Abstract: A device for phase detection testing any kind of optical system, in particular an ophthalmic lens, comprises along an optical axis, an emission device which constitutes a light source, a holding station which receives the optical system under test, an array, a receiving device which receives the image observable downstream of the array, and a data processing device which exploits this image by phase detection. Between the holding station and the array is a convergence adapter element and the data processing device includes a ray plotting program and a calibration system allowing for theoretical and manufacturing aberrations due to the convergence adapter element.

Abstract: A device for phase detection testing any kind of optical system, in particular an ophthalmic lens, comprises, along an optical path, an emission device which constitutes a light source, a holding station which receives the optical system under test, an array, a receiving device which receives the image observable downstream of the array, and a data processing device which exploits this image by phase detection. Between the light source and the holding station is a separator element which constitutes on the axis of the optical path a semi-reflecting surface. The receiving device is disposed to the side, in line with the separator element. The data processing device includes a ray plotting program and a calibration system allowing for theoretical and manufacturing aberrations due to the separator element.

Abstract: An interpupillary distance measuring device comprises a box with a front panel whose position corresponds to an eyeglass frame. The device has a main axis perpendicular to the front panel and equidistant from the eyes of the subject. A horizon plane perpendicular to the plane of the face passes through the main axis and the eyes of the subject. In the box are a master lens and a point light source at the focus of the lens and on the main optical axis. The point source creates at the center of the eyes of the subject corneal reflections, virtual images of which are formed by the lens. These virtual images form real objects for an objective lens which forms a pair of real images on a measurement scale formed by one or more linear arrays of photosensitive charge transfer devices. The device scans sequentially to identify the elements of the arrays at which the images are formed by means of the rank of those elements.

Abstract: A pattern simulator is for use with a grinding machine, especially a machine for grinding eyeglass frames, the machine comprising a grinding wheel support shaft, a pattern support shaft coplanar with the grinding wheel support shaft and a box member carrying the pattern support shaft and adapted to pivot relative to the grinding wheel support shaft. A bearing key in the grinding machine is adapted to support a pattern mounted on the pattern support shaft, an end of which overlies the bearing key. The pattern simulator is adapted to conjugate the distance between the grinding wheel support shaft and the pattern support shaft with the angle of rotation of the pattern support shaft on itself relative to a reference. The pattern simulator constitutes a self-contained mechanical entity and comprises a mounting piece adapted to be fitted to the pattern support shaft of the grinding machine and keyed to it to rotate with it.

Abstract: An optical component such as an intra-ocular implant or contact lens for correcting sight has an aspherical surface in at least the central part of at least one side. The parameters of this surface are chosen so that for the optical system comprising the optical component and an associated eye model the object proximity curve is a specific shape.

Abstract: A positive power ophthalmic lens has a central optically active area the diameter of which is at most equal to the diameter of its geometrical contour. It has an optional peripheral merging area around the central optically active area, between the latter and the geometrical contour. The diameter D.sub.1 in millimeters of the central optically active area is related to the power P of the lens in diopters by a general equation of the type:D.sub.1 =a-b.pwhere a is a numerical parameter taking a value between 84 and 89 and b is a numerical parameter taking a value between 4 and 4.9. This equation makes it possible to obtain well corrected positive power ophthalmic lenses with a large diameter that are relatively light in weight.

Abstract: The proximity P of a simultaneous vision optical lens for correcting presbyopia is defined as the reciprocal of the distance D at which a light ray parallel to and at a distance h from its axis crosses the axis after passing through the lens. The curve representing the proximity P of the lens lies between a lower envelope curve P.sub.inf and an upper envelope curve P.sub.sup satisfying the following equations:P.sub.inf =f(h)=(.SIGMA.A'.sub.i h.sup.i)+P.sub.VLP.sub.sup =f(h)=(.SIGMA.A".sub.i h.sup.i)+P.sub.VLin which P.sub.VL is the proximity for distant vision and A'.sub.i, A".sub.i are numeric coefficients depending on the proximity addition added for near vision to the proximity for far vision. The lens may be implemented as a contact lens, an intra-ocular implant or an intra-corneal lens.

Abstract: An optical system for improving the sight of a person suffering from macular degeneration comprises a high positive power ophthalmic lens adapted to be disposed in front of the eye to be treated and a high negative power intra-ocular lens adapted to be implanted in the eye to be treated after removal of its crystalline lens. At least one surface of each lens is an aspherical surface of revolution. This aspherical surface of revolution preferably has a generatrix that is a conic section.

Abstract: An ophthalmic lens centering and mounting device includes a base which receives and centers the ophthalmic lens. A support receives a holding and securing device for the lens in a removable way and is carried by an arm mounted to swing on the base to apply the holding and securing device to the ophthalmic lens. A barrel mounted to rotate on the arm carries the support. A template support carried by the barrel receives in a removable way a template that has to be superposed on the lens before the holding and securing device is placed on the lens.

Abstract: To measure automatically a distance related to the interpupillary distance of a person, a light source generates a corneal reflection on at least one eye of the person. By means of a scanning system such as a rotating mirror, a sensor receiver is scanned transversely to the general direction of observation of the person to direct light rays from the corneal reflection or reflections onto the sensor receiver in which is a measurement reference mark relative to which the corneal reflection or reflections is or are located.

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 hinge comprises two parts and a pin by which these two parts are hinged together. An end portion of the pin is force fitted in an opening in one of the two parts. A head on the pin is in stressed axial bearing engagement with a bearing surface on one of the two parts. The hinge may be employed to articulate the lateral support temples to the front assembly of an eyeglass frame.

Abstract: An eyeglass frame comprises two surrounds each receiving a respective lens. A bridge joining together the surrounds comprises a generally omega-shaped spring. This has two lateral lugs by each of which it is attached to a respective surround. Its middle part has two ends with concave sides facing towards each other and set back relative to the lateral lugs. A nose-side support arrangement is fitted to the bridge and comprises a U-shaped support having two branches each of which is interlocked with a respective end of the middle part of the bridge.

Abstract: An opthalmic lens centering device comprises a frame on which is a translucent first support plate which receives an opthalmic lens to be centered. There is a frosted screen at the base of the first support plate. A projector system above the first support plate projects an image of the ophtlalmic lens onto the frosted screen. A first observation channel and an opening in the frame enable an operator to view the frosted screen. A second support plate receives a template with which the opthalmic lens is to be compared. A second observation channel in conjunction with the same opening in the frame enables the operator to view the second support plate. The first and second observation channels have a common emergent section of which the opening in the frame forms part. There is a recess in the frame, opening onto its front surface, by means of which the second support plate is disposed at the front of the frame.

Abstract: An elongate deformable structure, that can be used as part of an eyeglass frame, for example, comprises a central core member made from a shape memory alloy. A plurality of annular members are threaded onto the core member. At least one of the annular members has at least one transverse surface disposed obliquely to the axis of the bore through it.

Abstract: The front assembly of an eyeglass frame comprises two rim members. Each of these is adapted to hold a respective lens. The two rim members are joined together by a bridge member. Each rim member comprises at least one part made from a shape memory alloy and a main part made from a neutral material.

Abstract: A progressive multifocal ophthalmic lens has a main meridian along at least part of which the curvature of the lens varies continuously. On each side of the main meridian the areas of aberration are symmetrical to each other. The main meridian intersects a horizontal plane through the optical center of the lens at a point which, relative to a vertical plane passing through the optical center, is spherically offset towards the nose. This offset is between 0.8 and 1.33 millimeters. The plane containing the main meridian is at an angle between 5.5 degrees and 7.5 degrees to the vertical plane. The main meridian converges towards the nose in the lower part of the lens.

Abstract: This bearing ring is of the kind comprising, for contact with the semi-finished blank to be processed, a limited number of bearing areas appropriately distributed circumferentially around the axis of the assembly. The planes tangential to the ends of each of the bearing areas form between them a dihedron, the bearing surface that a bearing area of this kind provides being in practice generally convex.

Abstract: A workpiece holder apparatus is disclosed for use with a surfacing tool for surfacing optical lenses having a surface of revolution especially afocal ophthalmic lenses. A workpiece holder comprises a chamber having an endwall, a sidewall and an open end, for receiving an optical lens. The chamber is connected in operation to a source of compressed air, and an air cushion is established between the endwall and the lens. There is radial clearance annularly between the edge of the sidewall and the edge of the lens. The air cushion is controlled by an annular projection protruding from the endwall, in cooperation with a facing portion of the lens. The entire workpiece holder is adapted to be fitted on a conventional fluid actuator for applying the lens against the surfacing tool.

Abstract: In a grinding machine for beveling or grooving an ophthalmic lens in guided or non-guided modes, the support shaft for the grinding tool is mounted to be movable relative to that carrying the ophthalmic lens to be processed. Associated with it are displacement means adapted to procure its guided displacement parallel to its axis. Between this mobile support shaft and the associated displacement means are selectively engageable coupling means. These procure either axial displacement of the mobile support shaft by virtue of the drive action of said displacement means or disengagement relative to said displacement means at least.