DE102023212897A1 - Device and method for generating control data for correcting the refraction of an eye by displacing a tissue volume in the cornea - Google Patents

Abstract

The present invention relates to a planning unit (P) for generating control data for correcting the refraction of an eye by corneal modification, comprising an interface (S1) for receiving data on a hyperopic or myopic refraction correction requirement of an eye with a cornea (50), and a calculation device (C) which is connected to the interface (S1) and configured to receive the data on the refraction correction requirement.
The object of the present invention is to describe a device and method which can ensure a correction of ametropia over a wide diopter range.
The object is achieved by a planning unit (P), the calculation device (C) of which is designed to calculate a first tissue volume (110) of the cornea (50) and a cut surface (70) as well as a displacement of the first tissue volume (110), wherein the first tissue volume (110) has a subtractive refraction change value, the first tissue volume (110) in conjunction with the additive refraction change value, and the subtractive together with the additive refraction change value results in the refraction correction requirement.
The task is further solved by a corresponding planning procedure and by a computer program product.

Description

The present invention relates to a planning unit for generating control data for correcting the refraction of an eye by corneal modification as well as a corresponding planning method and device.

Refractive errors in the human eye have long been corrected using lenses in the form of glasses. In recent years, however, there have been various approaches to correcting refractive errors by modifying the cornea. The modification changes the curvature of the cornea and thus the refractive power of the eye. This is typically done by removing tissue from the cornea. To correct myopia (nearsightedness), the curvature of the cornea must be reduced; this is done by removing more corneal volume from the center of the cornea - in the area of the eye's visual axis - than from the edges. Conversely, to correct hyperopia (farsightedness), the curvature of the cornea must be increased; this is done by removing less corneal volume from the center of the cornea - in the area of the eye's visual axis - than from the edges. By removing corneal tissue from the eye, the refractive power of the cornea is changed in such a way that - taking into account the overall imaging properties of the eye - the refractive error is reduced or even completely corrected.

In the SMILE procedure developed by Carl Zeiss Meditec AG, a so-called lenticule is isolated from the cornea using pulsed laser radiation. This lenticule can be removed through a lateral incision. There are many degrees of freedom in the shape of the lenticule. It can be shaped so that its removal from the cornea changes its refractive power in a defined manner, thus enabling the correction of myopia and hyperopia with or without astigmatism. This is the case, for example, in WO 2008/055697 A1 The described procedure results in a subtractive correction, as a volume is removed from the cornea.

To ensure the biomechanical stability of the eye after a subtractive correction, there are limits to the amount of tissue removed. An established safety measure to maintain sufficient biomechanical stability is to ensure a minimal residual stromal thickness of 250 µm after the correction. Since the initial stromal thickness varies but is typically in the range of 500 µm, the correction range for myopia correction through tissue removal is generally limited to approximately 20 diopters (D). However, there are other physiological aspects that make corrections beyond 10 D rare in practice.

In another approach, the refractive error of the eye can be corrected by inserting an implant. DE 102013218415 A1 Describes how the technology for the SMILE procedure can be used and further developed to plan and perform cuts in the cornea of the eye to create special incisions in a recipient eye that serve to securely fix a graft or implant. This approach thus provides an additive correction by adding volume to the cornea.

Such additive corrections allow, for example, larger hyperopia corrections of more than 5 dpt.

However, it has been shown that there are numerous challenges in ensuring long-term tolerability in the recipient with artificial implants and transplants. In the publication " “The Safety and Predictability of Implanting Autologous Lenticule Obtained by SMILE for Hyperopia” by Ling Sun et al. (Journal of Refractive Surgery 2015,31(6):374-379). ) it was shown that this problem can be avoided with autologous transplants. A lenticule taken from a myopic eye was implanted into the stroma of the neighboring eye to correct its hyperopia. WO 2016050711 A1 It is shown how the precision of hyperopia correction can be improved by implanting a lenticule into a corneal pocket - also called a "pocket" - using relief incisions.

A particular problem with synthetic implants is the lack of long-term functional compatibility. On the other hand, there is a significant shortage of suitable human tissue for transplantation. Added to this is the technical and bureaucratic effort involved in transferring tissue from a donor to a recipient.

There is potential here for autologous transplants, where donor and recipient are the same person. In the publication " Intrastromal Lenticule Rotation for Treatment of Astigmatism Up to 10.00 Diopters Ex Vivo in Human Corneas” by IB Damgaard et al. (Journal of Refractive Surgery 2019; 35(7):451-458 ) reports on in-vitro experiments to cut out only 5 dpt as a lenticule in cases of regular astigmatism up to 10 dpt and then rotate this by 90° to correct 10 dpt. This could be shown to be feasible in principle, however, the refractive correction and the axial position of the autologous lenticule could only be approximated. achieved; the need for improvement was identified. Furthermore, such autologous transplants are rarely possible, as purely astigmatic refractive errors are clinically rare. EP 3906903 A1 The method and device for autologous transplantation are also shown.

The object of the present invention is therefore to provide a device for generating control data for correcting the refraction of an eye by corneal modification and a corresponding method with which the disadvantages of the prior art are eliminated and with which, in particular, a correction of ametropia over a wide dioptre range can be ensured.

According to the invention, the object is achieved by the features of the independent claims. Preferred developments and refinements are the subject of the dependent claims.

The invention combines an additive correction of a myopic or hyperopic eye by means of corneal modification with a subtractive correction, wherein the additive correction is realized by a tissue volume that originates from a tissue volume of the same eye and that causes the additive correction by means of displacement in the eye.

A first aspect of the invention relates to a planning unit for generating control data for correcting the refraction of an eye through corneal modification. The planning unit comprises an interface for receiving data representing a hyperopic or myopic refraction correction requirement of an eye with a cornea. The generated control data thus serves to correct the refractive error of a nearsighted or farsighted eye. The correction requirement can also include the correction of astigmatism or other image defects that are not purely rotationally symmetrical. The interface of the planning unit can be a plug or socket for a cable (e.g., USB, Firewire, RS232, CAN bus, Ethernet, etc.); it can also be a wireless interface such as a WLAN, UMTS, or Bluetooth receiver.

The planning unit further comprises a computing device connected to the interface. The computing device may be a computer having a processor and a memory. The computing device may comprise at least one processor or processing element, e.g., a CPU (central processing unit) (optionally in the form of a microprocessor), a GPU (graphics processing unit), a TPU (tensor processing unit), and/or an FPGA (field programmable gate array). The computing device may comprise a computer memory, optionally a semiconductor memory chip. The processor may be configured to execute a computer program. The computer program may be stored in the computer memory.

The calculation device is connected to the interface and configured to receive data about the refractive correction requirement. Furthermore, the calculation device is configured to calculate, based on the refractive correction requirement, a first tissue volume of the cornea of the eye and a displacement of the first tissue volume in the cornea. According to the invention, the calculation is performed such that the first tissue volume has a subtractive refractive change value, and the first tissue volume, in conjunction with the displacement in the cornea, has an additive refractive change value.

If the first tissue volume were removed from the cornea, this would result in a change in the eye's refraction, which contributes to the subtractive refractive change value. The first tissue volume can be solely responsible for the subtractive refractive change value and can cause, form, or provide it alone; then there are no further volumes that contribute to a subtractive refractive change value. According to the invention, however, the first tissue volume is not to be removed; rather, the first tissue volume is to be displaced within the cornea. The displaced first tissue volume remains within the cornea, where it creates a change in the eye's refraction and provides an additive refractive change value.

The first tissue volume therefore contributes to the subtractive refractive change value and provides or is responsible for the additive refractive change value. This occurs due to the calculated displacement, since the first tissue volume is no longer located at its original location in the cornea after the displacement and there is a lack of tissue volume in at least one location there (subtractive effect). Rather, additional tissue volume is located at a different location in the cornea after the displacement (additive effect).

In addition, the calculation device for calculating, on the basis of the refraction correction requirement, the first tissue volume of the cornea and the displacement of the first tissue volume in the cornea is configured according to the invention such that the subtractive refraction change value together with the additive refraction change value results in the refraction correction requirement. Is If the first tissue volume is solely responsible for the subtractive and additive refractive change value, then the first tissue volume alone determines both the subtractive and the additive refractive change value through its displacement in the cornea and is responsible for fulfilling the refractive correction requirement.

In order to avoid systematic overcorrection or undercorrection, the statement that “the subtractive refractive change value together with the additive refractive change value results in the refractive correction requirement” is to be understood as meaning that the subtractive refractive change value together with the additive refractive change value correspond to between 40% and 160% of the refractive correction requirement, preferably between 60% and 140%, or between 80% and 120%.

Finally, the calculation device for calculating, based on the refractive correction requirement, the first tissue volume of the cornea and the displacement of the first tissue volume in the cornea is configured according to the invention such that the displacement is a rotation, a translation, a folding, and/or a turning. Thus, a local displacement of the first tissue volume in the cornea is calculated; this displacement is not an identical mapping. A rotation is typically described by a rotation axis and a rotation angle (not equal to 0°); a translation can be described by a translation vector (with a length not equal to 0 µm); a folding can be described, for example, by a folding axis and, if applicable, a folding angle (not equal to 0°). Turning is understood to mean that a surface of the first tissue volume that (before turning) faced the front of the eye faces the retina of the eye after turning. The aforementioned displacement parameters can be part of the control data.

Furthermore, the calculation device is configured to calculate a cutting surface. According to the invention, the calculation device calculates the cutting surface such that the cutting surface in the cornea delimits the first tissue volume for the displacement. To this end, the cutting surface can isolate the first tissue volume, i.e., the first tissue volume is completely surrounded by the calculated cutting surface. An isolated first tissue volume is no longer connected to the cornea from which it was isolated (apart from small tissue bridges). Alternatively, the cutting surface can be calculated such that the calculated displacement of the first tissue volume in the cornea can be realized without isolating the first tissue volume; this is also what is understood by the verb "delimit". Such a delimitation is particularly advantageous if the displacement is a fold. In this case, the calculated cutting surface can end at a fold edge, so that the folding can be carried out particularly precisely.

Additionally, the calculation device is configured to calculate the cutting surface in such a way that the cutting surface simultaneously defines a chamber for the first tissue volume to be displaced. This ensures that the first tissue volume can be moved to the desired location in the cornea via the calculated displacement in order to achieve the calculated effect for the additive refractive change value.

Finally, the calculation device is configured to calculate the cutting surface such that the cutting surface provides a first access for the displacement of the first tissue volume. The first access can be an opening incision through which a tool can be inserted into the cornea to perform the calculated displacement of the first tissue volume. The first access extends to the front of the cornea. Such incisions are described, for example, in document DE 102007019813 A1 described. Alternatively, the access to the incision surface can be a so-called flap, which is opened to relocate the first tissue volume and then closed again after relocation.

For a permanent repositioning, it may be advantageous to fix or adhere the first tissue volume to its new location in the cornea after repositioning. This can be done with a biocompatible adhesive such as fibrin glue. If the first tissue volume is to be fixed after repositioning, the initial access is best designed to allow for fixation. To achieve this, the initial access can be large enough to allow the insertion of a syringe tip for the adhesive.

Finally, the calculation device is configured to generate control data describing the cutting surface.

Advantageously, the planning unit further comprises a further interface via which the generated control data describing the cutting surface can be provided. The further interface can be identical to the interface described above, which is designed to receive the data on the refractive correction requirement. The generated control data can be transmitted to a control unit of an ophthalmological Laser therapy device. This device can create the incision surface in the cornea of the eye based on the generated control data.

In summary, the planning unit according to the invention is configured to generate control data describing a cutting surface that delimits a first tissue volume in the cornea that can be moved according to a calculated displacement in the cornea, thus contributing to both a subtractive (before the displacement) and an additive (after the displacement) refraction change value. The subtractive refraction change value, together with the additive refraction change value, determines the refraction correction required by which the refraction of the eye can be corrected. According to the invention, the displaced first tissue volume forms an autologous transplant and thus ensures long-term compatibility in the recipient. Furthermore, the displacement of the first tissue volume can achieve a greater myopia or hyperopia correction than is possible with a subtractive correction for the same isolated tissue volume. In this way, the diopter range of a refractive error correction is expanded while maintaining biomechanical stability, while simultaneously ensuring a permanent correction.

According to an advantageous embodiment of the planning unit, the calculation device is further configured to calculate, based on the refractive correction requirement, a second tissue volume of the cornea, wherein the first and second tissue volumes together provide the subtractive refractive change value. If the first and second tissue volumes were removed from the cornea, this would result in a change in the refraction of the eye that corresponds to the subtractive refractive change value. The first and second tissue volumes together are responsible for the subtractive refractive change value and solely cause or solely provide it; there are no other volumes that contribute to the subtractive refractive change value.

Furthermore, in the said advantageous embodiment of the planning unit, the calculation device is configured to calculate the cutting surface in such a way that it isolates the second tissue volume in the cornea, and that the cutting surface provides a second access via which the second tissue volume can be removed from the cornea, wherein the second access can be identical to the first access.

The calculated cut surface thus additionally isolates the second tissue volume, which can be removed from the cornea via the second access point. The second tissue volume is therefore not intended for relocation within the cornea; rather, it is intended to be removed from the cornea. The second tissue volume therefore only contributes to the subtractive refractive change value.

The removal of the second tissue volume does not have to be performed with a mechanical tool. This can also be achieved by ablation, for example, using an excimer laser. Such ablation is also understood in the context of the application as isolating the second tissue volume.

The relative position of the first tissue volume to the second tissue volume within the cornea is irrelevant. The calculated cutting area can also be calculated such that, during the surgical procedure, the first tissue volume must first be removed from the cornea in order to remove the second tissue volume (mechanically or by ablation). The first tissue volume is then reinserted into the corneal chamber and placed in the position according to the calculated displacement (and, if necessary, fixed there).

The described design of the planning unit offers the advantage that the second tissue volume to be removed from the cornea provides more degrees of freedom for the geometry of the first tissue volume, which provide the additive refraction change value after a displacement of the first tissue volume.

In a further advantageous embodiment of the planning unit, the calculation device for calculating the first and/or second tissue volume is configured such that the first tissue volume is contiguous and/or that the second tissue volume is contiguous.

If the first tissue volume is continuous, the displacement of the first tissue volume can advantageously be performed in a single step. This simplifies the surgical procedure and reduces the risk that the placement of the first tissue volume will not be carried out in accordance with the calculated displacement and thus will not lead to the calculated additive refractive change value. If the second tissue volume is continuous, the removal of the second tissue volume through the second access can advantageously be performed in a single step. This also simplifies the surgical procedure and reduces the risk that remnants of the second tissue volume mens remain in the cornea and thus worsen the result of the refractive correction.

According to a first embodiment, the planning unit is characterized by the fact that the refractive correction requirement has an astigmatic component and a rotationally symmetric component. This means that the rotationally symmetric component merges into itself upon rotation by any angle around the corresponding rotation axis (axis of symmetry); it is therefore a spherical or aspherical component. The rotationally symmetric component (or "second component") of the refractive correction requirement is different from zero diopter. The astigmatic component (or "first component") merges into itself upon rotation by 180° (or π) around an associated axis of symmetry. The rotationally symmetric component therefore represents the spherical or aspherical refractive correction requirement, while the astigmatic component represents the astigmatic requirement. The astigmatic portion of the refractive correction requirement is also different from zero diopters, i.e., it has a cross-section plane encompassing the axis of symmetry where a change in refractive power is desired that is different from zero diopters. The refractive correction requirement thus corresponds to a myopia or hyperopia correction that simultaneously corrects astigmatism. It should be noted that the refractive correction requirement may also include a portion corresponding to a higher image aberration.

The calculation device is further configured to calculate the cutting area in such a way that the first tissue volume is isolated.

Additionally, the planning unit in the first embodiment is characterized in that the calculation device is further configured to assign an astigmatic refractive power to the first tissue volume and to calculate the first tissue volume such that the first tissue volume has an astigmatic anterior and/or an astigmatic posterior boundary surface. The anterior boundary surface of the first tissue volume faces the front of the cornea, while the posterior boundary surface of the first tissue volume faces the retina of the eye. The first tissue volume is lens-shaped; it can also be referred to as a “lenticule.” At least one of the lens surfaces is astigmatic. This astigmatic boundary surface can additionally have a rotationally symmetric (spherical/aspherical) curvature, which is superimposed on the cylinder to correct the astigmatism. The boundary surfaces have the astigmatic refractive power assigned to the first tissue volume.

Finally, the planning unit in the first embodiment is characterized in that the displacement of the first tissue volume comprises a rotation about a first axis of rotation. The displacement can be a pure rotation (without any translation, folding, or turning), but it can also be a rotation and turning (without any translation and folding). Preferably, the first axis of rotation is identical to the axis of rotation (axis of symmetry) of the rotationally symmetrical (second) portion of the refractive correction requirement and/or identical to the axis of symmetry of the astigmatic (first) portion of the refractive correction requirement. To enable displacement by rotation, the cutting surface is calculated—as described above—in such a way that it isolates the first tissue volume.

The rotation calculated by the calculation device has a rotation angle R1α of 90°±10°. Rotating the first tissue volume by a rotation angle of 90° can satisfy the astigmatic component of the refractive correction requirement. However, it may also be advantageous to use a rotation angle R1α other than 90°, for example, to counteract systematic axial rotation. Therefore, deviations of 5°, 10°, or even 20° from a rotation angle of 90° are possible.

In this first form, the spherical or aspherical refractive correction requirement can be provided via the first and second tissue volumes together (or the subtractive refractive change value generated jointly by the first and second tissue volumes). After removing the second tissue volume and assumingly removing the first tissue volume (which, however, is not performed because the first tissue volume is displaced, or rotated and possibly turned; in this case, the first tissue volume can be removed from the cornea for the rotation or turning and then replaced in a rotated/turned state), this rotationally symmetrical (second) portion of the refractive correction is realized.

In this case, the astigmatic (first) part of the refractive correction requirement is corrected by the rotated first tissue volume: By shifting (rotating, if necessary, turning) the first tissue volume around the first rotation axis, the astigmatic part of the refractive correction is realized via the additive refractive change value generated thereby.

By dividing the need for refraction correction into the two parts (spherical/aspheric and astigmatic), it is possible to achieve less tissue volume from the cornea, ensure refractive error correction over a wide diopter range, and achieve it with greater biomechanical stability, compared to the state of the art, where the need for correction is met by simply removing tissue volume.

It should be noted that a relocation that includes both rotation and flipping (also called a “flip”) can be particularly beneficial because flipping improves the stability of the eye or its cornea after the procedure.

According to an advantageous embodiment of the planning unit according to the first aspect, it is characterized in that the calculation device is further configured to calculate the first and second tissue volumes such that the first tissue volume and the second tissue volume have a common interface at least in sections. The common interface contributes a maximum of 50% of the astigmatic refractive power assigned to the first tissue volume, preferably a maximum of 20%, particularly preferably a maximum of 10% or 3%.

"At least in sections" means that at least 50% of the interface of the first tissue volume facing the second tissue volume corresponds to the common interface, preferably at least 70%, particularly preferably at least 90%. Additionally or alternatively, "at least in sections" means that at least 50% of the interface of the second tissue volume facing the first tissue volume corresponds to the common interface, preferably at least 70%, particularly preferably at least 90%.

For example, if the first tissue volume is positioned posterior to the second tissue volume, the anterior interface of the first tissue volume is (at least partially) identical to the posterior interface of the second tissue volume. If the astigmatic contribution to the refractive power of the (common) anterior interface of the first tissue volume is only 3%, the posterior interface of the first tissue volume contributes 97% to the associated astigmatic refractive power. A small astigmatic contribution to the refractive power of the shared interface is advantageous. This results from the following considerations:

In a first example, the astigmatic component of the required refractive correction is 1 dpt; i.e., in addition to a spherical/aspherical correction, an astigmatism (cylinder) of one diopter must be corrected. If the posterior interface of the first tissue volume is designed so that it can be assigned an astigmatic refractive power of 0.5 dpt, the anterior interface (which is at least partially identical to the posterior interface of the second tissue volume) can be designed with purely rotational symmetry. By rotating the first tissue volume by 90°, the astigmatic error of the eye is then completely corrected. The additional spherical/aspherical correction requirement can be met by removing the second tissue volume. If, as in this example, the astigmatic correction is achieved precisely by the non-shared interface of the first tissue volume, the astigmatic power assigned to the first tissue volume must correspond to just 50% of the astigmatic correction required. The contribution of the shared surface to the astigmatic power is therefore 0%. The interfaces of the second (to be removed) tissue volume can both be purely rotationally symmetric.

In a second example, the astigmatic component of the required refractive correction is again 1 D, and the posterior interface of the first tissue volume is now designed so that it can be assigned an astigmatic refractive power of only 0.4 D. By rotating the first tissue volume by 90°, an astigmatic correction of 2 x 0.4 D = 0.8 D is generated across the posterior interface. Thus, the anterior interface (shared with the second tissue volume) must add a further 0.2 D to meet the required astigmatic refractive correction. In this example, the contribution of the shared surface is one-third: 0.2 D / (0.4 D + 0.2 D) = 1/3.

This reasoning shows that in this second example, the astigmatic power assigned to the first tissue volume must be greater than in the first example (0.6 D versus 0.5 D). This means that the first tissue volume also requires more volume to meet the astigmatic refractive correction requirement. It is therefore advantageous to keep the astigmatic power contribution of the common interface low.

Furthermore, at least one of the interfaces of the second tissue volume is advantageously rotationally symmetric; ie, it has a spherical or aspherical shape. Typically, at least the non-common interface is rotationally symmetric. Preferably, both interfaces are chen rotationally symmetric; in this case, the common interface of the first tissue volume contributes exactly 0% to the astigmatic refractive power.

It is particularly advantageous to calculate the second tissue volume such that, when removed from the cornea, it corresponds to the rotationally symmetric portion of the required refractive correction. In this case, the rotationally symmetric correction can be achieved solely via the second (to be removed) lenticule, while the astigmatic correction can be achieved by displacing the first tissue volume. Such an allocation of the portions of the required correction to the tissue volumes requires a particularly small first tissue volume to be displaced and a particularly small second tissue volume to be removed. In practice, however, there may be limits to this strict division, since the tissue volumes cannot be arbitrarily thin. Therefore, it is advantageous if the interfaces of the second tissue volume are calculated such that a rotationally symmetric refractive power assigned to the interfaces corresponds to at least 50% of the rotationally symmetric portion of the required refractive correction, preferably at least 70%, particularly preferably at least 90%.

A particularly advantageous embodiment of the planning unit according to the first embodiment is characterized in that the calculation device is configured to calculate the anterior and posterior boundary surface of the first tissue volume such that the assigned astigmatic refractive power corresponds to between 20% and 90% of the astigmatic portion of the refractive correction requirement, preferably between 30% and 80%, particularly preferably between 40% and 70%. The assigned astigmatic refractive power is evaluated according to the calculated (and imaginary) displacement.

Furthermore, the astigmatic refractive power of the second tissue volume (after the intended removal) preferably corresponds to less than 20% of the astigmatic portion of the refractive correction required, preferably less than 10%, and particularly preferably less than 3%. The greatest "saving" in terms of tissue removal and relocation occurs when the second tissue volume provides 0% of the astigmatic portion of the refractive correction required. However, this is not always possible, since the tissue volumes should have finite thicknesses.

An astigmatic power assigned to the first tissue volume of 50% of the astigmatic portion of the refractive correction requirement allows (after displacement with a rotation angle of 90°) an exact correction of the eye's astigmatic error if the second tissue volume does not contribute to the astigmatic refractive correction requirement and if the share of the common interface in the astigmatic power assigned to the first tissue volume is 0%. However, a deviation from the 50% as described above advantageously allows for the avoidance of systematic under- or overcorrection of astigmatism.

A further embodiment of the planning unit according to the first aspect is characterized in that the calculation device is further configured to calculate the first tissue volume such that it has a marking and/or is provided with a structured edge cut. The markings and/or structures are calculated such that they mark a correct displacement according to the calculated rotation angle R1α.

Since it can be difficult to precisely execute the rotation around the calculated rotation angle, it is helpful if the first tissue volume to be rotated is designed to support exact positioning. The markings and/or structured edge cuts according to the invention allow precisely such precision. The markings/structures can be designed as a grid structure; this can also prevent the autologous transplant (the first tissue volume) from twisting or otherwise changing its position in the cornea even after the actual procedure. The markings can also be designed as so-called "noses," for example.

The markers/structures can be four, arranged at a 90° angle. This ensures complete, precise locking of the relocated first tissue volume.

According to a second embodiment, the planning unit, whose calculation device is also configured, as described above, to calculate a second tissue volume and a corresponding cut area, is characterized in that the refractive correction requirement is hyperopic. This means that the correction of hyperopia is desired; the refractive correction requirement is different from zero diopters. The refractive correction requirement may also include astigmatism (or higher image aberrations).

Furthermore, the planning unit according to the second embodiment is characterized in that the displacement comprises a folding around a folding axis that is assigned to the folding. The calculation device is thus designed to act as a storage, a fold is calculated, whereby the folding occurs around a folding axis. The folding axis is assigned to the calculated fold. The displacement preferably does not include rotation or translation. However, the displacement may also include a turning in addition to the folding.

Advantageously, the calculation device is configured to calculate the cutting surface in such a way that the calculated folding axis coincides with a section of an edge of the cutting surface.

A displacement by folding allows a particularly precise positioning of the first tissue volume after the displacement, since the desired position of the first tissue volume is precisely predefined via the folding axis, which typically coincides with a section of an edge of the cut surface.

The cut surface can isolate the first tissue volume. In this case, it is particularly advantageous if the folded tissue volume is subsequently fixed (and/or glued). The cut surface can also be calculated so that the first tissue volume is particularly thin in the area of the fold axis, so that no unwanted bulging occurs due to the folding. In this case, the first tissue volume is not isolated (but only delimited); here, too, it can be advantageous to fix (glue) the displaced first tissue volume.

If hyperopic refractive correction of S diopters (D) is required, the first and second tissue volumes are preferably calculated such that their union corresponds to a lenticule with a lower refractive power than S, S _P (S _P < S), if the combined tissue volume were removed from the cornea. Due to the lower refractive power and the fact that the first tissue volume remains in the cornea (after displacement), it is clear that a greater hyperopia correction can be achieved than is possible with subtractive correction alone while maintaining biomechanical stability. In this way, the diopter range of a refractive error correction is expanded, while at the same time ensuring a permanent correction.

An advantageous embodiment of the planning unit according to the second aspect is characterized in that the calculation device is configured to calculate the first tissue volume such that the first tissue volume has at least three sub-volumes, preferably at least four sub-volumes, particularly preferably at least eight sub-volumes. A folding axis is assigned to each sub-volume. Thus, a folding axis is calculated for each of the calculated sub-volumes of the first tissue volume.

Additionally, the calculation device is configured to calculate the first tissue volume such that the subvolumes are arranged symmetrically around a second rotation axis. This means that upon an imaginary rotation of the subvolumes around the second rotation axis by a rotation angle other than 0° (or a multiple of 360°), the subvolumes are transformed into themselves.

Finally, the calculation device is configured to calculate the first tissue volume such that the folding axes assigned to the partial volumes are also arranged symmetrically around the second rotation axis.

Typically, the second rotation axis traverses the corneal vertex of the eye requiring refractive correction. The second rotation axis may additionally or alternatively run parallel to an optical axis of the eye.

For example, if three subvolumes of the first tissue volume are calculated, the three folding axes form an equilateral triangle. If, for example, four subvolumes of the first tissue volume are calculated, the four folding axes form a rectangle or a square. Similarly, if M subvolumes of the first tissue volume are calculated, the M folding axes form a symmetrical (or even equilateral) M-corner.

Advantageously, the sub-volumes of the first tissue volume are calculated such that, viewed radially from the second rotation axis, they extend from the outside to the respective assigned folding axis. Therefore, no section of a sub-volume is closer to the second rotation axis than the distance between the assigned folding axis and the second rotation axis. Particularly advantageously, the sub-volumes extend, viewed radially from the second rotation axis, to a maximum of twice the distance between the assigned folding axis and the second rotation axis. If the sub-volumes and the folding axes are calculated in this way, the respective sub-volumes can be folded "inwards" (i.e., toward the second rotation axis) over the respective folding axes. This does not result in an overlap of the folded sub-volumes in the area of the second rotation axis.

A displacement of the first tissue volume described in this way allows corneal tissue to be moved “from the outside to the inside.” In this way, the curvature of the cornea can be advantageously skin, thus enabling the correction of hyperopia. The second tissue volume is advantageously calculated in such a way that the "gaps" created by the displacement of the first tissue volume (for distances from the second rotation axis beyond the folding axes) are taken into account in such a way that the removal of the second tissue volume compensates for or avoids greater image aberrations that would arise if only the first tissue volume were displaced (without removing the second tissue volume).

A planning unit marked as described here allows for particularly precise correction of hyperopia.

A further development of the design of the planning unit according to the second embodiment is characterized in that the sub-volumes are arranged in a star shape around the second axis of rotation.

If the subvolumes each have the shape of a star point, they can be folded along the assigned folding axes in the direction of the second rotation axis, so that after all folds, the subvolumes do not overlap but lie next to each other. This allows the desired shape of the cornea to be achieved with particular precision after the first tissue volume has been relocated.

According to an embodiment of the planning unit according to the second aspect, it is characterized in that the subvolumes have different thicknesses. The thickness of a subvolume is understood to be the extent of the subvolume in a direction parallel to the second rotation axis.

In this way, higher image defects (such as astigmatism) that exist beyond the need for hyperopic refractive correction can be corrected.

According to an alternative second embodiment of the planning unit, whose calculation device, as described above, is also configured to calculate a second tissue volume and a corresponding cross-sectional area, this is characterized in that the refractive correction requirement is myopic. Deviating from the second embodiment described above, the sub-volumes (arranged symmetrically around a rotation axis) extend from the rotation axis to the associated (symmetrically arranged) folding axes. By shifting them, the sub-volumes are moved "outwards" (to greater radial distances from the rotation axis). In this way, a flattening of the anterior surface of the cornea can be achieved, which allows for myopia correction.

According to a third variant, the planning unit is characterized by the need for refractive correction being myopic. This means that the correction of myopia is desired; the refractive correction need is different from zero diopters. The refractive correction need may also include astigmatism (or higher aberrations).

Furthermore, the planning unit according to the third embodiment is characterized in that the displacement comprises a rotation about a third axis of rotation with an optional, simultaneous translation along the third axis of rotation. The calculation device is thus designed to calculate a rotation as the displacement, wherein the rotation occurs about the third axis of rotation. The displacement by means of rotation can simultaneously result in a translation along the third axis of rotation; however, this does not have to be the case. The displacement does not comprise folding. Furthermore, the displacement preferably does not comprise turning.

The calculation device is further configured to calculate the cut surface in such a way that the first tissue volume is isolated. Only then is subsequent displacement by rotation possible.

Furthermore, according to the third embodiment, the calculation device of the planning unit is configured to calculate the first tissue volume such that the first tissue volume, in conjunction with the rotation in the cornea, together with a cavity created by the rotation, corresponds to the additive refractive change value. The first tissue volume has different distances between an anterior and a posterior boundary surface for different azimuth angles around the third rotation axis.

Preferably, the first tissue volume has a symmetry with respect to the third rotation axis. This means that the first tissue volume merges into itself when it is rotated about the third rotation axis by a rotation angle that is different from 0° (or a multiple of 360°). The first tissue volume can, for example, have four regions with a larger distance between the anterior and posterior interfaces and four regions with a smaller distance in between. These regions can be arranged such that the first Tissue volume merges into itself when rotated by 90° around the third rotation axis.

Advantageously, for the displacement, a rotation angle about the third rotation axis is calculated by the calculation device of the planning unit according to the third embodiment such that an area with a greater distance (compared to an average distance, for example, averaged over all azimuth angles) between the anterior and posterior interfaces of the first tissue volume is rotated by the rotation into a position where, prior to the rotation, there was a smaller distance (compared to an average distance) between the anterior and posterior interfaces of the first tissue volume. Due to the distances between the interfaces, the rotation can be associated with a translation of the first tissue volume along the third rotation axis; the translation of the first tissue volume then occurs in the direction of an anterior interface of the cornea. In this way, the amount of corneal tissue increases in this area, so that a change in the shape of the cornea can be created that corresponds to the desired refractive correction requirement.

In regions of the cornea where the rotation rotates an area with a smaller distance (compared to a mean distance) between the anterior and posterior interfaces of the first tissue volume to a position where, prior to the rotation, there was a larger distance (compared to a mean distance) between the anterior and posterior interfaces of the first tissue volume, a cavity typically forms after the displacement (rotation) of the first tissue volume. If this cavity is filled with a material whose refractive index corresponds to that of the cornea, this cavity also contributes to the additive refractive change value.

Since the refractive power of the anterior corneal surface is achieved by reducing the curvature or increasing the radius of curvature during myopia correction, the prior art always involved a greater removal of tissue from the center of the cornea than from the edge. However, a reduction in refractive power can also be achieved by "padding" the peripheral region of the cornea. According to the invention, this padding is achieved as described above. It should be noted that the first tissue volume, which has the shape of a lenticule of variable thickness, must be prepared free of residual tissue bridges on the upper and lower sides of the corneal stroma, i.e., the first tissue volume must be isolated.

In the region of a transition zone in the cornea, in which the first and/or second tissue volumes end, viewed radially from the third rotation axis, tensions (caused by the padding) can arise after the displacement of the first tissue volume. These tensions can be reduced or even completely eliminated if the calculation device is further configured to calculate the incision area in such a way that it provides a relief incision. Preferably, several relief incisions are provided, which are distributed azimuthally around the third rotation axis - preferably evenly. In this case, one relief incision is wedge-shaped and/or oblique to the anterior surface of the cornea. The relief incision advantageously extends to the anterior surface of the cornea and/or to the chamber (for the first tissue volume to be displaced). A wedge-shaped relief incision has a wedge angle of at least 5°, preferably at least 10°, particularly preferably at least 15°. An oblique relief incision has an angle of at least 20°, preferably at least 30°, particularly preferably at least 45°, relative to the surface normal of the anterior surface of the cornea.

The relief incision can compensate for a shift of the corneal tissue (after a shift of the first tissue volume) to the relief incision without creating a corneal gap.

According to an embodiment of the planning unit according to the third aspect, it is characterized in that the different distances along the azimuth angle are formed in steps. These steps make it possible to perform the rotation around the third rotation axis step by step, with each step also including a translation step along the third rotation axis. This simplifies the process of relocating the first tissue volume and reduces the risk of damaging or incorrectly positioning the first tissue volume.

In a further embodiment of the planning unit according to the third aspect, it is characterized in that the different distances along the azimuth angle have notches. The notches can be in the form of spikes or a sawtooth. The notches advantageously prevent the first tissue volume from rotating back on its own in a period following the surgical procedure. This ensures that the autologous tissue enables a temporally stable refraction correction.

According to a further embodiment of the planning unit according to the third embodiment, it is characterized in that for the calculation of the additive refraction change value it is assumed that the cavity resulting from the displacement of the first tissue volume is filled with tissue fluid, hyaluronic acid and/or with an artificial filling material.

These fluids can be introduced into the cavity during the surgical procedure; tissue fluid can also accumulate in the resulting cavity after the procedure. The refractive indices of these fluids correspond (approximately) to those of the cornea, so that a cavity filled in this way cannot lead to unwanted light refraction.

Additionally, a support structure can be inserted into the cavity, the dimensions of which correspond to the cavity's geometry. This support structure can also be filled with the aforementioned fluids. This can improve the temporal stability of the cavity's geometry.

A second aspect of the invention relates to an ophthalmic laser therapy device. According to the invention, this device comprises a planning unit according to one of the embodiments and configurations described above.

The ophthalmic laser therapy device further comprises a control unit with an interface to the planning unit for receiving the control data for controlling the ophthalmic laser therapy device. The control unit is connected to the devices of the ophthalmic laser therapy device described below in order to control them. For this purpose, the control unit can convert the control data into signal data and forward it to the corresponding devices; however, the control data provided by the planning unit can also be forwarded directly to the corresponding devices.

The control unit can typically access all controllable devices of the ophthalmic laser therapy device. It can be a single- or multi-part design and communicate with the controllable devices of the ophthalmic laser therapy device via wired or wireless communication channels. The interface between the control unit and the planning unit can allow wired or wireless transmission of control data.

The ophthalmic laser therapy device further comprises a laser device for providing a pulsed laser beam. The laser device is preferably a device that provides laser pulses with a pulse duration of femtoseconds or picoseconds, and whose focused laser beam is capable of severing the tissue of a patient's eye by means of optical breakdown due to nonlinear absorption. For this purpose, the laser device can comprise, for example, a femtosecond laser or a picosecond laser. In addition, the laser device can be configured to ablate tissue of a patient's eye (LASIC; for a second tissue volume that may be removed); for this purpose, the laser device can have an additional laser source.

A femtosecond laser, for example, has a wavelength in a range from 750 nm to 1100 nm. However, the use of femtosecond lasers at other wavelengths is also conceivable in principle. The pulse duration of a femtosecond or picosecond laser that can be used here can be selected from a pulse duration range of 50 fs to 5 ps. The pulse energy of a femtosecond or picosecond laser that can be used here is advantageously in a pulse energy range of 20 nJ to 2 µJ. A pulse energy of approximately 130 nJ is particularly preferred. Typically, a laser device can provide laser pulses with a laser pulse frequency of up to 50 MHz. However, the laser device can be configured to reduce the laser pulse frequency.

The ophthalmic laser therapy device further comprises a focusing device for focusing the pulsed laser beam into a focus for severing the cornea. The focusing device is designed to focus the pulsed laser beam in the tissue of the patient's eye, so that an optical breakthrough is achieved at the focus. The focusing device is preferably designed to take into account the optical properties of the patient's eye (such as the radii of curvature of the optically effective interfaces—for example, on the cornea or the lens of the eye—or the refractive indices of the tissue being irradiated). Furthermore, the focusing device can be designed to generate a focus of the pulsed laser beam in the tissue of the patient's eye, with a contact lens arranged in the beam path upstream of the patient's eye.

In addition, the ophthalmic laser therapy device includes a scanning device for shifting the focus of the pulsed laser beam in the cornea of the eye to create the cutting surface.

The scanning device of the ophthalmic laser therapy device allows the focus of the pulsed laser beam to be shifted or scanned within the tissue of the eye. Scanning of the pulsed laser beam should be possible without restriction in all three spatial directions: x, y, and z. Accordingly, the scanning device should be designed to perform both lateral scans in the x and y directions as well as z scans along the optical axis of the pulsed laser beam.

The ophthalmic laser therapy device according to the invention allows the control data generated by the planning unit to be used in such a way that a cutting surface can be created in an eye by means of pulsed laser radiation, that a first tissue volume can be displaced via a first access (and, if necessary, a second tissue volume can be removed from the cornea via a second access), so that the refractive correction requirement of the eye is met.

It should be noted that the ophthalmic laser therapy device described above is particularly suitable for generating the calculated incision surface due to its high precision. In principle, the planning unit according to the invention (in its forms and configurations) is not limited to use in a laser-based device. The calculated control data can also be used in a device that can generate an incision surface in the eye using a different mechanism of action.

A third aspect of the invention relates to planning methods for generating control data for correcting the refraction of an eye through corneal modification. The planning method comprises receiving data about a hyperopic or myopic refractive correction requirement of an eye with a cornea. The hyperopic or myopic refractive correction requirement is different from zero diopter; it may additionally include a requirement for correcting an astigmatic (or higher) image defect.

Furthermore, the planning method comprises calculating, on the basis of the refractive correction requirement, a first tissue volume of the cornea and a displacement of the first tissue volume in the cornea, wherein the first tissue volume has a subtractive refractive change value, the first tissue volume in conjunction with the displacement in the cornea provides an additive refractive change value, the subtractive refractive change value together with the additive refractive change value results in the refractive correction requirement, and wherein the displacement is a rotation, a translation, a folding and/or a turning.

Furthermore, the planning method comprises, as a method step, calculating a cutting surface such that the cutting surface in the cornea delimits the first tissue volume for the displacement, the cutting surface simultaneously delimits a chamber for the first tissue volume to be displaced, and that the cutting surface provides a first access for the displacement of the first tissue volume.

Finally, the planning process includes generating control data describing the cutting surface.

The planning process can be performed before the actual surgical intervention on the cornea. Only the data regarding the eye's refractive correction needs are required. If additional measurement data about the eye is available, these can be taken into account in the planning process, for example, when calculating the initial tissue volume and/or the incision area. Such measurement data can be, for example, measurements from a wavefront measurement device, an optical coherence tomography (OCT), a Scheimpflug camera, or an ultrasound imaging system.

According to a further development of the planning method, it is characterized in that the refractive correction requirement has an astigmatic component and a rotationally symmetric component, and that the displacement comprises a rotation around a first rotation axis with a rotation angle R1α of 90°±10°. The displacement may additionally include a turning. Preferably, the calculated displacement does not include any translation or folding.

The planning method further comprises the step of calculating a sectional area that isolates the first tissue volume. Furthermore, the method includes the step of assigning an astigmatic refractive power to the first tissue volume. The method also includes calculating an astigmatic anterior boundary surface of the first tissue volume such that the boundary surfaces satisfy the assigned astigmatic refractive power.

Furthermore, the method comprises calculating, based on the refractive correction requirement, a second tissue volume of the cornea, wherein the first and second tissue volumes together provide the subtractive refractive change value.

The planning method further includes calculating the incision surface such that it isolates the second tissue volume in the cornea, and such that the incision surface provides a second access through which the second tissue volume can be removed from the cornea. The second access may be identical to the first access.

According to an alternative further development of the planning method, this is characterized in that the refractive correction requirement is hyperopic and that the displacement comprises a folding around a folding axis which is associated with the folding.

The planning method further comprises the method step of calculating, on the basis of the refraction correction requirement, the first tissue volume such that the first tissue volume has at least three sub-volumes, preferably at least four sub-volumes, particularly preferably at least eight sub-volumes, wherein each sub-volume is assigned a folding axis, that the sub-volumes are arranged symmetrically about a second rotation axis, and that the folding axes assigned to the sub-volumes are also arranged symmetrically about the second rotation axis.

The planning method further includes calculating, based on the refractive correction requirement, a second tissue volume of the cornea, wherein the first and second tissue volumes together provide the subtractive refractive change value, and calculating the incision surface such that it isolates the second tissue volume in the cornea, and such that the incision surface provides a second access through which the second tissue volume can be removed from the cornea. The second access may be identical to the first access.

According to a further alternative development of the planning method, this is characterized in that the refractive correction requirement is myopic, and that the displacement comprises a rotation about a third rotation axis with an optional, simultaneous translation along the third rotation axis.

The planning method further includes the step of calculating the first tissue volume based on the refractive correction requirement such that the first tissue volume, in conjunction with the rotation in the cornea, together with a cavity created by the rotation, corresponds to the additive refractive change value. The first tissue volume has different distances between an anterior and a posterior interface for different azimuth angles around the third rotation axis.

It should be noted that the planning procedures described can be performed without the eye to be treated being connected to an ophthalmic therapy device. Rather, all steps of the planning procedures can be performed well (e.g., hours or days) before a surgical procedure, so that the control data is already available before the eye is optically coupled to the ophthalmic therapy device.

A fourth aspect of the invention relates to a computer program product. According to the invention, the computer program product comprises program code. When this program code is loaded into a computer, it executes a planning method as described above.

A fifth aspect of the invention relates to a method for correcting the refraction of an eye by corneal modification. According to the invention, the method comprises planning steps according to a planning method as described above. Furthermore, the method comprises cutting the cornea of the eye according to the calculated cutting area. Furthermore, the method comprises performing the displacement of the first tissue volume in the cornea according to the calculations. Optionally, the method comprises removing the second tissue volume from the cornea of the eye through the second access. This means that the second tissue volume is removed if the cutting area is calculated to isolate a second tissue volume. Cutting the first tissue volume can take place before or after removing the second tissue volume. The method can further comprise—after the displacement—fixing and/or gluing the first tissue volume.

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

• - 1 ein Schema einer Ausführungsform eines erfindungsgemäßen ophthalmologischen Lasertherapiegerätes;
• - 2 einen Schnitt durch die Hornhaut eines Auges mit einer Schnittfläche, die mit einer Planungseinheit nach der ersten Ausprägung gewonnen wurde, vor (2a) und nach (2c) der Verlagerung des ersten Gewebevolumens und Entnahme des zweiten Gewebevolumens, sowie eine Aufsicht auf das erste Gewebevolumen (2b);
• - 3 einen Schnitt durch die Hornhaut eines Auges mit einer Schnittfläche für ein Lentikel zur Korrektur von Hyperopie nach dem Stand der Technik;
• - 4a und 4b einen Schnitt durch die Hornhaut eines Auges mit einer Schnittfläche, die mit einer Planungseinheit nach der zweiten Ausprägung gewonnen wurde, vor (4a) und nach (4b) der Verlagerung des ersten Gewebevolumens und der Entnahme des zweiten Gewebevolumens;
• - 5a bis 5c eine Aufsicht auf die Hornhaut eines Auges mit Schnittflächen, wie sie in 4A und 4b dargestellt sind;
• - 6a und 6b Schnittflächen, die mit einer Planungseinheit nach der dritten Ausprägung gewonnen wurden, in einer Schnittebene (6a) sowie in einer Aufsicht (6b) mit dazugehörigen Seitenansichten aus zwei Richtungen;
• - 7a und 7b zwei verschiedene Schnitte durch das erste Gewebevolumen, wie es in 6b dargestellt ist;
• - 8a und 8b Schnittflächen wie in 6a und 6b (die mit einer Planungseinheit nach der dritten Ausprägung gewonnen wurden) nach der Verlagerung des ersten Gewebevolumens;
• - 9a und 9b eine Seitenansicht einer Schnittfläche, die mit einer Planungseinheit nach der dritten Ausprägung gewonnen wurden, vor (9a) und nach (9b) der Verlagerung, wobei das erste Gewebevolumen Rasten aufweist.

The invention is explained in more detail below by way of example with reference to the accompanying drawings, which also disclose essential features of the invention. They show:

• - 1 a diagram of an embodiment of an ophthalmological laser therapy device according to the invention;
• - 2 a section through the cornea of an eye with a cutting surface covered with a pla tion unit was obtained after the first expression, before ( 2a) and after ( 2c ) the displacement of the first tissue volume and removal of the second tissue volume, as well as a top view of the first tissue volume ( 2b) ;
• - 3 a section through the cornea of an eye with a cutting surface for a lenticule for correcting hyperopia according to the state of the art;
• - 4a and 4b a section through the cornea of an eye with a cut surface obtained with a planning unit after the second expression ( 4a) and after ( 4b) the relocation of the first tissue volume and the removal of the second tissue volume;
• - 5a until 5c a top view of the cornea of an eye with cut surfaces, as shown in 4A and 4b are shown;
• - 6a and 6b Sectional surfaces obtained with a planning unit according to the third characteristic in a section plane ( 6a) as well as in a supervision ( 6b) with corresponding side views from two directions;
• - 7a and 7b two different sections through the first tissue volume, as shown in 6b is shown;
• - 8a and 8b Cutting surfaces as in 6a and 6b (obtained with a planning unit after the third expression) after the displacement of the first tissue volume;
• - 9a and 9b a side view of a section surface obtained with a planning unit according to the third characteristic ( 9a) and after ( 9b) the displacement, whereby the first tissue volume has notches.

In 1 An embodiment of an ophthalmic laser therapy device 1 is schematically shown. A laser device 10 emits a pulsed laser beam 15. The laser beam 15 is deflected laterally by a scanning device 30 and axially by another scanning device 35. The focusing device 20 bundles the pulsed laser beam 15 into a focus 60 in the cornea 50. In 1 The focus 60 is shown as an example for two positions in the cornea 50 for different settings of the lateral scanning device 30 and the axial scanning device 35. A possibly advantageous fixation of the eye by means of a patient interface relative to the ophthalmic laser therapy device 1 is not shown.

During operation, the laser device 10, the scanning devices 30, 35, and the focusing device 20 are controlled fully automatically via signal data transmitted from the control unit 40 to the respective devices 10, 20, 30, 35. This is indicated by arrows pointing from the control unit 40 to the devices 10, 20, 30, and 35, respectively. The control unit 40 ensures suitably synchronous operation of the laser device 10, the three-dimensional scanning devices 30, 35, and, if applicable, the focusing device 20. The signal data can be transmitted via signal data lines or wirelessly. The signal data required during operation is determined in the control unit 40 based on the control data. The control unit 40 receives the control data in advance from the planning unit P as a control data set via unspecified communication channels, such as a control line. The control data can also be transmitted via memory chips (e.g., via USB or memory stick), magnetic storage devices (e.g., floppy disks), wirelessly via radio (e.g., WLAN, UMTS, Bluetooth), or wired (e.g., USB, Firewire, RS232, CAN bus, Ethernet, etc.). As an alternative to direct communication, it is also possible to arrange the planning device P spatially separate from the control unit 40 and to provide a corresponding data transmission channel. The transmission preferably takes place before the operation of the ophthalmic laser therapy device 1, i.e., before signal data is transmitted to the laser device 10, the scanning devices 30, 35, and, if applicable, to the focusing device 20.

Preferably, the control data record is transmitted to the control unit 40 of the ophthalmic laser therapy device 1 via an interface S2 (the “further” interface) of the planning device P, and further preferably, operation of the ophthalmic laser therapy device 1 is blocked until a valid control data record is present at the control unit 40. A valid control data record can be a control data record that is fundamentally suitable for use with the control unit 40 of the ophthalmic laser therapy device 1. In addition, however, validity can also be linked to the passing of further tests. For this purpose, it can be checked, for example, whether additional information about the ophthalmic laser therapy device 1 stored in the control data record, e.g. a device serial number, or about the patient, e.g. a patient identification number, match other information that was, for example, read out on the ophthalmic laser therapy device 1 or entered separately as soon as the patient is in the correct position for operation of the ophthalmic laser therapy device 1.

The planning device P generates the control data or the control data set, which is made available to the control unit 40 of the ophthalmic laser therapy device 1 for carrying out the surgical procedure. The measuring device M included in this embodiment generates measurement data from the patient's eye to be treated (indicated by a double arrow with a line of dots and dashes). In the embodiment shown here, a hyperopic or myopic refractive correction requirement is determined based on the measurement data from the measuring device M and confirmed by the operator via an input device (not shown), or the refractive correction requirement can be adjusted by the operator. The refractive correction requirement can then be transmitted from the measuring device M to the planning unit P via a data line. The planning unit P receives the data on the refractive correction requirement via an interface S1.

The planning unit P comprises a calculation device C. This is connected to the interface S1 and receives the refraction correction requirement of the eye. In the calculation device C, control data for correcting the refraction of the eye by means of corneal modification are then calculated. The control data are transmitted to the control unit 40 via the further interface S2. Using the transmitted control data, the control unit 40 can generate signal data and transmit it to the devices 10, 20, 30, 35, so that a cut surface 70 can be created in the cornea 50 of the eye.

It should be noted again that the planning unit P can generate the control data regardless of whether the eye is connected to the ophthalmic laser therapy device 1.

The presence of the measuring device M is optional. The need for refractive correction can also be determined based on measurement data that was not obtained with a measuring device that is part of the ophthalmic laser therapy device 1.

In 2a A section through the cornea 50 of an eye is shown with a cutting surface 70, which was obtained with a planning unit P after the first expression. The convex (anterior) front surface 52 of the cornea 50 is shown at the top of the figure; the concave (posterior) rear surface 54 of the cornea 50 delimits the cornea 50 in the figure at the bottom. In this and the following figures, the cornea 50 is shown with a dot pattern, the first tissue volume 110 has an oblique hatching, and the second tissue volume 120 is marked by a rectangular structure. The cutting surface 70 in 2a isolates a first tissue volume 110 and a second tissue volume 120; the second tissue volume 120 is located closer to the front surface 52 of the cornea 50 than the first tissue volume 110. Such an arrangement of the two tissue volumes has the advantage that the second tissue volume 120 can be removed more easily via the access 130 without damaging the first tissue volume 110. The first tissue volume 110 has a posterior interface 114 facing the back surface 54 of the cornea 50, and an anterior interface 112 facing the front surface 52 of the cornea 50 and in the 2a is shown as a dotted line. The anterior interface 112 of the first tissue volume 110 delimits it from the second tissue volume 120 and is a common interface.

To correct the refraction of the eye, the tissue volumes 110, 120 and the cut surface 70 are calculated such that the required refraction correction is achieved by removing the second tissue volume 120 through the access 130 and by displacing the first tissue volume 110 in the form of a rotation about a first rotation axis R1 by a first rotation angle R1α. The displacement is also enabled here via access 130. The first access (for displacing/rotating the first tissue volume 110) and the second access (for removing the second tissue volume 120) are therefore identical and correspond to the indicated access 130.

In the example shown, the refractive correction requirement has an aspherical component (i.e., a rotationally symmetric component; in this case, myopia) and an astigmatic component. The posterior interface 114 of the first tissue volume 110 and the anterior interface of the second tissue volume 120 are (as a common interface) aspherically shaped (i.e., they each have pure rotational symmetry). Thus, in this example, the contribution of the common interface to the astigmatic refractive power assigned to the first tissue volume (110) is precisely 0%. The posterior interface 114 of the first tissue volume 110 is astigmatically designed; it contributes 100% to the astigmatic refractive power assigned to the first tissue volume (110). The first tissue volume (110) alone satisfies the astigmatic component of the refractive correction requirement. In addition, the two boundary surfaces (112, 114) of the first tissue volume (110) are designed in such a way that they do not contribute to the rotationally symmetrical part of the refractive correction requirement.

As already described, the posterior interface of the second tissue volume (120) has an aspherical shape. In addition, the anterior interface of the second tissue volume (120) is also aspherically shaped. The curvatures of the two interfaces of the second tissue volume 120 are calculated precisely to satisfy the rotationally symmetric portion of the refractive correction requirement; they do not contribute to the astigmatic portion.

In the present example, as already described, the anterior 112 and posterior 114 interfaces of the first tissue volume 110 are shaped precisely to achieve a purely astigmatic effect (and have no spherical or aspherical refractive power). A section through the cornea 50 in a plane (through the first rotation axis R1) perpendicular to the 2a shown section plane, would show an anterior interface 112 of the first tissue volume 110, the curvature of which differs from that shown in 2a shown curvature. The first tissue volume 110 can also be referred to as an astigmatic lenticule or cylindrical lenticule.

2b shows the first tissue volume 110 in a top view; this corresponds to a view of the first tissue volume 110 along the first rotation axis R1, which is depicted here as a cross. As already described above, the first tissue volume 110 has an astigmatic shape. By rotating around the first rotation axis R1 by a first rotation angle R1α of 90°, the axis of the cylindrical lenticule is rotated by exactly 90°.

In plan view, the first tissue volume 110 has a circular shape and, at four points on the outer edge, has a structure 160 that corresponds to the shape of a "nose" 160. These four noses are evenly distributed azimuthally; neighboring structures 160 are at angles of 90° to each other. The noses 160 of the first tissue volume 110 correspond to gaps in the cornea 50. Due to the selected number of noses 160, it is possible to precisely adjust the desired rotation angle R1α during displacement (in this example, it is exactly 90°), since the noses 160 fit back into gaps even after rotation. They thus help to improve the result of the corneal modification.

In 2c is a cut through the cornea 50 of the eye as in 2a shown. 2c the second tissue volume 120 has already been removed via the access 130. The removal of the second tissue volume 120 has changed the shape of the anterior surface 52 of the cornea 50. Depending on the refractive correction requirement and the shape of the second tissue volume 120, the anterior surface 52 has a smaller curvature than it had before the removal of the second tissue volume 120 (cf. 2a) In this way, the rotationally symmetric (second) portion of the refractive correction requirement was met. A cavity 180 may remain in the outer region of the removed second tissue volume, which fills with fluid.

The displacement of the first tissue volume 110' (in this and the following figures, displaced first tissue volumes are indicated by a line in the reference symbol), which has an astigmatic shape, is in 2c This can be seen in the fact that the anterior interface 112 has a stronger curvature than in the 2a shown section. The displaced first tissue volume 110' thus corrects an astigmatic error corresponding to the astigmatic (first) portion of the refractive correction required.

Based on the 2a to 2c The advantage over prior art solutions becomes clear once again: According to the prior art, a lenticule would have to be removed from the cornea whose volume is larger than the first and second tissue volumes 110, 120 combined, since these two tissue volumes together barely cover the aspheric (or spherical) portion of the refractive correction requirement. The lenticule to be removed would have to be additionally enlarged by the astigmatic portion of the refractive correction requirement. In the solution according to the invention, however, the total volume of the tissue isolated in the cornea 50 (first and second tissue volumes 110, 120 combined) is smaller, with the displaced first tissue volume 110' remaining in the cornea 50 as an autologous transplant. The demonstrated advantage is particularly evident for a myopic second portion of the refractive correction requirement.

In 3 A section through the cornea 50 of an eye is shown with cut surfaces for a lenticule 190 for correcting hyperopia according to the prior art. The anterior interface of the lenticule 190 according to the prior art, which faces the front surface 52 of the cornea 50, has a smaller curvature than the posterior interface, which faces the back surface 54 of the cornea 50. Between the cut for the anterior and the cut for the posterior interface, there is a peripheral connecting cut, which essentially creates a transition zone. The cuts for the anterior and posterior interfaces, as well as the peripheral connecting cut, isolate the lenticule 190 in the cornea 50, which is removed for hyperopia correction according to the prior art. Any additional edge cut and a Access incisions (through which the lenticule 190 can be removed) are not shown in this schematic diagram.

In the 4a and 4b A section through the cornea 50 of an eye is shown with cut surfaces 70, which were obtained with a planning unit according to the second embodiment. The result of the corneal modification, which can be achieved by the cut surface 70 shown here, the removed second tissue volume 120' and the displaced partial volumes 110.i' of the first tissue volume, corresponds to that of a lenticule removal according to the state of the art, as described in 3 is shown.

4a shows a section through the cornea 50 with a cut surface that delimits the first and second 120 tissue volumes. The first tissue volume is divided into several subvolumes 110.i; two of these are shown here (110.1 and 110.2). The subvolumes 110.i are arranged symmetrically around a second rotation axis R2, which is shown as a dashed line. In the example shown, the second rotation axis R2 coincides with the optical axis of the eye.

The partial volumes 110.i are not isolated by the cutting surface 70, but merely delimited. For this purpose, the cutting surface 70 is designed such that the anterior boundary surface extends from the peripheral edge (maximum distance from the second rotation axis R2) to the second rotation axis R2. The posterior boundary surface, however, does not fall below a finite (non-zero) distance from the second rotation axis R2. The partial volumes 110.i of the first tissue volume thus remain firmly connected to the cornea 50. In the example shown, the connections are located in the chamber created by the cutting surface 70 on the posterior side. The connections serve as folding axes for the displacements of the partial volumes 110.i; this is shown in 5a and 5b explained in detail.

The second tissue volume 120 is connected radially outwards to the partial volumes 110.i. The second tissue volume 120 is continuous, as shown in the 5a to 5c will be explained later.

In 4b is the one in 4a The section shown is after the removal of the second tissue volume 120' and after the displacement of the partial volumes 110.i' of the first tissue volume (here, too, the reference symbols marked with a dash indicate a removed or displaced volume). The removal of the second tissue volume 120' takes place via the access 130. The displacement of the partial volumes 110.i' was also carried out via the same access; the first and second accesses are therefore identical in the example shown. The displacement of the partial volumes 110.i' involves folding. Each partial volume 110.i was folded around a folding axis (in 4a and 4b not shown), so that the partial volumes 110.i' after the displacement have a smaller distance from the second rotation axis R2 than the corresponding partial volumes 110.i before the displacement. The folds shifted tissue volume from larger radial distances (from the second rotation axis R2 or the optical axis of the eye) to smaller radial distances. In this way, it is possible to increase the curvature of the anterior surface 52 of the cornea 50 in order to meet a hyperopic refractive correction requirement.

A comparison of 4a and 4b with cutting surfaces 70 according to the invention opposite 3 with a lenticule 190 according to the prior art shows that to provide the same refractive correction requirement, a smaller tissue volume must be extracted from the cornea 50, since the correction is carried out both subtractively (via the extraction of the second tissue volume 120') and additively (via the folding of the partial volumes 110.i' of the first tissue volume as an autologous transplant). This allows for a higher biomechanical stability to be achieved for a given refractive correction requirement. Furthermore, it is possible to provide refractive error correction over a wide diopter range. The advantage according to the invention is achieved in that for a hyperopic refractive correction requirement of 5 diopters (as in 3 ), the first and second tissue volumes were calculated so that their union corresponds to a lenticule with a refractive power S _P lower than S (S _P < S).

• 5a bis 5c zeigen eine Aufsicht auf die Hornhaut eines Auges. Dabei befindet sich die Zeichenebene senkrecht zur zweiten Rotationsachse R2, deren Durchstoßpunkt durch die Zeichenebene als Kreuz dargestellt ist. In einer schrägen Schraffur sind in 5a insgesamt acht Teilvolumina (110.1 bis 100.8) dargestellt, in die das erste Gewebevolumen unterteilt ist. Diese sind symmetrisch um die zweite Rotationsachse R2 angeordnet. Die Teilvolumina 110.i zeigen die Form eines Sterns. Während sich die Schnittfläche auf der anterioren Seite der Teilvolumina 110.i von einem maximalen Abstand von der zweiten Rotationsachse R2 bis hin zur zweiten Rotationsachse R2 erstreckt (vgl. auch 4a und Beschreibung dazu), so reicht die Schnittfläche auf der posterioren Seite der Teilvolumina 110.i lediglich bis zu einem von Null verschiedenen Abstand zu zweiten Rotationsachse R2. Das ist dadurch dargestellt, dass die schraffiert dargestellten Teilvolumina 110.i lediglich die „Zacken“ des „Sterns“ umfassen.

Advantageously, the partial volumes 110.i are designed so that they do not overlap after folding. Rather, it is advantageous if they lie next to each other and connect seamlessly after folding. This is 5a until 5c and is described in detail below:

• 5a until 5c show a top view of the cornea of an eye. The drawing plane is perpendicular to the second rotation axis R2, whose intersection point is shown as a cross. In an oblique hatching, 5a A total of eight subvolumes (110.1 to 100.8) are shown, into which the first tissue volume is divided. These are arranged symmetrically around the second rotation axis R2. The subvolumes 110.i show the shape of a star. While the section area on the anterior side of the subvolumes 110.i extends from a maximum Distance from the second rotation axis R2 to the second rotation axis R2 (see also 4a and description thereof), the cutting surface on the posterior side of the subvolumes 110.i only extends to a distance different from zero to the second rotation axis R2. This is illustrated by the fact that the hatched subvolumes 110.i only encompass the "points" of the "star."

An inner region of the "star" has the shape of an equilateral octagon. The cut surface extends posteriorly to this octagon; there, the respective folding axes F.i. are located.

The second tissue volume 120 (marked by a pattern of horizontal and vertical stripes, rectangular structure) radially surrounds the star-shaped subvolumes 110.i of the first tissue volume. It extends to a maximum distance from the second rotation axis R2.

In 4a An access 130 is shown. In the example shown, this is designed as a corneal flap (a so-called "flap") that can be opened for the surgical procedure. In the dotted area, the corneal flap remains connected to the cornea. The second tissue volume 120 can be removed via access 130 (for example, mechanically or by ablation); the partial volumes 110.i can also be relocated via this access.

5b shows a top view of the cornea after the displacement of the partial volumes 110.i and after the removal of the second tissue volume 120. According to the invention, the first partial volume 110.1 is folded inwards along the first folding axis F.1, so that the "point" is displaced into the octagonal region. Analogously, the further partial volumes 110.2 to 110.8 are each folded along the corresponding folding axes F.2 to F.8. All eight displaced partial volumes 110.i' now jointly cover the octagonal region. As a result of the displacement, the multi-part first tissue volume is thus combined practically seamlessly to form a displaced first tissue volume. The displaced partial volumes 110.i' can be fixed after the displacement. The displacement can - as shown in the example - take place on the stromal bed, which is temporarily exposed for this purpose by folding away the anterior corneal lamella. Alternatively, only a small access incision could be created, allowing the repositioning to occur in the corneal chamber defined by the incision. After the corneal flap is folded back, or immediately after removal and repositioning (in the case of a minimal access incision without opening a flap), the cornea (or its anterior surface) reshapes itself according to the refractive correction required.

Based on the 4a and 4b or 5a and 5b It becomes clear that the cutting path for creating the cutting surface is particularly advantageously carried out in such a way that the derivative of the distance function of the cuts (profile function) disappears at later points of contact of the displaced partial volumes, if possible. It is understood that the cutting surface is advantageously shaped in such a way that it supports a seamless joining of the displaced partial volumes 110.i'. A compromise is necessary here between this requirement and the requirement for the subtraction step (subtractive refraction change value). This problem can also be solved by post-processing the transplant - i.e. the first tissue volume with its partial volumes 110.i - with an ablative laser. Bends can occur in the area of the joining edges of the displaced partial volumes 110.i'; i.e. the derivative of the area function has a discontinuity there. Continuity can only be achieved with little effort at the central point (in the area of the second rotation axis R2). The kinks that occur are the “price” for the geometric simplicity of the subtractive part (provided by the second tissue volume 120), but are not particularly clinically relevant because the epithelial layer in the eye compensates for this.

In 5c Finally, the removed second tissue volume 120' is shown. In the example shown, the second tissue volume 120' is designed as a continuous piece. However, it may also be advantageous to divide it into several parts that must be removed individually from the cornea.

The 4a to 5c show an example of a purely hyperopic refractive correction requirement. However, astigmatic or other higher image aberrations can also be corrected in this way. In this case, the subvolumes 110.i have different thicknesses (extensions in a direction parallel to the second rotation axis R2).

In 6a and 6b a section 70 is shown, which was obtained with a planning unit P after the third expression. 6a a section through the cornea 50 in a plane that includes the third rotation axis R3. The cut surface 70 isolates a first tissue volume 110, which after its displacement (as shown in 8a and 8b shown) satisfies a myopic refractive correction requirement. The first tissue volume 110 has a posterior boundary surface 114 facing the back surface 54 of the cornea 50 The anterior interface has different distances to the posterior interface 114 for different azimuth angles around the third rotation axis R3. The parts of the anterior interface that have a greater distance are marked with the reference numeral 112a (with a solid line in 6a and 8a) , while the parts of the anterior interface which have a smaller distance are marked with the reference numeral 112b and in 6a and 8a are shown as a dotted line. The cutting surface 70 also has an access 130 that extends to the anterior surface 52 of the cornea 50.

6b shows a top view of the first tissue volume 110 (round structure with a "+" in the center, which marks the point of intersection of the third rotation axis R3). In addition, two side views of the first tissue volume 110 are shown, which are drawn below and to the left of the top view. For a better understanding of the shape of the first tissue volume 110, the curvature of the posterior interface 114 is "subtracted" in the side views so that it appears flat. In the top view and the two side views, the parts of the anterior interface that have a greater distance (112a) or a shorter distance (112b) to the posterior interface 114 are drawn. For a better assignment of the different perspectives on the first tissue volume 110, auxiliary lines consisting of lines and two dots are drawn.

The top view of the first tissue volume 110 shows that portions of the anterior interface that are at a greater or smaller distance from the posterior interface 114 are arranged point-symmetrically to the third rotation axis R3. The first tissue volume 110 has four regions of azimuth angles in which there is a greater distance from the posterior interface 114, as well as four regions with a smaller distance. The different distances along the azimuth angle are formed as steps. In a central region around the point where the third rotation axis R3 passes through the first tissue volume 110, no different distances occur.

It should be noted that the incision surface can additionally isolate a second tissue volume in the cornea 50. This would be removed from the cornea 50 via an access.

In the 6a and 6b In the example shown, the portions with a greater distance and those with a smaller distance all have the same heights. If, for example, two azimuthally opposite portions had different heights than the other two portions (which are at 90° to them), an astigmatic refractive correction requirement could be corrected. In such a case, the second tissue volume (to be removed) could advantageously be designed to be purely rotationally symmetrical in order to satisfy the purely myopic portion of the refractive correction requirement, while the astigmatic (or higher) portion is covered by a displacement of the first tissue volume 110.

In 6b Two cutting axes S1 and S2 are shown in the top view of the first tissue volume 110. These serve as orientation for the following figures.

In 7a and 7b are two different sections through the first tissue volume 110, as shown in 6b shown. 7a a section through the first tissue volume 110 with a cutting plane that 6b The section axis S1 and the third rotation axis R3 are shown. The posterior interface 114 has a continuous (aspherical) curvature over the entire region. However, on the anterior interface, there is a central region with a smaller distance 112b to the posterior interface 114, as well as a radially adjacent region with a larger distance 112a. At the transition between the two regions, the anterior interface exhibits a discontinuity in the curvature.

7b shows a section through the first tissue volume 110 with a cutting plane that 6b The posterior boundary surface 114 comprises the section axis S2 and the third rotation axis R3. The posterior boundary surface 114 exhibits a continuous (aspheric) curvature over its entire area. In addition, the anterior boundary surface also exhibits a continuous (aspheric) curvature.

In 8a and 8b are cutting surfaces 70 as in 6a and 6b (obtained with a planning unit (P) after the third expression) - in these figures, however, after the displacement of the first tissue volume (110'). The displacement is a rotation by a rotation angle R3α around the third rotation axis R3; white filled arrows indicate in 8b the rotation angle R3α. In the present example, the rotation angle R3α is 45°. As a result, portions of the anterior interface that are at a greater distance from the posterior interface 114 (marked with reference numeral 112a) are positioned at positions where, prior to the displacement, portions were at a smaller distance (marked with reference numeral 112b). This leads to a padding of the cornea 50; in the peripheral region, the cornea 50 is raised by an amount Δ. This The value Δ results from the height difference of the parts of the anterior interface with a greater distance compared to the part with a smaller distance. 8a The section through the cornea 50 shows how the cornea 50 or its front surface 52 is lifted by the displacement and the associated padding; this is represented by the dashed line, which corresponds to the amount Δ compared to the portion of the anterior interface with a greater distance from the posterior interface 114.

To clarify the position of the rotated first tissue volume 110', the two side views of the 8b Additionally, the cornea 50 (with a dot pattern) is drawn. These figures clearly show that due to the rotation through the rotation angle R3α of 45° (direction of rotation indicated by white-filled arrows), the portions with greater spacing 112a come to lie directly on the portions with lesser spacing 112b (before the displacement). This results in, on the one hand, padding by the amount Δ; on the other hand, cavities 180 are created in the cornea 50. Such a cavity 180 can be filled with tissue fluid, hyaluronic acid, and/or an artificial filler material.

The padding causes the cornea 50 to become “thicker” in the area of greater distances from the third rotation axis R3; as a result, the curvature of the front surface 52 of the cornea 50 becomes smaller (cf. 8a) In this way, the myopic refractive correction requirement is met according to the invention, wherein, in contrast to prior art solutions, the remaining volume of the cornea 50 is larger, so that improved biomechanical stability can be achieved.

In 9a and 9b is a side view of a section 70 obtained with a planning unit (P) after the third expression, before ( 9a) and after ( 9b) the relocation. In contrast to the 6a to 8b In the representations shown, the first tissue volume 110 has so-called notches. The anterior interface 112 therefore does not have two discrete "steps" compared to the posterior interface 114. Rather, there is a height profile with spikes, the design of which ensures that after displacement (rotation; indicated by the white-filled arrow), the first tissue volume 110' is in a position in the cornea 50 that is stabilized against subsequent movements.

The displacement results in a padding by an amount Δ, as shown in 9b is shown. In this example, cavities 180 are also created in the cornea 50, which can be filled with tissue fluid, hyaluronic acid and/or an artificial filling material.

The features of the invention mentioned above and described in various exemplary embodiments can be used not only in the specified exemplary combinations, but also in other combinations or alone, without departing from the scope of the present invention. A description of a device related to method features applies analogously to the corresponding method with respect to these features, while method features correspondingly represent functional features of the described device.

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

• WO 2008/055697 A1 [0003]
• DE 102013218415 A1 [0005]
• WO 2016050711 A1 [0007]
• EP 3906903 A1 [0009]
• DE 102007019813 A1 [0023]

Cited non-patent literature

• The Safety and Predictability of Implanting Autologous Lenticule Obtained by SMILE for Hyperopia" by Ling Sun et al. (Journal of Refractive Surgery 2015,31(6):374-379 [0007]
• Intrastromal Lenticule Rotation for Treatment of Astigmatism Up to 10.00 Diopters Ex Vivo in Human Corneas” by I. B. Damgaard et al. (Journal of Refractive Surgery 2019; 35(7):451-458 [0009]

Claims (21)

Planning unit (P) for generating control data for correcting the refraction of an eye by corneal modification, comprising - an interface (S1) for receiving data about a hyperopic or myopic refraction correction requirement of an eye with a cornea (50), and - a calculation device (C) connected to the interface (S1) and configured ◯ to receive the data about the refraction correction requirement, ◯ to calculate, based on the refraction correction requirement, a first tissue volume (110) of the cornea (50) and a displacement of the first tissue volume in the cornea (50), wherein ▪ the first tissue volume (110) has a subtractive refraction change value, ▪ the first tissue volume (110) provides an additive refraction change value in conjunction with the displacement in the cornea (50), ▪ the subtractive refraction change value together with the additive Refraction change value determines the need for refraction correction, and ▪ the displacement is a rotation, a translation, a folding and/or a turning, ◯ for calculating a cutting surface (70) such that ▪ the cutting surface (70) in the cornea (50) delimits the first tissue volume (110) for the displacement, ▪ that the cutting surface (70) simultaneously delimits a chamber for the first tissue volume (110) to be displaced, and ▪ that the cutting surface (70) provides a first access (130) for the displacement of the first tissue volume (110), and ◯ for generating control data describing the cutting surface (70). Planning unit (P) according to Claim 1 , characterized in that the calculation device (C) is further configured - to calculate, on the basis of the refractive correction requirement, a second tissue volume (120) of the cornea (50), wherein the first (110) and second (120) tissue volumes together provide the subtractive refractive change value, and - to calculate the cutting surface (70) further such that ◯ the cutting surface (70) in the cornea (50) isolates the second tissue volume (120), and ◯ that the cutting surface (70) provides a second access via which the second tissue volume (120) can be removed from the cornea (50), wherein the second access can be identical to the first access (130). Planning unit (P) according to one of the preceding claims, characterized in that the first tissue volume (110) is contiguous and/or that the second tissue volume (120) is contiguous. Planning unit (P) according to Claim 2 or 3 , characterized in that - the refractive correction requirement has an astigmatic component and a rotationally symmetrical component, - that the calculation device (C) is configured to calculate the cutting surface (70) in such a way that the first tissue volume (110) is isolated for the displacement, - that the calculation device (C) is further configured to assign an astigmatic refractive power to the first tissue volume (110) and to calculate the first tissue volume (110) in such a way that the first tissue volume (110) has an astigmatic anterior (112) and/or an astigmatic posterior (114) interface, so that the interfaces (112, 114) satisfy the assigned astigmatic refractive power, and - that the displacement comprises a rotation about a first rotation axis (R1) with a rotation angle (R1α) of 90°±10°. Planning unit (P) according to Claim 4 , characterized in that the calculation device (C) is further configured to calculate the first (110) and the second (120) tissue volume such that the first tissue volume (110) and the second tissue volume (120) have a common interface at least in sections, wherein the common interface has a contribution of a maximum of 50% of the astigmatic refractive power assigned to the first tissue volume (110), preferably a maximum of 20%, particularly preferably a maximum of 10% or 3%. Planning unit (P) according to Claim 4 or 5 , characterized in that the calculation device (C) is further configured to calculate the anterior (112) and posterior (114) interface of the first tissue volume (110) such that the associated astigmatic refractive power corresponds to between 20% and 90% of the astigmatic portion of the refractive correction requirement, preferably between 30% and 80%, particularly preferably between 40% and 70%. Planning unit (P) according to one of the Claims 4 until 6 , characterized in that the calculation device (C) is further configured to calculate the first tissue volume (110) in such a way that it has a marking and/or is provided with a structured edge cut (160), wherein the markings and/or structures of the edge cut (160) ensure a correct Mark displacement according to the calculated rotation angle (R1α). Planning unit (P) according to Claim 2 or 3 , characterized in that the refractive correction requirement is hyperopic, and in that the displacement comprises a folding about a folding axis (Fi) associated with the folding. Planning unit (P) according to Claim 8 , characterized in that the calculation device (C) is configured to calculate the first tissue volume (110) in such a way that - the first tissue volume (110) has at least three partial volumes (110.i), preferably at least four partial volumes (110.i), particularly preferably at least eight partial volumes (110.i), each partial volume being assigned a folding axis (Fi), - the partial volumes (110.i) are arranged symmetrically about a second axis of rotation (R2), and - the folding axes (Fi) assigned to the partial volumes (110.i) are arranged symmetrically about the second axis of rotation (R2). Planning unit (P) according to Claim 9 , characterized in that the partial volumes (110.i) are arranged in a star shape around the second axis of rotation (R2). Planning unit (P) according to one of the Claims 1 until 3 , characterized in that - the refractive correction requirement is myopic, - the displacement comprises a rotation about a third axis of rotation (R3) with an optional, simultaneous translation along the third axis of rotation (R3), - the calculation device (C) is configured to calculate the cutting area (70) in such a way that the first tissue volume (110) is isolated for the displacement, and in that - the calculation device (C) is further configured to calculate the first tissue volume (110) in such a way that the first tissue volume (110) in conjunction with the rotation in the cornea (50) together with a cavity (180) resulting from the rotation corresponds to the additive refractive change value, wherein the first tissue volume (110) has different distances between an anterior (112) and a posterior (114) interface for different azimuth angles about the third axis of rotation (R3). Planning unit (P) according to Claim 11 , characterized in that the different distances along the azimuth angle are formed in steps. Planning unit (P) according to Claims 11 or 12 , characterized in that the different distances along the azimuth angle have notches. Planning unit (P) according to one of the Claims 11 until 13 , characterized in that for the calculation of the additive refraction change value it is assumed that the cavity (180) resulting from the displacement of the first tissue volume (110) is filled with tissue fluid, hyaluronic acid and/or with an artificial filling material. Ophthalmological laser therapy device (1), comprising - a planning unit (P) according to one of the Claims 1 until 14 , - a control unit (40) with an interface to the planning unit (P) for receiving the control data for controlling the ophthalmological laser therapy device (1), - a laser device (10) for providing a pulsed laser beam (15), - a focusing device (20) for focusing the pulsed laser beam (15) in a focus (60) for severing the cornea (50), and - a scanning device (30, 35) for displacing the focus (60) of the pulsed laser beam (15) in the cornea (50) of the eye to produce the cutting surface (70). Planning method for generating control data for correcting the refraction of an eye by corneal modification, comprising - receiving data about a hyperopic or myopic refraction correction requirement of an eye with a cornea (50), - calculating, based on the refraction correction requirement, a first tissue volume (110) of the cornea (50) and a displacement of the first tissue volume (110) in the cornea (50), wherein ◯ the first tissue volume (110) has a subtractive refraction change value, ◯ the first tissue volume (110) in conjunction with the displacement in the cornea (50) provides an additive refraction change value, ◯ the subtractive refraction change value together with the additive refraction change value results in the refraction correction requirement, and ◯ the displacement is a rotation, a translation, a folding and/or a turning, - calculating a cutting surface (70) such that ◯ that the cut surface (70) in the cornea (50) delimits the first tissue volume (110) for the displacement, ◯ the cut surface (70) simultaneously delimits a chamber for the first tissue volume (110) to be displaced, and ◯ the cut surface (70) has a first access (130) for the displacement of the first tissue volume (110) and - generating control data describing the cutting surface (70). Planning procedures according to Claim 16 , characterized in that - the refractive correction requirement has an astigmatic component and a rotationally symmetrical component, - the displacement has a rotation about a first rotation axis (R1) with a rotation angle (R1α) of 90°±10°, and - the planning method further comprises the following steps: ◯ calculating the cutting surface (70) such that the first tissue volume (110) is isolated, ◯ assigning an astigmatic refractive power to the first tissue volume (110), ◯ calculating, on the basis of the refractive correction requirement, an astigmatic anterior (112) and/or astigmatic posterior (114) boundary surface of the first tissue volume (110), such that the boundary surfaces (112, 114) satisfy the assigned astigmatic refractive power, ◯ calculating, on the basis of the refractive correction requirement, a second tissue volume (120) of the Cornea (50), wherein the first (110) and second (120) tissue volumes together provide the subtractive refractive change value, ◯ calculating the cutting surface (70) further such that ▪ it isolates the second tissue volume (120) in the cornea (50), and ▪ that the cutting surface (70) provides a second access via which the second tissue volume (120) can be removed from the cornea (50), wherein the second access can be identical to the first access (130). Planning procedures according to Claim 16 , characterized in that - the refraction correction requirement is hyperopic, - the displacement is a folding around a folding axis (Fi) assigned to the folding, and - the planning method further comprises the following steps: ◯ Calculating, on the basis of the refraction correction requirement, the first tissue volume (110) such that ▪ the first tissue volume (110) has at least three sub-volumes (110.i), preferably at least four sub-volumes (110.i), particularly preferably at least eight sub-volumes (110.i), wherein each sub-volume (110.i) is assigned a folding axis (Fi), ▪ the sub-volumes (110.i) are arranged symmetrically around a second rotation axis (R2), and ▪ the folding axes (Fi) assigned to the sub-volumes (110.i) are arranged symmetrically around the second rotation axis (R2), ◯ Calculating, on the basis of the refraction correction requirement, a second tissue volume (120) of the cornea (50), wherein the first (110) and second (120) tissue volumes together provide the subtractive refractive change value, ◯ calculating the cutting surface (70) further such that ▪ it isolates the second tissue volume (120) in the cornea (50), and ▪ that the cutting surface (70) provides a second access via which the second tissue volume (120) can be removed from the cornea (50), wherein the second access can be identical to the first access (130). Planning procedures according to Claim 16 , characterized in that - the refractive correction requirement is myopic, - the displacement comprises a rotation about a third axis of rotation (R3) with an optional, simultaneous translation along the third axis of rotation (R3), and - the planning method further comprises the following steps: o Calculating, on the basis of the refractive correction requirement, the first tissue volume (110) such that the first tissue volume (110) in conjunction with the rotation in the cornea (50) together with a cavity (180) created by the rotation corresponds to the additive refractive change value, wherein the first tissue volume (110) has different distances between an anterior (112) and a posterior (114) interface for different azimuth angles about the third axis of rotation (R3). Computer program product with program code which, when loaded into a computer, implements a method according to one of the Claims 16 until 19 to execution. Method for correcting the refraction of an eye by corneal modification, comprising - planning steps according to a planning method according to one of the Claims 16 until 19 , - cutting the cornea (50) of the eye according to the calculated cutting area (70), - carrying out the displacement of the first tissue volume (110) in the cornea (50) according to the calculations, and - optionally removing the second tissue volume (120) from the cornea (50) of the eye through the second access.

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