Method and apparatus for automated placement of scanned laser capsulorhexis incisions
Systems and methods are described for cataract intervention. In one embodiment a system comprises a laser source configured to produce a treatment beam comprising a plurality of laser pulses; an integrated optical system comprising an imaging assembly operatively coupled to a treatment laser delivery assembly such that they share at least one common optical element, the integrated optical system being configured to acquire image information pertinent to one or more targeted tissue structures and direct the treatment beam in a 3-dimensional pattern to cause breakdown in at least one of the targeted tissue structures; and a controller operatively coupled to the laser source and integrated optical system, and configured to adjust the laser beam and treatment pattern based upon the image information, and distinguish two or more anatomical structures of the eye based at least in part upon a robust least squares fit analysis of the image information.
1. A system for cataract surgery on an eye of a patient, comprising:
a. a laser source configured to produce a treatment beam comprising a plurality of laser pulses;
b. an integrated optical system comprising an imaging assembly operatively coupled to a treatment laser delivery assembly such that the imaging assembly and the treatment laser delivery assembly share at least one common optical element, the integrated optical system being configured to acquire image information pertinent to one or more targeted tissue structures and direct the treatment beam in a 3-dimensional pattern to cause breakdown in at least one of the targeted tissue structures; and
c. a controller operatively coupled to the laser source and integrated optical system, and configured to:
1) adjust the laser beam and treatment pattern based upon the image information,
2) process the image information to identify a first set of candidate edge locations for at least one anatomical structure of the eye, the first set of candidate edge locations being disposed in a first boundary surface portion of the at least one anatomical structure,
3) use a least-squares technique to fit a first mathematical surface model to the first set of the candidate edge locations,
4) process the image information based on proximity to the first mathematical surface model to identify a second set of candidate edge locations for the at least one anatomical structure, the second set of candidate locations being disposed in a second boundary surface portion of the at least one anatomical structure that is different from the first boundary surface portion, and
5) use a least-squares technique to fit a second mathematical surface model to the combined first and second sets of candidate edge locations.
2. The system of claim 1 , wherein the at least one anatomical structure comprises a cornea.
3. The system of claim 1 , wherein the at least one anatomical structure comprises a sclera.
4. The system of claim 1 , wherein the at least one anatomical structure comprises a limbus.
5. The system of claim 1 , wherein the at least one anatomical structure comprises an iris.
6. The system of claim 1 , wherein the at least one anatomical structure comprises a lens.
7. The system of claim 1 , wherein the at least one anatomical structure comprises a lens capsule.
8. The system of claim 1 , wherein the controller is configured to conduct a series of three or more least-squares fit analyses, and to separately process the image information to identify additional candidate edge locations so that a greater number of candidate edge locations are used in each successive least-squares fit analysis.
9. The system of claim 1 , wherein at least one of the first and second mathematical surface models is a spherical surface.
10. The system of claim 1 , wherein at least one of the first and second mathematical surface models is an aspherical surface.
11. The system of claim 1 , wherein the controller is further configured to locate two or more boundaries between a corresponding three or more anatomical structures of the eye.
12. The system of claim 11 , wherein the boundaries include the intersection between a cornea of the eye and a sclera of the eye.
13. The system of claim 11 , wherein the boundaries include the intersection between a cornea of the eye and an iris of the eye.
14. The system of claim 11 , wherein the boundaries include the intersection between a lens of the eye and an iris of the eye.
15. The system of claim 1 , wherein the controller is configured to utilize rejected candidate edge locations of a least-squares fit analysis to identify an anatomical structure of the eye.
16. The system of claim 1 , wherein the second boundary surface portion completely surrounds the first boundary surface portion.