Ophthalmic apparatus

Details Ophthalmic apparatus Ophthalmic apparatus

1995-04-27

1997-10-07

Dang, Hung X.

Optics: eye examining, vision testing and correcting

Eye examining or testing instrument

Subjective type

351222, A61B 302

Patent

active

056753993

ABSTRACT:
An ophthalmic apparatus includes a visual target indicating portion for indicating patterns of at least three directions each consisting of a plurality of parallel lines, a visual target optical system for making variable a diopter of the pattern presented to an examinee, and a response inputting device for inputting a response of the examinee. A refractive power of an eye of the examinee is obtained from a diopter of the pattern at the time the examinee inputs a response thereof through the response inputting device at the limit of his visual recognition of the pattern. In another arrangement, a refractive power of an eye of the examinee is obtained from intervals of the parallel lines at the time the examinee inputs a response thereof through the response inputting device at the limit of visual recognition of the pattern, the intervals of the parallel lines of which change over time.

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patent: 5249003 (1993-09-01), Kohayakawa
patent: 5420650 (1995-05-01), Kohayakawa

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