Abstract: This invention relates to a method for preparing a photochromic latex, photochromic thin films obtained therefrom, and articles coated with such thin films, in particular photochromic ophthalmic lenses.

Abstract: This invention relates to a method for preparing a photochromic latex, photochromic thin films obtained therefrom, and articles coated with such thin films, in particular photochromic ophthalmic lenses.

Abstract: The ophthalmic lens according to the invention comprises a substrate made of organic glass, having front and rear main faces, at least one primer layer deposited on at least one of the main faces of the substrate, the said primer layer comprising an aggregate of at least two-phase particles, a first phase of which consists of a polymer P1 with a soft character having a glass transition temperature (Tg) of less than 20° C. and a second phase of which consists of a polymer P2 with a hard character having a glass transition temperature (Tg) of greater than 50° C., and at least one layer of an abrasion-resistant coating composition deposited on the primer layer. Application to lenses for spectacles.

Abstract: This invention relates to a method for preparing a photochromic latex, photochromic thin films obtained therefrom, and articles coated with such thin films, in particular photochromic ophthalmic lenses.

Abstract: In this method of making a mold for molding an optical lens an annular closure sleeve is fitted around two molding shells and cooperates with them to define the required molding cavity. The closure sleeve is made from a heat shrinkable synthetic material and is heated to shrink it onto the molding shells. Applications of the method include molds for molding ophthalmic lenses.

Abstract: In a method of manufacturing a transparent polymer material article having a refractive index gradient the polymer base material is caused to absorb a swelling agent including at least a monomer adapted to yield a polymer having a refractive index different than that of the polymer base material. A first preform having a first geometry is formed from the polymer base material sufficiently polymerized for the first preform to be self-supporting. A confinement space is defined between the first preform and an abutment member having facing it a second geometry at least partly different than the first geometry and having a greater volume than the latter. The first preform is brought into contact in the confinement space with a sufficient quantity of swelling agent for the swelling to which it is then subject to cause it to be urged actively into contact with all points of the second geometry.

Abstract: To produce a graded index polymer there is diffused into a base material formed of at least one partly polymerized monomer adapted to yield a homopolymer with refractive index N1 in the gel state an additive material formed of at least one monomer adapted to yield a homopolymer with refractive index N2 different from N1. The polymerization of the base material treated in this way is then completed. The additive material comprises a mixture of at least two monomers and the composition of this mixture is varied with time.

Abstract: The wettable silicone elastomer is obtained by crosslinking of a composition of epoxidized silicones. The elastomer thus obtained is made wettable by grafting saccharide compounds on epoxy groups of the elastomer.The invention is applied in particular to the manufacture of contact lenses.

Abstract: In this method of manufacturing a flexible contact lens from a protein biological material, such as a protein polymer of the gelatine type or a type IV enriched human collagen, a hydrogel is first made by hydrating the protein biological material, in water or a physiological serum. A lens preform is then made from the hydrogel at a temperature between ambient temperature and the temperature at which the material liquefies, at which temperature the hydrogel has a paste-like consistency. This preform, which reproduces the shape of the finished lens with a greater or lesser degree of accuracy, but always with excess material, is then placed in a mold made from a low-loss dielectric material. The mold is in at least two parts which, when locked together, define a three-dimensional shape and a finished lens surface state. The hydrogel is then liquefied by irradiating the mold with an electromagnetic field at a frequency between 10.sup.8 and 10.sup.10 Hz.

Abstract: A contact lens has a rear surface, a front surface and a peripheral edge surface extending between the front and rear surfaces. The peripheral edge surface extends generally forwardly and obliquely from the rear surface to the front surface. The invention is more particularly, but not exclusively, applicable to flexible contact lenses, such as contact lenses manufactured of silicone and similar materials, for example.

Abstract: The apparatus comprises a circulation circuit including, in series, a cell containing the degradable solution and a pump for circulating the solution. A second, regeneration circuit is connected to the circulation circuit by valves for injecting into the latter solution having a concentration greater than that of the circulation circuit. The regeneration circuit has a surge tank or a collector vessel for collecting degraded solution from the circulation circuit.

Abstract: An improved flexible contact lens is provided having hydrophilic and lipophobic properties which allow extended duration of wear by eliminating or greatly reducing the risk of rupture of the natural tear film produced by the cornea. These properties are achieved by crosslinking a selected water soluble polymer which has been grafted onto a pre-formed substrate, for example crosslinking polyvinyl pyrrolidone which has been previously grafted onto a silicone substrate. The grafting and the crosslinking are accomplished in separate stages.

Abstract: An improved flexible contact lens is provided having hydrophilic and lipophobic properties which allow extended duration of wear by eliminating or greatly reducing the risk of rupture of the natural tear film produced by the cornea. These properties are achieved by crosslinking a selected water soluble polymer which has been grafted onto a pre-formed substrate, for example crosslinking polyvinyl pyrrolidone which has been previously grafted onto a silicone substrate. The grafting and the crosslinking are accomplished in separate stages.