrical discharge frequency of 13.56 MHz, at 0.1 to 1.0 torr, for example air. Oxides such as water, peroxides, O ₂ (oxygen gas), or combinations thereof. The plasma treatment time is at least 4 minutes per side, preferably at least 5 minutes per side, more preferably about 6 to 60 minutes per side, most preferably about 8 to 30 minutes per side for effective and efficient production. to be. A relatively "strong" oxidation plasma may be present at this initial oxidation (e.g. 3 to 30% by weight, preferably 4 to 15% by weight, more preferably at a flow rate of 50 to 500 sccm, more preferably 100 to 300 sccm). Ambient air having passed through a solution of 5 to 10% by weight of hydrogen peroxide solution.

Such plasma treatment directly produces a relatively thick and smooth film that can approach the point where optical transparency is affected, i. Since a significant portion of the thickness may be lost during subsequent processing, the backside plasma coating thickness should preferably be greater than 1000 mm 3. As further mentioned below, after hydration and autoclaving, the surface is cracked and the thickness may be reduced by at least 50% of the initial coating thickness and may be reduced by at least 90%.

In order to obtain the required coatings, process parameters may need to be adjusted to obtain the ablation and glass molding formulations that produce the required coatings after further processing step runs. The thickness of the coating is sensitive to plasma flow rate and chamber temperature. Higher flow rates tend to cause more ablation, and lower pressures tend to produce thicker coatings in the plasma chamber. However, higher temperatures tend to produce surfaces that are not glassy and have poor adhesion.

Because the coating depends on various parameters, the optical parameters need some adjustment to obtain the required or optimal coating. If one parameter is adjusted, supplemental adjustment of one or more other parameters may be appropriate, so any trial and error method and extrapolation thereof may be necessary to obtain a coating according to the present invention. However, in the present disclosure and in the art plasma processing, adjustment of such process parameters should not include experiments that are unnecessary. As mentioned above, the general relationship between process parameters is known to those skilled in the art, and plasma processing techniques have recently been improved. The following examples provide Applicants' best method for forming coatings on silicone hydrogel lenses.

Following the surface treatment step 8 in the embodiment of FIG. 1, the lens can be extracted 9 to remove residue from the lens. In general, in the manufacture of contact lenses, some monomer mixtures do not fully polymerize. Incompletely polymerized material from the polymerization process can affect optical transparency or be harmful to the eyes. Residual material may contain additives that may have been removed from solvents not completely removed by pre-solvent removal operations, unreacted monomers from monomer mixtures, oligomers present as by-products from the polymerization process, or molds used to mold lenses. It may include.

Conventional methods for extracting such residual material from polymerized contact lens materials include extracting with an alcohol solution for several hours (for hydrophobic residue extraction) followed by extraction with water (for hydrophilic residue extraction). Thus, some alcoholic extraction solutions remain in the polymerized network of polymerized contact lens materials and must be extracted from the lens material prior to wearing the lens safely and comfortably on the eyes. Extraction of alcohol from the lens can be accomplished using water heated for several hours. Incomplete extraction of residues from the lens can adversely affect lens use, so extraction should be as complete as possible. Such residues can also impact lens performance and comfort by hindering optical transparency or the required uniform hydrophilicity of the lens surface. It is important to choose an extraction solution that does not adversely affect the optical transparency of the lens in any way. Optical transparency is primarily understood as the level of transparency observed when the lens is illuminated in terms of visibility.

Following extraction (9), the lens is hydrated (10), at which time the lens is fully hydrated with water, buffered with saline, and the like. When the lens is ultimately fully hydrated (the lens can typically swell by more than 10 to about 20%), the coating is intact and attached to the lens to provide a durable hydrophilic coating that has been found to be resistant to thin layers.

After hydration 10, the lens may be subjected to a surface inspection 11, in which an experienced inspector inspects the contact lens for transparency and absence of defects such as holes, particles, bubbles, marks, torn gaps. . 10x magnification is desirable. After the lens has undergone a surface inspection 11 step, the consumer is ready to package 12 in a vial, plastic blister package, or other container to keep the lens sterile. Finally, the packaged lens is sterilized (13), which can be done in conventional autoclave sterilization, an air pressure sterilization cycle is preferred, and sometimes means an air-vapor mixing cycle, as will be appreciated by those skilled in the art. The autoclave sterilization is preferably performed at 100 ° C. to 200 ° C. for 10 to 120 minutes. After sterilization, the lens dimensions of the sterilized lens should be checked before storage.

After the hydration and sterilization step, the silicate containing coating produced by the plasma treatment was modified into its final form, which appeared as a mosaic-shaped protruding plate surrounded by spaced gaps, similar in appearance to nearby islands surrounded by rivers. When viewed on a 50x50 square micron image with an atomic force microscope, (i) the distance (depth) of the peak to valley of the gap is on average about 100 to 500 Å, and (ii) on average about 40% to 99% on the plate protection (surface protection). And (iii) the result of elemental nitrogen analysis is about 6.0 to 10.0%, where it is at least 10% concentrated relative to the surface of the lens previously treated with plasma when measured by XPS analysis at a previously measured depth. . The depth of the gap can be considered by "coating thickness" measurement, where the gap exposes the underlying hydrogel material at the silicate-containing, glass-like coating load. Preferably, the peak to valley distance of the gap is preferably about 150 to 200 mm 3 on average, and the plate protector is on average about 50% to 99%, more preferably 60% to 99%. Preferably, according to the XPS measurement process described in the examples below, the results of nitrogen element analysis are about 7.0 to 9.0%, wherein at least 20% of the concentration is concentrated on the lens surface prior to plasma treatment, more preferably 7.5% nitrogen Greater, with 25% nitrogen enrichment greater.

The term "average" means a statistical mean value of the values measured for a plurality of selected lenses adjusted during the manufacture of a commercial product based on the average measurement of each lens in the optics field. Preferably the average value of each lens is calculated based on the evaluation of three 50 × 50 square micron images per side of each lens, as in the following examples. The term “controlled manufacturing” or “controlled process” means that the manufactured product is continuously manufactured and quality controlled to include an average value within a predetermined range in terms of gap depth and plate protection, or in a predetermined range of specifications. To be included within. The term persistence is preferably at least 70%, more preferably at least 80% and most preferably at least 90% of the manufactured lenses at the 95% confidence level meeting the required ranges in terms of coating thickness and plate protection. It is to let. Preferably, the average value of the manufactured lens should be within the required range in terms of surface protection and coating thickness, at a 90% confidence level, more preferably at a 95% confidence level.

Example 1

This example discloses a representative silicone hydrogel lens material for use in the following examples. Material compositions are provided in Table 1 below.

ingredient Parts by weight TRIS-VC 55 NVP 30 V ₂ D ₂₅ 15 VINAL One n-nonanol 15 Darocure 0.2 Colorant 0.05

The following materials have been specified above:

TRIS-VC Tris (trimethylsiloxy) silylpropyl vinyl carbamate

NVP N-Vinyl Pyrrolidone

Silicon-containing vinyl carbonates described in US Pat. No. 5,534,604 before V ₂ D ₂₅

VINAL N-vinyloxycarbonyl alanine

Darocura Darocur-1173, ultraviolet initiator

Colorant 1,4-bis [4- (2-methacryloxyethyl) phenylamino] anthraquinone

Example 2

This embodiment describes a method of surface modification of a contact lens according to the present invention. The silicone hydrogel lens manufactured in the configuration of Example 1 is a casting cast from a polypropylene mold. Under an inert nitrogen atmosphere, 45 μl constructs are injected into a clean polypropylene concave half-frame and covered with a complementary polypropylene convex half-frame. The molds were pressed at a pressure of 70 psi and the mixture was cured for about 15 minutes in the presence of ultraviolet light (6-11 mW / cm ² as measured by spectroscopic UV meter). The template was further exposed to ultraviolet light for about 5 minutes.

The upper half mold was removed and the lens was kept at 60 ° C. for 3 hours in an enhanced air oven to remove n-hexanol. The lens edges were then relaxed rounded for 10 seconds at 2300 rpm with a strength of 60 g. The lens was then plasma treated as follows: The lens was placed on the aluminum coated tray with the concave side up and the tray placed in a plasma treated chamber. An air / H ₂ O / H ₂ O ₂ gas mixture was prepared by preparing the atmosphere by passing air through a 8% peroxide solution at 400 sccm into the chamber. The lens was plasma treated for 8 minutes (350 watts, 0.5 torr). Thereafter, the chamber was filled with ambient pressure. The tray was then removed from the chamber, the process was repeated to flip the lens and plasma treat the other side of the lens.

The lenses were analyzed directly after the whole process from the plasma chamber. The whole process involved plasma treatment followed by extraction, hydration and autoclaving. The extraction used isopropanol at room temperature for 4 hours (at least 48 hours after extraction for 4 hours at about 85 ° C. in water during commercial preparation). The lens was then immersed in buffered saline to hydrate the lens. Autoclave sterilization was carried out in a vial with a lens immersed in an aqueous packaging solution.

The plasma chamber was a direct current DC RFGD manufactured by Branson GaSonics Division (model 7104). The chamber was a cold equilibrium planar configuration with a maximum force of 500 watts. All lenses were prepumped in the chamber at 0.01 torr before any plasma treatment from the remaining air. This process reduced the relative treatment level of the polymer by adjusting the gas pressure.

In this study all lenses were analyzed as received. The lenses were analyzed dry before and after plasma. The fully processed lens was separated from the vial and desalted in HPLC grade water in static form for at least 15 minutes. Pre- and post-plasma three lens backsides and three lens fronts and each lot of fully processed lenses were analyzed by X-ray photoelectron spectroscopy (XPS).

XPS data was obtained by physical and electronic [PHI] model 5600 spectroscopy. To collect the data, the aluminum anode of the apparatus was operated at 300 Watts, 15 kV, and 20 mA. The Al Ka line was the excitation light monochromatic by the annular lens system. A 7 mm filament was used in the X-ray monochromator to focus on the X-ray source, which increases the need for charge cancellation through the use of neutralizers. The low pressure of the device was 2.0 x 10-10 torr, while it was 1.0 x 10-9 torr during operation. A hemispherical energy analyzer measures electron kinetic energy. The actual sample depth of the device is about 74 mm 3 at a sample angle of 45 ° for carbon. All elements were charged corrected to the CH _X peak of carbon binding energy of 285.0 eV.

Each plasma modified sample was analyzed by XPS using low resolution irradiation spectra [0-1100 eV] to identify elements present on the sample surface. High resolution spectra can be implemented on such elements detected from low resolution scans. Elemental composition was measured from the high resolution spectrum. The atomic composition was calculated from the area under the optoelectronic peak and the orbital cross section of interest after photosensitizing the area with the device's transfer function. Since XPS does not detect the presence of hydrogen or helium, these elements cannot be included in any atomic ratio calculation. Atomic composition data is shown in Table 2.

Example 1 Oxygen nitrogen carbon silicon Fluoride Before plasma AVG 18.6 6.2 64.7 10.5 0.0 STDEV 1.2 0.4 1.3 0.7 0.0 After plasma AVD 47.6 3.1 29.0 18.9 1.6 STDEV 1.3 0.2 1.3 0.3 0.1 Complete machining AVG 19.5 7.8 64.8 7.9 0.0 STDEV 0.8 0.3 0.9 0.3 0.0 Example 2 Before plasma AVG 18.0 6.0 65.2 10.8 0.0 STDEV 0.5 0.5 0.9 0.7 0.0 After plasma AVG 49.4 2.7 26.5 20.1 1.4 STDEV 1.5 0.3 2.0 0.9 0.2 Fully processed AVG 19.6 7.7 64.8 7.8 0.0 STDEV 0.3 0.3 0.8 0.7 0.0 Example 3 Before plasma AVG 18.1 6.0 66.8 9.1 0.0 STDEV 1.2 0.7 1.5 0.8 0.0 After plasma AVG 50.2 1.7 22.0 23.1 2.6 STDEV 1.3 0.3 1.9 1.0 0.5

Each experiment involved testing six lenses from lenses of sample product 50-100. The irradiation spectra for the pre-plasma lenses of Experimental Examples 1 to 3 include optoelectronic peaks representing oxygen, nitrogen, carbon and silicon. The silicon 2p _3/2 peak position (102.4 eV) indicated that the silicon detected on the surface was derived from the silicon derivative. The irradiation spectrum for the lenses after the plasma of Experimental Examples 1 to 3 includes photoelectron peaks representing oxygen, nitrogen, carbon and silicon and fluorine. Fluoride is a plasma ablation byproduct of Teflon runners that hold the trays used to hold the lenses. Silicon 2p _3/2 photoelectron peak position (103.7 eV) indicated that the silicon detected on the surface was derived from the silicate and varied the presence of the coating. As demonstrated, some differences in the different experimental elemental analyzes may arise from slight changes in plasma process parameters, chamber position, or as a result of the inherent surface properties of the lenses of a particular product.

In addition, atomic force microscopy (AFM) was used to study the shape of contact lens surfaces. AFM works by measuring the force in the nano range (10 ^-9 N) between a sharp needle and an atom at the lens surface. The saliva is raised onto the cantilever substrate. The deflection of the cantilever measured by the laser detection system is processed to yield the height information. While collecting the height information, the needles are lined on the xy plane to produce a three-dimensional phase image of the lens surface. In the optical region of each lens, three images were sampled on both sides of the lens.

The fraction of the lens surface protected by the coating is referred to as "plate protector" or "surface protector". This measurement is sometimes made easy by finding columnar plots of surface height. However, if the coating is too thin (<10 nm), the protection cannot be obtained from the columnar plot. In this case, the AFM image in question is compared with the previous AFM image where the correct guard is known. If this visible method is used, the guards are predicted and corrected within ± 10%.

FIG. 2 is an atomic force microscope (AFM) phase image showing a plasma treated lens prior to further processing by hydration and autoclaving. The image shows a lens coating with a smooth surface that is very similar in appearance to the surface before the plasma treatment (100% surface protection). This is because most plasma coatings are similar to conventional surfaces. Obviously, the surface is not completely smooth. The surface shows some fine multi-directional scratches with a cutting mark.

FIG. 3 is an atomic force microscopy (AFM) photograph showing a sterile sterile plasma treated lens (completely processed) after 4 minutes plasma treatment time per side for comparison with the lens surface according to the present invention, but comparable to the process conditions of this embodiment . The coating thickness is only 4 +/- 2 nm thick and only about 20% is protected. The colored part in the image represents the remarkable height of the surface. The brighter areas correspond to the raised shapes, while the darker areas correspond to the back shapes. In the image of FIG. 3, the covering is seen to split and fall into thin pieces, exposing the surface of the lens and thus showing a relatively smooth surface with a barely visible plate.

4 is an atomic force microscope (AFM) image of a plasma treated lens after extraction with isopropanol. The lens thickness is about 100 nm (which will be reduced during subsequent autoclave sterilization) and the surface protection is about 50%. Since the AFM image is made in a dry state, the surface protection of the extracted and fully processed lens is comparable.

FIG. 5 shows an atomic force microscope (AFM) phase image (50 × 50 square microns) showing a hydrated, autoclaved and plasma treated lens (completely processed in accordance with the present invention) after 8 minutes and a remarkable plate with good surface protection. )to be. The coating thickness is about 10 +/- 2 nm thick (100 mm 3) and has a surface protection of about 95%.

The average gap depth (also referred to as "coat thickness") of the sheath was measured directly with AFM software. The thickness of three to five islands (optionally selected) in each picture was measured and averaged to calculate the overall coating thickness for each image. Preferably the RMS roughness of a fully processed lens is about 50 nm or less, more preferably about 2 to about 25 nm, most preferably 5 to 20 nm.

This comparison indicates that, in addition to other parameters such as pressure or airflow velocity, plasma treatment time is an important control parameter during plasma processing to obtain the required coating.

Comparative Example 3

The silicone hydrogel lens of the Example 1 configuration was plasma treated for 4 minutes per side and used for clinical studies. Due to the variety of lens surface phases, some products are investigated using surface imaging by atomic force microscopy (AFM), where a 50 x 50 micron square image is made with a common lens area equal to 1.5 x 10 ⁸ square micron. In this case, a plate having a smooth surface was shown without proof of which plate. The thirteenth article examined the entire range of surfaces and was classified as "mosaic to transitional" (hereafter "mosaic") and "transitional to smooth" (hereafter "smooth"). About 42% of the lenses showed a smooth surface. The term "smooth" refers to a lens surface in the lens that does not represent a silicate plate surrounded by valleys or gaps, and is similar to nearby islands surrounded by rivers. The sleek lens also included a lens with a surface protection of less than 30% and a bone depth of more than about 50 microns. The mosaic lens had at least 30% protection and at least 50 mm bone depth.

To relate surface properties to clinical performance, lenses used in clinical studies were screened for the degree of deposition based on the information provided by the researchers included in the study. Grade levels corresponding to increasing levels of deposition through slit lamp analysis were 0-4. For Grade 0 and Grade 1, as the number of patients increases, one can remove the lens to test half of the grade for lipids and the rest for protein. As the number of lenses in grades 2, 3 and 4 is smaller, these lenses can be cut in half (using surgical scalpels and gloves) to test each lens for proteins and lipids. Data from these lenses was doubled to indicate deposition across the entire lens. The lenses were worn for 3 months with enzyme washing on the weekend of wear week and disinfection overnight with ReNu MPS solution. In some cases, the lens was removed before 3 months for some reason. In all other cases, the lenses were worn for the entire study period. After 3 months, all the lenses were shipped (dry) and stored in the refrigerator upon arrival.

In addition to correlating surface properties with deposition, protein and lipid analysis of the deposits were performed. Protein analysis was performed using a colorimetric BCA assay (Sigma). This method used a protein that reduces Cu (II) to Cu (I). After addition of biscinconic acid (BCA) to the reduced copper, a purple complex (A _MAX = 562 nm) was formed. Complex strength is shown to be directly proportional to the protein concentration range of 5 μm / ml to 2000 μm / ml. After incubation at 37 ° C., the rate of development of the color is sufficiently slowed so that many samples can be carried out in one operation. The standard protein solution used was BSA with a standard concentration range of 0-200 μg. The assay design is as follows:

1) To prepare the standard, the unweared lens is taken out of the vial, air dried and placed in a plastic centrifuge tube with a standard BSA solution. The wearing lens (also air dried) is placed in a centrifuge tube. A mixture of BCA / copper sulfate solution was added to the dry lens.

2) The tubes are then placed in a 37 ° C. water bath for 15 minutes. After incubation, a purple complex is produced.

3) Read samples and samples at 562 nm.

4) The protein concentration is then determined from the standard plot of absorbance versus concentration (μg).

5) The recorded protein results show the total amount of protein attached.

Gas chromatography (GC) is a method of determining total lipid concentration. Tripalmitin (C ₁₆ ) was used as a standard based on prior GC runs of lipids of C ₁₂ -C ₂₂ chain length all showing similar retention times. The stock solution of the standard was 1 mg / ml of tripalmitin in methylene chloride and the concentration range of the standard was 0-100 μg. The assay design includes the following steps:

1) BF ₃ / MeOH 1) Hexane Extraction

Contaminated lens and ----------> heated to 60 ℃ ----------> GC injection

2) CH ₂ Cl ₂ 2) Solvent Removal

The same experiment as above is used for the standard, with the non-wear lens placed in a glass test tube along with the standard solution. Otherwise, the experiment is as follows:

1) If hexane is added to the lens (heating), the lens will dissolve and finally settle to the bottom of the tube. Will form two phases. The bottom layer is cloudy (MeOH layer) and the upper layer (hexane layer) is clear. The hexane layer is extracted. Extraction of samples and standards is carried out twice. The fact that the lens dissolves during this process can determine the total amount of lipids that are potentially buried in both surfaces and the lens matrix.

2) N ₂ flow is used to remove hexane from the tube. The samples and standards are then resuspended in 50 μl of hexane.

3) Hexanes are run through GC (2 μl) to indicate peaks with appropriate retention times.

4) Then, inject 2 G quantity into each GC from each tube. The injector was washed 10-14 times with hexane between each run. Lipid retention time corresponds to the length of the chain. C ₈ -C ₁₂ , C ₁₂ , C ₁₄ , and C ₁₆ -C ₁₈ appear at increasing intervals. Since GC is a capillary CG 30 ft HPRI column attached to the FID detector (weight), the weight can be read (in μg) corresponding to the peak.

5) The standard curve of tripalmitin shows the peak area versus lipid amount in μg.

Based on the investigator's grading range, 86% of patients involved in this study were classified as grades 0-2, reflecting minimal or no surface deposition. The mean protein concentration was 34.2 μg between these grades and the average amount of lipid was 17.5 μg. The detailed results of the protein and lipid analysis in this study are shown in Table 3 below:

0 rating (84 *) 1 rating (46 *) 2 rating (28 *) 3 star (19 *) 4 star (5 *) Average Protein Concentration: Range: 24.7 μg 0 to 105 μg 42.7 µg 8.6-80 µg 35.3 µg 2.6 to 75 µg 39.7 μg 0 to 92 μg 43.4 μg 25 to 60 μg Average Lipid Concentration: Range: 0 μg- 16.0 μg 0 to 51 μg 19.1 µg 0 to 61.4 µg 40.1 μg 0 to 92 μg 65.0 μg 30 to 96 μg

* Numbers in bold indicate the total number of patients with that grade of deposition.

Observed concentration ranges of proteins and lipids represent individual changes in the degree of deposition as well as changes in the investigator's assessment of deposition grade. Overall, among all the grades, the protein grade remains relatively constant (˜35-40 μg), except for a slightly smaller number (25 μg) and zero grade. However, lipid deposition continues to increase with grade, indicating that heavy contaminants are on average more likely to be lipid deposition than proteins. All. Of the 24 patients classified as grade 3 and 4 depositions, 5 experienced discomfort. There was no observed correlation between lens age (wear time) and degree of deposition.

The following table shows the distribution of the product among the deposition grades showing the relative ease of infection in particular product to deposition.

Lens product # # Lens rating 0 # Lens grade 1 # Lens class 2 # Lens grade 3 # Lens grade 4 One 8 6 4 3 One 2 7 5 One 4 One 3 8 4 0 3 4 8 2 One One 5 12 5 0 3 6 12 3 One 0 7 10 One One 3 2 8 6 2 2 One 9 5 2 2 5 10 2 2 One 2 One 11 4 6 5 3 12 6 5 One 0 13 6 3 2 One

Correlation of lens surface and deposition, results are as follows:

Mosaic Slick product surface % 2-4 product surface % 2-4 3 2 9% 2 3 11% 4 1.75 5% 5 2.75 15% 6 2.25 6% 7 2.5 17% 8 One 7% 8 3 16% 10 2 14% 9 2.75 13% 12 2 7% 11 3 11% 13 2.75 13%

* These products are listed on the field as products with less wettability and / or heavier deposition.

These results show that the plasma treated lens exhibits a "mosaic" surface characteristic similar to that of Figure 3 above in Example 2, wherein the ratio of lenses having a deposition ratio of more than 2 is 8%, while similarly in FIG. As a plasma treated lens that does not exhibit “mosaic” surface properties (such as the lens shown in FIG. 4), the ratio of lenses having a deposition ratio of more than 2 is 14%, indicating that the mosaic type is statistically excellent.

Example 4

In order to show the change in the wettability of the lens according to the invention, the contact angles were measured after untreated lenses (before plasma treatment), plasma treated lenses (just after plasma treatment) and after complete processing (including hydration and heat sterilization). The contact angle was measured as follows. Platinum wire (Pt) was used to minimize contamination. To ensure that the water used for the test (HPLC grade) is exposed to a fresh, clean metal surface free of contamination, the Pt line is flamed with a Bunsen burner until the line reaches a faint red (orange) flame. Added. About 2 μl of water was moved from the bottle to the line, and this process placed the maximum amount of line under the liquid, including tipping the bottle. Water on the line was transferred to the lens made from the material of Example 1 without pulling along the surface. Once moved, the NRL-100 Rhame-Hart contact angle goniometer is used to measure the contact angle. Set the baseline by adjusting the step height until a baseline draws between the bottom of the drip and its reflection. After the baseline was established, the contact angle formed by dropping was measured on the right and left sides. Another drop was added to the first drop, and the contact angle was recalculated on the left and right sides. A total of four measurements were averaged. Using this measurement, the lens surface before treatment showed a water contact angle of about 90 dynes / cm. After the plasma treatment, the water contact angle was about 0 dynes / cm. After heat sterilization, the fully treated lens showed a contact angle of 72.4 +/- 2 dynes / cm. All measurements were made with dry lenses.

Many modifications and variations of the present invention are possible in accordance with the teachings herein. It is therefore to be understood that the invention may be practiced otherwise than as specifically described herein within its scope.

Claims (20)

Surface of a silicone hydrogel contact lens containing bulk, 5-50 wt% of at least one silicone macromonomer, 5-75 wt% of at least one polysiloxaneylalkyl (meth) acrylic monomer, and 10-50 wt% of lactam containing monomer As a method of modifying the above method, (a) at a wattage of 100 to 1000 watts and a pressure of 0.1 to 1.0 torr, plasma treating the lens with an oxygen-containing atmosphere for at least 4 minutes per side to form a silicate-containing coating; (b) immersing the lens in an aqueous solution to hydrate, wherein the amount of water absorbed by the lens is at least 5% by weight of the lens material, and (c) a controlled preparation comprising heat sterilizing the hydrated lens, Thus, in a 50x50 square micron AFM image, the heat sterilized lens has a silicate containing coating characterized by a mosaic-shaped protruding plate surrounded by spaced gaps, wherein (i) the depth of the gaps averages about 100 to 500 mm, ( ii) the plate protector averages about 40% to 99%, and (iii) the nitrogen element analysis results are about 6 to 10%, and when measured by XPS analysis, nitrogen is 10% or more relative to the lens surface before plasma treatment. Way. The method of claim 1 wherein the plasma treatment step of (a) is performed at 300 to 500 watts for 6 to 60 minutes per side. The method of claim 1 wherein the elemental nitrogen analysis results are about 7.0-9.0% and nitrogen is concentrated at least 20% relative to the lens surface prior to plasma treatment. The method of claim 1 wherein autoclaving is performed at 100 ° C. to 200 ° C. for 10 to 120 minutes. The method of claim 1, wherein the gap depth is on average about 150 to 200 mm 3. The method of claim 1, wherein the plate protector is on average about 60-80%. The method of claim 1, wherein at least 80% of the lenses in a commercially manufactured lot fall within the gap depth and plate protection range. The method of claim 8, wherein at least 90% of the lenses fall within the range. The method of claim 1 wherein the silane macromonomer is a poly (organosiloxane) capped with an unsaturated group at two or more ends. The method of claim 9, wherein the silane macromonomer is a silicon-containing vinyl carbonate or vinyl carbamate or a polyurethane-polysiloxane having at least one hard-soft-hard block and end capped with a hydrophilic monomer. The method of claim 1 wherein the polysiloxaneylalkyl (meth) acrylic monomer is methacryloxypropyl tris (trimethyl-siloxy) silane. The method of claim 1 wherein the lactam containing monomer is vinyl lactam. 15. The method of claim 14, wherein the lactam containing monomer is N-vinyl pyrrolidone, methacrylamide. A silicone hydrogel contact lens containing bulk, 5 to 50 weight percent of at least one silicone macromonomer, 5 to 75 weight percent of at least one polysiloxaneylalkyl (meth) acrylic monomer, and 10 to 50 weight percent of a lactam-containing monomer. In a 50x50 square micron AFM image of a fraudulent lens, as a result of a controlled production process with a silicate containing surface coating characterized by a mosaic-shaped protruding plate surrounded by spaced gaps, (i) the average depth of the gaps averages about 100 to 500 Iii, (ii) an average of about 40% to 99% of the plate protector, and (iii) about 6 to 10% of the elemental nitrogen analysis results, when measured by XPS analysis. Contact lenses that are at least%. The contact lens according to claim 14, wherein the gap has an average depth of 150 to 200 microseconds. The contact lens of claim 14, wherein the plate protector is on average about 60-99%. 15. The contact lens of claim 14, wherein the lactam containing monomer is N-vinyl pyrrolidone. The method of claim 14, wherein the silane macromonomer is a poly (organosiloxane) capped with an unsaturated group at two or more ends. 15. The contact lens of claim 14, wherein the silane macromonomer is a silicon-containing vinyl carbonate or vinyl carbamate or a polyurethane-polysiloxane having at least one hard-soft-hard block and end capped with a hydrophilic monomer. 15. The contact lens of claim 14, wherein the polysiloxaneylalkyl (meth) acrylic monomer is methacryloxypropyl tris (trimethyl-siloxy) silane.