Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Patent
1997-09-19
1999-02-09
Dang, Hung Xuan
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
351211, A61B 514
Patent
active
058701680
ABSTRACT:
A vision-testing device for examining the crepuscular vision, which has several visual signs which can be placed at random into the beam path, and a glare light source, all in a closed housing. The device has in extension of the axis of the eye a partially transparent mirror inclined with respect to the axis of the eye and a refractive element. The vision-testing device is compact, light and robust in design and enables a testing of the crepuscular visual acuity and the dazzle sensitivity. The refractive element consists of an achromatic lens inserted into the beam path, and covering the visual range of both eyes or a concentrating reflector, at the focal point of which is provided the visual sign location. The carrier for the visual signs to be located at the visual sign location can be arranged movably such that any of the multiple visual signs placed on the carrier can be moved into the beam path. A filter can also be swung into and out of the beam path between the light source and the visual sign location. The glare light source is arranged stationarily next to the transilluminated visual sign location. One or several diaphragms with varying diaphragm openings are provided above the visual sign carrier, which diaphragms can be moved selectively into the beam path.
REFERENCES:
patent: 5793469 (1998-08-01), Feiertag et al.
Feiertag Carsten
Kirchhuebel Rainer
Dang Hung Xuan
Oculus Optikgeraete GmbH
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