The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 12, 1981
Filed:
Nov. 21, 1977
Otto Trotscher, Aalen, DE;
Erwin Wiedmann, Essingen, DE;
Carl Zeiss-Stiftung, Oberkochen, DE;
Abstract
The invention contemplates a refractometer that images a test mark on the retina and is automatic in its determination of both refractive-power and astigmatism parameters, for the eye under examination. An imaging lens serves both (1) to project the test mark to the retina and (2) to convey that image for refocus external to the eye, to a scanner having the ability to digitally establish the eye's focal length. In the process of establishing the eye's focal length, the instrument automatically positions the imaging lens to best serve infinity viewing by the eye, and a prism then rotates the test mark while the scanner photoelectrically tracks the refocused image for the angles at which response is at a maximum, thus establishing astigmatism parameters. The instrument provides selective direct indication or print-out of the automatically determined parametric values.