US3609017A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Means for extending the range of keratometers
Assignee: Individual
•
Filing: 1970-05-21
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Granted: 1971-09-28
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Expires: 1990-05-21
Abstract
Abstract Means for extending the range of a keratometer to measure the curvature of a cornea in a region spaced a greater distance from the optical axis of said keratometer than the region normally measured. Said means includes a further set of illuminated mires adapted to produce a virtual image inside the cornea larger than the virtual image produced by the original mires, and diverging lens means for producing a secondary virtual image from the virtual image produced by said further set of mires which can be read directly by said keratometer while being representative of the radius of curvature in the new region.
Inventors
- 👤 Benjamin Nuchman
- 👤 Sang Y Whang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:41
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/107
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
215 words
In a keratometer, the improvement which comprises a first set of mire means aligned with the optical axis of said keratometer; first illumination means for illuminating said first set of mire means for producing a virtual image inside a human cornea, the dimensions of said image being a measure of the curvature of said cornea in a first region spaced a first distance from said optical axis; a second set of illuminated mires aligned with said optical axis; second illumination means for illuminating said second set of mire means for producing a virtual image inside said cornea having dimensions representative of the curvature of said cornea in a second region spaced a second distance from said optical axis; and diverging lens means disposable on the optical axis of said keratometer to produce when so disposed a secondary virtual image from the virtual image produced by said second set of mire means, said diverging lens means, the relative position along said optical axis of said diverging lens means and said first and second sets of mire means and the relative dimensions of said first and second sets of mire means all being selected so that the keratometer reads directly the radius of curvature at said second region by measuring the dimensions of said secondary virtual image.
Claim 2
Dependent Claim
215 words
In a keratometer, the improvement which comprises a first set of mire means aligned with the optical axis of said keratometer; first illumination means for illuminating said first set of mire means for producing a virtual image inside a human cornea, the dimensions of said image being a measure of the curvature of said cornea in a first region spaced a first distance from said optical axis; a second set of illuminated mires aligned with said optical axis; second illumination means for illuminating said second set of mire means for producing a virtual image inside said cornea having dimensions representative of the curvature of said cornea in a second region spaced a second distance from said optical axis; and diverging lens means disposable on the optical axis of said keratometer to produce when so disposed a secondary virtual image from the virtual image produced by said second set of mire means, said diverging lens means, the relative position along said optical axis of said diverging lens means and said first and second sets of mire means and the relative dimensions of said first and second sets of mire means all being selected so that the keratometer reads directly the radius of curvature at said second region by measuring the dimensions of said secondary virtual image.
Claim 3
Dependent Claim
26 words
The arrangement as recited in claim 1, including displacement means for selectively displacing said diverging lens means into and out of alignment with said optical axis.
Claim 4
Dependent Claim
21 words
The arrangement as recited in claim 2, including switch means for selectively actuating one or the other of said illumination means.
Claim 5
Dependent Claim
61 words
The arrangeMent as recited in claim 3, wherein said switch means is coupled with said displacement means for the simultaneous positioning of said diverging lens means in alignment with said optical axis when said second illumination means is actuated and for the simultaneous positioning of said diverging lens means away from said optical axis when said first illumination means is actuated.
Claim 6
Dependent Claim
49 words
The arrangement as recited in claim 1, wherein said first and second illumination means are each formed from a substantially toroidal fluorescent lamp positioned respectively substantially adjacent to said first and second mire means, said keratometer including light diverging means intermediate each fluorescent lamp and its associated mire means.
Claim 7
Dependent Claim
45 words
The arrangement as recited in claim 1, wherein said keratometer includes a head portion in alignment with the optical axis thereof, said first and second mire means, said first and second illumination means, and said diverging lens means all being mounted within said head portion.
Claim 8
Dependent Claim
145 words
The arrangement as recited in claim 1, wherein said diverging lens, the relative position along said optical axis of said first and second mire means and said diverging lens, and the dimensions of said first and second mire means are selected so that the dimensions of said secondary virtual image substantially equals the dimensions of the virtual image that would be produced by said first set of mire means were the radius of curvature at said first region equal to the radius of curvature at said second region, and so that said secondary virtual image is spaced from said first set of mire means when said keratometer is focused on said secondary virtual image a distance equal to the spacing between the virtual image produced by said first set of mire means when said keratometer is focused thereon and said first set of mire means.
Claim 9
Dependent Claim
204 words
In a keratometer for producing a virtual image inside a human cornea from a first set of illuminated mire means, the dimensions of said image being a measure of the curvature of said cornea in a first region spaced a first distance from the optical axis of said keratometer, the improvement which comprises a second set of illuminated mire means spaced along said optical axis from said first set of mire means and dimensioned to produce a virtual image inside said cornea having dimensions representative of the curvature of said cornea in a second region spaced a second distance from said optical axis; and diverging lens means disposed in front of said keratometer on said optical axis to produce a secondary virtual image from the virtual image produced by said second set of mire means, said lens means and the spacing between said first and second sets of mire means being selected so that the keratometer reads directly the radius of curvature at said second region by measuring the dimensions of said secondary virtual image and wherein the virtual image produced by said second set of mire means is larger than the virtual image produced by said first set of mire means-has been inserted.
Claim 10
Dependent Claim
204 words
In a keratometer for producing a virtual image inside a human cornea from a first set of illuminated mire means, the dimensions of said image being a measure of the curvature of said cornea in a first region spaced a first distance from the optical axis of said keratometer, the improvement which comprises a second set of illuminated mire means spaced along said optical axis from said first set of mire means and dimensioned to produce a virtual image inside said cornea having dimensions representative of the curvature of said cornea in a second region spaced a second distance from said optical axis; and diverging lens means disposed in front of said keratometer on said optical axis to produce a secondary virtual image from the virtual image produced by said second set of mire means, said lens means and the spacing between said first and second sets of mire means being selected so that the keratometer reads directly the radius of curvature at said second region by measuring the dimensions of said secondary virtual image and wherein the virtual image produced by said second set of mire means is larger than the virtual image produced by said first set of mire means-has been inserted.
Claim 11
Dependent Claim
136 words
The arrangement as recited in claim 8, wherein said lens means and the spacing between said first and second sets of mire means are selected so that the dimensions of said secondary virtual image equals the dimensions of the virtual image that would be produced by said first set of mire means were said radius of curvature at said first region equal to said radius of curvature at said second region, and so that said secondary virtual image is spaced from said first set of mires means when said keratometer is focused on said secondary virtual image produced by said second set of mire means a distance equal to the spacing between the virtual image produced by said first set of mire means when said keratometer is focused thereon and said first set of mire means.
Claim 12
Dependent Claim
26 words
The arrangement as recited in claim 9, including means for blocking said first set of mire means to prevent the production of a virtual image thereby.
Claim 13
Dependent Claim
74 words
An arrangement as recited in Claim 8, wherein said first and second sets of mire means each includes at least one pair of spaced mire means, said pair of spaced mire means of said second set being spaced twice the spacing of said pair of mire means of said first set, said second set of mire means lying in a plane spaced 4.417 cm. from the plane including said first set of mire means.
Claim 14
Dependent Claim
39 words
An arrangement as recited in claim 11, wherein said diverging lens means includes a diverging lens having a focal length of 5.796 cm. (-17.25 diopters), said lens being disposed in the plane including said second set of mire means.
Claim 15
Dependent Claim
27 words
An arrangement as recited in claim 8, wherein said diverging lens means includes a concave lens disposed in the plane including said second set of mire means.
Claim 16
Dependent Claim
48 words
An arrangement as recited in claim 8, including a housing for carrying said second set of illuminated mire means and said lens means, and means for mounting said housing on said keratometer with said second set of mire means and lens means aligned with the optical axis thereof.
Claim 17
Dependent Claim
50 words
An arrangement as recited in claim 14, wherein said keratometer includes a head portion containing said first set of mire means, and a pair of projections extending laterally from said head portion, said mounting means including a pair of arms extending from said housing and adapted to engage said projections.
Claim 18
Dependent Claim
26 words
An arrangement as recited in claim 14, including lighting means disposed within said housing behind said second set of mire means for illuminating said mire means.
Claim 19
Dependent Claim
40 words
An arrangement as recited in claim 8, wherein said lighting means comprises a toroidal fluorescent lamp in substantial alignment with said second set of mire means and diffusing means intermediate said fluorescent lamp and said second set of mire means.
Claim 20
Dependent Claim
116 words
An arrangement as recited in claim 8, wherein said first and second sets of mire means each includes at least one pair of spaced mire means, said pair of spaced mire means of said second set being spaced twice the distance of said pair of mire means of said first set, said second set of mire means lying in a plane about 3 cm. in front of the plane including said first set of mire means, said diverging lens means including a diverging lens having a focal length of about 3.03 cm. (-33 diopters), said lens being disposed in a plane about 2.8 cm. in front of the plane including said second set of mire means.
References Cited (Backward Citations)
US3542458A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |