Abstract: A polymeric bifocal lens production process including the steps of selecting a single vision lens or lens blank with a convex surface, and a bifocal mould with a smaller radius of curvature; toughening the convex surface of the lens or lens blank; assembling the mould and lens or lens blank with catalysed monomer between the mould and the lens or lens blank; holding the lens or lens blank and the mould in position relative to one another so that the lens or lens blank contacts the mould; curing the monomer; removing the mould and post-curing to relieve stress in the bifocal lens and to allow the cured monomer to shrink in a controlled manner thereby causing a power decrease in the bifocal segment, whereby the cured monomer cast on to the lens or lens blank is of higher refractive index than the lens or lens blank.

Abstract: A polymeric composition suitable for use in ophthalmic devices such as contact lenses, intraocular lenses and other medical and non-medical devices which composition comprises a copolymer that incorporates repeating units containing a solvolyzable group and various desired hydrophilic repeating units in predetermined ratios, which copolymer is mechanically stable and upon hydration the dimensions of polymeric articles which as formed therefrom can be controlled. In particular, the hydrophilic compositions resulting from the invention are user in applications where stresses and distortions of the polymer article due to water absorption etc. must be minimized or, if possible, eliminated.

Abstract: Fabrication of an eyeglass lens to meet a specific ophthalmic prescription is simplified by arranging back lens wafers of different sphere powers and cylinder corrections in order of the through sphere powers of the lenses that are produced by laminating each back lens wafer with front lens wafers that have the same base curve. The front lens wafers of like segment style are grouped together and include sub-groups of wafers of similar base curve which are arranged in order of add power. Each lens wafer is maintained in an individual package prior to lamination and the back wafer packages display the through sphere powers that result from laminating the wafer with different ones of the front wafers. Reference to a conventional component selection chart is unnecessary as the correct back lens wafer can be directly located from the data on the prescription and the package of the back lens wafer directs the technician to the correct front lens wafer.

Abstract: A contact lens of generally disc-like configuration having a central axis extending through the contact lens and about which the contact lens is substantially symmetric in configuration. The contact lens hasa pupil zone through which the central axis extends and which comprises the area immediately circumferentially surrounding the central axis;an iris zone, which comprises the area circumferentially surrounding the pupil zone; anda peripheral zone which comprises the area circumferentially surrounding the iris zone and extends to the edge of the contact lens.Further in the area immediately adjacent to the periphery of the iris zone and the contact lens and circumferentially extending therearound a band of dark substantially light-absorbing color is provided.

Abstract: A dispenser for dispensing sterile solution which includes a valve to control the dispensing of the sterile solution from a container. The valve comprises a solution outlet and an air inlet opening having an associated filter membrane to filter the air passing into the container. When dispensing the solution, force applied to the container causes the solution outlet to open and prevents access of the solution to the air inlet opening. When the force is relieved, a partial vacuum is formed in the container which causes the solution outlet to close. Air is then drawn into the container via the air inlet opening and through the filter membrane.

Abstract: A series of back wafers for a laminated ophthalmic lens, wherein successive members of the series have a diopter difference in their concave curvature which is sufficiently small to enable a member of the series to be used in combination with any design and power of front wafer to produce a finished lens within the normal tolerance for such a lens. Preferably the diopter difference is 1/8 of a diopter. The invention also comprises a method of producing a laminated lens from the wafers. The series of back wafers enables the production of a finished lens within the normal tolerances for such lenses.

Abstract: An oxygen permeable bifocal contact lens with a Dk of at least 10.times.10.sup.-11 in which a distance vision portion having a refractive index of not more than 1.49 is formed as a preform in which there is provided a recess, and a near distance vision portion having a refractive index of at least 1.540 is formed by filling the recess with a monomer mixture and polymerizing. It is preferred that the distance vision portion be formed as an interpenetrating network copolymer by partially polymerizing one monomer mixture to a predetermined relative viscosity and then adding a second monomer mixture and copolymerizing the resulting mixture. The near distance vision portion may also be formed as an interpenetrating network in the same manner.

Abstract: A method of manufacturing a contact lens with an iris simulating pattern by moulding comprising applying to the mould at least two differing designs so as to form an overall pattern. This overall pattern is transferred to the surface or surfaces of the contact lens during moulding and curing thereof, where the designs transferred interact with each other to substantially cover the iris and produce a coloured natural simulation of the iris of the eye when in use.

Abstract: Hydrophobic casting moulds are treated with electrical discharge, such as corona discharge, to provide enhanced compatibility with hydrophilic objects introduced into the mould, without interfering with the release properties of the mould. A preferred embodiment involves treatment of contact lens casting moulds with corona discharge to provide improvements in the lens manufacturing procedure, as well as enhancement in the quality of the contact lenses themselves. The invention is particularly applicable to the production of contact lenses having a colored iris pattern imprinted thereon.

Abstract: Lens wafers which are bonded together with adhesive to form a laminate lens for use in eyeglasses or for other purposes enables immediate visual detection of the installation of an unlaminated lens wafer in the eyeglasses or the like. At least a portion of the safeguarded wafer has a visually observable region which impairs use of the wafer in the absence of the adhesive and another wafer. The impairment becomes invisible during the process of bonding the wafer to another wafer. The visually observable impairment may have an outline which conveys information such as optical parameters of the wafer or the angular position of the wafer relative to the other wafer at the start of the bonding process.

Abstract: Injection molding methods and apparatus for the production of casting molds for toric lenses having ballast oriented properly with respect to the cylinder axis of the toric surfaces. A calibrated rotatable ring mechanism is used within the injection molding body, for producing a slot or other alignment means on the lens casting mold at a point which is offset a predetermined number of degrees from the axis of the toric surfaces being formed in the casting mold. When the casting mold containing a newly cast lens is mounted on a precision lathe, the mating of the slot with a permanent ridge on the lathe spud ensures that the mold seats on the lathe at the same established place each time with respect to the position of the cutting tool. The offset between the toric axis and the position of the cutting tool has already been established, and therefore there is no need for the lathe operator to make any measurements or resetting of the cutting tool.

Abstract: A blocking mechanism comprises a similified rotary dial mechanism and a l clamp which automatically depressurizes a molten alloy tank in response to a release of the lens clamp pressure. A lens seat is provided with a raised resilient pad to accommodate the recessed portion of a bifocal lens. The application of final lens clamping pressure cannot occur until the lens clamp contacts the lens in order to assure that an operator's finger cannot become accidentally pinched.

Abstract: Hard, wettable, gas-permeable, optically acceptable mechanically stable vision correction lenses can be made from a substantially hydrophobic polymeric matrix having randomly polymerized throughout the matrix residues derived from a hydrolyzable silicone-containing ethylenically unsaturated monomer.