US4421392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for detecting visual field defects of the eye
Assignee: Individual
•
Filing: 1979-09-11
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Granted: 1983-12-20
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Expires: 1999-09-11
Abstract
Abstract A perimeter for testing visual field light-sensitivity presents a moving spot or a set of fixed spots visually to a patient. The spot or spots have ill-defined edges so that the effect of visual acuity is minimized. A hand-held device is proposed whereby mass monitoring, particularly for the effects of glaucoma, is possible.
Inventors
- 👤 Ronald Pitts Crick
- 👤 Jonathan C. Pitts Crick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:07
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/02; A61B3/024
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
101 words
An apparatus for detecting visual field defects of an eye of a patient, said apparatus comprising: means for displaying to a patient a visual stimulus comprising a plurality of spots having predetermined positions in the field of vision of the patient, each said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply defined and outlined pattern regardless of the patient's visual acuity, said spots being characterized by stimuli which lack high frequency components and which contain only those frequencies necessary to give adequate separation of the closest stimuli.
Claim 2
Independent Claim
101 words
An apparatus for detecting visual field defects of an eye of a patient, said apparatus comprising: means for displaying to a patient a visual stimulus comprising a plurality of spots having predetermined positions in the field of vision of the patient, each said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply defined and outlined pattern regardless of the patient's visual acuity, said spots being characterized by stimuli which lack high frequency components and which contain only those frequencies necessary to give adequate separation of the closest stimuli.
Claim 3
Dependent Claim
25 words
An apparatus as claimed in claim 1, wherein said plurality of said spots comprise a sequence of predetermined patterns, each said pattern being displayed briefly.
Claim 4
Dependent Claim
19 words
An apparatus as claimed in claim 1, wherein each said spot is graduated in density from the center outwards.
Claim 5
Dependent Claim
14 words
An apparatus as claimed in claim 3, wherein the graduation in density is continuous.
Claim 6
Dependent Claim
16 words
An apparatus as claimed in claim 4, wherein said graduation in density has a sine-wave characteristic.
Claim 7
Dependent Claim
59 words
An apparatus as claimed in claim 2, wherein said displaying means comprises a screen having windows and a sheet bearing images, said sheet being positioned closely behind said screen and capable of sliding movement relative thereto so that said images appear briefly in said windows, thereby presenting said spots to the patient, at least said windows having ill-defined edges.
Claim 8
Dependent Claim
33 words
An apparatus as claimed in claim 6, wherein said screen comprises an open-ended envelope having two opposite sides between which said sheet slides, said two sides having therein different patterns of said windows.
Claim 9
Dependent Claim
37 words
An apparatus as claimed in claim 7, wherein said pattern of windows in a first said side of said envelope is the mirror image of said pattern of windows in a second said side of said envelope.
Claim 10
Dependent Claim
57 words
An apparatus as claimed in claim 6, wherein said sheet has along at least one edge thereof a series of notches, said sheet being pushed manually behind said screen to the extent of one said notch at a time, the disposition of said images on said sheet giving different patterns of said spots for different said notches.
Claim 11
Dependent Claim
40 words
An apparatus as claimed in claim 6, wherein said screen has therein an aperture and said sheet has therein a slot aligned with said aperture, wherein the eye of the patient may be viewed through said aperture and said slot.
Claim 12
Dependent Claim
35 words
An apparatus as claimed in claim 6, further comprising distance cord means of predetermined length connected to said screen for enabling said screen to be held a predetermined distance from an eye of the patient.
Claim 13
Independent Claim
110 words
A method for detecting visual field defects of an eye of a patient, said method comprising: displaying to the patient a visual stimulus comprising a plurality of spots having predetermined positions in the field of vision of the patient, each said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply defined and outlined pattern regardless of the patient's visual acuity, said spots being characterized by stimuli which lack high frequency components and which contain only those frequencies necessary to give adequate separation of the closest stimuli; and noting the ability of the patient to observe said stimulus.
Claim 14
Independent Claim
110 words
A method for detecting visual field defects of an eye of a patient, said method comprising: displaying to the patient a visual stimulus comprising a plurality of spots having predetermined positions in the field of vision of the patient, each said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply defined and outlined pattern regardless of the patient's visual acuity, said spots being characterized by stimuli which lack high frequency components and which contain only those frequencies necessary to give adequate separation of the closest stimuli; and noting the ability of the patient to observe said stimulus.
Claim 15
Independent Claim
102 words
An apparatus for detecting visual field defects of an eye of a patient, said apparatus comprising: means for displaying to a patient a visual stimulus comprising a single spot having a predetermined locus in the field of vision of the patient, said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply focused or defined and outlined pattern regardless of the patient's visual acuity, said spot being characterized by stimuli which lack high frequency components and which contains only those frequencies necessary to give adequate seperation of the closest stimuli.
Claim 16
Independent Claim
102 words
An apparatus for detecting visual field defects of an eye of a patient, said apparatus comprising: means for displaying to a patient a visual stimulus comprising a single spot having a predetermined locus in the field of vision of the patient, said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply focused or defined and outlined pattern regardless of the patient's visual acuity, said spot being characterized by stimuli which lack high frequency components and which contains only those frequencies necessary to give adequate seperation of the closest stimuli.
Claim 17
Dependent Claim
18 words
An apparatus as claimed in claim 13, wherein said spot is graduated in density from the center outwards.
Claim 18
Dependent Claim
14 words
An apparatus as claimed in claim 14, wherein the graduation in density is continuous.
Claim 19
Dependent Claim
16 words
An apparatus as claimed in claim 15, wherein said graduation in density has a sine-wave characteristic.
Claim 20
Independent Claim
111 words
A method for detecting visual field defects of an eye of a patient, said method comprising: displaying to a patient a visual stimulus comprising a single spot having a predetermined locus in the field of vision of the patient, said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply focused or defined and outlined pattern regardless of the patient's visual acuity, said spot being characterized by stimuli which lack high frequency components and which contains only those frequencies necessary to give adequate seperation of the closest stimuli; and noting the ability of the patient to observe said stimulus.
Claim 21
Independent Claim
111 words
A method for detecting visual field defects of an eye of a patient, said method comprising: displaying to a patient a visual stimulus comprising a single spot having a predetermined locus in the field of vision of the patient, said spot having ill-defined edges to an extent such that said spot is incapable of being viewed by the patient as a sharply focused or defined and outlined pattern regardless of the patient's visual acuity, said spot being characterized by stimuli which lack high frequency components and which contains only those frequencies necessary to give adequate seperation of the closest stimuli; and noting the ability of the patient to observe said stimulus.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-19 | 1987-06-20 | 1987-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-19 | 1991-06-20 | 1991-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-19 | 1995-06-20 | 1995-12-20 | $7700.00 | Window Closed / Lapsed |