Vision testing device

Details Vision testing device Vision testing device

1980-11-17

1983-11-01

Rosenberger, R. A.

Optics: eye examining, vision testing and correcting

Eye examining or testing instrument

Subjective type

351237, 351243, A61B 300

Patent

active

044127294

ABSTRACT:
A vision testing device, wherein projected or transilluminated indicia in the form of characters and/or symbols of different sizes and recognizabilities are shown to a subject under a test in a test field. The characters or symbols appear bright with a luminance of preferably about 70 cd/m.sup.2. A darker field surrounds the characters or symbols, with the darker field having a luminance of about one-fifth to one-eighth of the luminance of the characters or symbols. Brighter areas with a luminance of 250-1000 cd/m.sup.2 are provided adjacent the darker surrounding field.

REFERENCES:
patent: 2321915 (1943-06-01), Higley
patent: 2738701 (1956-03-01), Hudson
patent: 3684355 (1972-08-01), Molner
patent: 4155638 (1979-05-01), Wolbarsht

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