Abstract: A lens meter in which light from a measurement light source is passed though a lens to be measured into a photoelectric conversion element so as to find optical characteristics of the lens to be measured based on photoelectric conversion signals from the photoelectric conversion element. The measurement light source is capable of emitting at least two rays of light having different wavelengths. The lens meter includes computing device for calculating optical characteristics of the lens to be measured based on photoelectric conversion signals from the photoelectric conversion element in response to the two rays of light having different wavelengths. This configuration ensures an accurate measurement of optical characteristics of the lens to be measured whole optical characteristics are unknown.

Abstract: A corneal configuration measuring apparatus is disclosed. It comprises target projecting means for projecting target beams from a plurality of targets towards a cornea of an eye to be tested, light receiving means, measuring optical system for projecting the target beams reflected on the cornea towards the light receiving means and forming target reflection images on the light receiving means, and variable power optical system for varying imaging power of the target reflection images to be formed on the light receiving means.

Abstract: An ophthalmological measuring apparatus is disclosed. It comprises a projecting systems for projecting a target image to the cornea and retina of an eye to be tested, respectively, a measuring optical system for being introduced a corneal reflecting beam of light and a retina reflecting beam of light from the eye, a light receiving portion for receiving the corneal reflecting beam of light and the retina reflecting beam of light through the measuring optical system and photoelectrically transferring the same, an image displaying device for displaying an image of the anterior portion of the eye based on a signal from the light receiving portion, and a calculating device for calculating and measuring a corneal configuration and an eye refractive power of the eye to be tested based on the signals of the corneal reflecting beam of light and the retina reflecting beam of light detected by the light receiving portion.

Abstract: In an ophthalmoscopic instrument such as an eye fundus camera or an eye refractometer, a device is provided for detecting the position of a patient's eye. The device includes a target projecting system for projecting a light beam to the patient's eye, an imaging lens for imaging the light beam as reflected at the patient's eye and a detector for sensing the reflected light beam. A chopper is provided for selectively passing the reflected light beam to the detector for making it possible to produce a signal which includes informations of imaging condition of the light beam at the detector.

Abstract: A refractory power measuring device for measuring the refractory power of the human eye or a lens. The device includes a target projecting optical system having two optical elements which are movable along the optical axis of the system independently from each other. The device can measure simultaneously the refractory powers along two astigmatic axes.

Abstract: An actuating means for an ophthalmoscopic instrument wherein the adjustment knobs and handle are relatively located such that the knobs can be conveniently actuated by fingers of a hand gripping the handle.

Abstract: A vision testing instrument has a projecting optical system for projecting a test chart to produce an aerial image. In the optical system, there is provided a focusing reflector for producing a chart image at a far point. A second focusing reflector is provided so that it can be retractably inserted into the projecting optical path for producing a chart image at a near point.

Abstract: An apparatus for detecting astigmatic axes and measuring refractive powers such as the lens of a human eye. A disc has a first group of slits oriented in one direction and a second group of slits oriented perpendicular thereto. Each slit has a deflecting means with a direction of deflection perpendicular to the lengthwise direction of its slits for measuring the refractive power. The apparatus also has astigmatic axis detecting target means which can be used immediately prior to the refraction so that the refraction on each astigmatic axis can be measured before conditions change in the eye.