High-precision ophthalmometer which is independent of distance

US4410242A · kind A · utility

Assignee

• Carl Zeiss Stiftung · DE

Inventors

• Ortwin Muller · Aalen, DE
• Kurt S. Schulz · Williston, US
• Viktor Stopar · Oberkochen, DE

Key dates

• Filing date: Jan 12, 1981
• Grant date: Oct 18, 1983
• Expiry date: Jan 12, 2001

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B7/001
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An ophthalmometer measurement system employs two flat glass plates which move in opposite pivoted directions, to determine the distance between two mirror images on the cornea. The pivot suspensions and pivotal-displacement mechanism are free of play and account for a three-fold improvement in precision of measurement. Provision is made for adjustment to compensate for manufacturing tolerances, in glassplate thickness and mechanical-parts manufacture.