Handpiece for the phacoemulsification of an eye lens

Abstract

The invention relates to a handpiece for the phacoemulsification of an eye lens, having a needle with an aspiration line arranged therein for transporting an aspiration fluid and at least one drive element for generating a longitudinal wave, wherein the drive element is arranged in such a way that the longitudinal wave can be coupled directly into the aspiration fluid.

Claims

1. A handpiece for effecting a phacoemulsification of an eye lens, the handpiece comprising: a needle; an aspiration line configured to transfer an aspiration fluid; said aspiration line being arranged within said needle; at least one drive element configured to vibrate and generate kinetic energy as a longitudinal wave; and, said at least one drive element being arranged so as to cause said longitudinal wave to be coupled directly into said aspiration fluid to impart a fluid pressure thereto to effect the phacoemulsification of the eye lens via said fluid pressure.

2. The handpiece of claim 1, wherein said at least one drive element is arranged within said aspiration line and in direct contact with the aspiration fluid.

3. The handpiece of claim 1, wherein said at least one drive element includes piezoelectric elements.

4. The handpiece of claim 1, wherein said at least one drive element has an annular shape.

5. The handpiece of claim 1, wherein: said needle has a distal end; and, said needle has a funnel-shaped region with a tapering end oriented toward said distal end.

6. The handpiece of claim 5, wherein: said aspiration line defines a center axis; said funnel-shaped region in cross section defines an inner wall contour; and, said inner wall contour is curved with respect to said center axis with a center of curvature in such a manner that said center of curvature is oriented toward said tapering end of said funnel-shaped region.

7. The handpiece of claim 1, wherein: said needle has a distal end; and, said distal end has an inner diameter lying in a range of 0.4 mm to 1.1 mm.

8. The handpiece of claim 1, wherein said needle has a distal end made of polymer plastic.

9. A handpiece for effecting a phacoemulsification of an eye lens, the handpiece defining a longitudinal axis and comprising: a needle; an aspiration line configured to transfer an aspiration fluid; said aspiration line being arranged within said needle; a drive element configured to generate movement energy in the direction of said longitudinal axis; and, said drive element being arranged so as to cause said movement energy to generate a longitudinal wave directly coupled only into said aspiration fluid to impart a fluid pressure thereto to effect the phacoemulsification of the eye lens via said fluid pressure while avoiding a transfer of kinetic energy to said needle which remains stationary during the phacoemulsification of the eye lens.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described with reference to the drawings wherein:

(2) FIG. 1 is a schematic cross-sectional view of a first embodiment of a handpiece according to the invention;

(3) FIG. 2 is a schematic cross-sectional view of a second embodiment of the handpiece according to the invention;

(4) FIG. 3 is a schematic cross-sectional view of a third embodiment of the handpiece according to the invention; and,

(5) FIG. 4 is a schematic of isobars which emerge in the region of the needle tip during the use of the handpiece according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

(6) FIG. 1 shows a handpiece 1 in accordance with a first embodiment of the invention. The handpiece 1 has a needle 10 with an aspiration line 2 for transporting aspiration fluid 3, which can be suctioned together with lens particles at a distal end 9 of the needle 10. Here, suctioning away from the distal end 9 of the needle 10 takes place into the handpiece in the direction of the arrow 4. The handpiece 1 furthermore has a drive element 5, which is arranged within the aspiration line. In the embodiment depicted in FIG. 1, the drive element 5 has four piezoelectric elements, which are directly connected to one another. Such a drive element 5 is provided with an electrical insulation 51 such that there can be no short circuit by way of the aspiration fluid.

(7) The drive element 5 can be actuated in such a way that a longitudinal movement is generated in the direction of the arrows 6. The movement energy emitted by the drive element 5 generates a longitudinal wave, which is directly coupled into the aspiration fluid. What is important here is that, in this embodiment of the handpiece, the drive element cannot transfer its kinetic energy to the needle, but only to the aspiration fluid. Consequently, the needle remains stationary without movement, and so only the aspiration fluid can transport the energy to the distal end 9 of the needle 10.

(8) The energy emitted by the drive element 5 can be concentrated particularly well if the aspiration fluid is guided into a funnel-shaped region 7. In this first embodiment depicted in FIG. 1, the aspiration fluid, starting from the drive element 5, reaches an opening zone 71 of the funnel-shaped region 7, whereupon the cross section of the funnel-shaped region 7 increasingly tapers in the direction toward the distal end 9 of the needle 10, until, finally, an end 72 of the funnel-shaped region 7 is reached. In the embodiment depicted in FIG. 1, the funnel-shaped region 7 has a length L1. Starting from the end 72 of the funnel-shaped region 7, the needle 10 is continued in the form of a hollow cylinder. The overall length of the needle 10 including the funnel-shaped region 7 has a length L2. Preferably, the length L1=10 mm and the length L2=50 mm.

(9) A particularly high concentration of the energy emitted by the drive element 5 can be achieved if, in the cross section, the funnel-shaped region 7 has an internal wall contour 11 which is curved toward the central axis A of the aspiration line 2 in such a way that an associated center of curvature 12 is oriented toward the end 72 of the funnel-shaped region 7.

(10) FIG. 2 shows a second embodiment of a front part of the handpiece according to the invention. This handpiece also has a funnel-shaped region, see reference sign 107, which has a first zone I and a second zone II. Here, the second zone II is formed analogously to the funnel-shaped region 7 in accordance with FIG. 1 by virtue of this region 7 having an internal contour which is oriented toward the central axis A of the aspiration line 2 in such a way that an associated center of curvature 120 is oriented toward an end 172 of the funnel-shaped region 107. However, the first zone I is configured in such a way that a center of curvature 130 associated therewith is arranged on an opposite side in relation to the position of the center of curvature 120 of the second zone II. Therefore, the center of curvature 130 is not oriented toward the tapering end 172 of the funnel-shaped region 107, but rather in a direction toward an opening zone 171 of the funnel-shaped region 107, wherein the opening zone 171 is arranged opposite to the end 172 of the funnel-shaped region 107.

(11) FIG. 3 schematically shows a cross-section of a third embodiment of a front part of the handpiece according to the invention. A funnel-shaped region 207 with an opening zone 271 and an end 272 is embodied in such a way that an associated internal wall contour 210 has a free-form contour. If this free-form contour is embodied appropriately, there are no eddies, and so a high concentration of the energy emitted by the drive element 5 can be achieved in the direction toward the distal end 9 of the needle 10.

(12) FIG. 4 depicts a needle 10 of the handpiece 1 according to the invention, wherein isobars (IB1, IB2, IB3) have additionally been plotted. When calculating the isobars, the following boundary conditions were considered:

(13) Ultrasound wave speed in the aspiration fluid: c.sub.0=1484 m/s

(14) Ultrasonic frequency of the drive elements: f.sub.0=40 000 Hz;

(15) Ultrasound wavelength in the aspiration fluid:

(16) l.sub.0=c.sub.0/f.sub.0=37.1 mm;

(17) Amplitude of the drive elements: a.sub.0=50 m.

(18) Taking into account these boundary conditions, a sound pressure level of IB1=276 dB emerges in the direct vicinity of the distal end 9 of the needle 10. This sound pressure level is directly applied onto the lens to be emulsified. At a distance of approximately 7 mm from the distal end 9 of the needle 10, there is a sound pressure level of approximately IB2=200 dB and a sound pressure level of approximately IB3=160 dB is prevalent at a distance of approximately 15 mm from the needle tip. The sound pressure level in the direct vicinity of the distal end 9 of the needle 10 in the case of the handpiece according to the invention reaches a value that is higher by approximately 50 dB than what can be reached in the case of a handpiece according to the prior art if the same boundary conditions are applied. This means that, in the handpiece according to the invention, a higher sound pressure level for emulsifying a lens of an eye can be generated with a stationary needle than what would be possible in the case of a vibrating needle in a conventional handpiece.

(19) It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.

LIST OF REFERENCE SIGNS

(20) 1 Handpiece in accordance with a first embodiment 2 Aspiration line 3 Aspiration fluid 4 Direction of the suctioning away 5 Drive element 51 Insulation of a drive element 6 Direction of the longitudinal movement 7 Funnel-shaped region 71 Opening zone of the funnel-shaped region 7 72 Tapered end of the funnel-shaped region 7 9 Distal end of the needle 10 10 Needle 11 Internal wall of the funnel-shaped region 7 12 Center of curvature of the internal wall 11 100 Handpiece in accordance with a second embodiment 107 Funnel-shaped region 110 Internal wall of the funnel-shaped region 107 120 Center of curvature of the second zone II of the funnel-shaped region 107 130 Center of curvature of the first zone I of the funnel-shaped region 107 171 Opening zone of the funnel-shaped region 107 172 Tapered end of the funnel-shaped region 107 200 Handpiece in accordance with a third embodiment 210 Internal wall 207 Funnel-shaped region 271 Opening zone of the funnel-shaped region 207 272 Tapered end of the funnel-shaped region 207 A Central axis of the aspiration line L1 Length of the funnel-shaped region (7, 107, 207) L2 Length of the needle 10 IB1, IB2, IB3 Isobars