US3797921A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographing apparatus for determining corneal radius
Assignee: INTERNATIONAL DIAGNOSTIC INSTRUMENTS Ltd A CORP OF OK
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Filing: 1972-06-05
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Granted: 1974-03-19
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Expires: 1992-06-05
Abstract
Abstract A camera by means of which a doctor can obtain a picture of the eye of a patient, having superimposed thereon one or more concentric circles, permitting determination by the doctor of the radius of the eye cornea so that a contact lens can be properly fitted. The patient supports his head on a chin rest and looks into an opening in the center of a spherically concave screen, focusing on a light dot. Light from within the camera passes through one or more concentric rings in the concave screen to form light circles on the eye cornea. On a viewing screen on the opposite end of the camera the doctor sees an image of the patient''s eye with the circles superimposed thereon. The doctor can adjust the elevation of the patient''s eye, the rotational alignment between the camera and the patient, and the focus of the image. When these adjustments are satisfactory, the doctor actuates the device to open the camera shutter and energize flash tubes, exposing film to the image of the patient''s eye as had been seen by the doctor. Light from the flash tubes passes through the one or more concentric rings so that one or more light circles appear on the image of the eyeball as photographed on the film. The film is preferably immediately developed within the camera. From the circles on the resulting print, the doctor determines measurements required for the proper fitting of a contact lens.
Inventors
- 👤 A Reynolds
- 👤 L Kilmer
- 👤 M Lively
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:33
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/107; A61B3/0075
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
332 words
Apparatus adapted for making a picture of an eye of a patient comprising: a housing having a first end and a second end; light source means within said housing and adjacent said housing first end; a focusing screen in the form of an opaque spherical segment having its concave surface as the exterior surface of said housing in said housing first end and having a transparent circle thereon for passage therethrough of light from said light source means to form on the eye of a patient whose eye is adjacent the opaque spherical surface center of curvature an image of a circle, the diameter of the focusing screen transparent circle subtending an angle of 120* at the center of curvature of the opaque spherical segment; support means for supporting the head of a patient with the cornea of an eye of the patient adjacent the opaque spherical segment center of curvature, such that the center of said cornea is substantially coincident with the center of curvature of said opaque spherical segment; a film holder for holding film adjacent said housing second end with the film exposed to the interior of said housing; a viewing screen in said housing second end; shutter means intermediate said housing first end and said housing second end and cooperating with said housing to define a first optical path from said housing first end, through said housing, to said viewing screen and a second optical path from said housing first end through said housing to said film holder, said shutter means movable between a first shutter position in which said first optical path is unblocked while said second optical path is blocked and a second shutter position in which said first optical path is blocked while said second optical path is unblocked to expose film within said film holder to the area adjacent said opaque spherical segment center of curvature; and actuation means for moving said shutter means between the first shutter position and the second shutter position.
Claim 2
Dependent Claim
332 words
Apparatus adapted for making a picture of an eye of a patient comprising: a housing having a first end and a second end; light source means within said housing and adjacent said housing first end; a focusing screen in the form of an opaque spherical segment having its concave surface as the exterior surface of said housing in said housing first end and having a transparent circle thereon for passage therethrough of light from said light source means to form on the eye of a patient whose eye is adjacent the opaque spherical surface center of curvature an image of a circle, the diameter of the focusing screen transparent circle subtending an angle of 120* at the center of curvature of the opaque spherical segment; support means for supporting the head of a patient with the cornea of an eye of the patient adjacent the opaque spherical segment center of curvature, such that the center of said cornea is substantially coincident with the center of curvature of said opaque spherical segment; a film holder for holding film adjacent said housing second end with the film exposed to the interior of said housing; a viewing screen in said housing second end; shutter means intermediate said housing first end and said housing second end and cooperating with said housing to define a first optical path from said housing first end, through said housing, to said viewing screen and a second optical path from said housing first end through said housing to said film holder, said shutter means movable between a first shutter position in which said first optical path is unblocked while said second optical path is blocked and a second shutter position in which said first optical path is blocked while said second optical path is unblocked to expose film within said film holder to the area adjacent said opaque spherical segment center of curvature; and actuation means for moving said shutter means between the first shutter position and the second shutter position.
Claim 3
Dependent Claim
39 words
Apparatus as claimed in claim 1 in which said support means includes a base member and mounting means for mounting said housing on said base member while permitting rotational and longitudinal movement between said housing and said base member.
Claim 4
Dependent Claim
39 words
ApparatuS as claimed in claim 2 in which said support means further includes a chin rest for supporting the chin of a patient and means for adjusting the height of said chin rest relative to said housing first end.
Claim 5
Dependent Claim
148 words
Apparatus as claimed in claim 1 in which said light source means includes: first light means for forming within said housing and adjacent said housing first end a target upon which a patient adjacent said housing first end can focus his eye and cooperating with said focusing screen transparent circle to form on the eye of a patient whose eye is adjacent said housing first end, an image of a circle to permit focusing of said apparatus; and second light means responsive to movement of said shutter means from the first shutter position to the second shutter position for providing a flash of light and cooperating with said focusing screen transparent circle to form on the eye of a patient whose eye is adjacent said housing first end an image of a circle to permit exposure of film within said film holder to the eye and circle image.
Claim 6
Dependent Claim
45 words
Apparatus as claimed in claim 4 in which said first light means includes a reflective surface and means for projecting onto said reflective surface a spot of light to cause reflection of the spot of light toward said housing first end to form the target.
Claim 7
Dependent Claim
54 words
Apparatus as claimed in claim 1 in which the opaque spherical segment has a plurality of concentric transparent circles thereon for passage therethrough of light from said light source means to form on the eye of a patient whose eye is adjacent said housing first end an image of a plurality of concentric circles.
Claim 8
Dependent Claim
30 words
Apparatus as claimed in claim 6 in which the diameter of the outermost concentric transparent circle subtends an angle of 120* at the center of curvature of the spherical segment.
Claim 9
Dependent Claim
49 words
Apparatus as claimed in claim 1 further comprising lens means intermediate said housing first end and said shutter means for focusing on said viewing screen and on film within said film holder an image of objects in the vicinity of the center of curvature of the opaque spherical segment.
Claim 10
Dependent Claim
30 words
Apparatus as claimed in claim 1 in which said film holder includes means for developing exposed film therein to form a positive print of images formed on the exposed film.
Claim 11
Dependent Claim
25 words
Apparatus as claimed in claim 1 in which said shutter means includes mirror means cooperating with said housing to define one of the optical paths.
Claim 12
Dependent Claim
21 words
Apparatus as claimed in claim 10 in which said mirror means cooperates with said housing to define the first optical path.
Claim 13
Dependent Claim
27 words
Apparatus as claimed in claim 1 in which said shutter means cooperates with said housing to define the first and second optical paths with equal path lengths.
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) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |