Vision testing system for testing the sight function of a patient

US5331358A · kind A · utility

Assignee

• Carl Zeiss Stiftung · DE

Inventors

• Hermann Schurle · Aalen, DE
• Wolfgang Grimm · Bremen, DE
• Hartmut Mennicke · Pullach, DE

Key dates

• Filing date: May 8, 1992
• Grant date: Jul 19, 1994
• Expiry date: May 8, 2012

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N13/324
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A vision testing system includes polarization spectacles having different polarization axes with or without .lambda./4 filters for the two polarization lenses forward of the eye of the patient to be tested. This system also includes a vision testing apparatus for generating light having a specific polarization direction. The vision testing apparatus includes essentially two polarization filters and two LCD-displays which are mounted alternately one behind the other. This arrangement can so influence the light coming from the light source that test figures or portions of the test figures can be seen by one eye or by both eyes. If a test figure is to be changed, then a corresponding command is issued via a key pad to a switching unit which drives two drive circuits of the two LCD-displays in a desired manner. By making appropriate modifications of the vision testing apparatus, a patient can be tested as to color-vision acuity.