System and method for determining a position for a scleral pocket for a scleral prosthesis

• US 20040073245A1
• Filed: 05/20/2003
• Published: 04/15/2004
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: Refocus Group Incorporated
• Original Assignee: Refocus Group Incorporated
• Inventors: Schachar, Ronald A., Cudmore, Donald P., Munck, William A.
• Granted Patent: US 7,909,780 B2
• Time in Patent Office: Days
• US Class Current: 606/166
• CPC Class Codes: A61F 2/147 Implants to be inserted in the stroma for refractive correction, e.g. ring-like implants
• CPC Class Codes: A61F 9/007 Methods or devices for eye surgery

Abstract

For use with a surgical tool for making incisions in the sclera of an eye to form a scleral pocket to receive a scleral prosthesis, a system and method is disclosed for determining a position on the sclera for locating the scleral pocket. The system and method determines an optimum location for the scleral pocket. The system and method determines a location on the sclera that represents the intersection of the lens equatorial plane with the external surface of the sclera. The front of the scleral pocket is placed at a location that is four hundred fifty microns posterior to the intersection of the lens equatorial plane with the external surface of the sclera.

Claims

1. For use with a surgical tool for making an incision in scleral tissue of an eye for forming a scleral pocket within the scleral tissue of the eye to receive a scleral prosthesis, an apparatus for locating a position on the sclera of the eye to form said scleral pocket, said apparatus comprising:

a controller that is operable to;

(i) receive eye measurements that measure a size of portions of said eye, wherein said controller comprises a software processor; and

(ii) use said eye measurements to create a mathematical model of said eye; and

(iii) determine from said mathematical model of said eye a location on said sclera of said eye for making an incision having the form of a scleral pocket that is capable of receiving said scleral prosthesis.

2. An apparatus as claimed in claim 1 wherein said controller is capable of determining from said mathematical model of said eye a location on the sclera of said eye where a projection of a lens equatorial plane of said eye intersects with the sclera of said eye.

3. An apparatus as claimed in claim 1 wherein said controller is capable of determining from said mathematical model of said eye a radius D of a scleral shell of said eye from a measured value of corneal diameter A of said eye, a measured value of mean radius of curvature C of said eye, and a measured value of an axial length B of said eye.

4. An apparatus as claimed in claim 2 wherein said controller is capable of determining from said mathematical model of said eye a location of said lens equatorial plane with respect to the anterior surface of a lens of said eye.

5. An apparatus as claimed in claim 4 wherein said controller is capable of determining from said mathematical model of said eye said location of said lens equatorial plane by multiplying a thickness of said lens by an empirical percentage stored within said controller.

6. An apparatus as claimed in claim 5 wherein said controller is capable of determining from said mathematical model of said eye a distance between a corneal plane of said eye and said lens equatorial plane of said eye.

7. An apparatus as claimed in claim 6 wherein said controller is capable of determining from said mathematical model of said eye a distance K from a center of said scleral shell of said eye to said lens equatorial plane.

8. An apparatus as claimed in claim 7 wherein said controller is capable of determining from said mathematical model of said eye a distance M from an axis of said eye to a point on said sclera of said eye where a projection of said lens equatorial plane of said eye intersects with the sclera of said eye.

9. An apparatus as claimed in claim 8 wherein said controller is capable of determining from said mathematical model of said eye a distance N from the center of a cornea of said eye to a position Q where it is optimal to locate a front of said scleral pocket on said sclera of said eye.

10. An apparatus as claimed in claim 9 wherein said controller is capable of determining from said mathematical model of said eye a distance from the center of said cornea of said eye to a position P on the sclera of said eye where it is optimal to place a center of a scleral tissue fixation tool to restrain the movement of said surgical tool when said surgical tool makes an incision in said sclera of said eye to form said scleral pocket.

11. An apparatus as claimed in claim 1 wherein said controller is capable of receiving information concerning said eye from an input unit.

12. An apparatus as claimed in claim 1 wherein said controller is further capable of providing information derived from said mathematical model of said eye to one of:

a data display, a surgical tool controller, and an applanation marking plate assembly.

13. For use with a surgical tool for making an incision in scleral tissue of an eye for forming a scleral pocket within the scleral tissue of the eye to receive a scleral prosthesis, a method for locating a position on the sclera of the eye to form said scleral pocket, said method comprising the steps of:

receiving eye measurements that measure a size of portions of said eye within a controller that comprises a software processor;

using said eye measurements within lllsaid controller to create a mathematical model of said eye; and

determining from said mathematical model of said eye a location on said sclera of said eye for making an incision having the form of a scleral pocket that is capable of receiving said scleral prosthesis.

14. A method as claimed in claim 13 further comprising the step of:

determining from said mathematical model of said eye a location on the sclera of said eye where a projection of a lens equatorial plane of said eye intersects with the sclera of said eye.

15. A method as claimed in claim 13 further comprising the step of:

determining from said mathematical model of said eye a radius D of a scleral shell of said eye from a measured value of corneal diameter A of said eye, a measured value of mean radius of curvature C of said eye, and a measured value of an axial length B of said eye.

16. A method as claimed in claim 14 further comprising the steps of:

determining from said mathematical model of said eye a location of said lens equatorial plane with respect to the anterior surface of a lens of said eye; and

determining from said mathematical model of said eye said location of said lens equatorial plane by multiplying a thickness of said lens by an empirical percentage stored within said controller.

17. A method as claimed in claim 16 further comprising the steps of:

determining from said mathematical model of said eye a distance between a corneal plane of said eye and said lens equatorial plane of said eye; and

determining from said mathematical model of said eye a distance K from a center of said scleral shell of said eye to said lens equatorial plane.

18. A method as claimed in claim 17 further comprising the steps of:

determining from said mathematical model of said eye a distance M from an axis of said eye to a point on said sclera of said eye where a projection of said lens equatorial plane of said eye intersects with the sclera of said eye; and

determining from said mathematical model of said eye a distance N from the center of a cornea of said eye to a position Q where it is optimal to locate a front of said scleral pocket on said sclera of said eye.

19. A method as claimed in claim 18 further comprising the step of:

determining from said mathematical model of said eye a distance from the center of said cornea of said eye to a position P on the sclera of said eye where it is optimal to place a center of a scleral tissue fixation tool to restrain the movement of said surgical tool when said surgical tool makes an incision in said sclera of said eye to form said scleral pocket.

20. A method as claimed in claim 13 further comprising the steps of:

receiving in said controller from an input unit information concerning said eye; and

providing information derived from said mathematical model of said eye to one of;

a data display, a surgical tool controller, and an applanation marking plate assembly.