Ceskoslovenska Akademie Ved

Spofa, Spojene Podniky Pro Zdravotnickou Vyrobu

Npd Technologies, Inc.

Spofa, Spojene Podniky Pro Zdravotnichou

Ceskoslovenska

Otto Wichterle

Jiri Coupek

Jiri Vacik

Artur Stoy

Jiri Trekoval

Vladimir Havlin

Jiri Michalek

Jiri Vodnansky

Ivan Wichterle

Vladimir Stoy

Miroslava Krivakova

Jiri Svantner

The invention pertains to apparatus for casting polymeric gels from volatile mixtures of monomers in open molds. The principle of the invention resides in the fact that the same concentrations of volatile components present in the polymerization mixture are also present in the gaseous state within a protective gas maintained above the free surface of the polymerization mixture, the gaseous volatile components being in the equilibrium state with those in the polymerization mixture at polymerization temperature. The apparatus includes a main pipe branch which introduces a pure protective gas into a polymerization apparatus and at least one auxiliary pipe branch for saturating the protective gas with a volatile component. These main and auxiliary pipe branches are formed by an inlet pipe connected to a control valve for setting a constant volume flow-rate and further leading to a device for measurement of the flow rate, where their outlet pipes are connected to a common inlet entering the polymerization apparatus and a saturator for a pure volatile component of the monomer mixture is arranged within the auxiliary branch before the outlet pipe.

Method for casting polymeric gels from volatile mixtures of monomer in

An improved intraocular lens, methods of fabricating the same, and methods of implantation of the intraocular lens in a human eye. The intraocular lens implant is a hydrogel and has an index of refraction approximating the refractive index of the natural crystalline lens of the human eye. Fabrication of the intraocular lens is effected in an open concave mold which has a sharp, well-defined peripheral mold edge. The intraocular lens is implanted in the posterior chamber after the cataract operation.

Method of molding an intraocular lens

A perforated soft contact lens which has at least one perforated formed inside the optical zone of lens, i.e. in the distance 0 to 3.5 mm from the lens center. It is manufactured by placing the lens in a swollen state with its inner surface on an elastic base and pressing a punch perpendicularly to the outer surface. Further possible method of manufacturing consists in sticking the soft hydrophilic lens on a hard base, drying and then drilling the openings, advantageously to the first contact of a drill with the base.

Perforated soft contact lens and a method for manufacturing thereof

A toric contact lens with the center of gravity displaced in the direction to its edge by the effect of an one-sided thickening of the lens, where, according to the invention, its optical zone has as far as to the diameter of 5 to 8 mm the center of gravity precisely in the lens axis and the thickening is performed at one place of its edge to displace the center of gravity of the whole lens outside its axis, which thickening has the form of a drop, which would be formed by running down a liquid wetting a front convex surface of the lens if the lens is placed in the vertical position, whereas the direction of displacement of the center of gravity includes the required angle with the direction of toricity of the optical zone. The casting surface of mould for production of the toric contct lens according to the invention is provided with a marginal cavity corresponding to the required thickening. Moulds charged with a metered amount of monomer mixture are used for casting of the lens according to the invention in common equipment either for spin casting or for static casting in closed moulds.

Toric contact lens with displaced center of gravity

A soft and elastic intracameral lens, the back surface of which is formed by a continuous rotation-symmetric convex surface and the front surface comprises a central convex surface of sphere or quadric rotation-symmetric body linked on the diameter of 4 to 8 mm, preferably through a rounded transition, to a concave ring surface of a sphere or a toroid, whereas the distance between the concave ring surface and the back surface is 0.05 to 1.5 mm. The intracameral lens according to the invention is manufactured by charging a mold, which has the negative shape of the required front surface of the lens and is provided at the periphery with a sharp edge protruding by 0.05 to 1.5 mm above the end of the peripheral ring surface, with a monomer mixture as high as above the sharp edge to form a continuous convex meniscus and the mold with the monomer mixture is then exposed to polymerization conditions.

Soft and elastic intracameral lens and a method for manufacturing thereof

Hydrophilic three dimensional polymers, the prevailing mass of which is formed by structural units corresponding to monomers miscible with water at any ratio, and the method for their production, wherein one weight part of the monomers miscible with water is copolymerized, by the effect of free-radical initiators, with 0.01 to 1 weight part of a polyfunctional unsaturated oligomer, which is prepared with an average degree of polymerization x=3 to x=100 by the anionic polymerization of allyl methacrylate, with the contingent addition of methacrylonitrile or methacrylic esters of univalent saturated alcohols containing 1 to 4 carbon atoms or methacrylic esters of monohydroxy compounds containing at least one etheric oxygen atom in the chain, or where 0.7 to 1 weight part of monomers miscible with water is copolymerized with 0.01 to 0.3 weight parts of hydrophobic monomers of the alkyl methacrylate or acrylate type in the presence of an oligomeric crosslinking agent with at least two olefinic double bonds added in the amount of 0.01 to 0.1 weight parts, advantageously up to 0.05 weight parts, by the effect of free-radical initiators.

Hydrophilic three dimensional polymer and a method for production thereof

According to the method of the invention, molds charged with a monomer mixture are arranged into columns with precisely coaxial casting surfaces inside these columns, namely, in tubes of cylindric shape with openings only 0.01 to 0.03 mm larger the diameter of the outer cylindric surface of the mold or the diameter of a hypothetical cylindrical surface circumscribed to any other, preferably a parallel outer surface of the casting mold. The tube with the inserted column of molds is provided with airtight seals at both ends whereas at least one seal is provided with a valve for alternating evacuation and refilling with an inert gas. The invention also provides apparatus by which a complete sequence of required operations including column tilting and rotation is carried out with the tubes charged in this way until the polymerization is completed without transferring the molds from sealed tubes from one apparatus to another or into intermediate magazines.

Method and apparatus for centrifugal casting of contact lenses in open

A method and apparatus are provided for spreading monomer mixture in molds for the centrifugal casting of contact lenses, wherein the said molds containing a monomer mixture are rotated around their axis with the frequency 0.5 to 5 revolutions per minute and, at the same time, the axis of molds is periodically tilted between extreme positions, the angle to the vertical direction of which is in the first extreme position 30.degree. to 60.degree. and in the second extreme position 70.degree. to 100.degree. and the frequency of tilting is twice to ten times lower than the frequency of rotation.

Method and apparatus for spreading monomer mixtures in molds for the

A perforated soft contact lens which has at least one perforation formed inside the optical zone of lens, i.e. in the distance 0 to 3.5 mm from the lens center. It is manufactured by placing the lens in a swollen state with its inner surface on an elastic base and pressing a punch perpendicularly to the outer surface. Further possible method of manufacturing consists in sticking the soft hydrophilic lens on a hard base, drying and then drilling the openings, advantageously to the first contact of a drill with the base.

The invention pertains to a method for producing contact lenses by centrifugal casting in molds inserted as a vertical row into a rotating polymerization column. According to this method of production, objects of cylindric shape, corresponding to the casting molds by the diameter and height, are inserted between the casting molds, whereas the ratio of weight to volume of these objects is larger than 3.

Method for producing contact lenses by centrifugal casting

An apparatus is provided for inserting molds containing a dosed monomeric mixture into a rotating polymerizing column by means of an alternate pushing and releasing of a column of molds falling from tubular magazines connected to said polymerizing column. Said apparatus comprises a body fabricated from a non-magnetic material which is adapted on its lower end for a firm affixation to the column and on its upper end for affixation to the magazine, and being provided with a through-opening of a diameter which is larger than the diameter of the molds, another through-hole, leading to said through-opening, which is formed perpendicularly to the axis of the said through-opening, movable jaws being movable one against the other and moved in the direction of the center by springs, and two stationary blocks placed outside said body in an opposite position while at least the outer ends of the jaws and the stationary blocks are constructed from materials which provide a mutual counterpole magnetic interaction. The apparatus may also be provided with means for eliminating the mutual counterpole magnetic interaction of the ends of the jaws and stationary blocks in accordance with the height of the column of the molds in the polymerizing column.

Apparatus for inserting molds filled with a monomer mixture into

The invention pertains to a method for casting polymeric gels from volatile mixtures of monomers in open molds and to apparatus for performing this method. The principle of the invention resides in the fact that the same concentrations of volatile components present in the polymerization mixture are also present in the gaseous state within a protective gas maintained above the free surface of the polymerization mixture, said gaseous volatile components being in the equilibrium state with those in the polymerization mixture at polymerization temperature. The apparatus for performing said method comprises a main pipe branch which introduces a pure protective gas into a polymerization apparatus and at least one auxiliary pipe branch for saturating the protective gas with a volatile component. These main and auxiliary pipe branches are formed by an inlet pipe connected to a control valve for setting a constant volume flow-rate and further leading to a device for measurement of the flow rate, where their outlet pipes are connected to a common inlet entering the polymerization apparatus and a saturator for a pure volatile component of the monomer mixture is arranged within the auxiliary branch before the outlet pipe.

Two plane-parallel prisms are placed in the optical axis of the examined eye, fitting close to each other in a horizontal plane lying in the optical axis. The prisms are rotated relative to one another in opposite directions at the same angle with respect to the optical axis, and having their parallel vertical optical surfaces parallel with their axis of rotation which intersects the optical axis. One prism is fixed to a scale. Two light sources are placed in a horizontal plane which passes through the optical axis and which are movable independently of one another, while their position with respect to the optical axis and to the examined eye is indicated on respectively associated scale.

Method and apparatus for measuring the shape of the eye

A centrifugal casting device employing a rotatable polymerization column adapted to accommodate a plurality of vertically aligned molds and a rotatable mold-dispensing magazine disposed at an angle .alpha. to the polymerization column and adapted to dispense molds one at a time into the polymerization column.

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Prague, Czechia

Otto Wichterle