US3693416A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Applanation tonometer arrangement
Assignee: American Optical Corp
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Filing: 1970-11-25
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Granted: 1972-09-26
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Expires: 1990-11-25
Abstract
Abstract An applanation tonometer having a bi-prism to indicate the displacement of the contact element against a corneal surface. The bi-prism is located at the entrance pupil of the associated optical system.
Inventors
- 👤 Joseph C Dianetti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:25
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
202 words
A combination slit lamp aNd applanation tonometer: said tonometer being removably attached to said slit lamp including, a transparent corneal contact element adapted to be biased against a corneal surface, a prism for doubling the image of the area of contact between said contact element and said corneal surface, said prism having its apex defined by prism faces disposed in equal angular orientation relative to the optical axis between said prism and said contact element, said slit lamp including a stereo optical system defining a pair of optical paths converging at said contact element and effective to observe the area of contact between said contact element and said corneal surface, said optical system including at least one objective lens, said prism being mounted adjacent to said objective lens on a cup-like element which is rotatably mounted relative to said objective lens, so that said prism is rotatable between alternate positions in and out of said optical paths, said cup-like element defining four apertures on parallel axes and spaced 90* apart in a circumferencial array, said prism being mounted over two diagonally opposed apertures and being clear of the remaining two said apertures, said cup-like element being rotatable between end positions 90* apart.
Claim 2
Dependent Claim
202 words
A combination slit lamp aNd applanation tonometer: said tonometer being removably attached to said slit lamp including, a transparent corneal contact element adapted to be biased against a corneal surface, a prism for doubling the image of the area of contact between said contact element and said corneal surface, said prism having its apex defined by prism faces disposed in equal angular orientation relative to the optical axis between said prism and said contact element, said slit lamp including a stereo optical system defining a pair of optical paths converging at said contact element and effective to observe the area of contact between said contact element and said corneal surface, said optical system including at least one objective lens, said prism being mounted adjacent to said objective lens on a cup-like element which is rotatably mounted relative to said objective lens, so that said prism is rotatable between alternate positions in and out of said optical paths, said cup-like element defining four apertures on parallel axes and spaced 90* apart in a circumferencial array, said prism being mounted over two diagonally opposed apertures and being clear of the remaining two said apertures, said cup-like element being rotatable between end positions 90* apart.
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) | 1975-09-26 | 1976-03-27 | 1976-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-26 | 1980-03-27 | 1980-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-26 | 1984-03-27 | 1984-09-26 | $7700.00 | Window Closed / Lapsed |