DE102012022081A1 - Planning device for generating control data for a treatment apparatus for eye surgery, has planning device main portion that is connected to measuring device for measuring position and location of pre-operative sections in planning - Google Patents

Abstract

The planning device (16) generates a cut surface in the cornea (17) of an eye (2) by a laser device (4). A planning device calculating unit is provided for defining cornea cut surfaces such as cap section, lenticle, and entrance section, for calculating the cornea cut surfaces based on the data of a refraction correction, and generating a set of control data for the control of the laser device. The planning device main portion is connected to a measuring device for measuring the position and location of the pre-operative sections in planning with respect to the calculation result. Independent claims are included for the following: (1) treatment apparatus; (2) method for generating control data for a treatment apparatus for eye surgery; (3) device for generating control data for a treatment apparatus for eye surgery; and (4) computer program product for generating control data for a treatment apparatus for eye surgery.

Description

The invention relates to a planning device for generating control data for a treatment device which generates at least one cut surface in the cornea by means of a laser device. The invention further relates to a treatment device having a planning device of the type mentioned. The invention further relates to a method for generating control data for a treatment device which generates at least one cut surface in the cornea by means of a laser device. Finally, the invention also relates to a method for eye surgery, wherein at least one cut surface in the cornea is produced by means of a treatment device with a laser device.

In the prior art, a variety of treatment methods with the aim of refraction correction in the human eye are known. The aim of the surgical methods is to modify the cornea in a targeted manner in order to influence the refraction of light in the eye. For this purpose, several surgical methods are used. The most widespread currently is the so-called laser in situ keratomileusis, which is also abbreviated LASIK. First, a corneal flap is unilaterally detached from the corneal surface and folded to the side. The release of this lamella can be done by means of a mechanical Mikrokeratoms, or by means of a so-called laser keratome, as z. From Intralase Corp., Irvine, USA. After the lamella has been loosened and flipped aside, the LASIK operation involves the use of an excimer laser, which ablates the corneal tissue thus exposed under the lamella. After vaporizing beneath the corneal surface in this manner, the corneal flap is folded back to its original location.

The use of a laser keratome to expose the lamella is advantageous over a mechanical knife because it improves geometric precision and reduces the frequency of clinically relevant complications. In particular, the blade can be made with a much more constant thickness when laser radiation is used. Also, the cutting edge is precisely shaped, which reduces the risk of healing disorders due to this interface remaining after surgery. A disadvantage of this method, however, is that two different treatment devices must be used, on the one hand, the laser keratome to expose the lamella and on the other hand, the corneal tissue evaporating laser.

These disadvantages have been resolved in a procedure recently implemented by Carl Zeiss Meditec AG, abbreviated FLEX. In this method for lenticule extraction, a cut geometry is formed by means of a short pulse laser, preferably a femtosecond laser in the cornea, which separates a corneal volume (so-called lenticle) in the cornea. This is then manually removed by the surgeon after the lenticle covering lamella has been flipped aside. The advantage of this method is, on the one hand, that the cut quality is further improved by the use of the femtosecond laser. On the other hand, only one treatment device is required; the excimer laser is no longer used. A further development of the FLEX method is referred to in the literature as the SMILE method, in which no flap is produced, but only a small opening cut serves as access to the lenticle located below the so-called cap. The separated lenticule is removed through this small opening incision, which lessens the biomechanical integrity of the anterior cornea than LASIK, FLEX or PRK. In addition, superficial less nerve fibers in the cornea are cut in this way, which has been shown to be beneficial in restoring the original sensation of the corneal surface. The symptom of dry eyes, which is often to be treated after LASIK, is thereby reduced in its severity and duration. Other complications after LASIK, which are usually associated with the flap (eg, wrinkles, epithelial ingrowths in the flap bed) occur less frequently without flap.

In the generation of cut surfaces in the cornea by means of laser radiation, the optical radiation effect is usually exploited in that an optical breakdown is produced by individual optical pulses whose duration can be between about 100 fs and 100 ns. It is also known to introduce individual pulses whose energy is below a threshold value for an optical breakthrough into the tissue or material in such a way that a material or tissue separation is achieved thereby. This concept of cut production in the corneal tissue allows a large variety of cuts.

There may be a need to perform a post-treatment or re-treatment. Reasons can be z. Example, that the original treatment had to be stopped or that the refraction values have changed so that a new refraction correction is necessary. For the FLEX method, a solution is known in the prior art ( DE 10 2007 019 814 A1 the entire contents of which are hereby incorporated by reference). This is based to arrange the new cuts so that they do not cut the pre-surgical cuts. This solution is not applicable to the SMILE method.

The invention is therefore based on the object of specifying a planning device for generating control data, a treatment device for refraction correcting eye surgery, and a method for generating control data for such a treatment device, which enables a subsequent refraction correction for the SMILE method.

This object is achieved according to the invention with a planning device of the type mentioned above, which has calculation means for defining a corneal incision surface, wherein the calculation means is connected to a measuring device for measuring the position of preoperative sections and the position of these preoperative sections are taken into account in the calculation.

The invention is further achieved with a treatment device which has a laser device which, by means of laser radiation according to control data, separates at least one cut surface in the cornea, and has a planning device according to the aforementioned type for generating the control data, wherein the planning device is provided with a measuring device for measuring the Situation of preoperative sections and takes into account the location of these preoperative sections in the planning.

Finally, the invention is also achieved with a method for generating control data according to the aforementioned type, which comprises: measuring the position of preoperative sections, generating a control data record for the cornea section surface for activating the laser device, the position of these preoperative sections being planned is taken into account.

Finally, the invention is also achieved with a method comprising: measuring the position of preoperative incisions, generating a control data set for the corneal incision surface, transferring the control data to the treatment device and generating the cut surfaces by driving the laser device with the control data set, wherein when generating the control data set the location of the preoperative sections is taken into account.

For the measurement of the position of the pre-operative cuts a number of measuring devices are suitable, for. As OCT (Optical Coherence Tomography), ultrasound, confocal laser scanning system, or others. It is important that the measuring accuracy is equal to or better than 2 μm and that the measuring device enables quasi-online measurement for aftertreatment. This ensures that measuring device and treatment laser can be geometrically balanced. If the measurement is to take place offline, an additional step is to assign the measured values to the coordinate system of the target coordinates of the treatment laser.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention.

The invention will be explained in more detail for example with reference to the accompanying drawings, which also disclose characteristics essential to the invention. Show it:

1 a schematic representation of a treatment device with a planning device for treatment in ophthalmic refractive correction,

2 a schematic representation of the effect of the laser radiation in the treatment device of 1 is used,

3 a further schematic representation of the treatment device of 1 with regard to the introduction of the laser radiation,

4 a schematic sectional view through the cornea to illustrate the removal of the corneal volume in connection with the ophthalmic refractive correction,

5 a schematic representation of the structure of the treatment device of 1 with particular reference to the planning equipment available there,

6 a schematic representation of a lenticular geometry SMILE with the cuts to be introduced according to the invention.

7 a schematic representation of a lenticule geometry without and with use of the present invention

8th a schematic representation of the structure of the treatment device of 5 with special reference to the existing measuring equipment

A treatment device for eye surgery is in 1 represented and with the general reference numeral 1 Mistake. The treatment device 1 is for the introduction of laser cuts in one eye 2 a patient 3 educated. For this purpose, the treatment device 1 a laser device 4 on, coming from a laser source 5 a laser beam 6 which gives off as a focused beam 7 in the eye 2 or the cornea is directed. Preferably, the laser beam 6 a pulsed laser beam with a wavelength between 300 nanometers and 10 micrometers. Next lies the pulse length of the laser beam 6 in the range between 1 femtosecond and 100 nanoseconds, with pulse repetition rates of 50 to 5000 kilohertz and pulse energies between 0.01 microjoules and 0.01 millijoules are possible. The treatment device 1 thus produces in the cornea of the eye 2 by deflecting the pulsed laser radiation, a cut surface. In the laser device 4 or their laser source 5 is therefore still a scanner 8th and a radiation intensity modulator 9 intended.

The patient 3 is on a couch 10 , which is adjustable in three directions to the eye 2 suitable for the incidence of the laser beam 6 align. In preferred construction is the couch 10 motor adjustable. The control can in particular by a control unit 11 take place, in principle, the operation of the treatment device 1 controls and to do so via appropriate data connections, such as interconnections 12 connected to the treatment device. Of course, this communication can also be done by other means, such as fiber optics or by radio. The control unit 11 takes the appropriate settings, timing on the treatment device 1 , in particular the laser device 4 before and thus accomplished corresponding functions of the treatment device 1 ,

The treatment device 1 also has a fixing device 15 on which the cornea of the eye 2 opposite the laser device 4 fixed in position. This fixing device 15 can be a known contact glass 45 to which the cornea is applied by negative pressure and which gives the cornea a desired geometric shape. Such contact lenses are known to those skilled in the art, for example from the DE 10 2005 040 338 A1 , The disclosure of this document is, as far as the description of a design of the for the treatment device 1 possible contact glass 45 affected is fully included here.

The treatment facility 1 also has a camera, not shown here, which through the contact glass 45 through a picture of the cornea 17 can record. The illumination for the camera can take place both in the visible and in the infrared range of the light.

The control unit 11 the treatment device 1 still has a planning device 16 on, which will be explained later in more detail.

2 shows schematically the operation of the incident laser beam 6 , The laser beam 6 is focused and falls as the focused laser beam 7 in the cornea 17 of the eye 2 , For focusing is a schematically drawn optics 18 intended. It causes in the cornea 17 a focus in which the laser energy density is so high that in combination with the pulse length of the pulsed laser radiation 6 a non-linear effect in the cornea 17 occurs. For example, each pulse of the pulsed laser radiation 6 in focus 19 an optical breakthrough in the cornea 17 generate, which in turn a in 2 only schematically indicated plasma bubble initiated. When the plasma bubble is formed, the tissue layer separation comprises a larger area than the focus 19 although the conditions for generating the optical breakthrough are only in focus 19 be achieved. In order for an optical breakthrough to be generated by each laser pulse, the energy density, ie the fluence of the laser radiation, must be above a certain, pulse length-dependent threshold value. This connection is the expert from the example of DE 69500997 T2 known. Alternatively, a tissue-separating effect can also be achieved by pulsed laser radiation by emitting a plurality of laser radiation pulses in one area, with the focus spots overlapping. It then act together several laser radiation pulses to achieve a tissue-separating effect. The type of tissue separation that the treatment device 1 but is not relevant to the following description; only essential is that a cut surface generation in the cornea 17 of the eye 2 takes place.

To perform an ophthalmic refraction correction, by means of the laser radiation 6 from an area within the cornea 17 A corneal volume is removed by separating tissue layers which isolate the corneal volume and then allow it to be removed. To isolate the cornea volume to be removed z. B. in the case of pulsed laser radiation introduced the position of the focus 17 the focused laser radiation 7 in the cornea 17 adjusted. This is schematically in 3 shown. The refractive properties of the cornea 17 are deliberately changed by the removal of the volume, so as to achieve the refraction correction. The volume is therefore usually lenticular and is referred to as a lenticle.

In 3 are the elements of the treatment device 1 only registered to the extent that they were able to understand the production of cut surfaces required are. The laser beam 6 becomes, as already mentioned, in a focus 19 in the cornea 19 bundled, and the location of the focus 19 in the cornea is adjusted, so that the focal surface generation at different points focusing energy from laser radiation pulses into the tissue of the cornea 17 is registered. The laser radiation 6 is from the laser source 5 preferably provided as pulsed radiation. The scanner 8th is in the construction of the 3 constructed in two parts and consists of an xy scanner 8a which is realized in a variant by two substantially orthogonally deflecting galvanometer mirror. The scanner 8a directs the laser source 5 coming laser beam 6 two-dimensional, so after the scanner 9 a deflected laser beam 20 is present. The scanner 8a thus causes an adjustment of the position of the focus 19 substantially perpendicular to the main direction of incidence of the laser beam 6 in the cornea 17 , To adjust the depth position is next to the xy scanner 8a in the scanner 8th another z scanner 8b provided, which is designed for example as an adjustable telescope. The z scanner 8b ensures that the z position is the location of the focus 19 ie, whose position on the optical axis of incidence is changed. The z scanner 8b can the xy scanner 8a be downstream or upstream.

For the operating principle of the treatment device 1 The assignment of the individual coordinates to the spatial directions is not essential, just as little as the scanner 8a deflects to each other at right angles axes. Rather, any scanner that is able to focus can be used 19 to adjust in a plane in which the axis of incidence of the optical radiation is not. Further, any non-Cartesian coordinate system can be used to distract or control the position of the focus 19 be used. Examples of this are spherical coordinates or cylindrical coordinates. The control of the location of the focus 19 done by means of the scanner 8a . 8b under the control of the control unit 11 , the appropriate settings on the laser source 5 which (in 3 not shown) modulator 9 as well as the scanner 8th performs. The control unit 11 ensures proper operation of the laser source 5 as well as the three-dimensional focus adjustment described here by way of example, so that ultimately a cut surface is formed which isolates a specific corneal volume which is to be removed for refractive correction.

The control device 11 operates according to predetermined control data, which, for example, in the here only exemplarily described laser device 4 are specified as target points for the focus adjustment. The control data are usually combined in a control data record. This results in geometric specifications for the cut surface to be formed, for example the coordinates of the target points as a pattern. In this embodiment, the control data record then also contains specific values for the focus position adjustment mechanism, eg. B. for the scanner 8th , The production of the cut surface with the treatment device 1 is exemplary in 4 shown. A cornea volume 21 in the cornea 17 is by adjusting the focus 19 in which the focused beam 7 is bundled, isolated. For this purpose, cut surfaces are formed, here exemplified as an anterior flap surface 22 as well as a posterior lenticule cut surface 23 are formed. These terms are merely exemplary in nature and are intended to refer to the conventional LASIK or FLEX process for which the treatment device 1 , as already described, is also formed. The only important thing here is that the cut surfaces 22 and 23 as well as the circumferential edge cut 25 which the cut surfaces 22 and 23 merge at the edges, the corneal volume 21 isolate. Through a opening cut 24 can further increase the corneal volume 21 Anterior limiting corneal flap can be folded down, leaving the corneal volume 21 is removable. Alternatively, and essential to the present invention, the SMILE procedure may be employed in which the corneal volume 21 is taken through a small opening cut, like that in the DE 10 2007 019 813 A1 is described. The disclosure of this document is incorporated herein in its entirety

5 shows schematically the treatment device 1 , and by her means the importance of the planning device 16 be explained in more detail. The treatment device 1 has at least two devices or modules in this variant. The already described laser device 4 gives the laser beam 6 on the eye 2 from. The operation of the laser device 4 takes place, as already described, fully automatically by the controller 11 ie the laser device 4 The generation and deflection of the laser beam starts in response to a corresponding start signal 6 and thereby creates cut surfaces that are constructed in the manner described. The control signals required for operation are received by the laser device 5 from the control unit 11 which previously provided appropriate control data. This is done by means of the planning device 16 , in the 5 merely as an example as part of the control unit 11 is shown. Of course, the planning facility 16 also be designed independently and wired or wirelessly with the controller 11 communicate. It is only essential then that a corresponding data transmission channel between the planning device 16 and the controller 11 is provided.

The planning device 16 generates a control record to the controller 11 to Execution of the ophthalmic refractive correction is provided. The planning device uses measured data about the cornea of the eye. These data come in the embodiment described here from a measuring device 28 that the eye 2 of the patient 3 measured before. Of course, the measuring device 28 be formed in any way and the appropriate data to the interface 29 the planning device 16 to transfer. In particular, the measuring device 28 as OCT or ultrasonic measuring system or confocal laser scanning system designed to provide the measurement data with the required accuracy.

The scheduler now assists the operator of the treatment device 1 in determining the cut surface for the isolation of the corneal volume 21 , This can go to a fully automatic definition of the cut surfaces, which can be effected, for example, that the planning device 16 From the measured data, the cornea volume to be taken 21 determined, defines the boundary surfaces as cutting surfaces and corresponding control data for the control unit 11 generated. At the other end of the automation level, the planning device 16 Provide input possibilities in which a user inputs the cut surfaces in the form of geometric parameters, etc. Intermediate stages provide suggestions for the cut surfaces which the planning device 16 automatically generated and then modified by an editor. In principle, all those concepts which have already been explained in the more general part of the description can be found here in the planning device 16 come into use.

To perform a treatment, the scheduler generates 16 Control data for the cutting surface production, which then in the treatment device 1 be used.

6a shows a schematic representation of a corneal cross-section in the SMILE method to illustrate the geometric relationships. The cornea 17 has an anterior cap incision 22 with a opening cut 26 on. The posterior lenticule cut 23 isolated the lenticle volume 21 which through the opening section 26 can be removed. If there is now a need to perform a second refractive treatment, a new lenticle should be calculated. This requires the location and shape of the cap's cut 22 the original treatment can be measured with the required accuracy. The way of such a measurement is in principle from the DE 103 23 422 A1 known, to which reference is hereby made in full. In this document, however, the measuring device serves a different purpose, namely to ensure the self-calibration of the treatment laser during the treatment to the required accuracy (better than 5 microns). The principle of ultrasonic measurement is in "Refractive Surface Ablation: PRK, LASEK, Epi-lasik, Custom, PTK, and Retreatment" by Paolo Vinciquerra, Fabrizio Camesasca - Chapter 36 Dan Z. Reinstein, Ronald H. Silverman, Timothy J. Archer - "Very high frequency digital ultrasound : artemis 2 scanning in corneal refractive surgery ", SLACK Inc. Thorofare, NJ, USA, 2007 explained, the achieved measurement accuracy is 1 micron and is therefore suitable for the task at hand. From the current situation of the Capschnitts 22 and the present need for the refractive correction is in the scheduler 16 a new lenticular interface 23 and a new edge cut 25 calculated and by means of the treatment device 1 in the cornea 17 cut. The position and shape of the reference surface, ie the cap section 22 may change postoperatively by epithelialization, changes in tear film, swelling of the cornea, edema in the cornea, or the like. Changes such as swelling, changes in the tear film, etc. can also occur when the operation is stopped (eg due to loss of negative pressure on the contact glass) and must also be taken into account. The changes will be made with the measuring device 28 measured and flow into the calculation of new lenticule slice area 23 one. 7 schematically shows a lenticule geometry without ( 7a ) and taking into account the actual position of the reference surface (Capschnitt 22 ). The shape of the lenticule slice 23 is due to the deviations of the Capschnitts 22 modified from the original form. The measurement of the reference area of the previous section allows for a precise meeting of the old and new sections even when decentering and tipping the new treatment compared to the original treatment. For this purpose, a recording or measurement of the docked cornea during the original treatment is generated and buffered in a database. If there is now a re-treatment, a recording or measurement of the docked eye is again generated and compared with the stored recording or measurement. In a simple expansion stage, initially only a comparison of the old cut with the planned new cut could be made and the system checks whether a re-treatment is possible. An output to the user informs him whether he can perform the post-treatment as planned or not. In a further development, the old cutting guide is included in the calculation of the new weft pattern and effects are considered as described above. Thus, a customized treatment according to the circumstances in the cornea of the patient is possible. Advantageously, the re-treatment by means of a single cut, since this is no distance to the previous Cut must be maintained and thus corneal tissue can be saved and therefore not as quickly reaches the limit of 250 microns residual current thickness. But even a new treatment below the first cut can be improved by registering the previous cuts, as the access incision (incision) to the new lenticle can be attached to the old access incision and no new incision to the surface is needed. This does not additionally weaken the cornea as it would make a new incision.

8th shows a schematic representation of the structure of the treatment device of 5 and the coupling of the measuring device 28 , The laser device 4 has a laser source 5 on which a laser beam 6 generated. A contact glass 45 serves the docking to the eye, not shown here. The measuring device 28 is via a coupling element 30 coupled. In this case, the coupling element 30 in the case of an optical measuring device 28 (OCT, confocal laser scanning system) may be formed as an optical beam splitter. In the case of an ultrasonic measuring device 28 is the coupling element formed as an acoustic beam splitter, as he, for example, in EP 343 432 A2 is described.

In addition, it should be noted that the treatment device 1 or the planning device 16 Of course, the implementation of the previously generally explained method realized in practice.

Another embodiment of the planning device is in the form of a computer program or a corresponding data carrier with a computer program that realizes the planning device on a corresponding computer, so that the input of the measured data via suitable data transmission means to the computer and the control data from this computer to the control unit 11 be transferred, which in turn come to the expert known data transmission means in question.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007019814 A1 [0006]
• DE 102005040338 A1 [0025]
• DE 69500997 T2 [0028]
• DE 102007019813 A1 [0032]
• DE 10323422 A1 [0037]
• EP 343432 A2 [0038]

Cited non-patent literature

• "Refractive Surface Ablation: PRK, LASEK, Epi-lasik, Custom, PTK, and Retreatment" by Paolo Vinciquerra, Fabrizio Camesasca - Chapter 36 Dan Z. Reinstein, Ronald H. Silverman, Timothy J. Archer - "Very high frequency digital ultrasound : artemis 2 scanning in corneal refractive surgery ", SLACK Inc. Thorofare, NJ, USA, 2007 [0037]

Claims (8)

Planning device for generating control data for an eye surgery treatment device which generates at least one cut surface in the cornea by means of a laser device, wherein the planning device has calculation means for defining corneal cut surfaces (cap section, lenticule cut, access cut), the calculation means comprising the cornea Define cut surfaces based on the data of a refractive correction, and generate a control data set for driving the laser device for the cornea cut surfaces, characterized in that the planning device is connected to a measuring device for measuring the position of pre-operative cuts and takes into account the location of these pre-operative cuts in the planning. Treatment device for eye surgery, the - Has a laser device which generates at least one cut surface in the cornea by laser radiation according to control data, and - A planning device for generating the control data according to claim 1, wherein the planning device is connected to a measuring device for measuring the position of pre-operative sections and takes into account the location of these pre-operative sections in the planning. A method for generating control data for an eye surgery treatment device that generates at least one cut surface in the cornea by means of a laser device, the method being characterized by the following steps: measurement of the position of pre-operative cuts, provision of corneal data based on data of a refraction correction, Determining corneal cut surfaces, and generating a control data set for driving the laser device for cutting the corneal cut surfaces, wherein the position of the pre-operative cuts is taken into account when generating the control data set. Method for eye surgery, wherein at least one cut surface in the cornea is produced by means of a treatment device with a laser device, the method being characterized by the following steps: measurement of the position of preoperative incisions, provision of corneal data based on data of a refraction correction, determination of the cornea -Cutting surfaces based on the corneal data, and generating a control data set for the corneal cut surfaces, transferring the scatter data to the treatment device and generating the cut surfaces by driving the laser device with the control data set, wherein the position of the pre-operative cuts is taken into account when generating the control data set. Device according to one of the preceding sections, characterized in that the measuring device for measuring the position of preoperative sections from the group of optical coherence tomography (OCT), ultrasonic measuring system and confocal laser scanning system comes. Device according to claim 5, characterized in that the measuring device is connected substantially online with the planning device. Computer program product with program code which, when executed on a computer, carries out the method according to one of claims 3 or 4. Data carrier with a computer program product according to claim 7.

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