Patent US3764658A successfully refreshed from Google Patents.
Patent EP0199218A2 successfully refreshed from Google Patents.
EP0199218A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Evoked potential autorefractometry system
Assignee: Westinghouse Electric Corp
•
Filing: 1986-04-11
•
Granted: —
•
Expires: 2006-04-11
Abstract
Abstract @ An evoked potential autorefractometry system includes a computer driving an alternating checkerboard mirror stimulus to project a stimulus pattern directly to a patient through a continuously variable focus lens controlled by the computer and maintaining a constant image size on the patient's retina. The evoked potentials produced by the patient are amplified and asynchronously filtered both in an analog and digital fashion to allow peak to peak detection of the evoked potentials to determine amplitude. The digital filter includes a 255 point running sum. The peak to peak amplitudes are asynchronously digitally filtered using a 16 point running sum to produce an amplitude measure of the evoked potentials. The lens is swept rapidly from one extreme of focus to the other extreme in relatively large steps to determine the area in which the peak amplitude occurs. The lens is then swept in smaller and smaller range sweeps using smaller and smaller steps around the peak amplitude until the peak in the amplitude is pinpointed within a desired diopter at which point the lens position is printed out on the printer as the patient's prescription.
Inventors
- 👤 Thomas Edward Bernard
- 👤 Emilie Matarasso Roth
- 👤 Edwin Renner Mohan
- 👤 Gary William Sherwin
- 👤 John Michael Zomp
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 22:55
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/68; A61B5/6801; A61B5/6813; A61B5/6814; A61B3/00; A61B3/10; A61B3/12; A61B3/103; A61B5/24; A61B5/25; A61B5/279; A61B5/28; A61B5/282; A61B5/316; A61B5/369; A61B5/377; A61B2562/00; A61B2562/22; A61B2562/221; A61B2562/222
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
129 words
An evoked potential autorefractometry system for a patient, characterized by: a stimulus production means for producing an alternating stimulus pattern output signal; a continuously variable focus lens adapted to receive said alternating stimulus output signal and to project the stimulus pattern directly to the patient with a continuously changing focus; evoked potential sensing means adapted to sense evoked potentials produced by the patient while observing said stimulus pattern; determination means adapted to receive and determine the maximum amplitude of the evoked potential produced by the patient during observation of said stimulus pattern as the focus of the lens is continuously changed; and prescribing means adapted to receive the output of said determining means and to prescribe corrective lenses for said patient based on said output of said determining means.
Claim 2
Dependent Claim
129 words
An evoked potential autorefractometry system for a patient, characterized by: a stimulus production means for producing an alternating stimulus pattern output signal; a continuously variable focus lens adapted to receive said alternating stimulus output signal and to project the stimulus pattern directly to the patient with a continuously changing focus; evoked potential sensing means adapted to sense evoked potentials produced by the patient while observing said stimulus pattern; determination means adapted to receive and determine the maximum amplitude of the evoked potential produced by the patient during observation of said stimulus pattern as the focus of the lens is continuously changed; and prescribing means adapted to receive the output of said determining means and to prescribe corrective lenses for said patient based on said output of said determining means.
Claim 3
Dependent Claim
28 words
A system as recited in claim 1 further characterized by said alternating stimulus pattern comprising an alternating checkerboard alternating at a frequency of approximately six cycles per second.
Claim 4
Dependent Claim
28 words
A system as recited in claim 2 further characterized by said alternating checkerboard having a spatial frequency of 8 cycles per inch at a distance of 32 inches.
Claim 5
Dependent Claim
73 words
A system as recited in claim 2 further characterized by said alternating checkerboard stimulus source comprising: a pair of light sources; a chopper wheel alternately interrupting the light from said pair of light sources; and a checkerboard mirror having a reflecting surface reflecting the interrupted light from one of the light sources toward the patient and transmitting the interrupted light from the other of the light sources of said pair toward said patient.
Claim 6
Dependent Claim
115 words
A system as recited in claim 4 further characterized by said alternating checkerboard stimulus source further comprising: a first matte filter transmitting the light from one of said pair of light sources; a first beam splitter reflecting the light from said first filter toward a reflecting surface of said checkerboard mirror; a second matte filter transmitting the light from the other of said pair of light sources; and a second beam splitter reflecting the light from the second matte filter to a transmissive surface of said checkerboard mirror to the patient, the light reflected from and transmitted through the checkerboard mirror passing through said first beam splitter as the light is transmitted to the patient.
Claim 7
Dependent Claim
60 words
A system as recited in claim 4 further characterized by said stimulus production means further comprising: a square wave generator; a phase locked stepper motor control circuit adapted to receive the output of said square wave generator; and a stepper motor adapted to receive the output of said phase locked stepper motor control circuit and to drive said chopper wheel.
Claim 8
Dependent Claim
24 words
A system as recited in claim 6 further characterized by said square wave generator producing a square wave at a frequency of 2.4 kilohertz.
Claim 9
Dependent Claim
68 words
A system as recited in claim 6 further characterized by said phase locked stepper motor control circuit comprising: a binary counter operatively adapted to receive the output of said square wave generator; a read only memory operatively adapted to receive the output of said binary counter; and power transistors adapted to receive the output of said read only memory and to provide drive signals for said stepper motor.
Claim 10
Dependent Claim
22 words
A system as recited in claim 4 further characterized by said chopper wheel being a phase locked stepper motor controlled light chopper.
Claim 11
Dependent Claim
34 words
A system as recited in claim 1 further characterized by said continuously variable focus lens maintaining a constant image size as perceived by the patient while the focus of said lens is continuously changed.
Claim 12
Dependent Claim
77 words
A system as recited in claim 1 further characterized by said continuously variable focus lens comprising: a fixed diopter lens receiving the stimulus pattern from said stimulus production means; a focusable telescope coupled to said fixed diopter lens and adapted to transmit the stimulus pattern to the patient; and focus means, coupled to said focusable telescope and adapted to receive the outputs of said determination means such that the focus of said focusable telescope is continuously changed.
Claim 13
Dependent Claim
30 words
A system as recited in claim 11 further characterized by said fixed diopter lens being a +1 diopter close-up lens and said focusable telescope being a 17 x 60 telescope.
Claim 14
Dependent Claim
33 words
A system as recited in claim 1 further characterized ,by said evoked potential sensing means comprising: an adjustable headband; and self-preparing electrodes mounted in said adjustable headband at positions for evoked potential measurement.
Claim 15
Dependent Claim
17 words
A system as recited in claim 13 further characterized by an electromagnetic shield surrounding said self-preparing electrodes.
Claim 16
Dependent Claim
35 words
A system as recited in claim 13 further characterized by said evoked potential sensing means including inner and outer electromagnetically shielded wires and a graphite layer adjacent the inner shielded wire connected to said electrodes.
Claim 17
Dependent Claim
18 words
A system as recited in claim 13 further characterized by said self-preparing electrode being a subkeratinous EEG probe.
Claim 18
Dependent Claim
37 words
A system as recited in claim 13 further characterized by said evoked potential sensing means including electrolyte application means for applying. an electrolyte to said self-preparing electrodes and the patient after said self-preparing electrodes are in position.
Claim 19
Dependent Claim
42 words
A system as recited in claim 17 further characterized by said electrolyte application means comprising: a pump for pumping the electrolyte; and tubing, connected to said pump and mounted adjacent to said self-preparing electrodes, for conveying the electrolyte to said self-preparing electrodes.
Claim 20
Dependent Claim
34 words
A system as recited in claim 13. further characterized by said self-preparing electrodes each comprising: a tulip probe; and a spring urging said tulip probe through a dead layer of skin without causing bleeding.
Claim 21
Dependent Claim
148 words
A system as recited in claim 1 further characterized by said determination means comprising: an amplifier, operatively connected to said evoked potential sensing means, adapted to receive the evoked potentials and amplifying same; a noise filter, operatively connected to said amplifier, adapted to filter the evoked potentials to remove environmental noise; an analog-to-digital converter, operatively connected to said noise filter, adapted to convert the evoked potentials into digital evoked potentials; a computer, operatively connected to said analog-to-digital converter, adapted to determine the maximum amplitude of the digital evoked potentials as the focus of the lens is continuously changed, to store the lens position at the maximum amplitude and to produce lens control signals; and . a lens control unit, operatively connected to said computer and said continuously variable focus lens, adapted to control the focus of said continuously variable focus lens in dependence upon the lens control signals.
Claim 22
Dependent Claim
18 words
A system as recited in claim 20, further characterized by said amplifier comprising a narrow band EEG amplifier.
Claim 23
Dependent Claim
159 words
A system as recited in claim 20 further characterized by said amplifier comprising: a clipping circuit adapted to receive the output of said evoked potential sensing means; a pair of high impedance low gain serially connected amplifying circuits adapted to receive the output of said clipping circuit; a differential amplifier adapted to receive the output of said pair of high impedance low gain amplifying circuits; a first isolating capacitor adapted to receive the output of said differential amplifier; a first bandpass filter adapted to receive the output of said first isolating capacitor; a second isolating capacitor adapted to receive the output of said first bandpass filter; a second bandpass filter adapted to receive the output of said second isolating capacitor; a low pass filter adapted to receive the output of said second bandpass filter; a high pass filter adapted to receive the output of said low pass filter and said noise filter; and an amplifier shield surrounding said amplifier.
Claim 24
Dependent Claim
25 words
A system as recited in claim 20, further characterized by said noise filter comprising a narrow bandpass filter with a center frequency of six hertz.
Claim 25
Dependent Claim
36 words
A system as recited in claim 20 further characterized by: said stimulus production means producing a clock signal; and said noise filter comprising a narrow bandpass filter having a center frequency determined by the clock signal.
Claim 26
Dependent Claim
74 words
A system as recited in claim 20 further characterized by said computer including: means for filtering the evoked potentials using a first running sum; means for detecting the peaks of the first running sum; means for filtering the peaks using a second running sum; and means for determining a maximum of the second running sum and storing the position of the continuously variable focus lens coincident with the maximum of the second running sum.
Claim 27
Dependent Claim
79 words
A system as recited in claim 20 further characterized by said lens control unit comprising: a binary up/down counter adapted to receive the outputs of said computer; a read only memory adapted to receive the output of said binary up/down counter; power transistors adapted to receive the outputs of said read only memory; and a stepper motor mechanically coupled to said continuously variable focus lens and adapted to receive as control signals the outputs of said read only memory.
Claim 28
Dependent Claim
49 words
A system as recited in claim 26 further characterized by said continuously variable focus lens including a focus control rod member; a first sprocket coupled to said focus rod member member; a second sprocket coupled to said stepper motor; and a sprocket chain coupling said first and second sprockets.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.