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:
Jun. 19, 1990
Filed:
Sep. 09, 1988
Charles E Campbell, Berkeley, CA (US);
Allergan Humphrey, San Leandro, CA (US);
Abstract
A prior art ultrasonic eye measuring device is fitted with pinhole optics. A fixation target is provided with the pinhole optics. The instrument is used to measure the dimension of the eye typically preparatory to cataract surgery. In use of the instrument, the patient has the cornea anesthetized. The patient is thereafter told to fixate on the spot of light leaking from the pinhole optics as the eye examiner brings the instrument into contact with the cornea of the eye. The point source of light approaches the eye. As it approaches, the point source increases in size. When the light source becomes sufficiently large, the fixation target becomes visible. Upon touching of the instrument to the eye, ultrasound measurement of the dimension of the eye preferably along the visual axis occurs. By the expedient of aligning the interrogating ultrasound axis to the line of sight of the fixation target, measurement of the visual axis length of the eye occurs. The appearance of the fixation target immediately before eye measurement minimizes undesired off axis measurement. In a preferred embodiment of the instrument, the conjugate image of a pinhole light source is relayed by optics through the lens of the eye. Consequently, the fixation target is not diffraction limited.