WO2011069516A1

WO2011069516A1 - Device for ophthalmic laser surgery

Info

Publication number: WO2011069516A1
Application number: PCT/EP2009/008747
Authority: WO
Inventors: Christof Donitzky; Klaus Vogler; Olaf Kittelmann; Claudia Gorschboth
Original assignee: Wavelight Gmbh
Priority date: 2009-12-07
Filing date: 2009-12-07
Publication date: 2011-06-16
Also published as: EP2445461A1; BR112012006400A2; MX2012003189A; EP2445461B1; JP5785182B2; CN102481205B; RU2012124965A; TW201127361A; ES2485910T3; CA2772138C; RU2526975C2; JP2013512740A; KR20120113711A; CA2772138A1; CN102481205A; KR101441100B1

Abstract

The present invention relates to a device 10 for ophthalmic laser surgery, with an optical imaging system for imaging a treatment laser beam 14 onto a focal point, with a temperature-measuring means for the measurement of a temperature assigned to the imaging system, and with an electronic control arrangement (22) connected to the temperature-measuring means and designed to control the focal point adjustnment as a function of the measured temperature. Moreover, the present invention also relates to an associated method.

Description

Device for ophthalmic laser surgery

The invention relates to a device for ophthalmic laser surgery and an associated method.

Pulsed laser radiation is used in numerous techniques of treating the human eye. The local control of the beam focus of the laser beam in the z-direction (meaning the propagation direction of the laser beam according to the usual notation) always takes place with reference to a known reference point or a known reference surface in the coordinate system of the laser device.

Depending on the type of treatment, different reference points or reference surfaces can serve as a reference for the z-control of the beam focus. In some of these techniques, the eye to be treated is pressed against a transparent contact element which, with its eye-facing contact surface, forms a reference surface for the positioning of the beam focus in the z-direction. In particular, treatment techniques which serve to produce sections (incisions) in the eye tissue by means of focused femtosecond laser radiation frequently make use of such contact elements as the z-reference for the laser focus. By the contact element is pressed against the eye, that adjusts a conforming planar contact of the eye to the eye-facing contact surface of the contact element, the contact element, the z-position of the frontal surface of the eye. By referencing the beam focus in the z-direction relative to this contact surface of the contact element is then ensured that the cut or the individual photodisruption (the production of cuts in the human eye by means of pulsed femtosecond laser radiation is based regularly on the effect of the so-called laser-induced optical breakthrough to a Photodisruption leads) is located at the desired position in the depth of the eye tissue.

Laser-produced sections are used, for example, in the case of the so-called Fs-LASIK, in which an anterior cover disc of the cornea known as flap is cut free by femtosecond laser radiation in order subsequently to resemble as in the classical LASIK technique (LASIK: Laser In Sito Keratomi-Ieusis) to flap aside in the hinge area on the remaining corneal tissue flap and ablatierend edit the thus exposed tissue by means of UV laser radiation. Another use case for the The intramedullary incision in the ocular tissue is the so-called corneal lentitele extraction, in which within the corneal tissue a lenticular disc is cut out completely by means of femtosecond laser radiation. This slice is then removed through an additional cut led out to the ocular surface (the additional incision is made either by means of a scalpel or likewise by means of femtosecond laser radiation). Corneal grafting (keratoplasty) or other incisions, for example for corneal ring segments, can also produce corneal incision by means of focused pulsed laser radiation.

For hygiene reasons, the contact element (applicator) carrying the contact surface is often a disposable article which must be exchanged before each treatment. Certain manufacturing tolerances can not be ruled out regularly in the manufacture of the contact elements, even with the greatest precision of manufacture. Therefore, after an exchange of the contact element, the z-position of the eye-facing Kontaktflädhe - albeit only slightly - be different than in the previously used contact element. In the case of laser treatments by means of focused femtosecond laser radiation, the smallest possible focal diameter is sought in order to limit the photodisruptive effect locally as closely as possible. Modern devices, for example, work with focus diameters in the low single-digit pm range. When performing interventions with femtosecond systems, it is often necessary to define the depth of cut in the target tissue with extremely high accuracy (incision depth tolerances <5 pm). As described above, in such procedures, the tissue to be treated and the optical system of the laser are usually fixedly coupled to one another by a contact element in order to achieve the required depth of cut with corresponding precision in the z-direction. This requires a correspondingly high manufacturing accuracy of the contact element, which, however, can not always be guaranteed. With reduced manufacturing precision of the contact element, therefore, the problem arises of a non-precise z-directional cut in the corneal tissue, i. the manufacturing tolerances for these contact elements go directly into the inaccuracies for the depth of cut in the tissue.

In the prior art applicators are generally used, which were manufactured precisely with the appropriate effort. When installing these applicators, the optical system of the laser is adjusted to the required distance between the optical system and the cutting plane by means of a reference applicator utilizing the interaction between laser radiation and material. This is already known, for example, from WO 2004/032810. The distance between tissue and laser system and thus directly the real depth of cut in the tissue is essentially determined by the dimension of the applicator, ie the real optical length of the applicator in the z-direction. This makes it necessary to achieve the required precision of the depth of cut that the applicators must be made with correspondingly small tolerances in terms of their dimension (the relative length accuracy is significantly << l% o), which significantly increases the manufacturing cost of these applicators and especially in In large quantities, the disposable items required directly affect the treatment costs and thus the so-called "Costs of Ownership".

From PCT / EP2009 / 006879 of the applicant is known to account for manufacturing inaccuracies of the contact element and compensate. For this purpose, a position measurement of the contact surface based on the propagation direction of the treatment laser beam is performed by means of a measuring device and adjusted by means of an electronic evaluation and control arrangement connected to the focus of the treatment laser beam depending on the position measurement data obtained by the measuring device.

Although known from the prior art approaches account for manufacturing inaccuracies of the contact element or try to avoid them by the highest possible precision (coupled with high costs), but \ ate wide ^¬ re the setting accuracy of the focal point in the z-direction influencing

Factors ignored.

The effective depth of cut is in addition to the specified manufacturing tolerances of temperature drifts the dimension of the applicator and the effective focal length of the entire optics dependent, ie the real optical length of the applicator in ^{¬ out} propagation of treatment laser beam and the focal length of the optics of a laser system vary depending on the temperature range. The mentioned drifts can easily add up to 30 μm in the conventional temperature range of medical devices from 15 ° C to 35 ° C to 30 μm. Thus, the desired cutting depth tolerances are <5 pm difficult or no longer achievable.

It is an object of the present invention to provide a device for ophthalmic laser surgery and an associated method, which allow a more precise laser treatment of an eye. To achieve this object, an apparatus for ophthalmic laser surgery is provided according to the invention comprising the following components: an optical imaging system for imaging a treatment laser beam on a focal point, a temperature measuring device for measuring a temperature associated with the imaging system and an electronic control device connected to the temperature measuring device is set up to control the focal point adjustment depending on the measured temperature.

In this case, the device may comprise a contact surface for the shaping of an eye to be treated and a radiation source for the provision of the treatment laser beam. Further, the imaging system may include optical components for directing the treatment laser beam through the contact surface to the eye.

The invention enables a control and / or readjustment of, for example, a preset position of the laser beam focus in the z-direction (corresponding to the propagation direction of the treatment laser beam) depending on the measured temperature of the critical components (eg the objective, the beam widening component, etc .) and around the device. The presetting of the focus point can be done in different ways.

The position of the focus in the z-direction can be preset, for example, by knowing the z-position of the contact surface with respect to a given reference point in a fixed coordinate system of the laser-surgical device. Preferably, in this case a patient adapter (applicator) is used whose real optical length in the propagation direction of the treatment laser beam (z-direction) has been produced with high precision, so that the focal point can be preset to the known length. Changes in the length of the applicator or changes in the effective focal length of the optical components contained in the device due to the temperature changing around the device can be detected by the temperature measuring device and taken into account accordingly by the control arrangement. Likewise, it is conceivable that the effective optical distance (the real optical length) between the eye-facing surface of the applicator (the contact surface) and the surface facing away from the eye (the surface facing the optical components of the device) has already been measured outside the device and has been impressed on the associated applicator via a coding. This coding can then by the device, eg automatically or manually, be read and passed on to the control arrangement. Based on the read value, the control arrangement may initially preset the focus point.

Alternatively, to preset the focus point, the z-position of the contact surface with respect to the given reference point can be measured. For this purpose, the device preferably has a measuring device for position measurement of the contact surface with respect to the propagation direction of the treatment laser beam. For this purpose, the measuring device comprises, for example, a second radiation source providing a measuring beam. The optical components are then preferably designed and arranged to also direct the measuring beam through the contact surface to the eye. The measuring device may preferably provide position measuring data by means of the measuring beam, which are representative of the measured position of the contact surface at at least one point thereof, and may pass on the determined position measuring data to the control arrangement. In response, the electronic control device may preset the focus point depending on the position measurement data. For different contact elements, a different z-position of the contact surface in the coordinate system or a different effective optical distance may result, depending on the manufacturing accuracy. By evaluating the measurement of the z-position of the contact surface and / or the real optical length of the applicator performed by the measuring device, the focal point can first be preset in the z-direction, so that manufacturing inaccuracies are reduced or avoided. Based on the measured temperature, the preset focus point can then be adjusted or readjusted.

The adjustment or readjustment of the preset focus point can take place at predetermined time intervals, for example, by a repeated measurement of the temperature by the temperature measuring device after predetermined periods of time. For example, a readjustment can take place when the measured temperature exceeds the previously measured temperature by a predetermined limit. In such a case, a significant temperature drift would be expected, which requires a readjustment of the focal point. A reduction of the predetermined limit value allows a more accurate but more complex readjustment of the focal point. Preferably, the predetermined time intervals and the predetermined limit value are stored in a memory connected to the control arrangement, so that the control arrangement reads these values as required and the temperature measuring device and the readjustment of the Focus point can control accordingly. It is also conceivable that a renewed temperature measurement only takes place when, for example, a user sends a corresponding instruction to the temperature measuring device or components connected thereto.

The temperature measuring device may include one or more temperature sensors disposed on one or more of the optical components and connected to the electronic control device. The optical components preferably form on the one hand a scanning unit for deflecting the treatment laser beam in a plane orthogonal to the beam path (x-y plane) or a 3D scanning unit for three-dimensional deflection of the treatment laser beam and on the other hand focusing optics for focusing the treatment laser beam into the laser beam focus. In this case, preferably two temperature sensors are respectively arranged on the scanning unit and on the focusing optics. However, in each case one or more than two temperature sensors can also be arranged on the scanning unit and on the focusing optics.

To adapt the focus point, the optical components comprise at least one controllable optical element. For example, the controllable optical element is formed by a position-variable in the propagation direction of the treatment laser beam lens. In order to control the lens, the control arrangement can generate a manipulated variable for readjustment of the preset focal point as a function of the measured temperature. The lens, for example, can be moved or repositioned mechanically along the optical beam path. In this case, the control arrangement is preferably configured to change the position of the positionally variable lens by the determined manipulated variable in order to adapt the focus point.

Alternatively, it is conceivable to use a controllable liquid lens of variable refractive power. With unchanged z-position and otherwise unchanged setting of the focusing lens, a z-displacement of the beam focus can be achieved by moving a longitudinally adjustable lens or by refractive power variation of a liquid lens, thereby adjusting the focus point to the changed temperature. It is understood that for z-adjustment of the beam focus also other components are conceivable, such as a deformable mirror.

The control arrangement may further comprise or be connected to a memory unit in which the dependency of the focal point on the temperature is stored as a function. The temperature dependencies of all in the Device used and all occurring in the device distances (for example, the distances of the optical components from each other or the real optical length of the applicator) can be used to calculate a temperature response of the effective focal length of the optical components from a reference temperature. The temperature response is preferably determined separately for the scanning unit and the focusing optics and recorded, but can also be calculated together for these. The determined temperature response can be stored as a set of curves in the memory unit and queried as needed by the control arrangement and used to adjust the focus point based on the stored set of curves.

By taking into account the temperature in the readjustment of the focal point of the treatment laser beam by the control arrangement, changes in the effective focal length as well as the effective optical distance of the applicator occurring due to temperature fluctuations are compensated. It is thereby achieved that a pattern to be realized in the eye or a pattern of photodisruptions to be realized actually lies at the desired location in the depth of the eye (ie at the desired location in the z-direction). In this way, high-precision cutting depths are possible, for example, in the production of a LASIK flap, in corneal lenticular extractions or in keratoplastics.

The control arrangement can also be set up to produce different manipulated variables for the controllable optical element in the z-direction at the regulation of the focal point at several different locations in an x-y plane orthogonal to the z-direction. This makes it possible, for example, individually compensate for different effects of temperature changes on the position of the contact surface in the x-y plane.

The measuring device is preferably a coherence-optical interferometric measuring device and has an optical interferometer for this purpose.

The contact surface will often be part of a replaceable disposable component, such as a disposable applicator. However, it should be emphasized that the invention does not assume a disposable character of the element carrying the contact surface. The invention is equally applicable in embodiments with permanently installed or at least reusable contact surface. The contact surface is preferably formed by a transparent applanation plate or a transparent contact glass. Applanation plates have at least on their facing plate side a flat applanation surface with which a leveling of the front of the eye is achieved. The use of applanation plates for referencing the eye to be treated is regularly favorable from the viewpoint of a high beam quality of the laser radiation. Nevertheless, it is equally possible within the scope of the invention to use as the contact element a contact lens with a typically concave or convex-shaped eye-facing lens surface. The advantage of such contact glasses is z. B. a lesser increase in intraocular pressure when pressed against the eye.

The contact surface is formed in a preferred embodiment of a transparent contact element, which is part of a patient with a focusing lens of the device, in particular interchangeable coupled patient adapter.

According to a further aspect, the invention further provides a method for controlling a focal point of a treatment laser beam for ophthalmic laser surgery, comprising the steps:

Imaging a treatment laser beam onto a focal point by means of an imaging system,

Measuring a temperature associated with the imaging system, and

- controlling the focus point adjustment depending on the measured temperature.

The method may further comprise the steps of forming a forming abutment contact between an eye and a contact surface and directing the treatment laser beam through the contact surface to the eye.

Also in the method aspect, position measurement data representative of a measured position of the contact surface at at least one location thereof relative to the propagation direction of the treatment laser beam may be determined or read as described above. Regardless of whether the position measurement data has been determined or read out, the focal point can be preset depending on the position measurement data and subsequently readjusted based on the measured temperature. The invention will be further explained with reference to the accompanying drawings. Show it:

1 is a highly schematic representation of a first embodiment of a device for ophthalmic laser surgery; and

2 is a highly schematic representation of a second embodiment of a device for ophthalmic laser surgery.

The laser surgical device according to both embodiments is indicated generally at 10.

The laser surgical device 10 according to the first embodiment has a femtosecond laser (Fs laser) 12, which emits pulsed laser radiation with pulse durations in the range of femtoseconds. The laser radiation propagates along an optical beam path 14 and finally reaches an eye 16 to be treated. Various components for guiding and shaping the laser radiation are arranged in the beam path 14. In particular, these components comprise a focusing objective 18 (for example an F-theta objective) and a scanner 20 connected upstream of the objective 18, by means of which the laser radiation provided by the laser 12 can be deflected in a plane orthogonal to the beam path 14 (xy plane) , A drawn coordinate system illustrates this plane as well as a z-axis defined by the direction of the beam path 14. The scanner 20 is constructed, for example, in a manner known per se from a pair of galvanometrically controlled deflection mirrors which are each responsible for the beam deflection in the direction of one of the axes spanning the x-y plane. A central control unit 22 controls the scanner 20 in accordance with a control program stored in a memory 24 which implements a cutting profile to be generated in the eye 16 (represented by a three-dimensional pattern of sampling points at which photodisruption is to be effected).

Furthermore, the mentioned components for guiding and shaping the laser radiation include at least one controllable optical element 26 for z-adjustment of the beam focus of the laser radiation. In the example shown, this optical element is formed by a lens. To control the lens 26, a suitable actuator 28 is used, which in turn is controlled by the control unit 22. For example, the lens 26 can be moved mechanically along the optical beam path 14. Alternatively, it is conceivable to use a controllable liquid lens of variable refractive power. turn. With unchanged z-position and otherwise unchanged setting of the focusing lens 18 can be achieved by moving a longitudinally adjustable lens or by refractive power variation of a liquid lens, a z-displacement of the beam focus. It is understood that for z-adjustment of the beam focus, other components are conceivable, such as a deformable mirror. Because of its comparatively higher inertia, it is expedient to perform only an initial basic adjustment of the beam focus (ie focusing on a predetermined z reference position) with the focusing objective 18, but the z-displacements of the beam focus predetermined by the cutting profile are compensated by a component arranged outside of the focusing objective 18 to accomplish with a shorter reaction rate. It is understood that the lens 26 can also be part of the scanner 20 and the scanner 20 formed thereby can be arranged both before and after the semitransparent deflection mirror 40. The case where the lens is part of the scanner 20 and the scanner 26 including the lens 26 is disposed in front of the reflecting mirror 42 will be explained later with reference to FIG.

On the side of the beam exit, the focusing objective 18 is coupled to a patient adapter 30, which serves to establish a mechanical coupling between the eye 16 and the focusing objective 18. Usually, in treatments of the type considered here a not shown in detail in the drawing, but known per se suction ring is placed on the eye and fixed there by suction. The suction ring and the patient adapter 30 form a defined mechanical interface, which allows a coupling of the patient adapter 30 to the suction ring. In this regard, reference may be made, for example, to International Patent Application PCT / EP2008 / 006962, the entire contents of which are hereby incorporated by reference.

The patient adapter 30 serves as a support for a transparent contact element 32, which in the example shown is designed as a plane-parallel applanation plate. The patient adapter 30 comprises, for example, a cone sleeve body, on whose narrower (in the drawing lower) sleeve end the applanation plate 32 is arranged. By contrast, in the region of the wider (in the drawing upper) sleeve end of the patient adapter 30 is attached to the focusing lens 18 and there has suitable formations that allow an optionally releasable fixation of the patient adapter 30 to the focusing lens 18.

Because it comes in contact with the eye 16 during the treatment, the applanation plate 32 is a hygienically critical article Therefore, it is expedient to replace it after each treatment. For this purpose, the applanation plate 32 can be exchangeably attached to the patient adapter 30. Alternatively, the patient adapter 30 together with the applanation plate 32 form a disposable unit, to which the applanation plate 32 can be permanently connected to the patient adapter 30.

In any case, the eye-facing underside of the applanation plate 32 forms a flat contact surface 34 against which the eye 16 is pressed in preparation for the treatment. This causes a planarization of the anterior surface of the eye with simultaneous deformation of the cornea of the eye 16, designated 36.

In order to be able to use the contact surface 34 as a reference for the presetting of the beam focus in the z-direction, it is necessary to know its z-position in the coordinate system of the laser-surgical device. Due to unavoidable manufacturing tolerances can not be ruled out that when installing different applan tion plates or different patient adapter 30, which are each equipped with a applanation plate 32, the z-position and possibly also the angular position of KontaktfJäcbe 34 shows more or less significant fluctuations. Insofar as these variations in the z-default of the beam focus are disregarded, unwanted errors in the actual position of the incisions produced in the eye 16 result.

Therefore, the laser surgical device 10 contains a coherence-optical interferometric measuring device 38, for example an OLCR measuring device (OLCR: Optical Low Coherence Reflectrometry), which emits a measuring beam, which is coupled into the beam path 14 by means of an immovably arranged, semitransparent deflecting mirror 40 which also the treatment laser radiation of the laser 12 is running. The measuring device 38 brings the generated measuring beam into interference with a reflection beam returning from the eye 16. From the interference measurement data obtained in this regard, the z-position of the contact surface 34 within the coordinate system of the laser-surgical device can be determined. Therefore, the interference measurement data can also be referred to as position measurement data. The control unit 22 receives the interference measurement data from the measuring device 38 and calculates therefrom the z-position of that point of the contact surface 34 at which the measuring beam impinged or through which the measuring beam passed. In the example shown, the measuring beam emitted by the measuring device 38 passes through the scanner 20. This makes it possible to use the deflection function of the scanner 20 also for the measuring beam. The scanner module 20 could also include a second separate scanner for the OLCR alone, which works much faster with smaller mirrors.

In the subsequent laser treatment of the eye 16, the control unit 22 takes into account the thus determined actual z-position of the contact surface 34 in the z-control of the beam focus, such that the incision is actually generated at the intended position in the depth of the cornea 36. For this purpose, the evaluation and control unit 22 references the z-position of the beam focus to be set to the measured z position of the contact surface 34.

By the procedure described above, however, the z-position of the beam focus is only preset, since temperature drifts of the effective focal length of the laser surgical device 10 and the real optical length of the patient adapter 30 in the z-direction are not taken into account. Accordingly, the jersey surgical device 10 has four temperature sensors 50, 52, 54, 56, two of which are disposed on the scanner 20 and two on the focusing lens 18. The temperature sensors measure the real temperature at their respective positions and relay the measured temperature values to the control unit 22. The transmission of the temperature values to the control unit 22 may be wireless or wired, i. the temperature sensors 50, 52, 54, 56 may be in wireless or wired communication with the control unit 22. In the exemplary embodiment illustrated in FIG. 1, the scanner 20 and thus the temperature sensors 50, 52 arranged on the scanner 20 are connected by wire to the control unit 22, while the temperature sensors 54, 56 arranged on the focusing lens 18 are wirelessly connected to the control unit 22 to pass their temperature readings to the control unit 22 for further processing.

In the memory 24, a temperature response of the effective focal length is deposited as a set of curves both for the scanner 20 and for the focusing lens 18. The control unit evaluates the corresponding function in the presence of a new temperature measured value and generates a corresponding manipulated variable for readjustment of the preset z-position of the lens 26. If one or both of the temperature sensors 50, 52 mounted on the scanner 20 determines a temperature value (during the measurement of two temperature values by the two temperature sensors 50, 52, an average temperature value formed from the two values is used), the temperature sensor transmits the measured temperature value to the control unit 22. The latter then searches the memory 20 for the associated temperature response for the scanner 20, generates a manipulated variable therefrom and transmits it to the actuator 28, which shifts the lens 26 in the z direction in accordance with the manipulated variable. As a result of this z-displacement of the lens 26, the preset position of the beam focus is readjusted in such a way that changes in the real optical length of the patient adapter and / or the effective focal length of the laser surgical device 10 that occur due to fluctuations in the real temperature are taken into account and compensated for.

According to the second embodiment of the laser surgical device 10 shown in FIG. 2, the scanner 20 comprises the lens 26, which is displaceable in the direction of propagation of the treatment laser beam, and is arranged in front of the deflection mirror 42 in the propagation direction of the laser radiation. In this way, the scanner 20 is a 3D scanner having three-dimensional scanning properties, so that the laser radiation can be deflected in any direction (x, y, z) from the 3D scanner 20.

The recording and evaluation of the temperature measured values by means of the temperature sensors 50, 52, 54, 56 and the control unit 22 takes place analogously to the first embodiment shown in FIG. In contrast to the first embodiment, in the second embodiment shown in FIG. 2, both the focus point presetting and the focus point readjustment are performed by the 3D scanner 20, which is controlled by the control unit 22.

Claims

claims

A device (10) for ophthalmic laser surgery, comprising

an optical imaging system for imaging a treatment laser beam (14) onto a focal point,

a temperature measuring device for measuring a temperature associated with the imaging system, and

an electronic control arrangement (22) connected to the temperature measuring device, which is set up to control the focus point adjustment as a function of the measured temperature.

2. Device (10) according to claim 1, further comprising a contact surface (34) for forming a system to be treated eye (16).

3. Device (10) according to claim 2, further comprising a measuring device (38) for position measurement of the contact surface (34) with respect to the propagation direction of the treatment laser beam (14), wherein the measuring device (38) provides position measurement data, which for the measured position of the contact surface (34) are representative of at least one location thereof, the electronic control arrangement (22) being arranged to preset the focal point in dependence on the position measurement data.

4. Device (10) according to one of the preceding claims, wherein the temperature measuring device comprises one or more temperature sensors (50, 52, 54, 56) arranged on at least one of optical components (18, 20, 42) of the optical imaging system and with the electronic control device (22) are connected.

5. Device (10) according to one of the preceding claims, wherein the optical components (18, 20, 42) have at least one controllable optical element (26) for controlling the focal point.

6. Device (10) according to claim 5, wherein the controllable optical element (26) at least one in the propagation direction of the treatment laser beam (14) positionally variable lens.

7. Device (10) according to claim 6, wherein the control arrangement (22) is adapted to generate a control variable for the control of the focal point for changing the position of the positionally variable lens.

The apparatus (10) according to any one of claims 5 to 7, wherein the control arrangement (22) comprises a memory unit (24) in which the dependency of the focal point on the temperature is stored as a function, and the

Control arrangement (22) is arranged to control the focal point based on the stored function and the measured temperature.

9. Device (10) according to one of claims 3 to 8, wherein the measuring device (38) comprises a radiation source providing a measuring beam and the optical components (18, 20, 42) are designed and arranged to also the measuring beam through the contact surface to focus on the eye.

10. Device (10) according to one of claims 3 to 9, wherein the measuring device (38) comprises an optical interferometer.

11. Device (10) according to one of claims 2 to 10, wherein the contact surface (34) is part of an exchangeably arranged disposable component.

12. Device (10) according to one of the preceding claims, wherein the pulse duration of the treatment laser beam (14) in the femtosecond range.

13. A method of controlling a focal point of a treatment laser beam for ophthalmic laser surgery, comprising the steps of:

Imaging a treatment laser beam (14) onto a focal point by means of an imaging system,

Measuring a temperature associated with the imaging system, and

- controlling the focus point adjustment depending on the measured temperature.

14. The method of claim 13, wherein the method further comprises:

Forming a forming abutment contact between an eye (16) and a contact surface (34),

- directing the treatment laser beam (14) through the contact surface (34) through the eye (16), Generating position measurement data representative of a measured position of the contact surface (34) at at least one location thereof relative to the propagation direction of the treatment laser beam (14), and

Presetting the focus point depending on the position measurement data.