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:
Jan. 07, 1997
Filed:
Jun. 22, 1995
Stephen L Trokel, New York, NY (US);
Other;
Abstract
An apparatus and method for measuring visual function under simulated nighttime conditions where the pupil is large by maintaining extremely low ambient illumination when the test is performed in a darkened room, the apparatus including a test field defining a plurality of recognizable indicia of variable irradiance which appear on a black background having zero irradiance or which indicia are completely black and surrounded by a bright background of variable irradiance, the test field being either illuminated by projection or transilluminated, and a field stop having a plurality of apertures of progressive sizes which are placed in front of the eye of the person being tested to ascertain the true functional optical zone of the cornea.