US4664110A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlled rate freezing for cryorefractive surgery
Assignee: University of Southern California
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Filing: 1985-03-18
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Granted: 1987-05-12
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Expires: 2005-03-18
Abstract
Abstract A method for freezing corneal tissue prior to cryorefractive surgery, including the controlled rate freezing of the tissue at a rate of less than seven degrees centigrade per minute.
Inventors
- 👤 David J. Schanzlin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:46
CPC Classifications
A; A61; A61F; A61F9/00; A61F9/007; A61F9/013; A01; A01N; A01N1/00; A01N1/10; A01N1/16; A01N1/162; A61B; A61B18/00; A61B18/02; A61F2/00; A61F2/02; A61F2/14; A61F2/142; A61L; A61L27/00; A61L27/36; A61L2430/00; A61L2430/16
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
72 words
In a method for refractive keratoplasty which includes freezing and latching a corneal portion to modify the surface curvature thereof, the improvement comprising the steps of cooling the corneal portion at a rate of less than about 7° C. per minute over a temperature range below +4° C. to a temperature above -40° C. to freeze the corneal portion, and lathing the surface of the frozen corneal portion to a predetermined curvature.
Claim 2
Dependent Claim
72 words
In a method for refractive keratoplasty which includes freezing and latching a corneal portion to modify the surface curvature thereof, the improvement comprising the steps of cooling the corneal portion at a rate of less than about 7° C. per minute over a temperature range below +4° C. to a temperature above -40° C. to freeze the corneal portion, and lathing the surface of the frozen corneal portion to a predetermined curvature.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the cooling proceeds at a rate of from about 1/2 to 41/2° C. per minute.
Claim 4
Independent Claim
23 words
The method of claims 1 or 2 wherein the corneal portion is cooled to a temperature of from -10° C. to -° C.
Claim 5
Independent Claim
78 words
A method for performing cryorefractive surgery on the cornea of a patient, comprising: obtaining a corneal portion; cooling the corneal portion, over a temperature range of below 4° C., at a rate of less than 7° C. per minute until the corneal portion is frozen; lathing the surface of the frozen corneal portion to a predetermined curvature; thawing the lathed corneal portion to about room temperature; and grafting the lathed corneal portion to the cornea of the patient.
Claim 6
Independent Claim
78 words
A method for performing cryorefractive surgery on the cornea of a patient, comprising: obtaining a corneal portion; cooling the corneal portion, over a temperature range of below 4° C., at a rate of less than 7° C. per minute until the corneal portion is frozen; lathing the surface of the frozen corneal portion to a predetermined curvature; thawing the lathed corneal portion to about room temperature; and grafting the lathed corneal portion to the cornea of the patient.
Claim 7
Dependent Claim
29 words
The method of claim 4 wherein the cooling proceeds at a rate of from about 1/2 to 5° C. per minute to a temperature of -10° to -20° C.
References Cited (Backward Citations)
US4483341A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |