Coupling interface between a laser source and a tissue to be treated

Abstract

The present invention relates to a coupling interface between a laser source and a tissue (2) to be treated, characterized in that the coupling interface comprises —a ring (3) including: ⋅a side wall (31), ⋅a proximal end (311) intended to come into contact with the tissue (2) to be treated, and ⋅a distal end (312) intended to receive the end of the laser source; —a window (32) transparent to a laser beam generated by the laser source, said window being mounted in a sealed manner on the distal end (312) of the ring (3) in such a way as to close the distal end (312) of the ring (3).

Claims

1. A coupling interface between a laser source and a tissue to be treated, wherein the coupling interface comprises: a ring including: a side wall, a proximal end intended to come into contact with the tissue to be treated, and a distal end intended to receive the end of the laser source, a window transparent to a laser beam generated by the laser source, said window being sealingly mounted on the ring so as to close the distal end of the ring, an aspiration through channel extending between an inner face and an outer face of the side wall, wherein the aspiration through channel is connected to an aspiration module for allowing the generation of a vacuum in an interior space defined between the window and the side wall, and an irrigation through channel extending between the inner and outer faces of the side wall, wherein the irrigation through channel is connected to an irrigation module for allowing the infusion of liquid into the interior space, and wherein an internal diameter of the irrigation through channel is smaller than an internal diameter of the aspiration through channel.

2. The coupling interface according to claim 1, which further comprises a bubble trap extending around the window.

3. The coupling interface according to claim 2, wherein the bubble trap consists of a circular inner groove extending between the side wall and the window.

4. The coupling interface according to claim 1, wherein the aspiration through channel extends in a plane containing the window.

5. The coupling interface according to claim 1, wherein the window is covered with a layer of hydrophilic material.

6. The coupling interface according to claim 2, wherein the window has a non-planar geometry with parallel faces, having for example a concavity allowing better evacuation of the bubbles toward the bubble trap.

7. The coupling interface according to claim 1, wherein the window has a non-planar geometry with non-parallel faces, having for example a biconvexity, thus giving the window an optical role.

8. The coupling interface according to claim 1, wherein the ring includes a flared neck of a frustoconical shape curved outwardly at its proximal end, the flared neck being capable of being applied to the outer surface of the tissue to be treated.

9. The coupling interface according to claim 1, wherein the window is attached to the ring by gluing.

10. A device comprising a laser source and a phacoemulsification apparatus, the device including an irrigation system and an aspiration system, wherein the device further comprises a coupling interface between the laser source and a tissue to be treated, said coupling interface having: a ring including: a side wall, a proximal end intended to come into contact with the tissue to be treated, and a distal end intended to receive the end of the laser source, a window transparent to a laser beam generated by the laser source, said window being sealingly mounted on the ring so as to close the distal end of the ring, an aspiration through channel extending between an inner face and an outer face of the side wall, wherein the aspiration through channel is connected to an aspiration module for allowing the generation of a vacuum in an interior space defined between the window and the side wall, and an irrigation through channel extending between the inner and outer faces of the side wall, wherein the irrigation through channel is connected to an irrigation module for allowing the infusion of liquid into the interior space.

11. The device according to claim 10, wherein the aspiration through channel of the coupling interface is connected to the aspiration system, and the irrigation through channel is connected to the irrigation system.

12. The device according to claim 10, wherein the device comprises a single aspiration and irrigation system including a pump and a vacuum sensor, said single aspiration and irrigation system being used for both a laser treatment and a phacoemulsification treatment.

13. The device according to claim 10, wherein the coupling interface further comprises a bubble trap extending around the window.

14. The device according to claim 13, wherein the bubble trap consists of a circular inner groove extending between the side wall and the window.

15. The device according to claim 10, wherein the aspiration through channel extends in a plane containing the window.

16. The device according to claim 13, wherein the window has a non-planar geometry with parallel faces, having for example a concavity allowing better evacuation of the bubbles toward the bubble trap.

17. The device according to claim 10, wherein the window has a non-planar geometry with non-parallel faces, having for example a biconvexity, thus giving the window an optical role.

18. The device according to claim 10, wherein the ring includes a flared neck of a frustoconical shape curved outwardly at its proximal end, the flared neck being capable of being applied to the outer surface of the tissue to be treated.

19. The device according to claim 10, wherein the internal diameter of the irrigation through channel is smaller than the internal diameter of the aspiration through channel.

Description

SHORT DESCRIPTION OF THE DRAWINGS

(1) Other characteristics and advantages of the invention will clearly emerge from the description which is carried out hereinafter, for illustrative and non-limiting purposes, with reference to the appended figures, in which:

(2) FIGS. 1, 2 and 4B are schematic representations of a coupling interface of the prior art;

(3) FIGS. 3, 4A, 5 and 6 are schematic representations of a coupling interface according to the invention,

(4) FIG. 7 illustrates a method for installing the coupling interface according to the invention.

DETAILED DISCLOSURE OF THE INVENTION

(5) The coupling interface according to the invention will now be described with reference to the figures. In these different figures, the equivalent elements are designated by the same reference numeral.

(6) The coupling interface is intended to be disposed between a laser source and a target to be treated 2. The target 2 is for example a human or animal tissue to be treated such as an eyeball and more specifically a cornea or a crystalline lens.

(7) In the remainder of the description, the invention will be described, by way of example, for the treatment of a cornea of a human or animal eye. Nevertheless, it is obvious to those skilled in the art that the coupling interface according to the invention can be used in other applications.

(8) 1. General Description of the Coupling Interface

(9) With reference to FIG. 3, the coupling interface comprises a ring 3 including: a side wall 31 having a generally cylindrical or conical shape, a proximal end 311 intended to come into contact with an eye 2 to be treated, and a distal end 312 intended to receive the end of the laser source.

(10) The coupling interface is remarkable in that it further comprises a window 32 transparent to the L.A.S.E.R. beam sealingly mounted on the distal end 312 of the ring 3 so as to close the distal end 312 of the ring 3. The ring 3 is therefore open only at its proximal end 311 intended to come into contact with the patient's eye 2.

(11) The attachment of the coupling interface on the eye 2 of the patient can then be performed by generating a vacuum in the interior space 37 defined between: the side wall 31 of the ring 3, the transparent window 32, and the eye 2 of the patient.

(12) Thus and unlike the existing coupling interfaces, the attachment of the coupling interface on the eye 2 by the generation of a vacuum, does not require a perfect bearing between two circular rims defining an annular groove.

(13) Due to this new design, the level of vacuum necessary to hold the coupling interface in position is considerably reduced since the aspiration force applies this time to the entire surface of the eyeball covered by the ring 3.

(14) Indeed, as illustrated in FIG. 4B, which is a schematic representation of the traditional coupling interface of FIG. 1, in order to obtain an aspiration force, for example, of 3 Newtons, it is necessary to apply a vacuum of:
P=F/S, namely P=3/136.10.sup.−6, namely P=22058 Pa=0.22 bar=165 mmHg.

(15) With the coupling interface illustrated in FIG. 3, for the same aspiration force of 3 Newtons, the required vacuum is only of:
P=F/S, namely P=3/301.10.sup.−6, namely P=9966 Pa=0.099 bar=74 mmHg (cf. FIG. 4A).

(16) Thus, with the coupling interface illustrated in FIG. 3, the attachment of the ring 3 on the eye 2 is obtained by generating a vacuum much lower than the vacuum required for holding the traditional coupling interfaces.

(17) 2. Detailed Description of the Coupling Interface

(18) 2.1. Ring

(19) In the embodiment illustrated in FIG. 3, the ring 3 includes a side wall 31 having a generally cylindrical shape. However, it is obvious to those skilled in the art that the ring 3 may have other shapes with symmetry of revolution about an axis A-A′, such as a frustoconical shape.

(20) The proximal end 311 of the ring 3 includes a flared neck of a generally frustoconical shape curved outwardly, and capable of being applied to the outer surface of the eye 2 in a non-traumatic manner. This flared neck has a concave profile of a radius of curvature substantially equal to the radius of curvature of the eye 2 allowing a tangential bearing.

(21) The fact that the ring comprises a single flared neck (rather than two circular rims in the traditional coupling interfaces) makes it easy to achieve a perfect contact over the entire circumference of the contact line between the eye 2 and the ring 3.

(22) The ring 3 comprises an annular crown 34 extending radially inwardly at its distal end 312. The annular crown 34 comprises a recess on its side face forming a cradle for receiving the transparent window 32. The recess makes it easy to place the transparent window 32. Any other method for sealingly attaching a transparent window on the distal portion, for example by welding, gluing or screwing, is of course conceivable.

(23) The annular crown 34 also comprises a circular groove 33 extending between the side wall 31 and the transparent window 32. This circular groove 33 forms an air bubble trap. Indeed, air bubbles are likely to be formed during the filling of the coupling interface with the liquid having a refractive index close to that of the cornea. These air bubbles can affect the efficiency of the treatment, in particular if they are positioned on the propagation path of the L.A.S.E.R. beam emitted by the laser source. The presence of an air bubble trap makes it possible to retain the air bubbles generated during the filling of the coupling interface out of the propagation path of the L.A.S.E.R. beam. This ensures good treatment efficiency to the practitioner. This can also be facilitated by a non-planar geometry of the transparent window, for example with a convexity towards the eye 2, while keeping parallel faces, so as to improve the conveyance of gas bubbles toward this groove.

(24) 2.2. Window

(25) With reference to FIG. 3, the window 32 transparent to the beam generated by the laser source has the shape of a disk. Of course, the window may have other shapes (square, rectangular, elliptical shapes) depending on the intended application.

(26) The window 32 may be designed in different materials such as glass or plastic (Polycarbonate, Poly(methyl methacrylate), etc.).

(27) In the embodiment illustrated in FIG. 3, the window 32 and the ring 3 made in two separate parts. Nevertheless, in some embodiments, the window 32 and the ring 3 can be made in one part (monoblock). This allows limiting the risks of leakage at the junction between the ring 3 and the window 32.

(28) When the window 32 and the ring 3 are two separate parts of the coupling interface, the window can be attached to the ring 3 by gluing, welding or any other technique allowing sealingly attaching the window 32 to the ring 3.

(29) The window 32 may be covered with a layer of hydrophilic material. This makes it possible to limit the adhesion of air bubbles to the window 32.

(30) The window 32 may be anti-reflective or have any other type of optical treatment in order to improve the transmission of the L.A.S.E.R. beam according to its wavelength.

(31) 2.3. Channels

(32) The coupling interface also comprises two tubular through channels arranged in the side wall 31 of the ring 3.

(33) Each through channel 35, 36 opens on the inner face of the side wall 31 of the ring, and extends radially outwardly perpendicular to the axis A-A′.

(34) Each channel allows the connection of a remote device to the coupling interface via a respective nozzle: A first channel 36 (called “irrigation channel”) allows the connection of the coupling interface to an irrigation device for the infusion of liquid into the interior space 37, A second channel 35 (called “aspiration channel”) allows the connection of the coupling interface to an aspiration device for the generation of a vacuum in the interior space 37.

(35) Preferably, the irrigation channel 36 extends under the plane containing the window 32.

(36) The aspiration channel 35 preferably opens on the inner face of the side wall 31 at the circular groove 33, that is to say, at the plane containing the window 32. This makes it possible to guarantee that the liquid comes into contact with the window 32 during the filling of the interior space 37.

(37) In the embodiment illustrated in FIG. 3, the first and second channels 35, 36 are disposed one above the other so that the nozzles—connected to the channels on the one hand and to the irrigation and aspiration devices on the other hand—are located on one and the same side of the coupling interface, this side corresponding to the temporal side of the patient's head so that the nozzles do not come into contact with the nose bridge.

(38) Advantageously, the irrigation channel 35 may have a diameter smaller than the diameter of the aspiration channel 36. The irrigation and aspiration devices being intended to be activated simultaneously, this difference in diameter makes it possible to keep a slight vacuum during the filling of the interior space 37 with liquid, and thus to ensure the sealing of the coupling interface during this step.

(39) For example, in the embodiment illustrated in FIG. 3, the diameter of the irrigation channel 35 is chosen equal to 0.5 mm, and the diameter of the aspiration channel 36 is chosen equal to 1 mm.

(40) 3. Principle of Operation

(41) The principle of operation of the coupling interface according to the invention will now be described in more detail with reference to the coupling device represented in FIGS. 3, 5 and 6, and to the method illustrated in FIG. 7. It is assumed that the first and second channels 35, 36 have been previously connected to the aspiration and irrigation device (not represented) via nozzles.

(42) In a first step 100, the practitioner positions the ring 3 of the coupling interface on the eye 2, and centers it prior to the implementation of the laser treatment.

(43) In a second step 200-300, the practitioner simultaneously activates the liquid aspiration device and the liquid irrigation device: the activation of the aspiration device allows creating a vacuum in the interior space 37 which exerts the suction, while the activation of the irrigation device allows filling the interior space 37 with liquid necessary to cover the corneal dome and reduce the corneal diopter.

(44) As indicated above, the fact that the diameter of the irrigation channel 35 is cleverly chosen to be smaller in size (typically 0.5 mm) relative to the diameter of the aspiration channel 36 (typically 1 mm) allows holding a slight vacuum during the infusion of liquid, and thus ensuring the sealing of the coupling interface during this second step.

(45) The enclosed interior space 37 defined between the cornea 2, the side wall 31 and the window 32 is filled in 1 to 2 seconds and simultaneously the air is aspired, creating a sufficient vacuum for the suction in 2 to 3 seconds.

(46) The filling is thus complete very quickly and without any manipulation, and there is no air between the closing window 32 and the cornea 2, the residual air being confined in the circular bubble trap 33, into which the aspiration channel 35 terminates.

(47) In addition, the aspiration circuit contains a volume of gas smaller than the traditional coupling interfaces, since part of this gas is replaced by non-compressible liquid simultaneously with the aspiration, which increases the speed of obtaining a firm holding by the suction.

(48) Once the liquid is in contact with the window, the practitioner deactivates the irrigation device, while keeping the aspiration device activated (step 400).

(49) The end of the laser source can then be attached to the coupling interface, without any contact between the end of the laser source and the liquid 38.

(50) 4. Conclusions

(51) The surgical procedures performed in ophthalmology and using a laser source (in particular femtosecond laser) typically use a system for holding the eyeball, which must be active throughout the entire duration of exposure of the patient to the laser beam.

(52) Indeed, the risk would be that, in case of unexpected and unexpected movement of the eyeball, the beam reaches areas not supposed to be affected and generates more or less serious lesions of the intraocular structures.

(53) The holding of the eyeball with a device of known geometry, is also a method for precisely knowing the position in the space of the eyeball in order to precisely direct the laser beam on its target.

(54) The holding of the eyeball is therefore a primordial step and the devices used, called coupling interfaces, are of paramount importance.

(55) However, the holding of the eyeball implies a contact between a foreign body and the surface of the eyeball, as well as the application of a force opposing the movements. This position cannot be held for a long time and it is commonly accepted that the duration for which the patient's eye remains sucked to a coupling interface should not exceed two to three minutes. Beyond that, the discomfort for the patient and the risks caused by overpressure on the eyeball become unacceptable.

(56) This limited time must be largely dedicated to the exposure to the laser beam, which performs some key steps of the surgical procedure. Therefore, the longer the time dedicated to placing the coupling interface, the shorter the time of exposure to the laser.

(57) It is therefore essential to simplify this action as much as possible, in order to reduce the time, but also to increase comfort of the patient and to reduce the risks.

(58) Finally, the possibility of using less consumable material, and therefore of making considerable savings, will allow this device to be accessible to the greatest number.

(59) The new coupling interface described previously, allows providing all these advantages.

(60) The reader will understand that many modifications can be made to the invention described above without physically departing from the new teachings and advantages described herein.

(61) For example in the foregoing description, the coupling interface was decoupled from the end of the laser source, the patient treatment procedure comprising a step of placing the end of the laser source on the interface. Alternatively, the coupling interface may be secured to the end of the laser source, the step of centering the interface on the patient's eye being in this case performed automatically by using means known to those skilled in the art.

(62) Consequently, all modifications of this type are intended to be incorporated within the scope of the appended claims.