Patent US4838684A successfully refreshed from Google Patents.
US4838684A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for and method of testing visual acuity
Assignee: Individual
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Filing: 1987-02-09
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Granted: 1989-06-13
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Expires: 2007-02-09
Abstract
Abstract A hand-held, rotatable, cylindrical drum provided with a series of sequentially interchangeable stimulus patterns that cover the drum which, when rotated in front of a patient, induces optokinetic nystagmus which is used to non-verbally assess the visual acuity of a patient.
Inventors
- 👤 Jeffery W. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:38
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/48; A61B5/4863; A61B3/00; A61B3/02; A61B3/06; A61B3/066; A61B5/16; A61B5/161
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
139 words
A hand-held, portable visual acuity testing device including a spindle having a handle at one end, a cylindrical drum rotatably mounted on said spindle, said drum including a first flange disposed on top of said drum extending beyond the periphery of said drum and a second flange disposed on the bottom of said drum also extending beyond the periphery of said drum, said first and second flanges defining a locating surface therebetween and a series of removable stimulus covers each of which is adapted to be releasably secured around said drum and consists of alternately adjacent, vertically disposed bars of equal width of two different colors, each cover in said series having bars of narrower width than the cover which precedes it in said series, whereby said drum may be used to measure the visual acuity of a patient.
Claim 2
Dependent Claim
139 words
A hand-held, portable visual acuity testing device including a spindle having a handle at one end, a cylindrical drum rotatably mounted on said spindle, said drum including a first flange disposed on top of said drum extending beyond the periphery of said drum and a second flange disposed on the bottom of said drum also extending beyond the periphery of said drum, said first and second flanges defining a locating surface therebetween and a series of removable stimulus covers each of which is adapted to be releasably secured around said drum and consists of alternately adjacent, vertically disposed bars of equal width of two different colors, each cover in said series having bars of narrower width than the cover which precedes it in said series, whereby said drum may be used to measure the visual acuity of a patient.
Claim 3
Dependent Claim
20 words
A hand-held, portable visual acuity testing device as in claim 1 wherein said bars are alternately colored black and white.
Claim 4
Dependent Claim
31 words
A hand-held, portable visual acuity testing device as in claim 1 in which the width of the vertical bars of said stimulus covers in said series varies from 1/2" to 3/32".
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) | 1992-06-12 | 1992-12-12 | 1993-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-12 | 1996-12-12 | 1997-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-12 | 2000-12-12 | 2001-06-13 | $7700.00 | Window Closed / Lapsed |