Balanced Phacoemulsification Tip

• US 20120072197A1
• Filed: 09/17/2010
• Published: 03/22/2012
• Est. Priority Date: 09/17/2010
• Status: Active Grant

• Current Assignee: Alcon Incorporated
• Original Assignee: Alcon Research, LLC (Alcon Incorporated)
• Inventors: Ovchinnikov, Mikhail A.
• Granted Patent: US 10,258,505 B2
• Time in Patent Office: Days
• US Class Current: 703/11
• CPC Class Codes: A61B 2017/320098 with transverse or torsional motion
• CPC Class Codes: A61F 9/00745 using mechanical vibrations, e.g. ultrasonic

Abstract

In various embodiments, a phacoemulsification tip may include a shaft and a cutting edge portion having at least a first and second bend. The geometry of the tip may be configured to result in a lateral displacement (u_x), perpendicular to the shaft during torsional vibration of the tip at frequencies between 10 kHz and 60 kHz, of less than approximately 5% to 25% (e.g., 15%) of the lateral displacement at the distal end point of the tip throughout a portion of the shaft extending from the end of a conical portion of the tip through to the first bend in the cutting edge portion of the tip. Software and/or physical modeling may be used to determine the tip geometry.

Claims

1. A phacoemulsification tip, comprising:

a shaft having a proximal end and a distal end;

a cutting edge portion at the distal end of the shaft, wherein the cutting edge portion comprises at least a first and second bend;

wherein a geometry of the shaft and the at least first and second bend is configured to result in a lateral displacement, perpendicular to the shaft, during ultrasonic torsional vibration of the tip, of less than approximately 5 to 25% of the lateral displacement at a distal end point of the tip throughout a portion of the shaft that extends from the proximal end of the shaft to the first bend of the cutting edge portion.

2. The phacoemulsification tip of claim 1, wherein the lateral displacement (u_x) is at least partially defined using the equation

3. The phacoemulsification tip of claim 2, wherein φ

is provided through the equation

4. The phacoemulsification tip of claim 3, wherein the equations

5. The phacoemulsification tip of claim 4, wherein the proximal end of the tip includes a conical portion and wherein a length of the conical portion is selected to increase twisting vibrations of the tip during ultrasonic torsional vibrations to provide a greater lateral displacement at the distal end point of the tip.

6. The phacoemulsification tip of claim 1, wherein the lateral displacement of the tip at the distal end point of the tip is approximately in a range of 40 to 200 microns.

7. A method of determining a phacoemulsification tip geometry, comprising:

providing a first tip geometry;

modeling the lateral displacement of the first tip geometry during ultrasonic torsional vibration of the tip;

providing a second tip geometry;

modeling the lateral displacement of the second tip geometry during ultrasonic torsional vibration of the tip;

comparing the lateral displacement of the first tip geometry and the lateral displacement of the second tip geometry; and

selecting the first tip geometry or the second tip geometry based on which tip geometry has a smaller lateral displacement along a portion of the tip shaft configured to be along an incision in an eye during a phacoemulsification procedure.

8. The method of claim 7, wherein the first tip geometry comprises at least:

l(z) the lateral displacement from the straight geometry,

ρ

as density of a tip material,

I(z) as a moment of inertia of a cylindrical tip cross-section around an axis collinear with a tip shaft,

S(z) as a cross-sectional area of the tip along the axis collinear with the shaft,

E as young'"'"'s modulus of the tip material,

I_y(z) as a moment of inertia of a cross-section of the tip around an axis perpendicular to the axis collinear with the shaft,

C(z)=I(z)*μ

, and

μ

as the torsional modulus of the tip material.

9. The method of claim 8, wherein modeling the lateral displacement (u_x) of the tip geometry during ultrasonic torsional vibration of the tip comprises determining lateral movement of the tip according to the equations

10. The method of claim 7, wherein the first and second tip geometry comprise a conical portion and wherein the method further comprises modeling twisting vibrations of the tip according to the equation

11. The method of claim 7, wherein the first and second tip geometries include at least a first and second bend and wherein the first and second tip geometries include a different location or curvature of the second bend.

12. The method of claim 7, further comprising determining whether the lateral displacement along a portion of the tip shaft configured to be along an incision in an eye during a phacoemulsification procedure is less than approximately 15% of the distal end point lateral displacement.

13. The method of claim 11, further comprising if the lateral displacement along a portion of the tip shaft configured to be along an incision in an eye during a phacoemulsification procedure is greater than approximately 15% of the distal end point lateral displacement, generating a third tip geometry, modeling the lateral displacement of the third tip geometry, and comparing the lateral displacement of the third tip geometry to at least one of the lateral displacement of the first or second tip geometry.

14. A method of determining a phacoemulsification tip geometry, comprising:

providing a first tip with a first tip geometry;

ultrasonically torsionally vibrating the first tip geometry;

determining a lateral displacement along the tip geometry during the ultrasonic torsional vibration of the first tip;

providing a second tip with a second tip geometry;

ultrasonically torsionally vibrating the second tip geometry;

determining a lateral displacement along the second tip geometry during the ultrasonic torsional vibration of the second tip;

comparing the lateral displacement of the first tip geometry and the lateral displacement of the second tip geometry; and

selecting the first tip geometry or the second tip geometry based on which tip geometry has a smaller lateral displacement along a portion of the tip shaft configured to be along an incision in an eye during a phacoemulsification procedure.

15. The method of claim 14, wherein selecting the first or second tip geometry further comprises determining which of the first tip geometry and the second tip geometry has a smaller lateral displacement of the tip shaft throughout a portion of the shaft extending from the proximal end of the shaft through at least half of the length of the shaft.

16. The method of claim 14, wherein the first and second tip geometries include at least a first and second bend.

17. The method of claim 16, wherein the first and second tip geometries include a different respective locations or curvatures of the second bend.

18. The method of claim 14, further comprising determining whether the lateral displacement along a portion of the tip shaft configured to be along an incision in an eye during a phacoemulsification procedure is less than approximately 5 to 25% of the lateral displacement at the distal end point of the tip.

19. The method of claim 18, further comprising if the lateral displacement along a portion of the tip shaft configured to be along an incision in an eye during a phacoemulsification procedure is greater than approximately 5 to 25% of the lateral displacement at the distal end point of the tip, generating a third tip geometry, modeling the lateral displacement of the third tip geometry, and comparing the lateral displacement of the third tip geometry to at least one of the lateral displacement of the first or second tip geometry.

20. The method of claim 14, wherein determining a lateral movement of the tip geometry comprises using at least one of thermal imaging, stroboscopy, or physical measurement of displacement.