Abstract:
Methods and devices are provided to obtain refractive correction with superior visual acuity (e.g., 20/10) by achieving an astigmatism-free customized refractive correction. The astigmatism-free customized refractive correction involves obtaining an objective and precise measurement of cylindrical power in a resolution between 0.01 D and 0.10 D in an eye using an objective aberrometer, reliably relating the cylindrical axis obtained from the objective aberrometer to that in a phoroptor, determining an optimized focus error of an eye through subjective refraction with a phoroptor, generating a customized refraction by combining the objective measured cylindrical power, the objective measured cylindrical axis, and the subjectively measured focus power, fabricating a custom lens with a tolerance finer than 0.09 D based on the generated customized refraction, and delivering an ophthalmic lens that can provide an astigmatism-free refractive correction for an eye.
Abstract:
A system for measuring a focal length of an optical lens includes an image processing device and an operating platform. The image processing device is configured for capturing a light spot image of the optical lens. The operating platform includes a mount, a holder and a measurer. The mount is configured for mounting the image processing device. The holder is configured for holding the optical lens. The mount is moved back and forth along the direction towards and away from the optical lens held by the holder. The measurer is configured for measuring and recording a distance between image processing device and the optical lens when a minimal light spot image of the optical lens is obtained. The distance is the focal length of the optical lens.
Abstract:
A method for measuring the optical properties of multifocal ophthalmic lenses. Collimated light is passed through an ophthalmic lens and onto an array of lenslets. Light exiting the array of lenslets is detected by a sensor. Blurred spots and/or double spots may represent diffractive zones of the wavefront. A centroid of the spot or a brighter of two spots may be used to determine the lateral position of the spot. Theoretical calculations, laboratory measurements, clinical measurements and experimental image spots may be generated, compared and cross-checked to determine a monofocal equivalent lens. A Modulation Transfer Function (MTF) may be used to evaluate and compare a diffractive lens and a monofocal equivalent lens.
Abstract:
An apparatus is for evaluating optical characteristics of an optical system based on an image forming position of a point image formed through the optical system. The apparatus includes a point image producing unit that forms a point image through the optical system in each point light source; an imaging unit that images the point images to produce a point image distribution image; and a moving unit that changes relative distance between the optical system and the point light source or the imaging unit in an optical axis direction. The apparatus also performs processing of detecting an image forming position in each different relative distance of the point image based on image information of the point image distribution images, the processing including calculating a regression expression for the detected image forming positions to obtain a shape parameter of the image axis in each of the point images.
Abstract:
A lens power measuring system has a light source and a fiber-optic light delivery system optically coupled to the light source to receive illumination light from the light source. The fiber-optic light delivery system has a transmit/receive end. The lens power measurement system also has a microscope objective optically coupled to the fiber-optic light delivery system through the transmit/receive end of the fiber-optic light delivery system, a movable mirror arranged to intercept at least a portion of light after having passed through the microscope objective, and an optical detection system optically coupled to the fiber-optic light delivery system to receive light after having been reflected from said movable mirror. The optical detection system is constructed to be able to determine a substantially maximum signal of light reflected from the movable mirror in correspondence with a relative position of the movable mirror to a lens to be measured. Methods of measurement include methods using such a lens system.
Abstract:
[Object] A measurement method and an evaluating apparatus are provided which are capable of easily and accurately evaluating the light amount of a spot beam, the diffraction efficiency, and the intensity distribution in the optical axis direction by detecting even a weak diffracted beam in an arbitrary wavelength range converged by a diffraction optical element as an imaging lens.[Means for Attaining the Object] Light emitted from a white light source 11 passes through a wavelength band-pass filter 12 and is diaphragmed by a pinhole slit 13. The resultant light is paralleled by a collimator lens 14 and enters a diffraction optical element 16 as an imaging lens. The light getting out from the diffraction optical element 16 is converged to be a spot beam 17, is magnified by a microscope 18, and is then projected on a CCD 19. A distance changing member 56 changes the distance between the CCD 19 and the diffraction optical element 16, and then, the intensity distribution in the optical axis direction is measured. In-plane intensity distribution perpendicular to the optical axis is also measured.
Abstract:
The device includes receiver elements (121, 114) for receiving the ophthalmic lens; on either side of the receiver elements, firstly lighting elements (S) for illuminating the ophthalmic lens (103) installed on the receiver elements, and secondly acquisition elements (122, 125, C) for acquiring the shadow of the ophthalmic lens illuminated by the lighting elements (S); measurement elements (S, 124, C) suitable for measuring the optical deflection power exerted by the ophthalmic lens on at least one light ray and for delivering a signal representative of the deflection power; and an electronic and computer system including geometrical correction calculation instructions for deducing from the measured deflection power a corrected shape for at least a portion of the shadow of the ophthalmic lens as perceived by the acquisition elements (122, 125, C)
Abstract:
A measurement apparatus which measures a transmittance distribution of an optical system, comprises a light source, a first spherical mirror which forms reference light by reflecting light which is emitted by the light source and is not transmitted through the optical system, a second spherical mirror which forms test light by reflecting light which is emitted by the light source and is transmitted through the optical system, a measurement unit which measures intensity distributions of the reference light and the test light, a unit which calculates reflectance distributions of the first spherical mirror and the second spherical mirror, and an arithmetic unit which calculates a transmittance distribution on a pupil plane of the optical system, on the basis of the intensity distributions of the reference light and the test light, and the reflectance distributions of the first spherical mirror and the second spherical mirror.
Abstract:
A method for measuring the optical properties of multifocal ophthalmic lenses. Collimated light is passed through an ophthalmic lens and onto an array of lenslets. Light exiting the array of lenslets is detected by a sensor. Blurred spots and/or double spots may represent diffractive zones of the wavefront. A centroid of the spot or a brighter of two spots may be used to determine the lateral position of the spot. Theoretical calculations, laboratory measurements, clinical measurements and experimental image spots may be generated, compared and cross-checked to determine a monofocal equivalent lens. An MTF may be used to evaluate and compare a diffractive lens and a monofocal equivalent lens.
Abstract:
A lens meter having a simple configuration, which is capable of precisely measuring optical characteristics such as refractive power distribution in a wide range of a subject lens to be measured at a time. The lens meter has a projection unit which projects a measurement light bundle, a projection lens which projects the measurement light bundle from the projection unit onto the subject lens placed on an optical axis of the projection lens, a diaphragm having an aperture disposed between the projection unit and the projection lens, and a two-dimensional photodetector which photo-receives the measurement light bundle passed through the subject lens after passed through the aperture of the diaphragm and the projection lens, and wherein the projection unit forms a target pattern, and the aperture of the diaphragm is disposed at a front focal point of the projection lens.