US3883235A
Expired / Lapsed
US
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Automatic visual field examination including fixation monitoring compensation
Assignee: Individual
•
Filing: 1973-02-26
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Granted: 1975-05-13
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Expires: 1993-02-26
Abstract
Abstract An illustrative embodiment of the present invention includes method and apparatus for determining locations in a test field at which a subject is able to perceive visual stimuli. The stimuli are presented on a test screen under control of a programmed automatic data processing system. The subject communicates with the data processing equipment via a subject response device and the system interprets the responses to alter the stimulus presentation regime dynamically while communicating feedback to the subject of correct or incorrect perception of each stimulus. Eye movement of the subject is monitored and compensated for in the presentation of the stimuli by other system apparatus which also communicates with the data processing equipment to continuously center the test field relative to the direction of gaze of the subject (which may not necessarily be the center of the test screen or a fixed point).
Inventors
- 👤 John R Lynn
- 👤 Jr George W Tate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:22
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/02; A61B3/024
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
137 words
An automatic machine implemented process for testing the visual field of a subject comprising the steps of: establishing a test field positioned relative to a predetermined point on a test screen; determining, under machine control, the instantaneous location of the direction of gaze of the subject relative to the predetermined point; translating the test field relative to the predetermined point on the test screen when the direction of gaze is not at said predetermined point to reposition the test field relative to the direction of gaze the same as the position of the test field relative to said predetermined point when the test field was initially established; presenting, on the test screen, under machine control, test stimuli of selected stimulus value at preselected locations in the test field; and determining whether the subject percieved the test stimuli.
Claim 2
Dependent Claim
137 words
An automatic machine implemented process for testing the visual field of a subject comprising the steps of: establishing a test field positioned relative to a predetermined point on a test screen; determining, under machine control, the instantaneous location of the direction of gaze of the subject relative to the predetermined point; translating the test field relative to the predetermined point on the test screen when the direction of gaze is not at said predetermined point to reposition the test field relative to the direction of gaze the same as the position of the test field relative to said predetermined point when the test field was initially established; presenting, on the test screen, under machine control, test stimuli of selected stimulus value at preselected locations in the test field; and determining whether the subject percieved the test stimuli.
Claim 3
Dependent Claim
23 words
A process as in claim 1 wherein said test stimuli are presented under machine control in a sequence not predictable by the subject.
Claim 4
Dependent Claim
44 words
A process as in claim 1 further including the steps of supplying an indication of correct perception to the subject if the subject correctly perceives a test stimulus and supplying an indication of incorrect perception if the subject incorrectly indicates perception of the stimulus.
Claim 5
Dependent Claim
19 words
A process as in claim 1 wherein the subject indicates perception of a stimulus by operating a manual device.
Claim 6
Dependent Claim
30 words
A process as in claim 1 wherein a determination that the subject perceived a stimulus is made by monitoring a change in the evoked cortical potentials in the occipital center.
Claim 7
Dependent Claim
37 words
A process as in claim 1 wherein a determination that the subject perceived a stimulus is made by detecting movement of the subject''s eye in the direction of the test location at which the stimulus was perceived.
Claim 8
Dependent Claim
27 words
A process as in claim 1 wherein a determination that the subject perceived a stimulus is made by monitoring a change in the diameter of the pupil.
Claim 9
Dependent Claim
26 words
A process as in claim 1 wherein said test stimuli are spots of light presented at selected test locations which are stationary in said test field.
Claim 10
Dependent Claim
46 words
A process as in claim 8 further including the steps of presenting, under machine control, additional momentary spots of light of varying stimulus value at said selected test locations, and determining the stimulus values at which the particular spots of light are perceived by the subject.
Claim 11
Dependent Claim
61 words
A process as in claim 9 wherein the stimulus value of an additional momentary spot of light to be presented at a particular test location is computed in response to the subject''s history of perception response at the test location in question, such that the threshold value of stimulus perceived at each selected test location in the test field is detected.
Claim 12
Dependent Claim
25 words
A process as in claim 8 further including the step of displaying under machine control, the threshold value of the stimulus at each selected location.
Claim 13
Dependent Claim
48 words
A process as in claim 1 wherein the step of determining, under machine control, the instantaneous location of the direction of gaze of a subject is performed by monitoring the relative location, on an image of the eye pupil, of the image of a point source of radiation.
Claim 14
Dependent Claim
17 words
A process as in claim 12 wherein the point source of radiation is located effectively at infinity.
Claim 15
Dependent Claim
51 words
A process as in claim 1 wherein the step of determining, under machine control, the instantaneous location of the direction of gaze of a subject is performed by monitoring the changes in the horizontal and vertical components of the electric field surrounding the eyeball caused by the shifting corneO-retinal standing potential.
Claim 16
Dependent Claim
39 words
A process as in claim 1 and further including the initial step, prior to commencing the initial determination of the subject''s instantaneous location of direction of gaze, of subjectively obtaining a refractive correction of the eye of the subject.
Claim 17
Dependent Claim
39 words
A process as in claim 1 and further including the initial steps of determing, under machine control, which eye of the subject is being tested and selecting, in response to such determination, the pattern of presenting said test stimuli.
Claim 18
Dependent Claim
37 words
A process as in claim 1 wherein translating the test field is performed by applying a pure translation to preselected test point coordinates having a fixed coordinate location relative to the direction of gaze of the subject.
Claim 19
Dependent Claim
40 words
A process as in claim 17 wherein the test screen is planar and further including the step of modifying the stimulus value of the test stimuli in accordance with the amount and direction of translation of the test point coordinates.
Claim 20
Dependent Claim
39 words
A process as in claim 18 wherein said test stimuli are spots of light and said modifying step comprises computing the stimulus value B1 of a spot of light at a translated test point in accordance with the expression
Claim 21
Dependent Claim
45 words
A process as in claim 1 further including the step of communicating an alarm signal and ceasing presentation of said test stimuli if the location of the subject''s direction of gaze deviates by a preselected limiting amount from said predetermined point in said test field.
Claim 22
Dependent Claim
41 words
A process as in claim 20 further including the step of resuming the presentation of said test stimuli when the direction of gaze of the subject returns to within said preselected limiting amount from the reference point in said test field.
Claim 23
Dependent Claim
38 words
A process as in claim 1 wherein said test stimuli are each initially presented at a selected location on said test field and then moved, relative to the test field and under machine control, in a certain direction.
Claim 24
Dependent Claim
29 words
A process as in claiam 22 wherein said test stimuli are spots of light and further including the step of determining when the subject perceives each spot of light.
Claim 25
Dependent Claim
29 words
A process as in claiam 22 wherein said test stimuli are spots of light and further including the step of determining when the subject perceives each spot of light.
Claim 26
Dependent Claim
44 words
A process as in claim 23 wherein said spots of light are each initially presented at a location on the test field which is outside the visual field of the subject and then moved toward the visual field until the subject perceives the spot.
Claim 27
Dependent Claim
28 words
A process as in claim 24 wherein the speed at which the spots of light are moved is varied as a function of eccentricity from the fixation spot.
Claim 28
Dependent Claim
27 words
A process as in claim 24 further including the step of determining the location on the test field at which the subject perceives each spot of light.
Claim 29
Dependent Claim
57 words
A process as in claim 23 wherein the location determining step includes the steps of: the subject indicating perception of a spot of light by operating a manual device, stopping movement of the perceived spot in response to the operation of the manual device, and determining the location on the test field where the spot was stopped.
Claim 30
Dependent Claim
63 words
A process as in claim 27, further including the step of determining an adjusted location on a path over which a spot of light moved prior to being stopped, the distance of said adjusted location from the location at which the spot was stopped being a function of the speed of movement of the spot multiplied by the reaction time of the subject.
Claim 31
Dependent Claim
42 words
A process as in claim 23 wherin said spots of light are initially presEnted at spaced locations about the perimeter of the test field and then moved toward the location on the test screen of the direction of gaze of the subject.
Claim 32
Dependent Claim
39 words
A process as in claim 29 wherein spots of light are initially presented at locations about the perimeter of the test field on either side of imaginary vertical and horizontal lines which divide the test field into four quadrants.
Claim 33
Dependent Claim
59 words
A process as in claim 29 further including the steps of a. determining, for two spots of light which move along adjacent paths, the locations at which the two spots are perceived by the subject, and b. presenting and moving another spot of light in a path which is substantially perpendicular to a chord extending between the two locations.
Claim 34
Dependent Claim
40 words
A process as in claim 31 wherein the perpendicular path is commenced a predetermined distance from the chord toward the perimeter of the test field and a spot of light is moved from the point of commencement toward the chord.
Claim 35
Dependent Claim
46 words
A process as in claim 31 wherein steps (a) and (b) are repeated for each pair of spots of light which move along adjacent paths until the locations at which each such pair are perceived by the subject are within a predetermined distance of each other.
Claim 36
Dependent Claim
50 words
A process as in claim 23 wherein said spots of light are each initially presented at a location on the test field within a previously detected scotoma of the subject and then moved consecutively in a plurality of directions from the location until the subject perceives the spot of light.
Claim 37
Dependent Claim
34 words
A process as in claim 34 wherein the spots of light are moved consecutively in four directions from the location, each of said four directions being oriented at least 90* from the other directions.
Claim 38
Dependent Claim
27 words
A process as in claim 35 further including the step of determining the location on the test field at which the subject perceives each spot of light.
Claim 39
Dependent Claim
77 words
A process as in claim 36 further including the steps of determining, for two spots of light which move along adjacent paths, the locations at which the two spots are perceived by the subject, and presenting and moving another spot of light in a path which intersects substantially at a right angle a chord extending between the two locations and which commences on one of the paths traversed by one of the previously moved spots of light.
Claim 40
Dependent Claim
31 words
A process as in claim 22 wherein said spots of light are presented on a planar screen and moved in accordance with velocities defined in terms of a Cartesian coordinate system.
Claim 41
Dependent Claim
31 words
A process as in claim 22 wherein said spots of light are presented on a hemispherical screen and moved in accordance with velocities defined in terms of a spherical coordinate system.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |