Reichert, Inc.

Leica Microsystems Inc.

Douglas H Hoover

Christopher J Percival

David A Luce

Donald E Miller

Carl E Hynes

David Biggins

A fast position detection system and related method for an ophthalmic instrument utilize stored geometrical relationships determined by multiple regression during instrument calibration to compute X-Y-Z alignment status of the instrument relative to a patient's eye based on local x-y position information from a pair of lateral detectors receiving corneally reflected light from a corresponding pair of lateral light sources. In a preferred embodiment, the lateral detectors are quad-cell detectors. A heads-up display image is preferably provided along an optical axis of the instrument for supplying instructive cues to an operator for moving the instrument to achieve alignment, whereby the operator sees both a macro-image of the patient's eye and the display image. The speed of the position detection system makes it particularly suitable for use in hand-held ophthalmic instruments.

Afocal position detection system and ophthalmic instrument employing said system

An alignment system for an ophthalmic instrument comprises an optical axis along which an operator can directly view the patient's eye and the patient can fixate on a dark fixation target surrounded by a bright background that helps to illuminate the eye for operator viewing. A position detection system utilizing stored geometrical relationships determined by multiple regression during instrument calibration computes X-Y-Z alignment status of the instrument relative to a patient's eye based on local x-y position information from a pair of lateral detectors receiving corneally reflected light from a corresponding pair of lateral light sources. A heads-up display image is provided along an optical axis of the instrument for supplying instructive cues to an operator for moving the instrument to achieve alignment based on signal information from the position detection system, whereby the operator sees both a direct macro-image of the patient's eye and the display image. The alignment system is particularly suitable for use in hand-held ophthalmic instruments.

Alignment system for an ophthalmic instrument

A subjective ophthalmic refractor is improved for operator visibility in a darkened examination room by forming a cylinder axis scale of the refractor as a light-transmitting component having opaque scale gradations and installing a polar array of illumination sources to project light through the cylinder axis scale, which preferably includes a translucent material for diffuse illumination. In an alternative embodiment, the cylinder axis scale includes a photoluminescent material to which the scale gradations are applied. The refractor is further improved by installing respective illumination sources near a cylinder power readout and a sphere power readout of the refractor. The disclosure additionally relates to a method for retrofitting an ophthalmic refractor to illuminate the cylinder axis scale, cylinder power readout, and sphere power readout.

Ophthalmic refractor having retrofittable readout illumination

A hand-held non-contact tonometer comprises a housing having a handle portion for enclosing a rechargeable D.C. power source and an upper head portion for enclosing alignment and tonometric measurement systems of the tonometer. An operator can directly view the patient's eye along an optical axis extending through the head portion of the housing, and an instructional display image is superimposed with the directly viewed image of the eye to guide the operator in X-Y-Z alignment based on data supplied by an afocal position detection system. A transceiver for wireless data exchange and a recharging support stand are also provided.

Hand-held non-contact tonometer

An objective refractor, having light source and detection paths intersecting at a beamnsplitter uses light normally lost during testing of an eye to self-calibrate for optical errors introduced during production of the instrument.

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Corfu, NY, United States of America

Douglas H Hoover