Abstract: A device for pinpoint application of micro-quantities of a pharmacologically suitable composition to the outer hard coat of the eye, comprises a micro-container with a fixation element. The micro-container comprises a bore whose aperture is adapted to contact the eye surface, and the fixation element is adapted for reversibly adhering to the eye surface.

Abstract: Front and rear lenses of a composite eyeglass lens are laminated together by holding the front lens in an X, Y adjustable stage on a laminating axis, holding the rear lens in a predetermined position relative to the laminating axis, and moving the two lenses together on the laminating axis to spread an adhesive between them. The rear lens holder is rotatable around the laminating axis and has three pressure feet arranged in a triangle for pressing the rear lens uniformly against the front lens in a process that can be observed by the operator. Then, the adhesive between the pressed-together lenses is cured by UV radiation directed through the front lens before the lenses are removed from the laminator.

Abstract: Lens measurement apparatus provides a holding device for holding a lens to be measured at a designated position, a first index projecting optical system for projecting a first refractive power measuring index onto the lens, a second index projecting optical system for projecting a second radius of curvature measuring index onto the concave surface thereof. A refractive power and a radius of curvature are obtained by arranging a light splitting member on the optical path of the first index luminous flux, or by moving a photoelectric detecting element for detecting each position of the first index and the second index along with the optical axis.

Abstract: An optical displacement sensor that has a light beam polariscope located on the light path of light reflected from a target surface, and means for detecting the focal point position and transverse position of the light beam from the polariscope. The focal point position corresponds to axial displacement at the target surface, and the transverse position corresponds to inclination of the target surface, so the effect of the inclination of the surface can be compensated for by using a transverse position detection signal to adjust the light beam polariscope.

Abstract: A lens meter having an optical measuring system which can measure optical characteristics of a progressive lens includes a memory means which stores the optical characteristics of each measuring point measured in a range from a far vision region to a near vision region by the optical measuring system, a distinguishing means which compares the optical characteristics of each measuring point stored in the memory means and distinguishes whether the measured points belong to a progressive band or areas located in both right and left sides of the progressive band, a display means which displays a result of the distinguishing means. With this structure, the optical characteristics of each measuring point can be measured ranging from the far vision region to the near vision region by the optical measuring system, and the results are stored in the memory means.

Abstract: A method and apparatus for measuring a refracting power of an optical system to be inspected. A beam source generates a luminous flux which passes through the optical system to be inspected. A rotating plate intermittently blocks the beam after passing through the optical system to be inspected. A beam receiving element receives the beam passing through the optical system to be inspected and intermittently blocked by the rotating plate, and outputs a beam reception signal based on the received beam. A rotational position detector detects a rotational position of the rotating plate and outputs a rotational plate detection signal based on the detected rotational position of the rotating plate. Further, a calculating means calculates the refracting power of the optical system to be inspected based on a change quantity from the detected rotational plate detection signal to the detected beam reception signal.

Abstract: Front and rear lenses of a composite eyeglass lens are laminated together by holding the front lens in an X, Y adjustable stage on a laminating axis, holding the rear lens in a predetermined position relative to the laminating axis, and moving the two lenses together on the laminating axis to spread an adhesive between them. The rear lens holder is rotatable around a laminating axis and has an adjustable center foot adhesively tacked to the rear lens and an array of surrounding pressure feet for pressing the rear lens uniformly against the front lens in a process that can be observed by the operator. Then, the adhesive between the pressed-together lenses is cured by UV radiation directed through the front lens before the lenses are removed from the laminator.

Abstract: A lens meter including an illumination light source for illuminating a measurement target, a target projection optical system for projecting the measurement target onto an inspected lens, an observation optical system for observing a focused state of the projected target image and target moving device for moving the measurement target in an optical axis direction or the like to thereby measure a refracting power of the inspected lens on the basis of an amount in which the measurement target is moved in the optical axis direction. This lens meter includes a lens holder for holding the inspected lens substantially parallel to a plane on which the lens meter is installed, and a reflection system optical element for reflecting a measurement light passed through the inspected lens even times so that the measurement light is introduced into the observation optical system.

Abstract: A lens meter projects measuring light onto a lens, detects the measuring light traveled through the lens at a light detecting element, and determines the optical characteristics of the lens on the basis of the detected data obtained from the light detecting element. The lens meter provides a display device for displaying the relation to adjust the lens to the optical axis of the measuring optical path, measuring mode selector device for selecting a measuring mode from a single focus lens measuring mode to a progressive focus lens measuring mode, a control device for measuring the lens at position measuring points distributed at predetermined intervals on the lens successively on a measuring optical axis and measuring the refractive power of the lens at each measuring point.

Abstract: An ophthalmic measuring apparatus includes a device for measuring the distance from a certain point (such as the center of the other of right and left spectacle lenses or the bridge position of the lenses) to the center of the lenses on the basis of the amount of displacement of a spectacle lens contacting member, and a device for measuring the distance from a certain point (such as the center of the pupil of the other of right and left eyes to be examined or the nose position) to the center of the pupil on the basis of the amount of displacement of an observation system for observing the front eye parts of the eyes to be examined therethrough.

Abstract: An automatic lensmeter for automatically measuring a lens characteristic of a lens to be tested, comprises: a measuring unit including an optical system for detecting a refraction characteristic of the lens; a calculation unit for calculating a lens characteristic value in accordance with information from the measurement unit; a display unit for displaying the lens characteristic value calculated by the calculation unit; an actual eccentricity calculation unit for calculating an actual eccentricity based on the lens characteristic value calculated by the calculation unit; and an optical axis position determination unit for determining whether the actual eccentricity calculated by the actual eccentricity calculation unit is within a predetermined range or not to determine whether the measurement and/or the marking are permitted. The display unit displays the determination of the optical axis position determination unit.

Abstract: An automated lensometer including a mounting device to support and center a lens to be tested along an axis. First and second arrays of light source patterns are positioned at different optical distances from the mounted lens and are projected along the axis through the lens. The images of the projected patterns are captured and stored in a camera imaging device located along the axis. A comparison of the patterns by a processor allows derivation of refractive power of the lens.

Abstract: A computer indicated lens movement direction protocol is utilized in combination with a lensmeter to designate required movement of lenses with respect to a lensmeter to insure sequential measurement of progressive addition lenses. Lens measurement occurs at four sample points closely spaced on the lens surface. The system uses power variations (PV.sub.1 and PV.sub.2) at each of the spaced apart lens sampling points to indicate when sampling of the lens occurs in a region of constant spherical power, when sampling of the lens occurs in a region of changing spherical power, and finally when sampling again occurs in a region of constant and increased spherical power. When sampling of the lens occurs in a region of changing power, lens movement is guided along a path of constantly changing sphere utilizing changes in astigmatism measured in the 45.degree.-135.degree. directions (C.sub.X).

Abstract: Optical properties of a lens, including localized defects, are determined by analyzing the refracted image produced by transmitting a beam of light through an aperture and a lens to be tested. The image is reflected onto a light sensitive detecting surface. Information obtained from the light detecting surface is digitized and sent to an Image Processing Unit which calculates the optical properties of the lens. The aperture may consist of a single shaped opening or alternatively a plurality of concentric, annular rings. Correction lenses may be employed, either permanently or selectively, to alter the refracted beam before the beam intersects the detecting surface.

Abstract: A grazing incidence interferometer (1) includes a laser (10) and a beamsplitter (16) for splitting an output of the laser into a reference beam (B) and into a sample beam (A). A surface (18) to be examined is disposed at a first angle such that the sample beam is incident on and reflects from the surface at an angle of incidence other than normal, thereby providing a grazing incidence configuration. A beam combiner (22) combines the reference beam and the sample beam that reflects from the surface into a combined beam (C). An image plane (24) is disposed for receiving the combined beam such that an interference pattern is formed at the image plane. The image plane is disposed at a second angle to the combined beam, the second angle being selected to compensate for a reduction in an aspect ratio of the interference pattern that results from the surface being disposed at the first angle.

Abstract: An automatic lensmeter for measuring optical characteristics of a lens to be examined is disclosed. The automatic lensmeter includes a display for displaying thereon an alignment target, first and second calculation devices for converting a shift between the optical center of the lens to be examined and a measurement optical axis into a prism power and a deviation respectively, and device for forming the alignment target at a predetermined position, whereby highly accurate alignment can be attained and accurate marking can be readily obtained.

Abstract: An automatic lens meter includes a projection optical system for projecting light beams onto a lens to be tested. The lens is held at a predetermined position in the direction of an optical axis. The meter also includes a receiving optical system having a light position detector. The receiving optical system receives light beams transmitted through the lens to be tested on the light-position detector. The meter further includes a calculator for calculating a diopter value and an eccentricity of the lens to be tested from the position of the tranmitted light beams on the light-position detector, a timer for measuring the time during which the eccentricity is within a predetermined range, and a display device for displaying the diopter value of the lens to be tested when the time during which the eccentricity is within a predetermined range exceeds a predetermined time.

Abstract: Adaptions of lensmeter optical trains are disclosed for enabling the measurement of contact lenses without the interference of spherical aberration from the highly meniscus lens formats of contact lenses. A generic system of measurement of the contact lenses when off of the eye is introduced by having light incident to or passing from the suspect contact lenses at an approximate aplanatic condition of the contact lens. The approximate aplanatic condition is determined by taking the average power of the posterior and anterior surfaces of the contact lenses for the general population--approximately 8 mm, assuming an index of refraction of approximately 1.5--calculating the aplanatic condition for such a "surface," and having light incident on the lenses for the interrogation of the lenses approximate the aplanatic condition.

Abstract: An apparatus and method are disclosed for characterizing the surface of mirrors in which a cross-grid type phase grating is illuminated from behind by light reflected from the mirror so as to create a grid-like interference pattern when observed along an observation axis. The fringe lines in the generated or observed interference pattern are correlated to the grating and observed for relative displacement from the grating axis. Apparent fringe index numbers for the fringe lines are used to determine coefficients for a plurality of monomial series which are in turn used to derive Zernike coefficients from which a wavefront contour is obtained. In order to reduce alignment errors during analysis, each fringe line is subtracted from the next lower order line and before monomial coefficients are determined.

Abstract: In an automated lensmeter, provision is made for estimating dispersion when high index glasses are utilized with lenses having relatively large diopter prescriptions and for eliminating error due to spherical aberration when determining the power of contact lenses. For estimation of dispersion--typically required for optical corrections in the range of 10 diopters--two discrete color light sources are used for optical measurement of the power of the suspect lens. As a result of the obtained power difference resulting from the differing colors used, dispersion can either be estimated and referenced back to a generally accepted standard or a look-up table can be utilized to identify the specific glass class or even specific glass type being measured. In the case of the measurement of power of contact lenses, differing points of measurement through the suspect contact lenses are made. Effects of possible dispersion are ignored and differences in lens power determined with different radii of measurement.

Abstract: An automatic lensmeter according to the present invention is used for accurately measuring optical characteristics of a lens to be examined. The automatic lensmeter incorporates a mode change-over switch for switching to an addition diopter measurement mode, memory means for storing cylindrical diopter of a measured far-vision area of the lens, calculation means for calculating a difference between the cylindrical diopter measured in the addition diopter measurement mode and the cylindrical diopter of the far vision portion, and display means for indicating a calculated result of the calculation means thereon.

Abstract: A method for evaluating the optical quality of a glazing using a projection technique in which the shadow of glazing (3) projected with a localized light source (2, 15) is analyzed by a camera (6) assisted by a computer. The illumination at a point (M) of screen (4) is compared to the illumination at same point (M) in the absence of glazing (3) and the measurement is weighted by the optical and geometric parameters of corresponding point (m) of glazing (3). The resolving power in one direction is adjustable by the modification of the dimension of the source in this direction. Application is to the inspection of windshields on a production line.

Abstract: To determine the focal power of an ophthalmic lens, a plurality of light rays are passed through the lens and a photosensitive position sensor is disposed on the exit side of the lens to measure the coordinates of the points at which the light beams impinge on an analysis plane perpendicular to the lens axis. The light rays comprise three light rays on a circle and a light ray on the system axis.

Abstract: A method and apparatus for aligning and positioning a lens such that the optical and/or cylinder axis of the lens is precisely aligned with a fixture for the purpose of assembly or further mechanical operations such as machining and polishing. According to another aspect of the invention, the lens apex is precisely positioned a constant distance from a reference point. In order to implement the above, a method and apparatus is disclosed for optically aligning and positioning lenses using digitzed video imaging, an X-Y-Z micron stage and a microprocessor (or computer) capable of performing image analysis.

Abstract: An apparatus and method are disclosed for increasing the alignment accuracy for off-axis mirrors in which a circular phase grating is illuminated from behind onto the mirror to be aligned creating a reflected image of the grating. The circular grating is aligned with the reflected image produced by the mirror so as to create at interference pattern when observed along an observation axis which is an approximate mirror optical axis. The generated or observed interference pattern is observed for the presence of moire lines and the mirror is translated or rotated about the observation axis until moire lines are minimized in, or disappear from, the observed interference pattern. The observation axis is then aligned with the optical axis of the mirror which can be recorded or marked. In further embodiments of the invention, the fringe pattern is transferred, using one or more lenses, to an image processing element such as a camera.

Abstract: A zoom lens is driven by an oscillating drive in continuous motion between different states of magnification to cause an image on a video screen to expand and collapse about the point on the optical axis of the lens. The expanding and collapsing image is viewed on the video screen and the location of the optical axis of the lens assembly is determined by identifying the point on the screen that does not move. The lens assembly is then adjusted so that the stationary point coincides with a reticle at the optical center of the image sensor.

Abstract: An autolensmeter for inspecting refracting power of optical systems is herein disclosed, which comprises a collimater lens for projecting light from a light source onto an optical system to be examined as a parallel luminous flux, a mask means having a mask pattern for selectively transmitting the luminous flux from the optical system and a photodetecting means for receiving the luminous flux partially transmitted through the mask pattern, disposed at a non-image forming position of the optical system, characterized in that an optical element is arranged in close vicinity of the mask pattern so that the light source and the photodetecting means are in an optical conjugate relationship with each other.

Abstract: There is disclosed a method and apparatus for providing spectacle correction on axis in a compound lens system. A lensometer having a lens stop assembly is used in conjunction with a collet fixture for positioning a lens and for aligning the lens in a compound lens system while employing the lensometer to enable optical alignment. The method operates by placing the lens in the fixture to firmly hold the lens and allowing the lens to protrude from the fixture. The fixture is then placed over the lens stop assembly of the lensometer and the compound lens system is then held against the lens as emplaced on the lens stop. By rotating the fixture, one can align the lenses on axis and determine the proper position of the lens in the compound system. The collet fixture which includes an inner tubular section having an open top and an open bottom. The tubular section is symmetrically disposed about an axis with the open top having a series of slots.

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 apparatus for measuring the optical characteristics of a lens disposed in a measuring optical system illuminated by the beams of a plurality of light sources, the apparatus includes photoelectric detecting means having a detecting surface disposed substantially orthogonal to the optical axis of the measuring optical system for detecting the positions of the light beams passed through the lens and producing a photelectric signal, optical characteristic calculating means responsive to the signal to calculate the spherical power, the cylindrical power and the principal meridians axis degree of the lens, deviation detecting means responsive to the signal to detect the amount of deviation of the central position of the light beams passed through the lens from the position of the optic axis of the measuring optical system, eccentricity calculating means for calculating the eccentricity of the optic axis of the lens from the optic axis of the measuring optical system in a two-dimensional coordinates system on the

Abstract: In an apparatus for measuring the optical characteristics of an optical system to be examined a light source determines a reference optical axis and generates a light beam that is passed through the optical system to be examined along the reference optical axis. A mask partly transmits the light beam therethrough and has a pattern comprising at least one straight line disposed off the reference optical axis in the light beam, the straight line of the pattern extending in a predetermined direction in a plane substantially orthogonal to the reference optical axis. A photosensitive detector receives the light beam passed through the optical system to be examined and the mask. The detector is fixedly disposed relative to the mask and has a substantial length in a direction substantially orthogonal to the reference optical axis and the straight line of the pattern.

Abstract: An apparatus which comprises a collimating lens, light source means for selectively forming light sources in two positions on the optical axis of the collimating lens, means for defining the position of the lens to be inspected opposite to the light source with respect to the collimating lens, a mask plate having translucent or opaque areas symmetrical to the optical axis, a relay lens for placing the mask plate at a position conjugate with the lens position, an imaging lens positioned opposite to the mask plate with respect to the relay lens, and photoelectric converting means for producing image signals corresponding to the positions, in a plane perpendicular to the optical axis, of the image of the translucent or opaque areas of the mask plate formed by the imaging lens.

Abstract: In aberration measurement, a light beam from a light source provided at the image plane position of a lens to be examined is caused to enter the lens to be examined, the light beam passed through the lens to be examined, is separated into a plurality of light rays in a plane perpendicular to a principal ray or in a plane perpendicular to the optical axis of the lens to be examined, and the position of each light beam is detected at a position which is spaced apart from a position optically conjugate with said image plane position with respect to the lens to be examined and at which the plurality of light rays can be separated from one another.

Abstract: An apparatus for indicating misalignment of the optical elements of an optical system (10) comprises a source (11 ) of optical radiation (which is in general nonpolarized), a beam splitter (12), an optical flat (13) and an off-axis beam sampling device (14). The beam splitter (12) divides an input beam (20) from the source (11) into a transmitted component (21) which passes along the optic axis of the optical system (10) to the optical flat (13), and a reflected component (22) which passes to the off-axis beam sampling device (14). The beam sampling device (14) divides the reflected component (22) of the input beam (20) into two angularly separated beams (24) and (25), which are returned to the beam splitter (12). The beam splitter (12) transmits components (24') and (25'), respectively, of the angularly separated beams (24) and (25) to a detector plane (23).

Abstract: The disclosure concerns the determination of the ophthalmic parameters of a thin astigmatic optical element without requiring initial location of its cylindrical axis. The effective optical power of the eye or other element is measured in three mutually spaced meridians that are selected without regard for the cylindrical axis. The ophthalmic parameters of the element, typically the spherical power, the cylindrical power and the cylindrical axis, are then derived from the measured powers and their selected meridian angles. The power of an astigmatic element in a selected meridian intermediate the principal meridians may be determined in generally conventional manner by adjusting a test optical system to produce a sharp image of a suitable target, preferably with limitation of the image-forming light to rays that traverse the element close to the selected meridian.

Abstract: At least three light beams are applied to different positions on an optical element to be measured. The light beams coming via the optical element to be measured are received through a light-receiving lens by a two-dimensional light position detecting system provided at the rearward focus position of the light-receiving lens or at a position conjugate therewith or are received by two-dimensionally disposed light position detecting system. Three deviation vectors are detected and the refractive powers in three meridian directions are detected, or at least five light beams are applied to different positions on an optical element to be measured and from five deviated beam positions, a general elliptical curve coupling them is specified, whereby the degree of astigmatism, the direction of astigmatism and the refractive power are calculated.

Abstract: An apparatus for measuring the optical characteristics of an optical system includes a light source, collimator means for collimating a beam of light from the light source, a mask means, a means for holding the optical system to be tested between the collimator means and the mask means, a detector, a calculator, and first beam splitting means. The mask means includes at least one mask provided in each optical path following the first beamsplitter means, each having a linear band group consisting of at least two parallel linear bands, with each mask disposed to provide a different orientation for the linear bands.

Abstract: A lens judging apparatus to be used in a lens meter is disclosed. It has at least one projecting device movably mounted on the both sides of a lens table with respect to its elongated direction. The projecting devices are movably arranged within a predetermined range in the traversing direction relative to the elongated direction of the lens table by receiving the respective spectacles hung thereon. It also has a detector for the movement of the projecting member, a device for judging whether the spectacle lens is for the right or left by detecting a signal emitted from the detector, and a display panel showing a character measuring either "right" or "left" based on the result of judgment made by the judging device.

Abstract: An automatic lens meter includes a first positive lens system, a second positive lens system having its forward focal plane coincident with the rearward focal plane of the first positive lens system, a pin-hole plate disposed in the forward focal plane of the second positive lens system, the optical axis of the first and second positive lens systems passing through the pin-hole of the pin-hole plate, four spot light source means disposed on the forward focus side of the first positive lens system, the four spot light source means being provided in a plane orthogonal to the optical axis and made conjugate with a predetermined position on the rearward focus side of the second positive lens system by the first and second positive lens systems, a lens to be examined being disposed at said predetermined position, a third positive lens system provided on the side opposite to the second positive lens system with respect to said predetermined position, light-receiving means disposed on the opposite side of the second

Abstract: The minimum edge thickness boundary of an ophthalmic lens is mathematically projected onto a plane containing a scaled image of the spectacle frame while the ground depth of the lens is dynamically varied to obtain circumscription with the image. Optimal tool settings are then determined which will result in a ground prescription lens having minimum overall thickness.

Abstract: A nondestructive optical test set-up for measurement of critical parameters of expanded beam connectors which does not require the insertion of fibers into the connector or contact to any critical surface. The method is independent of fiber preparation techniques, assembly procedure, and connector housing accuracy.

Abstract: An optical distortion analyzer system which is capable of automatically quantifying with a high degree of accuracy and repeatability the optical quality of transparencies such as windshields or windows. The analyzer system is made up of a platform adapted to support the transparency with two degrees of freedom. A probe beam of electromagnetic radiation emanating from, for example, a laser is passed through the transparency as the transparency is moved about a horizontal and vertical axis establishing a plurality of test points on the transparency. An analyzer unit receives the probe beam and therefrom establishes horizontal and vertical deviations in the transparency as well as determining the cylindrical and spherical lens power components and principal meridan angle of the transparency. A processor provides recognizable opthalmic parameters of the above characteristics of the transparency and correlates these parameters with the plurality of test points on the transparency.

Abstract: An apparatus for measuring the optical characteristics of an optical system includes a light source, a collimator lens, a mask, a detector, and a circuit for measuring information received from the detector. The light source projects a beam of light through the collimator lens and then through the optical system. The beam of light then passes through the mask, which has a pattern of at least two non-parallel, straight lines on it, and is projected onto the detector. With the information provided to the circuit by the detector the optical characteristics of the optical system are determined. The circuit determines the optical characteristics of the optical system by evaluating changes in the length and gradient angles of the lines projected onto the detector from the mask.

Abstract: The invention concerns a process and device for the positioning of an optical measuring instrument and a spectacle frame in relation to each other. The practitioner, operating from a position roughly determined by the point at which the two optical paths converge adjusts the relative position of the spectacle frame and measuring instrument so that the reflection of the side edge of the frame in a semi-transparent mirror located on each side of the device appears directly over the actual image of an alignment mark behind the mirror. This convergence indicates that the frame is in the correct position in relation to the measuring instrument.

Abstract: An automatic lens meter for measuring a pherical power, a cylinder power, an angle of cylinder axis, and a power of prism of an ophthalmic lens. The automatic lens meter is characterized by the use of a shading device to obtain the coordinates of the points at which respective light rays emitted from respective pin-holes of a multiple-pin-hole disc cross the second focal plane of an objective lens, according to a shading time lag among respective light rays.

Abstract: Given the known position of the optical center of an unfinished lens which is to be contoured for an eyeglass frame, this invention relates to a single device for locating and aligning the contemplated geometric center of what will be the finished lens with the optical center so that a block may be secured to the lens at such geometric center for holding the lens for contouring. The device comprises a lens holder situated above a slidable grid scale which is used in combination with a fixed scale to decenter the lens on the lens holder such that the contemplated geometric center of the lens will line up above the position of a block that may be accurately moved into place by moving the same slider containing the grid.

Abstract: A method and apparatus for aligning a lens blank upon a lens blocking device. The apparatus comprises a transparent aligning member, attached by arm means to a stanchion on the lens blocking machine. Vertically aligned perpendicular intersecting linear indicia are imprinted upon the upper and lower surfaces of the transparent member for vertically aligning an underlying lens without introducing a parallax error. A lens retaining member is also carried by the stanchion and is selectively pivoted into position to retain the aligned lens blank for blocking. The method consists of rotating a lens blank upon a lens blocking machine until perpendicularly intersecting linear indicia on the surface of the lens are vertically aligned with perpendicularly intersecting indicia on the upper and lower surfaces of a transparent aligning member.

Abstract: Apparatus is disclosed for determining, with improved accuracy, the back vertex power of a hydrated soft contact lens. The increased accuracy is determined by sequentially using several optical modes to provide additional information needed to accurately calculate back vertex power. Lens thickness, sagittal height and posterior radius values are also accurately obtained with the apparatus.Optionally, a mode for determining lens radius and thickness is also disclosed.

Abstract: An automatic lensmeter (48) for determining the refractive properties of a test lens (76) including optics (52, 58, 62, 64, 68, 70, 72, 74) for producing a collimated, nonrotational beam of light, equally disposed about and propagating along an optical axis (50), which is refracted by the test lens (76), a nonrotational mask (18) having an annulus (24) for generating a stationary elliptical loop (28) of light at a detecting plane (26), the loop (28) having a shape, size and location dependent on the refractive properties of the test lens (76), and a photodetector (31) at the plane (26) to intercept the loop 28. The lensmeter (48) has no moving optical components and, due to the loop 28, provides an infinite number of points to determine very accurately one or more of the refractive properties, thereby overcoming problems with prior automatic lensmeters having relatively rotational optics and/or providing a finite number of points at a detecting plane.

Abstract: A method of measuring optical properties of a transparency uses a video camera for focusing and then refocusing an image of a point source of light transmitted through a test region when the transparency is first absent and then later present at the test region. The distance the camera needs to be moved together with the focal length of a focusing lens used in carrying out the method provide sufficient quantitative data to calculate the spherical optical power of the transparency. Also, the camera generates video images of the point source both before and after the transparency is present in the test region. These images are displayed on a screen containing a grid pattern which facilitates measurement of the displacement of the image from the center of the grid or from the optical axis due to the presence of prismatic deviation in the transparency. Given the earlier data and supplemented by the latter displacement quantity, the prismatic deviation of the transpareny can also be calculated.