APPLANATION DEVICE INTENDED TO BE COUPLED TO AN OPTHALMOLOGICAL LASER SURGERY SYSTEM

Abstract

An applanation device designed to be positioned between the eye of a patient and a laser system, to hold the eye in position and create a reference plane for an ophthalmological laser surgery operation, the device comprising: an applanation cone defining an inner space, an upper opening and a lower opening; the applanation cone comprising an upper portion configured to be secured to a projecting portion of a focusing optical unit of the laser system and a lower portion comprising suction means; the lower opening being defined by a lower rim; an applanation glass that is transparent to the laser beam generated by the laser system and is positioned and held by the suction means against the lower rim so as to close the lower opening.

Claims

1. An applanation device configured to be positioned between the eye of a patient and a laser system, to hold the eye in position and create a reference plane for a laser ophthalmological surgery operation, said device comprising: an applanation cone defining an internal space, a top aperture and a bottom aperture; said applanation cone comprising an upper part configured to be fixed onto a protruding part of a focusing optical block of the laser system and a lower part comprising suction means; the bottom aperture being delimited by a bottom rim; an applanation glass that is transparent to the laser beam generated by the laser system being positioned and held by said suction means against the bottom rim so as to close the bottom aperture.

2. The applanation device as claimed in claim 1, wherein the suction means comprise at least one suction channel extending in the wall of said suction cone between a suction input and a plurality of suction orifices formed in the bottom rim.

3. The applanation device as claimed in claim 1, further comprising a fixing ring configured to be securely mounted on the protruding part of the focusing optical block, the upper part of said applanation cone being configured to be mounted with translational mobility in a direction parallel to an optical axis of the focusing optical block on said fixing ring.

4. The applanation device as claimed in claim 3, further comprising an angular orientation ring configured to be mounted with rotational mobility in a plane at right angles to the optical axis of the focusing optical block on said protruding part, the upper part of said applanation cone being configured to be mounted with translational mobility in a direction parallel to the optical axis of the focusing optical block on said angular orientation ring.

5. The applanation device as claimed in claim 1, wherein the applanation cone comprises at least one camera-holding element fixed onto the outer wall of the applanation cone and at least one side aperture arranged with respect to said holding element so as to allow the passage of an imaging beam generated by said at least one camera to view a cutting zone of the eye situated under the applanation glass.

6. The applanation device as claimed in claim 5, wherein said holding element is configured such that the imaging beam generated by said camera is inclined by an angle of between 30° and 50°, preferably between 45° and 47°, with respect to the optical axis of the focusing optical block.

7. The applanation device as claimed in claim 1, wherein the applanation glass comprises at least one pattern or a graduated rule produced on the surface or in the volume.

8. The applanation device as claimed in claim 1, wherein the applanation glass has a planar-planar or planar-concave geometry.

9. The applanation device as claimed in claim 3, wherein the upper part of said applanation cone comprises an axial displacement ring provided with an inner threading, designed to be engaged by screwing with an outer threading produced on the outer wall of the fixing ring or of the orientation ring, said axial displacement ring ensuring, in a screwing step, an axial displacement of said applanation cone in a direction parallel to the optical axis of the focusing optical block.

10. The applanation device as claimed in claim 3, further comprising a locking ring configured to lock the applanation cone in position.

11. The applanation device as claimed in claim 1, wherein the applanation cone is produced in a metallic material by additive manufacturing.

12. The applanation device as claimed in claim 1, wherein the applanation cone comprises a lower part fixed onto the upper part, said lower part having an upside-down truncated cone form.

13. An applanation assembly for holding an eye of a patient in position and creating a reference plane for a laser system for a laser ophthalmological surgery operation, said assembly comprising: an applanation device as claimed in claim 1; a suction ring designed to come into contact with a surface of the eye of the patient; a portion of said lower part of the applanation cone being configured to be inserted into the suction ring to position the applanation glass inside the suction ring.

14. An ophthalmological surgery appliance for making a cut in an ocular biological tissue, such as a cornea or a lens, comprising: a laser unit designed to deliver a laser beam, a focusing optical block for focusing the laser beam at a focal point in the ocular biological tissue; said focusing optical block comprising a protruding lower part extending from a bottom surface of the laser unit, an applanation device as claimed in claim 1 configured to be fixed onto the protruding lower part of the focusing optical block so as to position the applanation glass at a distance substantially close to the focusing distance with respect to the optical output of the focusing optical block.

15. The appliance as claimed in claim 14, further comprising at least one camera configured to view the cutting zone, said at least one camera being held in position on the outer wall of the applanation cone.

16. The appliance as claimed in claim 14, further comprising a centering camera configured for the centering of the optical axis of symmetry of the focusing system with respect to the biological tissue, one end of the centering camera being inserted into the applanation cone via one of the two apertures provided in the applanation cone.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0043] Other features, details and advantages of the disclosure will become apparent on reading the following detailed description, and on analyzing the attached drawings, in which:

[0044] [FIG. 1] represents an exploded view of the applanation device according to an embodiment of the disclosure, positioned between a focusing optical block and a suction ring placed above an eye;

[0045] [FIG. 2A] represents a perspective view of the applanation device in an assembled configuration;

[0046] [FIG. 2B] represents a perspective view from a bottom view of the device of FIG. 2A;

[0047] [FIG. 3A] represents a profile view according to the view from one of the two side vision cameras of the applanation device;

[0048] [FIG. 3B] represents a cross-sectional view of the applanation device on the line A-A in FIG. 3A;

[0049] [FIG. 4A] represents a perspective profile view of the applanation cone;

[0050] [FIG. 4B] represents a bottom perspective view of the applanation cone of FIG. 4A without the applanation glass;

[0051] [FIG. 5A] represents a profile view of the applanation cone;

[0052] [FIG. 5B] represents a cross-sectional view of the applanation cone on the line A-A in FIG. 5A showing the suction channels;

[0053] [FIG. 6] represents a perspective view of the angular orientation ring;

[0054] [FIG. 7A] represents an example of applanation by a planar-planar glass in position bearing against the surface of the cornea of the eye;

[0055] [FIG. 7B] represents an example of applanation by a planar-concave glass in position bearing against the surface of the cornea of the eye;

[0056] [FIG. 8] schematically represents a partial cross-sectional view of the assembly formed by a suction ring and a lower part of the applanation cone and the applanation glass applied to the cornea so as to shape the surface of the cornea to the geometry of the bottom surface of the applanation glass, whether it be planar or curved;

[0057] [FIG. 9] schematically represents an ophthalmological surgery appliance equipped with an applanation device according to an embodiment of the disclosure;

[0058] [FIG. 10A] schematically represents a front view of the arrangement of two side vision cameras;

[0059] [FIG. 10B] schematically represents a front view of the arrangement of the centering camera.

[0060] For greater clarity, similar elements have been identified by identical reference symbols throughout the figures.

DETAILED DESCRIPTION

[0061] The drawings and the description hereinbelow contain, for the most part, elements of definite character. They will therefore be able not only to serve to give a better understanding of the present disclosure, but will also contribute to the definition thereof, as appropriate.

[0062] The present disclosure proposes an applanation device which makes it possible, in a laser ophthalmological surgery operation, by applying an applanation glass into contact with the eye to be treated, to stabilize the eye with respect to the focal point of the laser beam. This device also makes it possible to flatten the eye of the patient by means of the applanation glass so as to create a reference plane to position the focal point of the laser on the zone of the eye to be treated. The applanation device is designed to be coupled on the one hand to a suction ring positioned on the eye of a patient and, on the other hand, to a laser system dedicated to laser ophthalmological surgery. The device of the present disclosure, through a suction mechanism, allows the applanation glass to be positioned and held accurately, simply and reproducibly.

[0063] FIG. 1 schematically represents an applanation device 10 according to an embodiment. Here the applanation device is schematically represented in a context of use for a surgical intervention involving cutting the cornea. The device is represented here between a focusing optical block 105 and a suction ring 40 positioned on the eye 4. The focusing optical block 105 is disposed on the optical path of a laser beam delivered by a laser system not illustrated in the figure and designed to focus the laser beam at a focal point in the thickness of the cornea. The laser beam delivered by the laser system is represented here by an arrow toward the focusing optical block 105. An optical axis of symmetry 8 passing through the center of the cornea and perpendicular to the surface of the cornea extends in a direction Z-Z orthogonal to a plane (XY). The cornea, when it is flattened by the applanation glass, extends substantially in the plane (XY) . During the ophthalmological surgery operation, the incident laser beam is focused at different depths in volume in the cornea in a direction parallel to the axis Z with a normal angle of incidence.

[0064] According to an embodiment of the disclosure, the applanation device 10 comprises an applanation cone 11 and an applanation glass 12 held by suction on a lower part of the applanation cone 11, an angular orientation ring 15 and a fixing ring 17 which is securely mounted by screwing on a protruding part 106 of the focusing optical block 105 when the applanation device is coupled to the laser system.

[0065] Preferably, the applanation glass is made of a material that is transparent in the visible, the surface of which is of optical quality, chemically inert, and of great dimensional stability.

[0066] FIGS. 2A and 2B illustrate the device in an assembled configuration. The hollow suction cone 11 receives a bottom part of the angular orientation ring 15 which is itself fixed via fixing screws onto the fixing ring 17. In the configuration in which the applanation device is coupled to the laser system for an ophthalmological surgery operation, the fixing ring 17 is mounted securely on the protruding part 106 of the focusing optical block 105. When all the parts of the device are assembled, the device is defined by an internal space 39, a top aperture 34 and a bottom aperture 18 that is closed by the applanation glass 12 which is transparent to the wavelength of the laser beam. The axis of symmetry of the applanation device 10 substantially coincides with the optical axis of symmetry 8 of the cornea and of the focusing optical block 105.

[0067] According to a particularly advantageous embodiment, the applanation device further comprises two camera-holding elements 27, 28 fixed onto the outer wall of the applanation cone and two side apertures 20 produced in the wall of a lower part of the applanation cone 13.

[0068] The holding elements 27, 28 each comprise a tubular housing 27A, 28A configured to receive a vision camera 107, 108, called side vision cameras. As illustrated in FIGS. 10A and 10B, the cameras are oriented so as to generate an imaging beam inclined by an angle of between 30° and 50°, preferably between 45° and 47°, with respect to the optical axis of symmetry of the focusing block. The apertures 20 are thereby arranged with respect to the holding elements so as to allow passage of the imaging beam generated by the camera to view a cutting zone of the eye situated under the applanation glass. The apertures 20 are situated plumb with the holding elements 27, 28.

[0069] The cameras 107, 108 allow the surgeon to view the cornea on a screen during the operation. By virtue of the presence of the side apertures 20, it is possible to introduce a centering camera 109 (FIG. 9) into the applanation cone, the field of view of which is centered with respect to the optical axis of the cornea so as to correctly position the surgical appliance above the eye of the patient.

[0070] The centering camera 109 is movable in a transverse direction between a first position in which it is in the internal space of the applanation cone 11, arranged between the focusing system and the tissue to perform the centering, and a second position in which it is removed before the start of the operation.

[0071] When the applanation cone 11 is mounted and positioned on the angular orientation ring 15, it is necessary to ensure that one of the apertures 20 is opposite the centering camera 109. For that, and referring to FIG. 6, the orientation ring 15 is provided for example with four oblong holes 30 in which fixing screws 29 are arranged. After having adjusted the distance H between the optical output of the focusing block and the applanation glass by rotating the applanation cone 11 on the orientation ring 15 to generate an axial displacement on the axis Z-Z, it is possible to rotate the angular orientation ring 15 in the plane (XY) by displacing the fixing screws 29 in the oblong holes 30 so as to place one of the apertures 20 opposite the centering camera. The rotation in the plane (XY) does not induce any axial displacement on the axis Z-Z. At the end of this rotation, the fixing screws 29 are fixed onto the fixing ring 17.

[0072] Referring to FIGS. 3 and 4, the applanation cone 11 is a hollow body defined by an internal space 22, a top aperture 17 and a bottom aperture 18. The bottom aperture 18 is centered with respect to the top aperture 17. The applanation cone 11 comprises an upper part 13 and a lower part 14. The upper part 13 takes the form of a ring that has the form of an upside-down truncated cone defined by a substantially cylindrical internal space. It is provided on its inner wall with an internal threading. The dimension of the internal space is designed to receive a bottom part of the orientation ring 15 which has a cylindrical form. The internal threading and the external threading produced on the outer wall of the orientation ring cooperate together to displace the applanation body 11 on the axis Z-Z on the orientation ring 15 in order to adjust the distance H between the optical output of the focusing optical block 105 and the applanation glass 12. The distance H corresponds substantially to the working distance of the focusing optical block. It is generally between 20 mm and 70 mm, preferably between 30 and 50 mm. For the remainder of the description, the upper part 13 of the applanation cone is called axial displacement ring.

[0073] Referring to FIGS. 5A and 5B, the lower part 14 also has the form of an upside-down truncated cone. It comprises a top rim 36 and a bottom rim 37 delimiting the bottom aperture 18. The bottom rim 37 forms a suction surface to hold the applanation glass 12 which closes the bottom aperture 18. The applanation glass 12 has a substantially circular form and is produced in a material transparent to the wavelength of the laser beam delivered by the laser system. The diameter of the applanation glass is substantially equal to the diameter of the base of the truncated cone 14. The diameter of the bottom aperture D forms the diameter of the working field of the laser beam which is approximately 10 mm at the level of the eye of the patient.

[0074] The lower part 14 comprises suction means for holding the applanation glass against the bottom rim. According to an exemplary embodiment illustrated in FIG. 5B, they comprise two suction channels 23, 24 formed in the wall of the lower part of the suction body. Hereinafter in the description, the lower part is designated by the term “suction cone”. Each channel 23, 24 extends between a suction input 25, 26 and a suction output situated in the bottom rim 37. According to an exemplary embodiment and referring to FIG. 4B, the suction output is formed by a plurality of suction orifices 28 situated in the bottom rim 37. The two main channels 23, 24 are therefore divided into a plurality of subchannels which are connected to the suction orifices 28. The two inputs 25, 26 are each provided with a connector designed to be connected to a vacuum generation means. When the applanation glass is placed on the bottom rim, a vacuum is applied to the two annular channels via the two inputs and generates a suction force which solidly presses the applanation glass against the bottom rim.

[0075] Referring to FIG. 5B, when the two parts are assembled together, the top rim 36 of the suction cone 14 is bearing against the base 39 of the truncated cone of the upper part 13. The two parts are fixed together by four screws 35.

[0076] According to an embodiment of the disclosure and referring to FIG. 1, the applanation device further comprises two locking rings 16 for locking the applanation body 11 in position on the angular orientation ring 15.

[0077] According to an embodiment of the disclosure, the applanation device is produced in a metal material such as Cr-Co by an additive manufacturing technique, called selective or powder bed laser fusion, for issues of technical feasibility on the one hand, and also of price. The blank produced by additive manufacturing is then trimmed by mechanical milling to impose a determined height, and polished by bead-blasting, sand-blasting or manual polishing.

[0078] Referring to FIG. 7A and FIG. 7B, when the applanation device is positioned in the suction ring 40 in a configuration ready for the operation, the applanation glass is pressed against the cornea of the eye of the patient to flatten the surface of the eye in order to create a reference plane for the different laser operations to be performed in the cornea. According to an exemplary embodiment illustrated in FIG. 7A, the applanation glass 32, called planar-planar glass, is flat on both of its surfaces. This glass is used for a great majority of operations, such as cutting on a surface or close to the top face of the cornea (examples: LASIK or KLA). It has a thickness of approximately 1 mm for example and a diameter of 14 mm. According to another exemplary embodiment illustrated in FIG. 7B, it can have a flat top surface and a concave bottom surface disposed facing the cornea. The radius of curvature of the concave surface is slightly greater than the average radius of curvature of the cornea. This so-called planar-concave glass 33 is used for more specific operations, such as cutting at depth in order to avoid the formation of folds in the corneal tissue (examples: lenticular ablation, intrastromal pockets, KT or KLP). It has a diameter of 15 mm and a thickness at the center of approximately 2 mm.

[0079] According to an embodiment, the applanation glass is provided with a pattern and/or a rule etched on the surface or in the volume to assist in the accurate positioning of the applanation cone with respect to the center of the eye of the patient, and to view the applanation diameter of the eye. Alphanumeric characters can also be added to the marking if necessary. The etchings can be produced by pico or femtosecond laser.

[0080] To accurately place the applanation glass with respect to the focal point of the laser, the heightwise dimension of the suction cone will be important to observe. By virtue of the upper part 13 of the applanation body which is translationally movable on the axis Z-Z, it is possible to refine the distance between the optical output of the focusing optical block and the applanation glass, for it to substantially match the working distance of the focusing optical block. In practice, the height of the suction cone must be adjusted so as to position the focal point of the laser beam just under the applanation glass. The tolerance on the positioning of the applanation glass with respect to the focusing optical block is ±10 .Math.m.

[0081] As illustrated in FIG. 1, the focusing optical block 105 generally has a substantially cylindrical form, the axis of which is parallel to the axis Z-Z and is centered on the optical axis of symmetry of the cornea 8. The focusing optical block is composed of an assembly of lenses so as to focus the laser beam in the thickness of the cornea to obtain impact points of constant size on the scale of a few microns over a working field with a diameter of at least 10 mm. When the focusing optical block is incorporated in a laser unit, it has a protruding part 106 with respect to the surface of the laser unit. The outer wall of the protruding part 106 of the optical block is provided with an external threading allowing the fixing ring 17, which is provided with a complementary internal threading, to be fixed thereto by screwing.

[0082] According to an embodiment and referring to FIG. 8, the applanation device is coupled to the eye via a suction ring 40, the function of which is to guide the applanation cone during the positioning of the applanation glass 12 on the eye. The suction ring is positioned and applied to the eye of the patient previously by the practitioner. The suction ring 40 comprises suction means which make it possible to hold it in position at a corneal part of the eye of the patient. To couple the applanation device to the suction ring, a portion of the lower part of the applanation cone 11 of the applanation device 10 is designed dimensionally and geometrically to be received in the suction ring 40 so as to position the applanation glass 12 in the suction ring in order to be placed in contact against the eye of the patient.

[0083] Referring to FIG. 9, the present disclosure also relates to an ophthalmological surgery appliance 100 for performing a cut in an ocular biological tissue, such as a cornea or a lens. It comprises a laser unit 104 designed to deliver a laser beam. This unit comprises a focusing block for focusing the laser beam at a focal point in the ocular biological tissue and an applanation device 10 as described above.

[0084] The laser unit 104 also comprises an optical system for displacement of the laser beam. The laser unit is designed to be mounted at the end of an articulated arm 103. The other end of the arm is mounted on a mobile electrotechnical rack 101. Some of the elements of the equipment are housed in the mobile electrotechnical rack 101. The self-balanced articulated arm makes it possible to position the laser unit above the eye of the patient.

[0085] The focusing optical block 105 illustrated in more detail in FIG. 1 comprises a protruding lower part provided on its outer wall with a threading and which extends from a bottom surface of the laser unit 104. The applanation device is fixed onto the protruding part of the focusing optical block via the fixing ring 17.

[0086] According to an embodiment of the disclosure, the appliance comprises two cameras 107, 108 configured to view the cutting zone, held in position by camera-holding elements 27, 28 fixed onto the outer wall of the applanation body 11. As FIG. 3B illustrates, the two cameras are oriented so as to direct the two imaging beams toward the inside of the suction cone 14 via corresponding apertures 20.

[0087] As FIG. 10A illustrates, the two side vision cameras 107, 108, provided with a lighting ring, positioned on either side of the optical axis of symmetry 8 of the focusing block, make it possible to view and illuminate the eye during the operation. The diameter of the image zone, which is approximately 12 mm, is greater than the cutting zone in which the laser spot is displaced. The two cameras make it possible to observe the cutting zone and to follow the cutting process. The two cameras are equipped with a lighting ring and an autofocus. The two cameras are positioned between the focusing optical block and the cornea such that the imaging beam is oriented by an angle of between 45° and 47° with respect to an optical axis of symmetry of the focusing system. These values allow the eye to be viewed over a field of 10.5 mm while taking into account the bulk of the optics and mechanics of the device, of the cameras and of the applanation device.

[0088] As FIG. 10B illustrates, the appliance further comprises a centering camera 109 configured for the centering of the optical axis of the focusing optical block with respect to the biological tissue, one end of the centering camera being inserted into the suction cone 14 via one of the two side apertures 20.

[0089] The centering camera 109 is a removable camera which is arranged between the focusing optical block and the eye. It generates a visual field which is returned at 90° by a mirror 110 so as to generate a visual field centered on the optical axis 8 of the focusing system, thus making it possible to position the appliance above the eye of the patient. Advantageously, the camera is equipped with a lighting ring generating an annular alignment spot thus allowing the patient to fix a light spot centered on the optical axis of symmetry of the focusing system. It is also equipped with an autofocus. The centering camera 109 is removed from the applanation body to start the operation.

[0090] The present disclosure makes it possible to have an applanation device that is efficient and simple to use for coupling the eye of the patient with a laser system to produce cuts of great quality in an ocular biological tissue, such as the cornea or the lens. One of the advantages of the applanation device of the present disclosure consists in using a suction mechanism incorporated in the wall of the applanation cone to securely hold the applanation glass against a surface of the applanation cone. That makes it possible to eliminate the variation of the thickness of the glue used in the known devices which introduces a distance variation between the optical output of the focusing block and the applanation glass in the plane (XY). The absence of the layer of glue between the bearing surface for the positioning of the glass and the applanation glass makes it possible to avoid bad positioning of the applanation glass with respect to the focal point of the laser which could impact the quality of the cut. By virtue of the accuracy and the reproducibility of the positioning of the applanation glass, it is no longer necessary to proceed with a calibration step before the start of the operation in order to know the position of the focal point formed in the ocular tissue. The tolerance on the positioning of the applanation glass with respect to the focusing system is ±10 .Math.m.

[0091] A specific combination of several mechanical parts of different functions further offers the possibility of adjusting the distance between the applanation glass and the focusing optical block, in order to make the coupling process the most accurate possible while simplifying the process of coupling between the applanation device and the laser system.

[0092] By virtue of the suction mechanism which makes it possible to avoid a permanent fixing of the glass on the cone, the latter is reusable after sterilization; only the glass is consumable.

[0093] The applanation device of the present disclosure finally makes it possible to easily incorporate vision cameras and to introduce a vision camera inside the suction cone.

[0094] The device of the present disclosure has a relatively low manufacturing cost, because it is produced in a metallic material, for example in Cr—Co, allowing manufacture by additive manufacturing.

INDUSTRIAL APPLICATION

[0095] The applanation device of the disclosure can be used in coupling with different laser systems such as femtosecond or picosecond lasers for the various laser operations to be performed in the cornea and refractive surgery.