Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Patent
1983-09-06
1985-07-23
Bovernick, Rodney B.
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
351247, A61B 314
Patent
active
045305790
ABSTRACT:
An astigmatic ruler for determining an amount of astigmatism associated with a cornea of a human eye by qualitative methods comprises a target member having a plurality of apertures therethrough. One of the apertures is circular and the remaining apertures are elliptical in shape. The elliptical apertures are associated with various incremental amounts of astigmatism. The target member is adapted to be positioned between the eye and an illuminated surgical microscope such that light is projected through a selected aperture and onto the eye. The amount of astigmatism associated with the eye is indicated when a selected aperture is presented to the eye and the aperture has a degree of ellipticity that generally balances the amount of astigmatism associated with the eye so that a generally circular image is reflected from the eye.
REFERENCES:
patent: 3264932 (1966-08-01), Hendricks
patent: 3552837 (1971-01-01), Volk
patent: 3895860 (1975-07-01), Townsley
patent: 3972602 (1976-08-01), Inns
patent: 4157859 (1979-06-01), Terry
patent: 4159867 (1979-07-01), Achatz et al.
patent: 4256385 (1981-03-01), Cohen et al.
patent: 4426141 (1984-01-01), Holcomb
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