METHOD FOR PROVIDING CONTROL DATA FOR AN EYE SURGICAL LASER OF A TREATMENT APPARATUS

Abstract

The invention relates to a method for providing control data of an eye surgical laser (18). A control device (20) ascertains (51) a lenticule geometry of the lenticule (12) to be separated from predetermined visual disorder data of a human or animal eye (36), wherein the lenticule geometry is defined by means of a refractive power value to be corrected and a lenticule diameter, ascertains (S2) a correction value for compensating for a deformation of the lenticule (12), which is generated by at least one contact element (28) of the treatment apparatus (10), wherein the correction value is determined by means of at least one preceding measurement of the treatment apparatus (10), ascertains (S3) a deformation geometry of the lenticule (12), wherein the deformation geometry is defined by means of the refractive power value and a deformation diameter, wherein the deformation diameter is calculated depending on the lenticule diameter and the correction value, and provides (S4) control data for controlling the eye surgical laser (18), which uses the deformation geometry for the separation of the lenticule (12).

Claims

1. A method for providing control data of an eye surgical laser of a treatment apparatus for the separation of a lenticule, wherein the method comprises the following steps performed by a control device: ascertaining a lenticule geometry of the lenticule to be separated, which includes a lenticule height, from predetermined visual disorder data of a human or animal eye, wherein the lenticule geometry is defined by means of a refractive power value to be corrected and a lenticule diameter; ascertaining a correction value for compensating for a deformation of the lenticule, which is generated by at least one contact element of the treatment apparatus, wherein the correction value is determined by means of at least one preceding measurement of the treatment apparatus; ascertaining a deformation geometry of the lenticule, which includes a deformation height, wherein the deformation geometry is defined by means of the refractive power value and a deformation diameter, wherein the deformation diameter is calculated depending on the lenticule diameter and the correction value; and providing control data for controlling the eye surgical laser, which uses the deformation geometry for separating the lenticule.

2. The method according to claim 1, wherein the correction value is ascertained from a deviation of the lenticule height, which is expected according to the lenticule geometry, and an achieved lenticule height, wherein the achieved lenticule height is determined after an application of the treatment apparatus without use of the deformation geometry.

3. The method according to claim 2, wherein the correction value is statistically determined from multiple preceding measurements of the lenticule height and the achieved lenticule height, in particular by means of a linear regression.

4. The method according to claim 2, wherein the achieved lenticule height is determined at least at two different points of time, and wherein the correction value is ascertained from an average value of the deviations at the at least two different points of time.

5. The method according to claim 2, wherein the correction value is combined with a refractive power correction value, the refractive power correction value is ascertained from a deviation of the refractive power value to be corrected and an achieved refractive power value, in particular by means of a linear regression from multiple preceding measurements and an average value from refractive power value deviations at different points of time, and the achieved refractive power value is determined after an application of the treatment apparatus.

6. The method according to claim 1, wherein the correction value is in a range from 0.7 to 1.5, in particular in a range from 1.0 to 1.4.

7. The method according to claim 1, wherein the deformation diameter is calculated by means of a multiplication of the lenticule diameter by a parameter depending on the correction value, and wherein the parameter is determined by means of a theoretical lenticule geometry model, in particular by means of the Munnerlyn formula.

8. The method according to claim 7, wherein a height is ascertained for the deformation height of the deformation geometry, which corresponds to a multiplication of the lenticule height by the reciprocal value of the correction value, in that the deformation diameter is calculated by means of a division of the lenticule diameter by the square root of the correction value.

9. A control device, which is formed to perform a method according claim 1.

10. A treatment apparatus with at least one eye surgical laser for the separation of a lenticule of a human or animal eye by means of photodisruption and at least one control device according to claim 9.

11. The treatment apparatus according to claim 10, wherein the laser is formed to emit laser pulses in a wavelength range between 300 nm and 1400 nm, at a respective pulse duration between 1 fs and 1 ns, and a repetition frequency of greater than 10 kHz.

12. The treatment apparatus according claim 10, wherein the control device comprises at least one storage device for at least temporary storage of at least one control dataset, wherein the control dataset or datasets include control data for positioning and/or focusing individual laser pulses in the cornea; and includes at least one beam device for beam guidance and/or beam shaping and/or beam deflection and/or beam focusing of a laser beam of the laser.

13. A computer program including instructions, which cause a treatment apparatus with at least one eye surgical laser for the separation of a lenticule of a human or animal eye by means of photodisruption, and at least one control device to execute a method according to claim 1.

14. A computer-readable medium, on which the computer program according to claim 13 is stored.

15. The treatment apparatus according to claim 11, wherein the laser is formed to emit laser pulses in a wavelength range between 700 nm and 1200 nm, at a respective pulse duration between 10 fs and 10 ps, and a repetition frequency of between 100 kHz and 100 MHz.

Description

[0026] Further features of the invention are apparent from the claims, the figures and the description of figures. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of figures and/or shown in the figures alone are usable not only in the respectively specified combination, but also in other combinations without departing from the scope of the invention. Thus, implementations are also to be considered as encompassed and disclosed by the invention, which are not explicitly shown in the figures and explained, but arise from and can be generated by separated feature combinations from the explained implementations. Implementations and feature combinations are also to be considered as disclosed, which thus do not comprise all of the features of an originally formulated independent claim. Moreover, implementations and feature combinations are to be considered as disclosed, in particular by the implementations set out above, which extend beyond or deviate from the feature combinations set out in the relations of the claims.

[0027] FIG. 1 shows a schematic representation of a treatment apparatus according to the invention according to an exemplary embodiment.

[0028] FIG. 2 shows an exemplary scatter plot of expected and achieved lenticule heights.

[0029] FIG. 3 shows a schematic method diagram according to an exemplary embodiment.

[0030] In the figures, identical or functionally identical elements are provided with the same reference characters.

[0031] FIG. 1 shows a schematic representation of a treatment apparatus 10 with an eye surgical laser 18 for the separation of a corneal volume/cornea volume predefined by a lenticule geometry of a cornea of a human or animal eye 36, thus a lenticule 12, which can also be referred to as volume body, with predefined interfaces 14, 16 by means of photodisruption. One recognizes that a control device 20 for the laser 18 can be formed besides the laser 18 such that it emits pulsed laser pulses for example in a predefined pattern into the cornea of the eye 36, wherein the ascertained interfaces 14, 16 of the lenticule 12 to be formed can for example be generated by a predefined pattern by means of photodisruption. Alternatively, the control device 20 can be a control device 20 external with respect to the treatment apparatus 10.

[0032] The ascertained interfaces 14, 16 form a lenticule 12 in the illustrated embodiment, wherein the position of the lenticule 12 is selected in this embodiment such that it can for example be located within a stroma 32 of the cornea. Furthermore, it is apparent from FIG. 1 that the so-called Bowman's membrane 34 can be formed between the stroma 32 and an epithelium.

[0033] Furthermore, FIG. 1 shows that the laser beam 24 generated by the laser 18 is deflected towards a surface 26 of the cornea by means of a beam device 22, namely a beam deflection device, such as for example a rotation scanner. The beam deflection device is also controlled by the control device 20 to generate the ascertained interfaces 14, 16, preferably also incisions or cuts 30, along preset incision progressions.

[0034] Preferably, the illustrated laser 18 can be a photodisruptive laser, which is formed to emit laser pulses in a wavelength range between 300 nm and 1400 nm, preferably between 700 nm and 1200 nm, at a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, and a repetition frequency of greater than 10 kHz, preferably between 100 kHz and 100 MHz. Additionally, the control device 20 optionally comprises a storage device (not illustrated) for at least temporary storage of at least one control dataset, wherein the control dataset or datasets include control data for positioning and/or for focusing individual laser pulses in the cornea. The position data and/or focusing data of the individual laser pulses, that is the lenticule geometry of the lenticule 12 to be separated, are generated based on predetermined visual disorder data, in particular from a previously measured topography and/or pachymetry and/or the morphology of the cornea or the optical visual disorder correction to be generated exemplarily within the stroma 32 of the eye 36. For determining the visual disorder data, which can for example indicate a value in diopters, or other suitable data for describing the visual disorder, the control device 20 can for example receive the corresponding data from a data server or the visual disorder data can be determined as a data input. The lenticule geometry of the lenticule 12 to be separated for correcting the visual disorder includes a lenticule height and is in particular defined by means of a refractive power value to be corrected, which can also be referred to as planned refractive power value, and a lenticule diameter, which is also referred to as optical zone. The lenticule height or also lenticule thickness is a variable value, which indicates the height of the lenticule in an anterior-posterior direction, that is parallel to an optical axis of the eye 36, depending on a position perpendicular to the optical axis, in particular depending on a position in a radial direction of the lenticule. An exact progression of the lenticule height depending on the position in radial direction can for example be determined by means of a theoretical lenticule geometry model, in particular by means of the Munnerlyn formula.

[0035] Further, a contact element 28 can be provided, which can be associated with the treatment apparatus 10. Alternatively, the contact element 28 can also be provided separately from the treatment apparatus 10. The contact element 28, which can be referred to as patient interface or fixing system, serves to fix the eye 36 for the treatment. Hereto, the contact element 28 can comprise a plano-concave lens, which is adapted to the eye 36 for fixing. By fixing by means of the contact element 28, however, it can occur that the cornea deforms and thus the ascertained lenticule geometry for separating the lenticule 12 does no longer optimally apply to the predetermined visual disorder data. Therefore, it can occur that a planned lenticule height or lenticule height to be corrected deviates from an achieved lenticule height after the treatment with the treatment apparatus 10.

[0036] Such a deviation, which arises by the contact element 28, can be known to a user of the treatment apparatus 10, in particular to a physician. Therefore, the physician will preferably adapt the refractive power value to be corrected in the planning according to his empirical values, for example by increasing the refractive power value, such that the achieved refractive power value corresponds to the desired correction after the treatment with the treatment apparatus.

[0037] The deformation by the contact element 28 can result in the fact that the removed lenticule height is not optimum. For example, an achieved lenticule height can be larger than required or planned. That is, more tissue would have been removed from the cornea than required. For example, this is presented in the scatter plot of FIG. 2. In FIG. 2, the lenticule height (in micrometers) is plotted on the x-axis, which is expected by the treatment, and the achieved lenticule height (in micrometers) one day after the treatment is plotted on the y-axis. In this example, a linear regression line LR can have a slope of 1.07.

[0038] In order to compensate for this deviation, it can be provided that the control device 20 performs the method steps S1 to S4 described below, which are for example presented as a method diagram in FIG. 3. In step S1, as described above, the lenticule geometry of the lenticule 12 to be separated is determined from the predetermined visual disorder data, wherein the lenticule geometry is defined by means of the refractive power value to be corrected and the lenticule diameter. Therein, the refractive power value to be corrected can be adapted according to empirical values from the physician. Subsequently, a correction value for compensating for the deformation by the contact element 28 can be determined from at least one preceding measurement with the treatment apparatus 10 in step S2. Preferably, the correction value can be statistically determined from the measurements of FIG. 2 in that the slope of the regression line LR is used as the correction value, thus 1.07 in the above example.

[0039] However, the previously shown numbers are only to represent examples of the correction value and the correction value can for example be different according to treatment apparatus and associated contact element. A type of the treatment, that is depending on the visual disorder data, and an adaptation of the refractive power value by the physician can also change the correction value. In particular, the correction value can be in a range from 0.7 to 1.5, preferably in a range from 1.0 to 1.4.

[0040] After ascertaining the correction value, a deformation geometry of the lenticule 12 can be ascertained by the control device in step S3, wherein the refractive power value of the lenticule geometry, in particular the refractive power value, which was set by the physician, can be adopted for the deformation geometry. The lenticule diameter can be divided by a parameter depending on the correction value as a deformation diameter of the deformation geometry, wherein the parameter is determined by means of a theoretical lenticule geometry model. For example, the lenticule geometry model can be that model, by means of which the lenticule geometry was previously determined. Preferably, the lenticule geometry model can be the Munnerlyn formula, wherein the parameter depending on the correction value is therein the square root of the correction value. This means that the deformation diameter is calculated in that the lenticule diameter is divided by the square root of the correction value, thus by the root of 1.07 in the above example. Accordingly, a deformation height is ascertained by means of the deformation geometry, which corresponds to the lenticule height divided by the correction value.

[0041] The deformation geometry thus determined can then be provided in the form of control data for controlling the eye surgical laser 18 by the control device 20 in a step S4. By means of the thus provided control data, which uses the deformation geometry for separating the lenticule 12, a compensation for the deformation by the contact element 28 can be achieved in simple manner, wherein a height of the lenticule 12 to be separated can be kept small. Hereby, a treatment with the treatment apparatus 10 can be improved.