Ординатура / Офтальмология / Английские материалы / Contact Lenses A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References_Parker_2003
.pdfPatents 255
Web site: http://www.delphion.com/details?pn=US04113686__
Hydrophilic polymers and contact lenses made therefrom
Inventor(s): Lim; Drahoslav (San Diego, CA), Kulkarni; Chidambar L. (San Diego, CA), Repella; Dennis A. (San Diego, CA)
Assignee(s): Barnes-Hind, Inc. (Sunnyvale, CA) Patent Number: 4,536,554
Date filed: February 22, 1984
Abstract: An interpenetrating network polymer is obtained by mixing hydrophilic monomer vinyl pyrrolidone and hydrophobic monomer (5-alkylene-m-dioxanyl) acrylic ester in the presence of at least two crosslinking agents and, optionally, hydroxyalkyl acrylic ester and catalysts and causing polymerization to occur. Contact lenses made from the polymer have high tensile strength and can absorb a high degree of water.
Excerpt(s): This invention relates to transparent optically clear interpenetrating network polymers suitable for manufacturing contact lenses, and particularly to such polymers that have been prepared with modifiers and crosslinking agents, and the method of preparation of the modified, crosslinked, optically transparent interpenetrating network polymers.... It is known that certain hydrophilic gel contact lenses of high water content have oxygen permeability which are order of magnitude greater than conventional polymethylmethacrylate lenses and provide sufficient amounts to cornea for its metabolic needs. The increased oxygen permeability makes possible increased wearing time with increased comfort and absence of most of the undesirable physiological symptoms resulting from the conventional lens wearing.... In order to optimize the foregoing advantages of these hydrophilic lenses, materials with high water content are desired. However, previously the strength of lenses with very high water content have been found to be low in tensile strength and having tear resistance which decreases progressively with the increase in water content. Such lenses are very fragile and are not very durable. In some instances such contact lenses can only be inserted and removed by a professional practitioner because of their fragility. Such polymers are found in the following patents. Brit. Pat. Nos. 1,391,438 and 1,475,605; U.S. Pat. Nos. 3,639,524, 3,721,657, and 3,943,045.
Web site: http://www.delphion.com/details?pn=US04536554__
Hydrophilic polymers and contact lenses of high water content
Inventor(s): Loshaek; Samuel (Chicago, IL), Shen; Chah M. (Chicago, IL) Assignee(s): Schering Corporation (Kenilworth, NJ)
Patent Number: RE31,422 Date filed: December 9, 1981
Abstract: Cross-linked hydrophilic interpolymers and contact lenses made therefrom comprising hydrophilic units of which the only or major proportion are derived from.Iadd.vinyl pyridine or.Iaddend.an N-vinyl heterocyclic monomer, hydrophobic units derived from the group consisting of styrene and ring-substituted styrenes, and cross-linking units derived from monmers containing two or more polymerizable double bonds per monomer unit.
256Contact Lenses
Excerpt(s): It is known in the ophthalmological field, that oxygen from the air must be made available to the eye in order to provide for the metabolic needs of the cornea. The placement of an oxygen impermeable contact lens over the cornea can seriously inhibit the transmission of oxygen to it and result in corneal trauma. This situation has been partially alleviated by the so-called pump design of corneal contact lenses which serves to replace the lachrymal fluid under the lens (containing carbon dioxide) with freshly oxygenated lachrymal fluid and thereby make oxygen available to the cornea. The oxygen deficiency problem has been further alleviated by limiting the length of time for which an impermeable lens can be continuously worn, ranging from about four hours to 16 hours of daytime wear depending on the individual, and no wear during sleeping hours. There is also a concomitant need for the carbon dioxide, which is produced by the corneal metabolic processes, to be carried away from the cornea.... It has been found that certain hydrophilic gel contact lenses of high water content have gas permeability orders of magnitude greater than conventional polymethylmethacrylate lenses and provide for the passage of the aforesaid gases through the lens in sufficient amounts to supply corneal metabolic needs. The term "gas permeability" as used herein refers broadly to air, oxygen and carbon dioxide permeability. It has been found, that the gas permeability increases with increasing water content of the hydrophilic polymer from which the contact lens is formed. The increased gas permeability makes possible increased wearing time with increased comfort and absence of most of the undesirable physiological symptoms produced by conventional lens wear.... In order to optimize the foregoing advantages of these hydrophilic lenses, materials with very high water content are desired. However, previously the strength of lenses with very high water contents, e.g., 60%-95% have been found to be low, the strength (resistance to tearing, puncturing, etc... ) decreasing progressively with increase in water content. Such lenses are readily damaged during handling, in general are not very durable, and have poorer visual acuity. In some instances such contact lenses can only be inserted and removed by a professional practitioner because of their fragility. Further, the high water content lenses of the prior art cannot withstand repeated heat disinfection or sterilization without deterioration or destruction of the lens. Polymers of the prior art which are of sufficiently high water content to give high gas permeabilities, e.g., about 60%-95% by weight of the combined weight of polymer plus water, and especially above about 70% water content, are very weak and are readily torn or otherwise physically damaged during handling. Such polymers are exemplified in British Pat. No. 1,391,438 and U.S. Pat. Nos. 3,639,524 and 3,943,045. The polymers are prepared from monomer compositions which contain a relatively high amount of cross-linking monomer, the latter being required to prevent the hydrophilic polymer from substantially dissolving in aqueous media. This excessive cross-linking frequently results in a weak polymer.
Web site: http://www.delphion.com/details?pn=US0RE31422__
Hydrophilic polymers and contact lenses therefrom
Inventor(s): Kuzma; Petr (1708 Westminster Blvd., Parlin, NJ 08859) Assignee(s): none reported
Patent Number: 4,465,794 Date filed: February 4, 1982
Abstract: There is prepared a hydrophilic water swellable water insoluble copolymer of
(1)at least 35% of a hydroxy (C.sub.2 -C.sub.4 -alkyl)-2-alkenoate, (2) 30 to 60% of a 2- alkenamide or an N,N-di (C.sub.1 -C.sub.6 -alkyl)2-alkenamide, (3) 5 to 20% of R --
Patents 257
OR.sub.1).sub.x Z where R is C.sub.1 -C.sub.6 alkyl, R.sub.1 is C.sub.2 -C.sub.4 alkylene, x is an integer of 1 to 4 and Z is 2-alkenoyloxy and (4) 0.3 to 5% of a polyethylenically unsaturated crosslinking agent having a relatively long aliphatic chain, the copolymer being capable of holding 80 to 80 weight % of water. The polymers are particularly useful in preparing hydrophilic contact lenses of high burst strength and extended wear properties.
Excerpt(s): The present invention relates to novel hydrophilic copolymers and soft contact lenses made therefrom.... A hydrophilic polymer suitable for use as an extended wear soft contact lens must have high oxygen permeability and good mechanical strength.... Tolerance of a soft lens by the ocular environment is affected by water content, shape, or geometry, thickness and edge quality. The surface of the lens should be smooth in order not to affect the normal precorneal tear film and the superficial epithelial layer. Such a smooth surface should not be affected by temperature, pH, tonicity and foreign body deposition, mucous adhesion, lipids of the tears or abrasion by the lids. Wettability of the lens surface is important in order to allow tears to fill the lens-corneal interspace. The lens should also be physiologically inert.
Web site: http://www.delphion.com/details?pn=US04465794__
Hydrophilic-gel contact lenses adapted into a planarized xerogel state and method for making the same
Inventor(s): Wichterle; Otto (Prague, CS)
Assignee(s): SPOFA, spojene podniky pro zdravotnickou vyrobu (Prague, CS) Patent Number: 4,322,139
Date filed: June 15, 1979
Abstract: The invention pertains to a method of temporary planarization of hydrogel contact lenses by drying of a lens swollen in a volatile hydrophilic swelling agent and clamped in the planarized state between two surfaces, at least one of which is formed by a thin foil permeable for the hydrophilic volatile swelling agent, as long as the swelling agent diffuses through the foil and the lens is transfered into a xerogel state. According to this invention, the planarized lens may have an enlarged surface and reduced thickness in comparison with the relaxed lens and may be provided with temporary marking comprising signs or lines showing the direction of cylindric axis with toric lenses, a marginal angle scale to enable easier truncation of toric lenses, and additional specifications of the lens. The temporary marking is achieved by pressing the planarized lens during drying against a base with embosed drawing or against projections at the compression foil. According to the invention, water, C.sub.1 -C.sub.5 alcohols, formic and acetic acid, acetone, methyl ethyl ketone, and dioxan are used as the volatile swelling agents individually or in mixtures and cellophane or polyamide for permeable foils. The planarized contact lens in xerogel state may advantageously contain up to 8 wt. % of hydrophilic plasticizers, e.g. glycerol, glycolor polyglycol, to reduce the brittleness of xerogel and make easier the final adaptation of lens.
Excerpt(s): The invention pertains to a method for the adaptation of hydrophilic-gel contact lenses into a planarized xerogel state.... Three-dimensional hydrophilic gels are noted for keeping permanently their shape in the relaxed swollen state irrespective of the previous deformations. If they are transfered into a glassy state under any kind of deformation caused by external stress, they retain this deformation until they are transfered into the state of high elasticity by swelling or heating, where they again
258Contact Lenses
acquire the non-deformed shape. This behavior was employed in the Czech. Pat. No. 134,722 (Brit. Pat. No. 1,174.683; U.S. Pat. No. 3,542,906; Ger. Pat. No. 1,704.530) to force contact lenses in a dry state, i.e. in the state of so called xerogel, into the planar shape, which served, according to that invention, exclusively to the easy removal of peripheral and surface defects by grinding and polishing.... The lenses were planarized, according to the aforesaid patent, by heating of a dry lens, which was usually entirely accidentally deformed by drying, to high temperature, i.e. to the temperature above the gel transformation into a highly elastic state, planarizing the lens in this state on a flat base, and temporary fixation of the lens in this deformed state for an arbitrary period of time.
Web site: http://www.delphion.com/details?pn=US04322139__
Hydrophilized cellulose esters, process for their preparation, their use as biomedical materials and contact lenses produced from these
Inventor(s): Wingler; Frank (Leverkusen, DE) Assignee(s): Bayer Aktiengesellschaft (Leverkusen, DE) Patent Number: 4,532,277
Date filed: December 27, 1983
Abstract: Contact lenses and implants for human medicine can be fabricated from a polymer blend comprising 98-80% by weight of component A and 2-20% by weight of component B wherein:component A is a cellulose ester of an aliphatic carboxylic acid with up to 40% by weight of total component A of an ethylene/vinyl acetate copolymer having 30-98% by weight, relative to ethylene/vinyl acetate, of incorporated vinyl acetate andcomponent B is a homopolymer or copolymer of water-soluble vinyl monomers and up to 10% by weight relative to the total polymer B of multifunctional crosslinker vinyl compounds.
Excerpt(s): The invention relates to hydrophilized polymers based on cellulose esters of aliphatic carboxylic acids. The hydrophilization according to the invention is carried out by impregnating the cellulose esters, where appropriate in the form of blends with ethylene/vinyl acetate copolymers in the solid phase or in a melt, with water-soluble vinyl monomers, and then polymerizing the vinyl monomers under the action of heat and/or light, where appropriate with the aid of radical initiators. The invention also relates to the use of hydrophilized materials of this type as biomedical materials in human or veterinary medicine, especially in ophthalmic contact optics.... A number of different hydrophilic polymers having water-absorbing capacities of 1 to about 60% by weight has already been employed in human medicine, for example as implants or as refractive materials in contact optics. In this connection, soft gels consisting of crosslinked (meth)acrylic acid oxyalkyl ester polymers or copolymers with vinylpyrrolidone, acrylic acid, methacrylic acid, acrylamide, methacrylamide or alkylsilyl esters of methacrylic acid, amongst others, are used. However, soft gels have the disadvantage that they can accumulate metabolites, infection-inducing substances and so forth, in their lattice. This has contributed to an increased use in contact optics of, instead of these soft gels, semihard materials of cellulose acetobutyrate or blends with ethylene/vinyl acetate copolymers (EVA) as is described, for example, in European Pat. No. 0,013,366. The water-absorbing capacity of cellulose esters or their blends with EVA is about 1 to 2%, depending on the content of free OH and the wettability with water is poor. To improve the compatibility with living tissue in the human biomedical sector, an improved wettability (in other words greater hydrophilicity) would be of great use. Since materials of this type are of particular interest for contact optics, it would be
Patents 259
desirable if the materials also had at the same time high permeability to light....
Accordingly, the object of the present invention was to improve the hydrophilicity or wettability with water of biomedical materials based on cellulose esters of aliphatic carboxylic acids or their blends with EVA, while retaining the permeability to light. The object was achieved by impregnating the material, in the solid form or in a melt, with 2 to 20% by weight of one or more water-soluble vinyl monomers, where appropriate with the addition of 0.01 to 0.5% by weight of a radical initiator which initiates the polymerization in vinyl polymerizations, and then exposing the impregnated material in the solid form or in a melt to a temperature of 60.degree. to 220.degree. C. and/or to the action of light.
Web site: http://www.delphion.com/details?pn=US04532277__
Hydroxyethyl cellulose derivatives containing pendant (meth)acryloyl units bound through urethane groups and hydrogel contact lenses made therefrom
Inventor(s): Harisiades; Paul (Woodhaven, NY), Rennwant; Ellen (North Tarrytown, NY)
Assignee(s): Ciba-Geigy Corporation (Ardsley, NY) Patent Number: 5,157,093
Date filed: May 9, 1991
Abstract: The instant invention relates to methacrylate functionalized hydroxyethyl cellulose which is crosslinked with conventional vinylic monomers to form soft hydrogel contact lenses possessing high oxygen permeability, wettability, and mechanical strength.
Excerpt(s): The instant invention relates to hydroxyalkylated cellulose (i.e. HEC) derivatives containing pendant (meth)acryloyl units bound to the cellulose backbone, through urethane groups, which are further reacted with a conventional vinylic monomer, and which can be crosslinked to form soft hydrogel contact lenses possessing high oxygen permeability, wettability and mechanical strength.... Hydroxyethyl cellulose has not been proposed as a contact lens material. Vision correction lenses such as contact lenses and intraocular lenses have been known as commercial products for over 25 years. An acceptable lens must be optically clear, mechanically stable, and must provide sufficient optical correction, gas permeability and wettability to insure that the lens is comfortable and safe during use. Gas permeability is important since the corneal surface of the eye respires by obtaining oxygen and other substances from tear fluid and by releasing carbon dioxide and other products of respiration into tear fluid. The intimate contact and position of the contact lens can substantially prevent the exchange of such Constituents between the corneal epithelial cells and tear fluid. As a result the cornea can become starved for oxygen and can accumulate harmful amounts of metabolites within the constituent cells. This can result in corneal edema (swelling) and often extreme discomfort to the wearer. Wettability of the lens is important because a nonwettable lens can be abrasive and irritating to the eye and lid and can cause significant wearer discomfort. A lens must have sufficient mechanical integrity to allow for easy cleaning and handling and maintaining the desired curvature and correction for the individual user. The lens should be immunologically compatible with the eye reducing chances of allergic reaction or toxic response. Further the lens should be permanently dyeable easily manufactured and available at low cost.... In the past contact lenses have been made from synthetic polymeric materials such as plastic matrices based on polyacrylates, polymethacrylates, poly(hydroxyethyl methacrylate), cellulose
260Contact Lenses
acetate butyrate, silicones, etc. More recently contact lenses have been made from collagen, a naturally occurring protein. Miyata, U.S. Pat. No. 4,223,984 is primarily directed to a contact lens made from solubilized defatted transparent crosslinked collagen. Miyata U.S. Pat. No. 4,260,228 is particularly directed to an improved collagen gel soft contact lens prepared from an aldehyde crosslinked gel containing a polyhydroxy compound such as glucose. Miyata, U.S. Pat. No, 4,264,155 is primarily directed to an improved lens made from collagen gel to which a water soluble organic polyhydroxy polymer has been added.
Web site: http://www.delphion.com/details?pn=US05157093__
Identifying means for polymeric contact lenses
Inventor(s): Erickson; Charles E. (Bellevue, WA), Neogi; Amar N. (Seattle, WA) Assignee(s): Precision Cosmet Corp. (Minneapolis, MN)
Patent Number: 4,193,671 Date filed: November 20, 1978
Abstract: A method for providing hydrophilic contact lenses with identifying means incorporated into lens blanks and the resulting lenses in which an elongated identifying strand, fiber, or rod is molded into a cylindrical lens blank rod positioned substantially parallel to the axis of the rod. Lens blanks or buttons are cut transversely to the axis and the lens blanks ground to the proper optical curvatures. The contact lens blanks each contain portions of the identifying means. The finished contact lenses each contain short segments of the identifying means thereby allowing classification of the contact lenses as to right or left eye, magnification power or other characteristic.
Excerpt(s): This invention relates to the manufacture of polymeric contact lens structures wherein the structure is produced with an identifying means comprising short segments of elongated strand, rod or fiber indicia molded into the structure during manufacture....
This invention further relates to contact lens manufacture wherein a lens is produced having a gradation or variation in physical properties from the central portion to the peripheral skirt portion of the lens and has means for identifying the lens incorporated into the lens during manufacture.... This invention also relates in one variant form thereof to a contact lens having a relatively harder central portion and a softer hydrophilic peripheral skirt portion with identifying means incorporated directly into the lens.
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Injection molding of contact lenses
Inventor(s): Ratkowski; Donald J. (1954 E. Glencove, Mesa, AZ 85203) Assignee(s): none reported
Patent Number: 4,254,065 Date filed: April 4, 1979
Abstract: The present invention relates to lenses and more particularly relates to the method of forming prescription contact lenses of the single vision, bicurve, lenticular, bifocal and other types by injection molding. The lens is formed from a blank having a cylindrical configuration with a concave or convex surface. The concave or convex
Patents 261
surface forms a surface such as the base curve of the completed lens minimizing finishing operations. The lens blanks are supplied to the practitioners in a series having a completed or substantially completed curved surface. The lenses are formed by injection molding closely controlling parameters such as injection pressure, time, and temperature to avoid internal stress in the lens.
Excerpt(s): Contact lenses formed of plastic material for optical applications are well known. A primary application is the area of contact lenses. Generally, contact lenses fall into two major categories generally characterized as soft hydrophillic and semi-rigid or hard contact lenses which are generally hydrophobic. In addition to characterization of lenses as "soft" or "hard", contact lenses are often classified as corneal or scleral. A scleral lens is a contact lens whose main bearing portion rests upon the sclera of the eye. A corneal lens covers or rests upon the cornea of the eye. Other specialized types of lenses as inter-occular lenses for surgical implantation in the eye are also known.... Because of the stringent quality requirements for first quality contact lenses, extreme precision is required in the making of these lenses. Most plastic contact lens blanks are formed by initially casting an elongate or cylindrical rod from a plastic material, as for example, cellulose acetate butyrate or polymethyl methacrylate. The cylindrical rod is transversely cut to form a number of cylindrical lens blanks or buttons. The blanks, having generally opposite planar surfaces are furnished to the manufacturer and the lenses are machined to prescription and fitted to the patient. Various machining operations may be accomplished. For example, it is common practice to abrade the lens blank using a lathe with a diamond bit or other machine tool such as a spherical rotating grinder. However, the abrading or machining operation will impart markings in the surface of the lenses which impairs optical quality. The lens surface must be optically polished to remove the machined surface markings.... Another problem in forming lenses from elongate rods is that it is difficult to fabricate the rods having a uniform density. Density variations create a considerable optical problem as variations in the refractive index and mechanical properties will result when the lens is manufactured.
Web site: http://www.delphion.com/details?pn=US04254065__
Interactive control system for packaging control of contact lenses
Inventor(s): Lepper; John M. (Jacksonville, FL), Edwards; Russell J. (Jacksonville, FL), Wang; Daniel T. (Jacksonville, FL)
Assignee(s): Johnson & Johnson Vision Products, Inc. (Jacksonville, FL) Patent Number: 5,607,642
Date filed: June 10, 1994
Abstract: An interactive control system for controlling the automatic packaging of contact lenses in a contact lens fabrication facility, the interactive control system consisting of a first robot device for periodically transferring individual arrays of a first predetermined amount of discrete contact lens packages each containing a contact lens therein from a first station to an intermediate conveyor where the individual arrays are conveyed to a second station, and a controller for initiating a time stamp for each individual array transferred from the first station and determining elapsed time data for each individual array and for generating position status data indicating a good array or a bad array of defective lenses for each individual array as it is conveyed to the second station, the controller shifting the elapsed time data and position status data for each individual array as it is conveyed on the intermediate conveyor for transfer to the second station.
262Contact Lenses
Excerpt(s): This invention relates generally to a contact lens manufacturing facility for producing ophthalmic contact lenses, and, in particular to a control system for consolidating the serial flow of lens packages for packaging thereof.... The direct molding of hydrogel contact lenses is disclosed in U.S. Pat. Nos. 4,495,313 to Larsen, 4,680,336 to Larsen et al., 4,565,348 to Larsen, and 4,640,489 to Larsen et al., the entire disclosures of which are hereby incorporated by reference in this patent application. Essentially, these references disclose an automated contact lens production process wherein each lens is formed by sandwiching a monomer in a mold cavity formed between back curve (upper) and front curve (lower) mold halves. The monomer is polymerized, thus forming a lens, which is then removed from the mold cavity and subject to further processing such as hydration, automatic lens inspection (ALI), and packaging for consumer use.... Prior art processes significantly reduce the thruput time by hydrating the lens and releasing the lens from the mold cavity with ionized water and a small amount of surfactant without any salts, so that the time consuming ionic neutralization of the polymer from which the lens blank is made does not occur during the hydration process. When deionized water is used, the final step of the process is to introduce buffered saline solution into the final package with the lens and then seal the lens within the package so that the final lens equilibrium (ionic neutralization, final hydration and final lens dimensioning) is accomplished in the package at room temperature or during sterilization.
Web site: http://www.delphion.com/details?pn=US05607642__
Lathe for making contact lenses
Inventor(s): Bendini; Alberto (VIA Vivaldi 18, Brescia, IT) Assignee(s): none reported
Patent Number: 4,134,315 Date filed: May 5, 1977
Abstract: A lathe for forming contact lenses in a single cut includes a support member for hingedly mounting the tool holder turret. A lever arm extends from the tool holder turret and perpendicular to the rotational axis thereof for supporting two rollers, the first of which is positioned at the free end of the lever arm and the second of which is positioned intermediate the first roller and the axis of rotation of the turret. There is also provided a circular cam having a rising profile on which the first roller rides.
Excerpt(s): The purpose and the behaviour of a contact lens, that is of the small concaveconvex lens which floatingly sticks to the cornea, on the interposed lachrymal liquid are well known.... It is also well known the geometric formulation of a contact lens which is indicated as being normal, due to it being free from those aberrations of sphericity which are obtained by machining, compensate for the symmetric imperfections of the corneal topography or natural optical system.... The multisphericity of the concave back is connected instead with the physiological opportunity to build up "in negative" on the lens as exactly as possible, the shape existing "in positive" on the corneal surface bearing the lens.
Web site: http://www.delphion.com/details?pn=US04134315__
Patents 263
Lens molds with protective coatings for production of contact lenses and other ophthalmic products
Inventor(s): Li; Hongwen (Palo Alto, CA), Ruscio; Dominic V. (Webster, NY), Lai; Yu Chin (Pittsford, NY), Huang; Horngyih (Penfield, NY)
Assignee(s): Bausch & Lomb Incorporated (Rochester, NY) Patent Number: 6,565,776
Date filed: June 12, 2000
Abstract: This invention relates to the preparation of molds for the production of contact lenses and other ophthalmic articles. By using an inorganic material to coat the optical surfaces and sidewalls of mold parts made from clear-resin materials, manufacturers can produce lens molds with greater dimensional stability and chemical resistance. In addition to protecting the clear resin from interaction with otherwise reactive monomers from which the molded article is made, such coatings can also be used to achieve preferential release of the molded article. The resulting mold is especially useful for providing an economical way to improve manufacturing quality of contact lenses.
Excerpt(s): This invention is directed to improved lens molds for the production of contact lenses, intraocular lenses, and other ophthalmic products. In particular, the invention involves protective coatings for allowing for the use of mold materials having improved dimensional stability and/or increased light transparency. The invention is also directed to a method of making the improved lens molds and their use in the manufacture of contact lenses.... The molds used in the manufacture of soft (hydrogel) contact lenses have been made from a variety of rigid thermoplastic resins. For example, U.S. Pat. No. 5,540,410 to Lust et al and U.S. Pat. No. 5,674,557 to Widman et al. disclose mold halves made from polystyrene, polyvinyl chloride, polyethylene, polypropylene, copolymers of polystyrene with acrylonitrile and/or butadiene, acrylates such as polymethyl methacrylate, polyacrylontrile, polycarbonate, polyamides such as nylons, polyesters, polyolefins such as polyethylene, polypropylene and copolymers thereof, polyacetal resins, polyacrylethers, polyarylether sulfones, and various fluorinated materials such as fluorinated ethylene propylene copolymers and ethylene fluoroethylene copolymers. Polystyrene is preferred by Widman et al because it does not crystallize and has low shrinkage. An earlier patent, U.S. Pat. No. 4,661,573 to Ratkowski et al, discloses, for the processing of fluorosilicone copolymers into extended wear lenses, molds formed of polypropylene, polyethylene, nylon, Teflon.RTM., glass, or aluminum having its mold surfaces coated with Teflon.RTM. polymer.... The manufacturers of soft contact lenses have discovered that if the molds used to make the lenses are sufficiently inexpensive, it is more economical to discard the molds after production of the lenses from the molds than it is to clean the molds to be reused. Polypropylene is a good example of an inexpensive resin that has been used to make molds that can be discarded at minimal cost. Another advantage of polypropylene is that unlike many resins, polypropylene can resist interaction with the monomers used to make the contact lenses. The ability to resist chemical interaction prevents the lens and the mold from adhering to each other and simplifies their separation following lens production.
Web site: http://www.delphion.com/details?pn=US06565776__
264 Contact Lenses
Liquid cleaner containing inactivated protease for protein soiled contact lenses
Inventor(s): Chanda; Subir (17 Arlington Dr., Pittsford, NY 14534), Riedhammer; Thomas M. (52 Appian Dr., Rochester, NY 14606), Tometsko; Andrew M. (105 Brooklawn Dr., Rochester, NY 14618)
Assignee(s): none reported Patent Number: 4,715,899 Date filed: April 11, 1984
Abstract: Protein soiled contact lenses are conveniently cleaned by the concurrent use of an aqueous solution containing an inactivated sulfhydryl protease and an aqueous mild thio reducing agent. The protease is allosterically inactivated by reaction with sodium tetrathionate.
Excerpt(s): This invention relates to a method for removing proteinaceous deposits from contact lenses and the inactivated protease used therein.... One of the problems connected with the soft contact lenses is the method of their cleaning. The very property of the hydrophilic soft lenses, which allows them to absorb up to 150% by weight of water, also allows formulations which might otherwise be used for cleaning to be absorbed and even concentrated and later released when the soft contact lens is on the eye. The release may be much slower than the uptake; therefore, the cleaner continues to build up in the lenses. This build-up eventually affects the physical characteristics of the lenses, including dimension, color and the like. This can have the harmful result of damaging or staining the contact lens itself and/or harming the sensitive tissues of the conjunctiva or cornea.... U.S. Pat. No. 3,910,296 to Karageozian and Rudko discloses a method of removing proteinaceous deposits from soft contact lenses by use of an aqueous solution of proteolytic enzyme such as papain. However, because this solution is autodigestive, its effective shelf storage life is only 12 to 24 hours. Therefore, the desired protease, along with enhancer, adjuvants and modifiers, must be prepared in an absolutely dry form tablet which is hermetically sealed and then distributed to the wearer of contact lenses. The ultimate wearer must then prepare the actual aqueous protease solution used to remove protein deposits from the contact lens. Absolute dryness of the tablet at all times is required if autodigestion and decomposition prior to actual use are to be avoided.
Web site: http://www.delphion.com/details?pn=US04715899__
Liquid composition for contact lenses and method for cleaning a contact lens
Inventor(s): Nakagawa; Akira (Nagoya, JP), Kondo; Satoko (Nagoya, JP), Oi; Yoshiko (Nagoya, JP)
Assignee(s): Tomei Sangyo Kabushiki Kaisha (Nagoya, JP) Patent Number: 5,281,277
Date filed: April 8, 1992
Abstract: A liquid composition for contact lenses, having from 5 to 40% (w/v) of glycerol and from 4 to 20% (w/v) of boric acid and/or a borate incorporated to a solution containing an effective amount of a protease, in such a ratio that the boric acid and/or the borate is from 10 to 100 parts, preferably 10-20 parts, by weight per 100 parts by weight of the glycerol.