Applicator and device for cell treatment

Abstract

An applicator configured for cell treatment with pressure pulses has a hollow needle with a wall, which encloses a cavity and has a closed-off design at a closed-off end. A target is arranged or formed at the closed-off end on the inner side of the wall and a laser radiation emitter for emitting preferably pulsed laser radiation is arranged in the cavity of the hollow needle, at a distance from the target. The laser radiation emitter is arranged so that the emerging laser radiation impinges directly on the target through an interspace situated between the laser radiation emitter and the target. Under the formation of a plasma, at least one pressure pulse can be generated at the target by the target being impinged upon by laser radiation from the laser radiation emitter. The wall of the hollow needle has a lateral emergence opening for the emergence of the pressure pulse.

Claims

1. An applicator, configured and intended for cell treatment, for epithelial cell removal or inactivation by means of pressure pulses and comprising: a) a hollow needle with a wall, which encloses a cavity and has a closed-off design at a closed-off end, wherein the hollow needle is situated in a liquid medium; wherein: b) a target area comprising a metal is arranged within the closed-off end on the inner side of the wall of the hollow needle; c) a laser radiation emitter for emitting pulsed laser radiation (L) is arranged in the cavity of the hollow needle, at a distance from the target area within the closed-off end; d) the laser radiation emitter is arranged in such a way that the emerging laser radiation (L) impinges directly on the target area within the closed-off end through an interspace situated between the laser radiation emitter and the target area, the target area being kept from contact with tissue by the closed-off end; e) under the formation of a plasma (P), at least one pressure pulse (S) is generated at the target area by the target area being impinged upon by laser radiation (L) from the laser radiation emitter; f) the wall of the hollow needle has a lateral emergence opening for the pressure pulse (S) to emerge from the cavity of the hollow needle and is completely closed off between the lateral emergence opening and the target area within the closed-off end; and g) the wall of the hollow needle has, at the closed-off end of the hollow needle, a closure on which the target area is arranged, the closure being formed to be convex and dome-shaped on the outside and the inner wall, h) the wall of the hollow needle, following on from the closure, forms a cylindrical liner wall around a longitudinal axis (A) of the hollow needle as a cylinder axis, i) the lateral emergence opening is formed in the cylindrical liner wall, and j) the lateral emergence opening is spaced apart from the closure of the hollow needle and the target area by an axial distance (a) to the target area which is larger than an outer diameter (D) of the cylindrical liner wall of the hollow needle.

2. The applicator as claimed in claim 1, wherein: the hollow needle is, at least in an interspace situated between the target area and the lateral emergence opening, filled with the liquid medium for transmitting the pressure pulses (S); the plasma (P) forms in the liquid medium (M); and the liquid medium adjoins or covers the cells to be treated in such a way that the pressure pulses (S) reach the cells through the liquid medium without direct contact with the target area inside the closed-off end.

3. The applicator as claimed in claim 1, wherein: the wall has a closure at the closed-off end of the hollow needle, on which closure the target area is arranged or formed; and the closure, has a convex, dome-shaped design on the outer side and the inner side or inner wall.

4. The applicator as claimed in claim 1, wherein: the wall of the hollow needle forms a cylindrical lateral wall about the longitudinal axis (A) of the hollow needle as a cylinder axis, adjoining the closed-off end; and the lateral emergence opening is formed in the lateral wall.

5. The applicator as claimed in claim 1, wherein the lateral emergence opening is distanced from the closed-off end of the hollow needle and the target area by a distance (a) that is greater than an external diameter (D), of the lateral wall, of the hollow needle and that is between 0.8 mm and 1.9 mm.

6. The applicator as claimed in claim 1, wherein: the laser radiation emitter comprises a laser radiation conductive fiber, the free end of which forms an emission surface for the laser radiation (L) and a second end of which is coupled to a laser radiation source for coupling laser radiation from the laser radiation source into the laser radiation conductive fiber.

7. The applicator as claimed in claim 1, wherein the emergence opening is symmetrical with respect to a symmetry plane containing the longitudinal axis of the hollow needle and also a central axis (B) which is aligned perpendicular to the longitudinal axis (A) and passes through the center of the emergence opening.

8. The applicator as claimed in claim 1, wherein: the emergence opening has a circular design with a diameter (b) about a central axis (B) aligned perpendicular to the longitudinal axis (A); and the diameter (b) is smaller than the external diameter (D), but greater than the internal diameter (y), of the hollow needle of the lateral wall.

9. The applicator as claimed in claim 1, wherein: the emergence opening is formed as an elongate hole, which extends parallel to the longitudinal axis (A) with a longitudinal direction or the longitudinal dimension (c) and which has an oval shape or else a stadium shape with two semicircular edge segments which are connected by edge segments extending in a straight line parallel to the longitudinal axis (A); and a transverse dimension (d) of the emergence opening, which is smaller than the longitudinal dimension (c), is smaller than the external diameter (D), but greater than the internal diameter (y), of the hollow needle of the lateral wall.

10. The applicator as claimed in claim 1, wherein: the diameter of the hollow needle reduces from a second opposite end to the closed-off first end; an axial first segment of the hollow needle, containing the closed-off first end, has a first external diameter and an axial second segment of the hollow needle, containing the second opposite end, has a greater external diameter than the first external diameter; a transition between the axial first and second segments of the hollow needle which respectively have a constant but mutually different diameter is formed by an intermediate segment which conically tapers towards the closed-off end or else forms a step; and the laser radiation conductive fiber is attached to the wall in the axial first segment of the hollow needle and not attached to the wall in the axial second segment of the hollow needle and in the intermediate segment.

11. A device for application or configured and intended for cell treatment, for epithelial cell removal or inactivation, by means of pressure pulses, called shockwaves (S), comprising: an applicator as claimed in claim 1, and at least one laser radiation source for generating laser radiation (L).

12. The device as claimed in claim 11, wherein: the laser radiation is pulsed with a pulse duration between 5 ns and 20 ns, and a pulse energy between 1 and 20 mJ; each laser pulse generates at least one pressure pulse; the hollow needle is at least predominantly filled with the liquid medium; and the hollow needle is situated in the liquid medium and the liquid medium adjoins or covers the cells to be treated in such a way that the pressure pulses (S) reach the cells through the liquid medium.

13. The applicator as claimed in claim 1, wherein: the wall has a closure at the closed-off end of the hollow needle, on which closure the target area is arranged or formed; and the closure is at least partly spherical, arched, curved or at least has a conical shape in the direction of the longitudinal axis (A) of the hollow needle.

14. The applicator as claimed in claim 1, wherein: the laser radiation conductive fiber extends in the cavity of the hollow needle along the longitudinal axis (A) thereof.

15. The applicator as claimed in claim 1, wherein: the free end of the laser radiation conductive fiber, which forms the emission surface, is arranged at a region of the wall of the hollow needle opposite to the lateral emergence opening and situated at a greater distance from the lateral emergence opening than the longitudinal axis (A).

16. The applicator as claimed in claim 1, wherein: the lateral emergence opening, as seen along the longitudinal axis (A) of the hollow needle, is arranged between, on the one hand, the closed-off end of the hollow needle and, on the other hand, the emission surface of the laser radiation emitter at the free end of the laser radiation conductive fiber.

17. The applicator as claimed in claim 1, wherein the emergence opening is produced by a chip-removing drilling through the wall of the hollow needle from the outside by means of a drill with a drilling direction aligned perpendicular to the longitudinal axis (A).

18. The applicator as claimed in claim 1, wherein: a transition between two segments of the hollow needle which respectively have a constant but mutually different diameter is formed by an intermediate segment; and the intermediate segment conically tapers towards the closed-off end.

19. The applicator as claimed in claim 1, wherein the laser radiation emitter comprises: a laser radiation conductive fiber, wherein: the laser radiation conductive fiber is attached to the wall of the hollow needle in an axial first segment of the hollow needle which contains the closed-off first end; and the laser radiation conductive fiber is not attached to the wall of the hollow needle in an axial second segment of the hollow needle nor in an intermediate segment formed between the axial first and second segments.

20. The applicator as claimed in claim 1, wherein: an axial first segment, containing the closed-off end, of the hollow needle has a first diameter; and an axial second segment, containing a second opposite end, of the hollow needle has a greater external diameter than the first diameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following text, exemplary embodiments of the invention are described in more detail with reference to the attached drawings in which:

(2) FIG. 1 shows a perspective view of an applicator for cell treatment, with a round lateral emergence opening;

(3) FIG. 2 shows a plan view of the applicator in accordance with FIG. 1;

(4) FIG. 3 shows an axial section through the applicator in accordance with line III-III in FIG. 2;

(5) FIG. 4 shows an axial section of a magnified detail, denoted by IV in FIG. 3, of the front region of the applicator;

(6) FIG. 5 shows a perspective view of an applicator for cell treatment, with an elongate lateral emergence opening;

(7) FIG. 6 shows a plan view of the front region of the applicator in accordance with FIG. 5; and

(8) FIG. 7 shows an axial section of the front region of the applicator in accordance with FIGS. 5 and 6.

(9) Mutually corresponding parts and variables are denoted by the same reference signs in FIGS. 1 to 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) FIGS. 1 to 7 show exemplary embodiments of applicators 1 for cell treatment, in general taking place in vivo, in particular destruction or inactivation of epithelial cells on the lens capsular bag of an eye, e.g. for treating or preventing PCO. In principle, the applicator 1 is not restricted to the treatment of epithelial cells, but it is particularly suitable for this.

(11) The applicator 1 comprises a hollow needle 2, which has a closed-off design at a first, free end 3 and has an opposing second end 4.

(12) In the axial direction of a longitudinal axis A, proceeding from the free first end 3 to the second end 4, the hollow needle 2 comprises, connected in series and preferably with an integral design, a first segment 5 with the first end 3, an intermediate segment 6 and a second segment 7 with the second end 4. The first segment 5 has a smaller external diameter D than the second segment 7, as a result of which there is a configuration where the external diameter, and preferably also the internal diameter, reduces toward the first end 3. In order to bridge the different external diameters of the first segment 5 and the second segment 7, the intermediate segment 6 is, in FIGS. 1 to 3, designed with a conical taper toward the first end 3, while, in FIG. 5, it is practically designed in the form of a step or in a step-like manner.

(13) The wall 20 of the hollow needle 2 can have an external diameter D of approximately 0.8 mm in the first segment 5 while having a wall strength of approximately 0.1 mm and an external diameter of approximately 1.2 mm in the second segment 7 while having approximately the same wall strength. In the case of the given external diameters, the intermediate segment 6 can have an aperture angle of approximately 10 degrees, as seen in the direction from the first end 3 to the second end 4.

(14) The whole hollow needle 2 can have a length of approximately 22.5 mm, wherein the second segment can, for example, have a length of 7 mm.

(15) The wall 20 of the hollow needle 2 encloses a cavity (or: channel) 22 in the interior of the hollow needle 2 and has, at the free first end 3, a dome-shaped closure 21, in which, on the inner side facing the cavity 22, a target (or: bombardment material) 13 is arranged or formed. The inner wall of the closure 21 is denoted by 24. Adjoining the closure 21 and the free first end 3, the wall 20 of the hollow needle 2 continues in the first segment 5 as a cylindrical lateral wall 23, which extends along the longitudinal axis A of the hollow needle 2 (as cylinder axis). The lateral wall 23 has an axially unchanging external diameter D and an axially unchanging internal diameter y, which forms the diameter of the region of the cavity 22 surrounded by the lateral wall 23.

(16) The target 13 is preferably formed by a portion of the closure 21 or else as wall section of the wall 20 and the closure 21 consists of the target or bombardment material of the target 13. Furthermore, the closure 21 is preferably formed integrally or monolithically with the remaining regions or formed from the same material as the lateral wall 23. The material of the target 13 and, optionally, of the closure 21 and the lateral wall 23 is preferably titanium or a titanium alloy.

(17) During the in vivo cell treatment, the hollow needle 2 is generally situated in a liquid medium M, in particular an irrigation fluid, and is filled with the latter.

(18) In the first segment 5 of the hollow needle 2, a laser radiation conductive fiber 10 (also abbreviated as fiber 10 in the following text), which extends parallel to the longitudinal axis A, lies against the inner side of the lateral wall 23 in the cavity 22. In the cavity 22 in the intermediate segment 6 and second segment 7, the fiber 10 is not attached to the wall 20 of the hollow needle 2, and emerges substantially axially from the cavity 22 of the hollow needle 2 at the second end 4 of the hollow needle 2, which is open. As a result of the loose arrangement of the fiber 10 in the intermediate segment 6 and the second segment 7 without being attached to the wall 20, the fiber 10 can extend freely with curvature or with a bend and can, as a result, be flexibly coupled without relatively large mechanical tension to a coupling device (not illustrated), in particular an optical plug-in connection, for coupling to a laser radiation source (not illustrated) for emitting laser radiation L.

(19) Together with the laser radiation source and, optionally, the coupling device, the applicator 1 forms a device for cell treatment, in particular epithelial cell treatment.

(20) The laser radiation conductive fiber 10 transmits the coupled-in laser radiation L as far as a free end of the fiber, at which the laser radiation L reemerges from the fiber 10 and the end face of which end therefore forms an emission surface 11 for the laser radiation L. In FIG. 4, the emission surface 11 lies in a plane perpendicular to the longitudinal axis A. A main emission direction 12 of the laser radiation L is directed at the target 13 on the closure 21 in the direction of the first free end 3. In the present case, the main emission direction 12 runs parallel to the longitudinal axis A and hence orthogonal to the emission surface 11. It follows that the laser radiation L emerging from the fiber 10 into the cavity 22 is transmitted, through the interspace in the cavity 22 between the emission surface 11 and the target 13, to the target 13 on the closure 21 in the main emission direction 12, generally through the liquid medium M which is situated in the cavity 22 and also outside of the hollow needle 2, and impinges on the target material.

(21) As a result of this impingement or irradiation of the target 13 with laser radiation L, more precisely with laser radiation pulses, with a correspondingly high energy, in particular 4 to 12 mJ at e.g. a wavelength of 1064 nm, or power, a shockwave or pressure wave S as pressure pulse, in this case in the liquid medium M, can be generated on the target 13 by an optical breakdown or laser radiation breakdown in the target material created in the process, and a plasma P being generated accompanying this, and can be transmitted further. The propagation directions of the shockwave S are illustrated by two broad arrows.

(22) The hollow needle 2 now has a lateral (or: side) emergence opening 8, which passes through the wall 20 and preferably points outward, radially or perpendicularly to the longitudinal axis A, for emergence or passage of the shockwave or the pressure pulse S from the cavity 22 of the hollow needle 2 to the outside. This lateral emergence opening 8 is generated or arranged in the lateral wall 23 of the hollow needle 2 in the region of the first segment 5. The emergence opening 8 is formed about a central axis B, which is preferably aligned perpendicular to the longitudinal axis A and extends radially with respect to the latter.

(23) The emergence opening 8 preferably is symmetrical or lies symmetrically with respect to a symmetry plane containing the longitudinal axis A of the hollow needle 2 and preferably spanned by the longitudinal axis A and the central axis B.

(24) The edge of the emergence opening 8 formed by the wall 20 or 23 is denoted by 80.

(25) In FIGS. 1 to 4, the emergence opening 8 is formed to be approximately circular in the plan view or in the cross section, with a diameter (or in general: a clear width) b, which is less than the external diameter D but in general greater than the internal diameter y of the hollow needle 2 or the lateral wall 23, i.e. y< b< D.

(26) Such a round emergence opening 8 can be produced by chip-removing drilling through the lateral wall 23 from the outside by means of a drill with a drilling direction aligned substantially perpendicular to the longitudinal axis A.

(27) The edge 80 of the emergence opening 8 emerges from the geometric cut from a cylinder with the diameter b along the central axis B through the cylinder with the diameter D along the longitudinal axis A of the lateral wall 23 and therefore has a hood-shaped design, as illustrated.

(28) By contrast, in FIGS. 5 to 7, the side emergence opening 8 is embodied as elongate hole, which extends parallel to the longitudinal axis A with a longitudinal direction. The longitudinal dimension of the emergence opening 8 parallel to the longitudinal axis A is denoted by c and the transverse dimension of the emergence opening 8 perpendicular to the longitudinal axis A and to the longitudinal dimension c is denoted by d. In this embodiment, the edge 80 of the emergence opening 8 is formed by two semicircular edge segments 80B which are connected by edge segments 80A extending in a straight line parallel to the longitudinal axis A such that this results in a stadium-like shape.

(29) Reference is made to the fact that the dimensions such as the clear width b or the longitudinal dimension c and the transverse dimension d of the emergence opening 8 are modified or adapted depending on the generated shockwaves or the shockwaves to be generated.

(30) The closure 21 has a convex, more particularly dome-shaped, design. In accordance with FIGS. 1 to 4, the closure 21 is preferably arched outward or curved, in particular in the direction of the longitudinal axis A, which closure is preferably substantially spherically, in particular with a center point on the longitudinal axis A. Thus, the external wall of the closure 21 forms a spherical blunt tip of the hollow needle 2. As is possible to identify from FIG. 4, the inner wall 24 of the closure 21 with the target 13 also has a spherical design, preferably with a center point on the longitudinal axis A, preferably the same center point as the external wall.

(31) In accordance with FIGS. 5 to 7, the closure 21 is, on its external side, assembled from an external partial wall region (or: external cone) 21A, formed conically about the longitudinal axis A, with the external cone angle , which is selected between 80 and 100, in particular at approximately 90, and a central spherically curved inner partial wall region 21B, which forms a blunt tip of the hollow needle 2. The partial wall regions 21A and 21B merge smoothly (in a continuously differentiable fashion) into one another. An inner cone shape with a tip and an internal cone angle , which is selected between 100 and 160, in particular at approximately 120, is realized on the inner side or inner wall 24 of the closure 21, which inner cone shape can, in particular, be created by a drill tip when drilling the cavity 22.

(32) As a result of the curvature or at least the convexity, there is a focusing effect, comparable to that of a lens, on the pressure pulse, more particularly the shockwave S, in the propagation direction from the target 13 to the lateral emergence opening 8 in both shapes of the closure 21. A blunt free end 3 of the hollow needle 2 is also created in both cases, which reduces the risk of injury to tissue when moving the hollow needle 2.

(33) The pressure pulse or the shockwave S initially propagates through the cavity 22 from the target 13 and then, through the lateral emergence opening 8, to the outside into the medium M which is also situated outside of the hollow needle 2 and said pressure pulse or shockwave can be used outside of the hollow needle 2 in tissue adjacent to the emergence opening 8 for cell treatment, in particular destruction, inactivation and/or removal of appropriate cells, in particular epithelial cells on the lens capsular bag of the eye.

(34) With its edge 80, the lateral emergence opening 8 is now distanced from the first end 3 or the inner side of the closure 21 or the target 13 by an axial distance a in the axial direction toward the longitudinal axis A or the center axis B of said lateral emergence opening is distanced by a distance a+b/2.

(35) The distance a between the first end 3 and the opening 8 is preferably selected to be longer than the mean free path of the plasma P which is created at the target 13. As a result of this, it is advantageously possible, at least to a large extent, to prevent the plasma P from emerging from the emergence opening 8, which can have a positive effect on the cell-treating effect of the applicator 1 since the plasma P cannot directly touch the surrounding cell tissue which is not to be treated, nor can it directly touch the cell tissue to be treated either. Hence, only the shockwave S in the surrounding medium M impinge on the cell tissue to be treated.

(36) The distance a is selected to be greater than the internal diameter y of the cavity 22 of the hollow needle 2, i.e. a>y, and preferably also greater than the external diameter D of the hollow needle 2, i.e. a>D, and, furthermore, also to be greater than the diameter or the longitudinal dimension b of the emergence opening 8, i.e. a>b. Absolute values for the distance a preferably lie at at least 0.7 mm, preferably between 0.8 mm and 1.9 mm. Furthermore, the distance a is generally selected to be greater if the energy of the laser radiation pulse is higher and/or if the pulse is shorter, and it is selected to be smaller if the energy is smaller or the pulse is longer.

(37) As can be seen from FIG. 4 in particular, the external dimension of the emission surface 11, and, in the present case, also the diameter x of the fiber 10, is smaller than the internal diameter y of the first segment 5. As a result of the present geometries, the diameter x of the fiber 10 is also smaller than the internal diameter of the intermediate segment 6 and of the second segment 7. A suitable fiber diameter x is approximately 350 m.

(38) As shown in FIG. 4, the emission surface 11, and accompanying this at least a terminating section of the fiber 10, is placed on the inner side of the wall 20 and the lateral wall 23 thereof, lying opposite to the emergence opening 8, and/or arranged at an axial distance from the target 13 or the inner side of the closure 21, which axial distance is at least a+b, preferably equals a+b, i.e. terminates flush with the edge of the emergence opening 8 facing away from the target. This prevents laser radiation L from being able to emerge directly from the opening 8.

(39) Correspondingly, the axial distance of the emission surface 11 from the target 13 or the inner wall 24 equals or is greater than a+c in FIGS. 6 and 7.

(40) An approximately pan or bowl-shaped region emerges within the hollow needle 2 between the first end 3 and the emergence opening 8, particularly with the specified geometric conditions. This bowl-shaped region is advantageous inasmuch as the plasma remains at least partly trapped therein, i.e. an emergence from the hollow needle is substantially prevented. In the case of an appropriate radiation power of the laser radiation source, a plasma is generated, the free path of which is shorter than the axial length of the bowl-shaped region, and what is achieved is that the plasma remains in the hollow needle 2 to a substantial degree.

(41) In order to prevent damage to the fiber 10, the edges of the hollow needle 2, i.e. of the second segment 7, are formed in a burr-free fashion in the region of the second end 4.

(42) Since optical fibers require comparatively little installation space, hollow needles with a comparatively thin cross section can be used for the applicator. However, it should be mentioned that the use of laser radiation sources within the hollow needle is also possible, provided that enough installation space is available.

(43) In the following text, a cataract operation with post cataract prevention is described as a particularly advantageous application of the applicator and the device. A cataract operation generally comprises the following method steps:

(44) First of all, a surgical instrument, for example a cannula, is used to open the front capsular bag, wherein an opening with dimensions of, in general, 4.5 mm to 5.5 mm is created (capsulorrhexis). Then, incisions are created, generally at opposite sides, in the cornea, in particular on the limbus, on the one hand for a photolytic laser handpiece and, on the other hand, for an irrigation handpiece. As a result of introducing a rinsing liquid, e.g. BSS, the eye lens is detached from the capsular bag and mobilized as a result thereof (hydrodissection). Rinsing fluid, generally likewise BSS, is now rinsed into the capsular bag by means of the irrigation instrument and, as a result of the pressure of the rinsing fluid built up thereby, the rear wall of the capsular bag is, in particular, prevented from coming too close to the laser handpiece, and the capsular bag is rinsed at the same time.

(45) The eye lens is successively photolytically decomposed by the pressure pulses or shockwaves generated by laser pulses and suctioned away, preferably by means of the applicator according to the invention or, optionally, also by means of a different applicator, which can, for example, be a laser handpiece by A.R.C. Laser GmbH or can have a design in accordance with U.S. Pat. No. 5,324,282 or 5,906,611, as mentioned at the outset. Here, the eye lens, in particular the nucleus thereof processed at the end, can be moved by means of the irrigation tool and optimized in terms of its position relative to the applicator. The tissue of the lens is destroyed piece by piece by means of a multiplicity of laser pulses and the shockwaves triggered thereby and the individual tissue parts can be suctioned away. Following the complete removal of the natural eye lens, an artificial eye lens is now subsequently inserted into the capsular bag. The surgeon operates with both instruments using a bi-manual technique.

(46) In accordance with the invention, the capsular bag inner side is now rid of epithelial cells by means of the applicator or a device according to the invention in order to avoid PCO, either before introducing the artificial lens or, preferably, after inserting the artificial lens since the artificial lens then seals the opening in the front capsular bag generated by capsulorrhexis.

(47) The wall of the lens capsular bag is now relatively thin and sensitive. As a result, the lens capsular bag is not able to maintain its shape after removing the natural eye lens, and so the capsular bag can nevertheless at least in part fall in on itself, even if rinsing fluid is introduced, and thus there is a risk of damage by the applicator.

(48) It has already been shown that the generated, comparatively strong shockwaves or pressure pulses are, nevertheless, generally harmless to the capsular bag wall if the capsular bag wall is sufficiently relaxed and can give way by deformation. Thus, a tense or, as it were, rigid capsular bag wall should be avoided when the shockwave for removing or divulsing the epithelial cells impinge thereon. It is for this reason that no suction function or only a low suction function is used during the epithelial cell removal and no negative pressure or only a small negative pressure is generated by means of a pump or the like so that the shockwave is not incident on the capsular bag wall in the strongly suctioned state or the capsular bag wall is not already suctioned in as a result of the negative pressure during suctioning and a tear or opening is created.

(49) In general, the pulse repetition rate for the laser radiation pulses, i.e. the number of laser radiation pulses applied per unit time, for example per second, is also kept so low that the capsular bag wall can return or oscillate back to a relaxed state after a laser radiation pulse and a shockwave generated thereby before the next laser radiation pulse and the associated shockwave, and, as a result, is specifically not in the deformed position, and hence under (maximum) tension, when the next laser radiation pulse impinges, in which position the capsular bag is liable to rip. The capsular bag should therefore so to speak be able to oscillate with the repeated pressure pulses.

(50) According to the invention, it was surprisingly discovered that the plasma, which is created during the optical generation of the pressure pulses by means of the laser radiation and which emerges from the applicator in known applicators, can also impinge on the capsular bag wall through the liquid medium and can surprisingly also lead to cellular damage there in the tissue adjacent to the epithelial cells.

(51) According to the invention, such an emergence of plasma is therefore substantially prevented by the above-described special design of the hollow needle of the applicator. However, the strength of the pressure pulses at the same time remains sufficient for ablating the epithelial cells.

(52) Hence, what is achieved by this preferred application with the aid of the applicator and the associated device is a sparing and effective removal or at least inactivation of epithelial cells on the lens capsular bag of an eye, in particular within the scope of preventing a secondary cataract or PCO.

(53) The pulse repetition rate of the pressure pulses of the device is, preferably already on the operating unit, restricted to in particular at most 10 Hz, i.e. 10 pulses per second, more particularly at most 4 Hz, by an appropriate actuation of the laser radiation pulses. However, in principle, higher frequencies are also possible. No restriction is required downward and it is possible to set pulse repetition rates down to nearly 0 Hz. The pressure pulses can be shockwaves or pressure waves or else be pressure currents or pressure beams connected with material transport.

(54) The frequency spectrum of the pressure wave before forming the shockwave as a result of nonlinear effects can range from the region of a few Hz up to the region of 100 kHz, whereby, in addition to sound oscillation in the audible range, ultrasonic waves or oscillations are also possible.

LIST OF REFERENCE SIGNS

(55) 1 Applicator 2 Hollow needle 3 First end 4 Second end 5 First segment 6 Intermediate segment 7 Second segment 8 Emergence opening 10 Fiber 11 Emission surface 12 Main emission direction 13 Target 20 Wall 21 Closure 21A Partial wall 21B Partial wall 22 Cavity 23 Lateral wall 24 Inner wall 75 Transition 80 Edge 80A Edge segment 80B Edge segment A Longitudinal axis B Central axis a Distance b Diameter c Longitudinal dimension d Transverse dimension D External diameter x Fiber diameter y Internal diameter L Laser radiation M Liquid medium P Plasma S Pressure pulse, in particular shockwave External cone angle Internal cone angle