Method for controlling an ophthalmic surgical laser in the presence of a transition zone on a volume

Abstract

The invention relates to a method for controlling an ophthalmic surgical laser (18) to separate a volume (12), the method comprising: - determining a target position of a pupil relative to a laser beam (24) and determining an optical zone (44) having a treatment center (52) at an interface (14, 16) relative to an optical axis (30) of the laser beam (24); - determining a transition zone (48) at the volume (12) as an extension of the interface (14, 16); - obtaining a current actual position of the pupil; - determining a deviation between the target position and the actual position; and - decentering the determined optical zone (44) relative to the optical axis (30) according to the determined deviation, so that an edge (46) of the volume (12) is produced concentrically relative to the optical axis (30) and the optical zone (44) is produced concentrically with the determined treatment center (52) and within the transition zone (48). The invention also relates to a treatment device (10), a computer program and a computer-readable medium.

Description

Technical Field

[0001] The invention relates to a method of an ophthalmic surgical laser for a therapeutic device for separating a volume having a front interface and a rear interface, in particular from a human or animal cornea, wherein the front interface and the rear interface contact each other at the edge of the volume. Furthermore, the invention relates to a therapeutic device, a computer program and a computer readable medium. Background Art

[0002] Opacity and scarring in the cornea, which may be caused by inflammation, injury or congenital diseases, can impair vision. In particular, when these pathological and / or unnaturally changed areas of the cornea are located in the visual axis of the eye, clear vision can be greatly disturbed. In a known manner, the so-called phototherapeutic keratectomy (PTK) is performed with the aid of an ablative effective laser, such as an excimer laser, to eliminate the area so changed. However, this is only possible when the pathological and / or unnaturally changed areas of the cornea are located in the shallow layers of the cornea. The area below cannot be reached by ablative laser methods, especially within the stroma. Here, additional measures must be taken with the aid of additional corneal incisions, such as exposure to the area below. By additional measures, the duration of treatment is disadvantageously greatly increased. In addition, there are other complications, such as complications of inflammation at the incision site occurring through additional corneal incisions. SUMMARY OF THE INVENTION

[0003] It is an object of the present invention to provide a method, a treatment device, a computer program and a computer-readable medium, by means of which an improved control of an eye surgery laser is possible.

[0004] This object is achieved by a method, a treatment device, a computer program and a computer-readable medium according to the independent claims. Advantageous configurations are given in the dependent claims.

[0005] One aspect of the invention relates to a method for controlling an ophthalmic surgical laser of a treatment device for separating a volume having a front interface and a rear interface, in particular from a human or animal cornea, wherein the front interface and the rear interface touch each other at the edge of the volume. A target position of the pupil of the eye relative to the laser beam of the laser in the neutral position of a beam deflection device of the treatment device is determined based on patient information, and an optical zone having a treatment center at at least one interface relative to the optical axis of the laser beam in the neutral position of the beam deflection device is determined based on the patient information. The transition zone on the volume is determined as an extension of the interface with the optical zone. The current actual position of the pupil is captured by means of an optical capture device of the treatment device. The deviation between the target position and the actual position is determined. The optical zone determined in the neutral position of the beam deflection device relative to the optical axis of the laser beam is decentered according to the determined deviation, so that in the neutral position of the beam deflection device the edge of the volume is produced concentrically with the optical axis of the laser beam, and the optical zone is produced concentrically with the determined treatment center and in the transition zone.

[0006] In other words, if there should be a deviation of the actual position from the target position, the volume can still be reliably separated based on the transition zone and the patient can be treated. In particular, the method can be carried out, for example, if perfect centering of the eye should not be achieved. No new settings have to be made from the eye and the laser, respectively, but the treatment can be continued according to the transition zone. Thus, the transition zone can be traveled in particular and the optical correction can still be achieved at the correct position.

[0007] In other words, a decentering of the optical zone of a volumetric body, which can also be referred to as a microlens, is provided, which can be decentered without displacing the laser. However, the edge of the microlens additionally remains concentric with the axis of rotation of the beam deflection device, which can also be referred to as a scanner. In particular, based on a difference vector between the actual position and the target position, an optical zone is applied within the microlens. The optical zone narrows in the direction of the decentration and widens in the opposite direction. Thus, in particular, an asymmetric transition zone can be provided.

[0008] In particular, the beam deflection device has a neutral attitude. For example, the beam deflection device can have two mirrors for deflecting the laser beam. The neutral attitude is then given to the so-called 0 / 0 attitude between the mirrors. By rotating the mirrors, the incident laser beam is deflected and can thus be positioned, for example, on the cornea. Therefore, the beam deflection device has a rotation axis, about which the incident laser beam can be rotated depending on the mirror position.

[0009] According to an advantageous embodiment, the optical zone and the transition zone are determined on the rear interface. Alternatively or additionally, the optical zone and the transition zone can be determined on the front interface. This allows the transition zone to be formed on both interfaces. Thus, the control of the laser can be achieved in particular such that eccentricity can be performed and the optical zone can still be reliably generated concentrically with the determined treatment center within the transition zone.

[0010] It is also advantageous if the transition zone of the volume body is produced as a crescent without centering. In other words, the volume body is formed in a lens-like manner in particular. Thus, a reliable separation of the volume body can be achieved.

[0011] It is further advantageous that in the neutral position of the beam deflection device the volume is generated asymmetrically and concentrically with respect to the optical axis of the laser beam. This allows the optical zone to be generated concentrically with respect to the determined treatment center within the transition zone. Thus, treatment can be reliably performed even without redirecting the laser.

[0012] It is further advantageous if the optical zone is decentered and / or displaced as a distance of the deviation between the target position and the actual position of the pupil. The deviation can be referred to in particular as a difference vector. Thus, the transition zone can be reliably determined based on the difference vector. The difference vector is then applied to the optical zone within the microlens so that the transition zone narrows in the direction of the decentering and in particular widens in the opposite direction. Thus, in particular an asymmetric transition zone can be provided.

[0013] Furthermore, it has proven to be advantageous if the optical zone is eccentric and / or displaced, thereby producing an asymmetric transition zone. However, due to the asymmetric transition zone, the optical zone can be reliably produced concentrically with the determined treatment center within the transition zone. Thus, the treatment of the patient can be improved.

[0014] It is further advantageous if the laser control is performed such that topographic and / or velocimetric and / or morphological data of the cornea are taken into account. Thus, in particular topographic and / or velocimetric measurements of the cornea to be treated and the type, location and extent of, for example, pathological and / or unnaturally altered areas within the corneal stroma can be taken into account. In particular, the control data set is generated at least by providing topographic and / or velocimetric and / or morphological data of an untreated cornea and providing topographic and / or velocimetric and / or morphological data of a pathological and / or naturally altered area to be removed in the cornea.

[0015] Another aspect of the invention relates to a treatment device having at least one surgical laser for separating a volume having a predetermined interface of a human or animal eye, for example by photodestruction, and having at least one control device for the laser or the lasers, which is formed to carry out the steps of the method according to the preceding aspect. The treatment device according to the invention allows to reliably avoid the disadvantages arising when using conventional ablative treatment devices, namely relatively long treatment times and relatively high energies input into the cornea by the laser. These advantages are achieved in particular by forming the eye surgery laser as a photodestructive laser.

[0016] Therein, the laser is suitable for emitting laser pulses in a wavelength range between 300 nm and 1,400 nm, preferably between 700 nm and 1,200 nm, with a respective pulse duration between 1 fs and 1 ns, preferably between 10 fs and 10 ps, ​​and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz.

[0017] In an advantageous embodiment of the treatment device, the treatment device comprises a storage device for at least temporarily storing at least one control data set, wherein one or more control data sets comprise control data for positioning and / or focusing individual laser pulses in the cornea, and comprises at least one beam device for beam guiding and / or beam shaping and / or beam deflection and / or beam focusing of the laser beam of the laser, wherein the control data set mentioned is usually generated based on the measured topography and / or velocimetry and / or morphology of the cornea to be treated and the type of pathological and / or unnaturally altered area to be removed in the cornea.

[0018] Further features and advantages thereof can be derived from the description of the first inventive aspect, wherein advantageous configurations of each inventive aspect are to be regarded as respectively advantageous configurations of the other inventive aspect.

[0019] A third aspect of the invention relates to a computer program comprising commands which cause a therapeutic device according to the second inventive aspect to perform the method steps according to the first inventive aspect. A fourth aspect of the invention relates to a computer readable medium on which a computer program according to the third inventive aspect is stored. Further features and advantages thereof can be derived from the description of the first and second inventive aspects, wherein advantageous configurations of each inventive aspect should be considered as advantageous configurations of the other inventive aspect, respectively.

[0020] Further features are evident from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned above in the description and the features and / or feature combinations mentioned below in the description of the drawings and / or the features and feature combinations shown only in the drawings can be used not only in the respectively specified combination but also in other combinations without departing from the scope of the invention. Therefore, embodiments are also to be considered as covered and disclosed by the invention, which are not explicitly shown and described in the drawings but are produced and generated by feature combinations separate from the described embodiments. Embodiments and feature combinations are also to be considered as disclosed and therefore do not include all features of the originally formulated independent claims. Moreover, embodiments and feature combinations are to be considered as disclosed, in particular by the embodiments described above, which exceed or deviate from the feature combinations described in relation to the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic side view of an embodiment of a therapeutic device.

[0022] Figure 2 is another schematic side view of an embodiment of a therapeutic device.

[0023] Figure 3 is a schematic cross-sectional view of a patient's eye;

[0024] Figure 4 is another schematic cross-sectional view of an eye of a patient; and

[0025] Figure 5 is another schematic cross-sectional view of a patient's eye.

[0026] In the figures, identical or functionally identical elements are provided with the same reference symbols. DETAILED DESCRIPTION OF THE INVENTION

[0027] Figure 1 A schematic diagram of a treatment device 10 with an ophthalmic surgical laser 18 is shown for separating a human or animal eye 40 ( Figure 3 ) of the cornea. It is recognized that in addition to the laser 18, a control device 20 for the laser 18 is formed so that it emits pulsed laser pulses into the cornea in a predetermined pattern, wherein the interface 14, 16 of the volume 12 to be separated is produced in a predetermined pattern by photodestruction. In the embodiment shown, the interface 14, 16 forms a lens-shaped volume 12, wherein the position of the volume 12 is selected in this embodiment so that the pathological and / or unnaturally altered area 32 (see Figure 2 ). In addition, from Figure 1It can be clearly seen that a so-called Bowman's membrane 38 is formed between the matrix 36 and the epithelium 28 .

[0028] Furthermore, it is recognized that the laser beam 24 generated by the laser 18 is deflected toward the surface 26 of the cornea by means of a beam deflection device 22 (e.g. a scanner). The beam deflection device 22 is also controlled by the control device 20 to produce the above-mentioned predetermined pattern in the cornea. The beam deflection device 22 comprises, for example, two mirrors. The incident laser beam 24 can be rotated by rotating it around an axis of rotation. In the neutral attitude of the mirrors, in particular a so-called optical axis 30 ( Figure 3 ).

[0029] The laser 18 shown is a photodestructive 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, with respective pulse durations between 1 fs and 1 ns, preferably between 10 fs and 10 ps and a repetition frequency greater than 10 kHz, preferably between 100 kHz and 100 MHz.

[0030] In addition, the control device 20 comprises a storage device (not shown) for at least temporarily storing at least one control data set, wherein the one or more control data sets comprise control data for positioning and / or focusing individual laser pulses in the cornea. The position data and / or focusing data of the individual laser pulses are generated based on previously measured topography and / or pachymetry and / or morphology of the cornea and pathological and / or unnaturally altered areas 32 removed, for example, within the stroma 36 of the eye.

[0031] Figure 2 A schematic diagram of the generation of the volume 12 to be separated according to an embodiment of the present method is shown. It is recognized that the interfaces 14, 16 are generated by a pulsed laser beam 24, which is directed to the cornea or to the surface 26 of the cornea through the beam deflection device 22. Therein, the interfaces 14, 16 form a biconvex lens-shaped volume 12, for example, enclosing a pathological and / or unnaturally changed area 32 within the stroma 36. In addition, in the embodiment shown, the laser 18 generates another incision 34, which intersects the volume 12 at a predetermined angle and a predetermined geometry and is formed to the surface 26 of the cornea. The volume 12 defined by the interfaces 14, 16 can then be removed from the cornea through the incision 34. In the embodiment shown, a pathological and / or unnaturally changed area 32 is formed within the stroma 36.

[0032] In the embodiment shown, the interface 14, i.e. the interface located deeper in the eye or stroma 36, ​​is first formed by means of the laser beam 24, wherein it then corresponds to the rear interface 14. This can be achieved by guiding the laser beam 24 at least partially circularly and / or helically according to a predetermined pattern. Subsequently, the interface 16 is generated in a similar manner, which then corresponds to the front interface 16, so that the interfaces 14, 16 form a biconvex lens-shaped volume 12 (see also Figure 1 ). Subsequently, the laser 18 also produces the cutout 34. However, the order in which the interfaces 14, 16 and the cutout 34 are produced can also be changed.

[0033] Figure 3 The eye 40 of a patient in a first situation is shown in a schematic cross-sectional view. At present, it can be seen in particular how the patient interface 42 of the treatment device 10 is placed on the eye 40. In particular, the volume 12 is formed by the front interface 16 and the rear interface 14. In the present embodiment, the rear interface 14 is to be regarded as the optical zone 44. At the edge 46 of the interface 14, 16, in particular a transition zone 48 is formed. In the present embodiment, the transition zone 48 is formed identically on both sides. In other words, the transition zone 48 is centered and symmetrical.

[0034] Figure 4 The eye 40 is shown in a schematic cross-sectional view in another situation. In particular, with respect to Figure 3 ,exist Figure 4 A non-optimal eye position relative to the patient interface 42 is shown in FIG.

[0035] In particular, Figure 4 , the front interface 16 and the rear interface 14 touch each other at the edge 46 of the volume 12. The target position of the pupil of the eye 40 relative to the laser beam 24 in the neutral position of the beam deflection device 22 can be determined based on the patient information, and the optical zone 44 with the treatment center 52 on at least one of the interfaces 14, 16 relative to the optical axis 30 of the laser beam 24 can be determined based on the patient information. The transition zone 48 at the volume 12 is determined as an extension of the interface 14, 16 with the optical zone 44. With the help of the optical capture device 50 ( Figure 1 ) captures the current actual position of the pupil. In addition, the deviation between the target position and the actual position is determined and the determined optical zone 44 is decentered relative to the optical axis 30 of the laser 18 according to the determined deviation, so that the edge 46 of the volume 12 is generated concentrically with the optical axis 30 and the optical zone 44 is generated concentrically with the determined treatment center 52 and in the transition zone 48.

[0036] In particular, Figure 4It is shown that an optical zone 44 and a transition zone 48 can be defined on the posterior interface 14. Alternatively or additionally, an optical zone 44 and a transition zone 48 can also be defined on the anterior interface 16.

[0037] Figure 5 The patient's eye 40 is shown in another schematic cross-sectional view. Figure 5 In the embodiment, the treatment center 52 is particularly shifted so that the transition zone 48 is formed only in Figure 5 Left side shown.

[0038] In particular, the transition zone 48 of the volume 12 can be formed as a non-centered crescent. Furthermore, it can be provided in particular that the volume 12 is produced asymmetrically and concentrically with respect to the optical axis 30. In particular, it can be provided that the optical zone 44 is eccentric and / or displaced by a distance as a deviation between the target position and the actual position of the pupil. In particular, the optical zone 44 can be eccentric and / or displaced so that an asymmetrical transition zone 48 is produced.

Claims

1. A computer program product storing instructions which, when executed, cause a computer to implement a method for controlling an ophthalmic surgical laser (18) of a treatment apparatus (10) for separating a volume (12) having a front interface (16) and a rear interface (14), wherein: The front interface (16) and the rear interface (14) are in contact with each other at an edge (46) of the volume (12), and the method comprises: - determining a target position of the pupil of the eye (40) relative to the laser beam (24) of the laser (18) in a neutral position of the beam deflection device (22) of the treatment device (10) based on the patient information, and determining an optical zone (44) having a treatment center (52) at at least one interface (14, 16) relative to the optical axis (30) of the laser beam (24) in a neutral position of the beam deflection device (22) based on the patient information; - determining a transition zone (48) at the volume (12) as an extension of the interface (14, 16) with the optical zone (44); - capturing the current actual position of the pupil by means of an optical capturing device (50) of the therapeutic device (10); - determining a deviation between the target position of the pupil and the determined actual position of the pupil such that after decentration the treatment center (52) of the optical zone (44) is not axially aligned with the optical axis (30); and - in accordance with the determined deviation, in the neutral position of the beam deflection device (22), the determined optical zone (44) is decentered relative to the optical axis (30) of the laser beam (24), so that in the neutral position of the beam deflection device (22), the edge (46) of the volume (12) is produced concentrically with the optical axis (30) of the laser beam (24), and the optical zone (44) is produced concentrically with the determined treatment center (52) and in the transition zone (48); In this case, the transition region (48) of the volume (12) is produced as a non-centered crescent with respect to the optical axis (30) of the laser beam (24) in the neutral position of the beam deflection device (22).

2. The computer program product according to claim 1, Features The optical zone (44) and the transition zone (48) are defined on the rear interface (14).

3. A computer program product according to claim 1 or 2, Features The optical zone (44) and the transition zone (48) are defined on the front interface (16).

4. The computer program product according to claim 1, Features In a neutral position of the beam deflection device (22), the volume (12) is generated asymmetrically and concentrically with respect to the optical axis (30) of the laser beam (24).

5. The computer program product according to claim 1, Features The optical zone (44) is decentered and / or displaced by a distance that is a deviation between the target position and the actual position of the pupil.

6. The computer program product according to claim 1, Features The optical zone (44) is decentered and / or displaced, thereby creating an asymmetric transition zone (48).

7. The computer program product according to claim 1, Features The laser (18) is controlled in such a way that topographic and / or pachymetric and / or morphological data of the cornea are taken into account as patient information.

8. A therapeutic device (10) comprising at least one surgical laser (18) for separating a volume (12) having a front interface (16) and a rear interface (14) of a human or animal eye (40), and comprising at least one control device (20) for the laser or multiple lasers (18), the control device being configured to execute the steps of a computer program product according to any one of claims 1 to 7.

9. The therapeutic device (10) according to claim 8, characterized in that The control device - comprises at least one storage device for at least temporarily storing at least one control data set, wherein one or more control data sets comprise control data for positioning and / or focusing a single laser pulse in the cornea; and - comprises at least one beam deflection device (22) for beam guiding and / or beam shaping and / or beam deflecting and / or beam focusing a laser beam (24) of a laser (18).

10. Computer program product comprising instructions for causing a therapeutic device (10) according to claim 8 or 9 to execute the computer program product steps according to any one of claims 1 to 7.

11. Computer readable medium having stored thereon a computer program product according to claim 10.

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