Tokyo Kogaku Kikai Kabushiki Kaisha

Shinzi Wada

Yasuo Kato

Ikuo Kitao

Taketoshi Ishihara

Yoshinori Oana

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.

Apparatus for detecting astigmatic axes and measuring refractive powers

An eye refractmeter comprising a target projecting optical system for projecting an image of a target means through a pupil of a patient's eye to produce a target image on a retina of the eye, an observing optical system including objective lens means for observing the target image through the pupil, and a sighting optical system for observing light reflected at the cornea of the eye to determine that the objective lens means is appropriately spaced from the patient's eye, means being provided in the projecting optical system so that the image of the target means is projected by an infrared ray, half-transparent optical means for passing therethrough one of the light bundles along the observing and sighting optical systems and reflecting the other of the bundles, means for directing both of the light bundles passing through the observing and sighting optical systems to a single image pick-up tube, the half-transparent optical means having a reflecting rate such that more than 50% of the light along the observing optical system and less than 50% of the light along the sighting optical system are directed to the image pick-up tube.

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Tokyo, Japan

Shinzi Wada