Patent · US Expired

Hand-held line grid interference retinometer

US5479221A · kind A · utility

9Cited by

7References

9Claims

0Family size

Assignee

HEINE Optotechnik GmbH & Co. KG · DE

Inventors

Helmut A. Heine
Anton Schneider · Gilching, DE
Otto H. Schmidt · Herrsching am Ammersee, DE

Key dates

Filing date	May 26, 1994
Grant date	Dec 26, 1995
Priority date	—
Expiry date	May 26, 2014

Classification

Technology area (CPC A)Human Necessities
CPC primaryA61B3/117
WIPO fieldMedical technology
WIPO sectorInstruments

Abstract

An apparatus for testing visual acuity, or clearness of vision, particularly when there is impaired refracting medium in an eye, includes a lamp (1) and a pin-hole diaphragm (4) arranged in a light-beam path downstream of the lamp with a single diffraction grating (6), being provided in the light-beam path downstream of the pin-hole diaphragm.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.