Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1995-06-07
2001-01-16
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C606S004000
Reexamination Certificate
active
06175754
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the field of eye surgery, and in particular to a method and apparatus for measuring the depth of an incision or pocket in a patient's cornea.
Some surgical procedures for the correction of visual disorders require incisions in the patient's cornea. For example, U.S. Pat. No. 4,452,235 describes a method and apparatus for corneal curvature adjustment. The method involves insertion of one end of a split-end Intrastromal Corneal Ring (ICR) into an incision formed in the patient's cornea and movement of the ring in a circular path until the ends of the ring meet. The ICR's thickness relates to the degree of corneal flattening that can be obtained, to provide for correction of varying degrees of myopia. ICRs are made by Keravision, Inc. and are further discussed in U.S. Pat. No. 5,318,047, entitled METHOD FOR CORNEAL CURVATURE VARIATION, and issued to Davenport et al. on Jun. 7, 1994, which is hereby incorporated by reference. Similarly, U.S. Pat. No. 5,090,955 describes the adjustment of corneal curvature through the injection of a polymeric gel into an incision made in a patient's cornea.
Both of these corrective procedures require precise measurement of the depth of the pocket into which the gel or ICR is to be inserted. Both procedures require an initial measurement of the corneal thickness, typically employing an ultrasonic pachymeter. An adjustable-depth diamond knife then makes a peripheral incision to a depth that corresponds to a predetermined fraction of the pachymetry measurement at the incision's side. For example, to insert an ICR, the incision depth corresponds to 68% of the pachymetry measurement.
After the initial incision is made, at least one lamellar pocket is formed for insertion of the gel or ICR. Using conventional technology, the depth of the pocket is estimated using a set of mechanical corneal thickness gauges, such as those manufactured by KeraVision, Inc., the assignee of the present invention. These gauges feature gaps of different widths for measuring corneal tissue thickness, and thereby pocket depth. If the measurement indicates that the pocket is not deep enough into the corneal stroma, the diamond knife is used to make a slightly deeper incision in order to create a second pocket at a deeper level. This procedure is repeated until a corneal pocket of a desired depth is created. After the pocket is finally created, the pocket is further formed into a annular shape for injection of a polymeric gel or an ICR.
Measuring the depth of the corneal pocket is a critical step in ICR implantation and other corneal surgery procedures. The depth must be measured accurately since the depth of the implant can affect the resulting refractive change. Therefore, it is desirable to provide an accurate and dependable way of measuring the depth of corneal pockets that are used for refractive correction and other ocular surgery procedures.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for measuring the depth of a pocket made in tissue. A controlled-depth incision is made into the tissue of a patient and the tissue is delaminated at the bottom of the incision to create a tissue pocket. The tissue has an anterior surface. Preferably, the tissue is the corneal tissue of an eye. A reflective element is inserted into the pocket. An energy source generates a radiant energy signal, which is directed toward the reflective element. Reflected energy is received from the reflective element. A detector determines the depth of the reflective element below the anterior surface based upon the energy reflected by the reflective element.
The speed of transmission of the radiant energy in the reflective element is different from the speed of transmission of the radiant energy in the tissue. Preferably, the speed of transmission in the reflective element is slower than the speed of transmission in the tissue. For optical reflection, the reflective element may have either a substantially different refractive index or a substantially higher reflectivity than the tissue being measured.
The reflective element may be in the form of a tool on which is disposed a biocompatible polymer layer, the layer comprising trapped air spaces. Alternatively, the reflective element may be a tool having an open space for containing trapped air.
The radiant energy may take the form of ultrasound generated by an ultrasonic probe, or light generated by a confocal microscope. The confocal microscope may employ longitudinal chromatic aberration to measure the depth of the reflective element. When a confocal microscope is used, the depth of the reflective element is a function of the reflected energy from the anterior surface and the reflected energy from the reflective element.
REFERENCES:
patent: 4423728 (1984-01-01), Lieberman
patent: 4429696 (1984-02-01), Hanna
patent: 4452235 (1984-06-01), Reynolds
patent: 4564018 (1986-01-01), Hutchinson et al.
patent: 4598714 (1986-07-01), Kremer et al.
patent: 4671276 (1987-06-01), Reynolds
patent: 4688570 (1987-08-01), Kramer et al.
patent: 4705037 (1987-11-01), Peyman et al.
patent: 4813435 (1989-03-01), Arms
patent: 4815463 (1989-03-01), Hanna
patent: 4829251 (1989-05-01), Fischer
patent: 4844617 (1989-07-01), Kelderman et al.
patent: 4881808 (1989-11-01), Bille et al.
patent: 4887592 (1989-12-01), Loertscher
patent: 4941093 (1990-07-01), Marshall et al.
patent: 4964862 (1990-10-01), Arms
patent: 4965441 (1990-10-01), Picard
patent: 4993428 (1991-02-01), Arms
patent: 4997437 (1991-03-01), Grieshaber
patent: 5063942 (1991-11-01), Kilmer et al.
patent: 5083220 (1992-01-01), Hill
patent: 5084612 (1992-01-01), Iwasaki et al.
patent: 5090955 (1992-02-01), Simon
patent: 5109276 (1992-04-01), Nudelman et al.
patent: 5117466 (1992-05-01), Buican et al.
patent: 5120953 (1992-06-01), Harris
patent: 5161052 (1992-11-01), Hill
patent: 5192980 (1993-03-01), Dixon et al.
patent: 5194918 (1993-03-01), Kino et al.
patent: 5196006 (1993-03-01), Klopotek et al.
patent: 5200819 (1993-04-01), Nudelman et al.
patent: 5200838 (1993-04-01), Nudelman et al.
patent: 5208648 (1993-05-01), Batchelder et al.
patent: 5215104 (1993-06-01), Steinert
patent: 5220403 (1993-06-01), Batchelder et al.
patent: 5225678 (1993-07-01), Messerschmidt
patent: 5241364 (1993-08-01), Kimura
patent: 5260569 (1993-11-01), Kimura
patent: 5283433 (1994-02-01), Tsien
patent: 5293870 (1994-03-01), Ophir et al.
patent: 5296700 (1994-03-01), Kumagai
patent: 5296703 (1994-03-01), Tsien
patent: 5306902 (1994-04-01), Goodman
patent: 5307203 (1994-04-01), Hill
patent: 5308355 (1994-05-01), Dybbs
patent: 5311021 (1994-05-01), Messerschmidt
patent: 5318047 (1994-06-01), Davenport et al.
patent: 5329352 (1994-07-01), Jacobsen
patent: 5355252 (1994-10-01), Haraguchi
patent: 5437657 (1995-08-01), Epstein
patent: 5497147 (1996-03-01), Arms et al.
patent: 5560356 (1996-10-01), Peyman
patent: 5601584 (1997-02-01), Obagi et al.
patent: 5611805 (1997-03-01), Hall
patent: 5651782 (1997-07-01), Simon et al.
patent: 5653725 (1997-08-01), Simon et al.
patent: 5662668 (1997-09-01), Kurwa
patent: 5772970 (1998-03-01), Colvard et al.
patent: 5984914 (1999-11-01), Cumming
patent: 5988824 (1999-11-01), Rowsey, Jr.
patent: 2144537 (1985-03-01), None
patent: 92/19930 (1992-11-01), None
Molesini et al., “Focus-Wavelength Encoded Optical Profilometer,”Optics Communications49(4): 229-233 (1984).
Maly et al., “Real-Time Stereoscopic Confocal Reflection Microscopy Using Objective Lenses with Linear Longitudinal Chromatic Dispersion,”Scanning16(3): 187-192 (1994).
Baker Phillip C.
Gandionco Isidro Matias
Kuhn William P.
Scholl John Anthony
Silvestrini Thomas A.
KeraVision Inc.
KeraVision, Inc.
Lateef Marvin M.
Macey Harry
Shaw Shawna J.
LandOfFree
Method and apparatus for measuring corneal incisions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for measuring corneal incisions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for measuring corneal incisions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534043