Patent ID: 12239577

DETAILED DESCRIPTION OF THE EMBODIMENTS

InFIG.1, reference numeral1relates to an ophthalmological device for treatment of a cornea20of an eye2by generating a void volume R inside the cornea20, using a pulsed laser beam B. Specifically, the ophthalmological device1is configured to generate the void volume R inside the cornea20for refractive correction of the cornea20and/or for other purposes, such as for inserting implants into the cornea20.

As illustrated schematically inFIG.1, the ophthalmological device1comprises a laser source11for generating the pulsed laser beam B, a focusing optical module12for focusing the pulsed laser beam B in the cornea20onto a focal spot S, and a scanner system13for moving the focal spot S to target locations in the cornea20. As explained later in more detail, the scanner system13is configured to move the focal spot S to target locations along work lines w and scan lines c in the cornea20.

The ophthalmological device1further comprises an electronic circuit10for controlling the laser source11and the scanner system13. The electronic circuit10implements a programmable control device and comprises e.g. one or more processors100with program and data memory and programmed software modules for controlling the processors100, and/or other programmable circuits or logic units such as ASICs (application specific integrated circuits).

The laser source11comprises a femtosecond laser for producing femtosecond laser pulses, which have pulse widths of typically 10 fs to 1000 fs (1 fs=10−15s). The laser source11is arranged in a separate housing or in a housing shared with the focusing optical module12.

The focusing optical module12is configured to focus the pulsed laser beam B or the laser pulses, respectively, in the cornea20onto a focal spot S, i.e. for making the pulsed laser beam B converge to a focus or focal spot in the cornea20. The focusing optical module12comprises one or more optical lenses. In an embodiment, the focusing optical module12comprises a focus adjustment device for setting the focal depth of the focal spot S, for example one or more movable lenses, in the focusing optical module12or upstream of the focusing optical module12, or a drive for moving the entire focusing optical module12along the projection axis p (z-axis). By way of example, the focusing optical module12is installed in an application head14, which can be placed onto the eye2.

FIGS.12to14illustrate schematically partially overlapping focal spots S, S′ with a spot diameter e typically in the range of 1 μm to 10 μm. It is pointed out here that the person skilled in the art will understand that a focal spot S refers to a laser interaction zone where tissue, here corneal tissue, is dissolved (ablated) to effect tissue cuts or volumetric tissue ablation. The extent of this zone or focal spot S, respectively, is in first approximation an ellipsoid with a length i (in z-direction or direction of projection p, respectively) and a diameter e (in the x/y-plane or normal to the z-direction or direction of projection p, respectively). Generally, the length i of a focal spot S is longer than its diameter e. Nevertheless, focusing optical modules with high numerical aperture may produce focal spots S with a more spherical shape where the length i corresponds to the diameter e.

FIGS.12to14illustrate schematically, the partial overlapping of the focal spots S moved along the scan line c.FIGS.12and14further illustrate schematically, the partial overlapping of the focal spots S of neighbouring scan lines c as indicated by focal spots S′, depicted partially with dashed lines inFIG.12(e.g. neighbouring in x/y-plane).FIGS.13and14, further illustrate schematically the partial overlapping of the focal spots S of superposed neighbouring scan lines c (e.g. superposed in z-direction). The person skilled in the art will further understand that, as an alternative to separating (corneal) tissue by way of dissolving/ablating the tissue in the separation area, using partially overlapping focal spots S, S′ and generating a cut surface or an ablation volume in the separation area, (corneal) tissue may also be separated by means of expanding gas bubbles, using non-overlapping and/or spatially separated focal spots, whereby expanding gas bubbles cause separation through tearing and/or cleavage of tissue but do not dissolve or ablate tissue.

As illustrated schematically inFIG.14, the void volume R is a three-dimensional void volume R generated by the ophthalmological device1ablating cornea tissue inside the cornea20with partially overlapping focal spots S, whereby two or more focal spots S partially overlap in direction of each of the three dimensions x, y, z of the area inside the cornea20where the void volume R or of at least a section of the void volume R′ is created. Accordingly, as shown inFIG.14, each of the focal spots S partially overlaps in direction of each of the three dimensions x, y, z of the void volume R with at least one other focal spot S. As illustrated inFIGS.2and11, the extent of the void volume R is determined by the anterior volume surface Ra of the void volume R, facing the exterior/anterior surface A of the cornea20, and the posterior volume surface Rp of the void volume R, facing the posterior surface P of the cornea20.

For creating the void volume R inside the cornea20, the cornea tissue is processed with parameters of the pulsed laser beam B, including pulse energy, pulse overlap, pulse rate, pulse duration, and/or focal spot size of the pulsed laser beam B, which are set to dissolve the corneal tissue such as to perform volumetric ablation of the corneal tissue. More specifically, the parameters of the pulsed laser beam B are set to keep the energy density at or above the optical breakdown threshold for ablation (e.g. at approximately 0.5 J/cm2to 1 J/cm2energy density of a single pulse). The area inside the cornea20where the void region R is to created is processed with parameters of the pulsed laser beam B set to cause ablation of the corneal tissue.

As illustrated schematically inFIG.1, the ophthalmological device1comprises a patient interface18for attaching the application head14or the focusing optical module12, respectively, onto the eye2. Depending on the embodiment, the patient interface18is connected to the application head14in a fixed or removable manner.

The patient interface18comprises a contact body15and one or more suction elements configured to fix the contact body15and thus the patient interface18to the cornea20. For example, the one or more suction elements are arranged in a fastening ring16, e.g. a vacuum-controlled suction ring, whereby the one or more suction elements are connected fluidically to a suction pump. The contact body15, also referred to as applanation body, is at least partly light-transparent.

As illustrated inFIGS.2and11, in the state where the patient interface18or the contact body15, respectively, is fixed to the cornea20, specifically to the exterior (anterior) surface A of the cornea20, applanated is an applanation zone Az of the cornea20, where the contact body15is in contact with the exterior (anterior) surface A of the cornea20.

As is further illustrated inFIGS.2and11, and also indicated inFIG.1, in the state where the patient interface18or the applanation body15, respectively, is fixed to the cornea20, the fastening ring16and the applanation body15form an external venting chamber17with the peripheral area Ap of the exterior (anterior) surface A of the cornea20outside the applanation zone Az. The venting chamber17is defined by an interior wall16iof the fastening ring16, the surface of the applanation body15contacting the cornea20, and the peripheral area Ap of the exterior (anterior) surface A of the cornea20outside the applanation zone Az.

The scanner system13is configured to move the focal spot S to target locations in the cornea20by guiding and directing the pulsed laser beam B and thus the focal spot S to target locations in the cornea20.

The scanner system13comprises one or more scanner devices131, also referred to as slow scanner device, configured to guide and direct the pulsed laser beam B and thus the focal spot S along a work line w, e.g. a spiral shaped work line, in a x/y-work-plane which is normal to a z-axis, whereby the z-axis is aligned with or essentially parallel to the projection axis p of the focusing optical module12, as illustrated schematically inFIG.1. Depending on the embodiment, the one or more scanner devices131comprise one or more actuators configured to move the focusing optical module12such that the focal spot S is moved along the work line w in the x/y-work-plane, and/or one or more deflection mirrors, each movable about one or two axes, configured to deflect the pulsed laser beam B and/or the laser pulses such that the focal spot S is moved along the work line w in the x/y-work-plane. To move the focal spot S along a work line w in the three-dimensional x/y/z-space, e.g. a spiral shaped work line w in the three-dimensional x/y/z-space, the one or more scanner devices131comprise one or more actuators configured to move the focusing optical module12or one or more of its optical lenses in z-direction, i.e. along the z-axis.FIG.3illustrates schematically in top view a spiral shaped working line w in the cornea20.FIG.4shows a schematic three-dimensional view of a section of a spiral shaped working line w in the cornea20.

The scanner system13comprises a further scanner device132, also referred to as fast scanner device, configured to guide and direct the pulsed laser beam B and thus the focal spot S along a scan line c at a scanning speed that is comparatively faster than the scanning speed of the aforementioned slow scanner device131. For example, the fast scanner device132comprises a polygon scanner. The fast scanner device132is configured to move the focal spot S, overlaid on the movement along the work line w, along a scan line c that runs through the work line w, at an angle to the work line w, as illustrated inFIGS.3,4,12, and14.

The scanner system13further comprises a divergence-modulator133, also referred to as z-modulator, configured to move the focal spot S along the z-axis that is aligned with or essentially parallel to the projection axis p of the focusing optical module12. The divergence modulator133is configured to dynamically change the divergence of the pulsed laser beam B. As illustrated schematically inFIGS.4and12, the combined (synchronized) movement of the focal spot S by the aforementioned fast scanner device132and by the divergence-modulator133constitutes a movement of the focal spot S along a scan line c, which is bent and/or tilted with a tilting angle α from the x/y-plane. The electronic circuit10is configured to control the divergence-modulator133to adjust the tilting angle α of the scan line c with respect to the shape of the anterior volume surface Ra of the void volume R and/or the posterior volume surface Rp of the void volume R.

In an embodiment, the scanner system13further comprises an optional length modulator130configured to modulate the length of the scan line c. For example, the length modulator130comprises an adjustable shutter device arranged downstream of the fast scanner device132. For example, the length d of the scan line c is adjusted by controlling the length modulator130, e.g. the shutter device, to let through a set number of laser pulses from the fast scanner device132for producing a corresponding number of focal spots S. The electronic circuit10is configured to control the length modulator130to adjust the length d of the scan line c with respect to the shape of the anterior volume surface Ra of the void volume R or the posterior volume surface Rp of the void volume R.

As illustrated inFIG.4, the synchronized combination of the movement of the focal spots S along the working line win the x/y/z-space by the slow scanner device131, with the overlaid movement of the focal spots S along the scan line c by the fast scanner device132, and the tilting of the scan line c with a tilting angle α from the x/y-plane by the divergence-modulator133, and optionally the adjustment of the length d of the scan line c by the length modulator130, makes it possible not only to generate plane or curved cut surfaces inside the cornea20, but also to perform with great flexibility volumetric ablation of corneal tissue. For example, volumetric ablation is achieved inside the cornea20by driving the scan line c overlaid on the work line w with a continuous increase Az in z-direction (per cycle) to generate superposed ablation layers with partially overlapping focal spots S along the scan line c (as illustrated inFIGS.12to14), among neighbouring scan lines c (as illustrated inFIGS.12and14), and among adjacent superposed ablation layers or scan lines, respectively (as illustrated inFIGS.13and14).

Various further and more specific embodiments of the scanner system13are described by the applicant in patent applications US 2019/0015250, US 2019/0015251, and US 2019/0015253 which are hereby incorporated by reference.

In an embodiment, the ophthalmological device1further comprises a measurement system19configured to determine positional reference data of the cornea20. Depending on the embodiment, the measurement system19comprises a video capturing system, an optical coherence tomography (OCT) system, and/or a structured light illumination system. Accordingly, the measurement data or positional reference data determined by the measurement system19includes video data, including top view data (comprising two-dimensional images), and/or OCT data of the cornea20(comprising three-dimensional tomography data). The measurement system19is configured to determine the positional reference data of the cornea20also in an applanated state of the cornea20. The measurement system19is connected to and/or integrated with the electronic circuit10, which is further configured to control the scanner system13, using the positional reference data from the measurement system19. For example, the measurement system19and/or the electronic circuit10are configured to determine as further positional reference data the peripheral area Ap of the exterior (anterior) surface A of the cornea20outside the applanation zone Az, using the measurement data or the positional reference data captured by the measurement system19.

The electronic circuit10is configured to control the scanner system13to move the focal spot S inside the cornea20to generate the void volume R inside the cornea20for treatment of the cornea20, such as for refractive correction of the cornea20or for inserting implants into the void volume R. More specifically, the electronic circuit10is configured to control the scanner system13to move the focal spot S inside the cornea20to generate the void volume R inside the cornea20by ablating the cornea tissue inside the void volume R. As describe above with reference toFIGS.12-14, to create the void volume R the cornea tissue is ablated by moving the focal spot S inside the cornea20such that consecutive focal spots S partially overlap. The electronic circuit10is configured to control the scanner system13to move the focal spot S inside the cornea20to generate the void volume R inside the cornea20such that the cornea tissue is ablated with partially overlapping focal spots S in direction of each of the three dimensions x, y, z of at least a section R′ of the area inside the cornea20where the void volume R is created.

To enable venting of gas, produced by generating the void volume R inside the cornea20, the electronic circuit10is further configured to control the scanner system13to move the focal spot S inside the cornea20to cut in the cornea20one or more venting channels Ch, Ch1, Ch2which connects fluidically the void volume R to an escape area. The venting channel(s) Ch, Ch1, Ch2make(s) it possible to vent the gas from the void volume R to the escape area. Depending on the embodiment and/or configuration, the escape area is outside the cornea20, i.e. exterior to the cornea20, or inside the cornea20, in a venting pocket P, described later in more detail. In the case where the escape area is exterior to the cornea20, the venting channels Ch, Ch1, Ch2connect fluidically the void volume R to an opening incision Ci, Ci1, Ci2in the exterior (anterior) surface A of the cornea20, as illustrated inFIGS.1-3and5-11.

In an embodiment, the electronic circuit10is configured to control the scanner system13to move the focal spot S inside the cornea20to cut one or more venting pockets P inside the cornea20.

In the following paragraphs, different arrangements and configurations of the void volume R, venting channels Ch, Ch1, Ch2, respective opening incisions Ci, Ci1, Ci2, and venting pockets P are described with reference toFIGS.1-3and5-11. For the sake of clarity, it is pointed out here that the electronic circuit10is configured to control the scanner system13to move the focal spot S to generate the void volumes R, venting channels Ch, Ch1, Ch2, opening incisions Ci, Ci1, Ci2, and venting pockets P in the cornea20according to one or more of these configurations and combinations thereof, for example, as selected or selectable by an operator.

FIGS.1and2illustrate in cross-sectional view andFIGS.3,5, and7-10illustrate in top view examples of the void volume R created inside the cornea20in shape of a lenticule for a desired myopic refractive correction of the cornea20.FIG.11illustrates in cross-sectional view andFIG.6illustrates in top view examples of the void volume R created inside the cornea20in shape of a ring for a desired hyperopic refractive correction of the cornea20.

WhileFIGS.1,3, and7-11illustrate examples with one venting channel Ch, andFIGS.2,5,6, and11illustrate examples with two venting channels Ch1, Ch2, it is pointed out for the sake of clarity, that the electronic circuit10may be configured to control the scanner system13to move the focal spot S to generate in all these examples one, two, or more venting channels Ch, Ch1, Ch2in the cornea20, for example, as selected or selectable by an operator.

The venting channels Ch, Ch1, Ch2have a channel width d, d1, d2defined by the width of the cut surface forming the venting channels Ch, Ch1, Ch2. As can be seen inFIGS.3and5-10, the channel width d, d1, d2is defined by the extension of the cut surfaces forming the venting channels Ch, Ch1, Ch2in a horizontal x/y-working plane, for example. The channel width d, d1, d2of the venting channels Ch, Ch1, Ch2is far smaller than the length of the venting channels Ch, Ch1, Ch2, extending from the respective opening incisions Ci, Ci1, Ci2to the void volume R. The relatively smaller channel widths d, d1, d2or diameter of the cross-sectional profile of the venting channels Ch, Ch1, Ch2is in the range of 0.1 mm to 0.8 mm, preferably in the range of 0.1 mm to 0.6 mm, whereas the length of the venting channels Ch, Ch1, Ch2is in the range of 1 mm to 6 mm. In an embodiment, the venting channels Ch, Ch1, Ch2are cut with a cross-shaped cross sectional profile of the venting channels Ch, Ch1, Ch2.

The electronic circuit10is further configured to control the scanner system13to move the focal spot S to cut in the cornea20the one or more venting channels Ch, Ch1, Ch2from the outside to the inside of the cornea20, i.e. commencing from the respective opening incision Ci, Ci1, Ci2in the exterior (anterior) surface A of the cornea20through the cornea tissue to the area of the void volume R inside the cornea20.

In an embodiment, the electronic circuit10is further configured to control the laser source11to set and use a comparatively higher energy level for cutting the opening incisions Ci, Coi1, Ci2in the exterior (anterior) surface A of the cornea20, and to reduce the energy level for cutting the venting channels Ch, Ch1, Ch2beyond the opening incision Ci, Ci1, Ci2.

It should be pointed out that cutting the one or more venting channels Ch, Ch1, Ch2from the outside to the inside of the cornea20produces gas which at least partially remains in the venting channels Ch, Ch1, Ch2and keeps the venting channels Ch, Ch1, Ch2open.

As is shown inFIGS.2and11, the opening incisions Ci, Ci1, Ci2of the venting channels Ch, Ch1, Ch2are arranged in a peripheral area Ap of the exterior (anterior) surface A of the cornea20, outside the applanation zone Az. Thus, the fluidic venting channels Ch, Ch1, Ch2enable the venting of the gas, produced by generating the void volume R inside the cornea20, through the respective opening incisions Ci, Ci1, Ci2to the exterior of the cornea20outside the applanation zone Az. More specifically, the opening incisions Ci, Ci1, Ci2of the venting channels Ch, Ch1, Ch2are arranged in a peripheral area Ap of the exterior (anterior) surface A of the cornea20bordering onto the venting chamber17. Thus, the fluidic venting channels Ch, Ch1, Ch2enable the venting of the gas through the respective opening incisions Ci, Ci1, Ci2into the venting chamber17.

In an embodiment, the one or more suction elements of the fastening ring16apply—interruptedly or non-interruptedly—a partial vacuum to the venting chamber17and thereby further facilitate the venting of the gas, produced by generating the void volume R inside the cornea20, through the fluidic venting channels Ch, Ch1, Ch2and their respective opening incisions Ci, Ci1, Ci2to the exterior of the cornea20, outside the applanation zone Az, into the venting chamber17.

In an embodiment, the electronic circuit10is configured to use the positional reference data from the measurement system19to control the scanner system13to move the focal spot S to cut in the cornea20the one or more venting channels Ch, Ch1, Ch2. For example, the electronic circuit10is configured to determine from the measurement data or the positional reference data, respectively, the peripheral area Ap of the exterior (anterior) surface A of the cornea20, outside the applanation zone Az. More specifically, the electronic circuit10is configured to determine from the measurement data or the positional reference data, respectively, the peripheral area Ap of the exterior (anterior) surface A of the cornea20, outside the applanation zone Az and bordering onto the venting chamber17. Moreover, the electronic circuit10is configured to determine the location of the opening incisions Ci, Ci1, Ci2inside the peripheral area Ap of the exterior (anterior) surface A of the cornea20. In an embodiment, the electronic circuit10is configured to receive operator input, e.g. via a data entry element and/or a touchscreen, for selecting, moving, and/or positioning the location of the opening incisions Ci, Ci1, Ci2within the peripheral area Ap of the exterior (anterior) surface A of the cornea20.

FIGS.5and6show scenarios where the electronic circuit10is configured to control the scanner system13to move the focal spot S along a radial trajectory r1, r2directed towards a central axis z of the void volume R to cut one or more of the venting channels Ch1, Ch2along the respective radial trajectory r1, r2. As illustrated inFIGS.5and6, the radial trajectories r1, r2are orientated at different angles α, β, e.g. with respect to a reference axis in the x/y-work plane, e.g. with respect to the x-axis, e.g. selected or set by the operator. As indicated inFIGS.5and6, the venting channels Ch1, Ch2may have different channel widths d1, d2, e.g. selected or set by the operator.

In an embodiment, the electronic circuit10is configured to control the scanner system13to move the focal spot S to cut the venting channels Ch, Ch1, Ch2with a channel width which increases from the void volume R to the opening incision Ci, Ci1, Ci2, starting with a comparatively smaller channel width at the perimeter of the void volume R and increasing to a comparatively wider channel width d, d1, d2at the opening incision Ci, Ci1, Ci2.

FIG.3shows a scenario where the electronic circuit10is configured to control the scanner system13to move the focal spot S along a working line w to cut the venting channel Ch and create the void volume R in a continuous movement of the focal spot S along the working line w. In the example illustrated inFIG.3, the working line for creating the void volume R is a spiral shaped working line w. For example, the venting channel Ch is cut along a straight trajectory t that leads onto the spiral shaped working line w, or along a curved or tangential trajectory t that runs curved or tangentially onto the spiral shaped working line w.

FIGS.7-10illustrate different examples of various arrangements and configurations of the venting pocket(s) P inside the cornea20.

In the example ofFIG.7, the venting pocket P is cut as the escape area. The venting pocket P ofFIG.7is fluidically connected to the void volume R by the venting channel Ch to enable the venting of the gas from the void volume R through the venting channel Ch to the venting pocket P that serves as the escape area.

In the example ofFIG.8, the venting pocket P is cut as an intermediary escape area. The venting pocket P ofFIG.8is fluidically connected to the void volume R, by a first part ChP1of the venting channel Ch. Further, the venting pocket P ofFIG.8is fluidically connected to the opening incision Ci in the exterior surface A of the cornea20, by a second part ChP2of the venting channel Ch. The arrangement and configuration illustrated inFIG.8enable the venting of the gas from the void volume R through the first part ChP1of the venting channel Ch to the venting pocket P, and from the venting pocket P through the second part ChP2of the venting channel Ch and through the opening incision Ci to the exterior to the cornea20.

In the example ofFIG.9, the venting pocket P is cut adjacent and fluidically connected to the void volume R as an intermediary escape area. The venting pocket P ofFIG.9is fluidically directly connected to the void volume R. Further, the venting pocket P ofFIG.9is fluidically connected by the venting channel Ch to the opening incision Ci in the exterior surface A of the cornea20. The arrangement and configuration illustrated inFIG.9enable the venting of the gas from the void volume R to the adjacent venting pocket P, and from the venting pocket P through the venting channel Ch and through the opening incision Ci to the exterior to the cornea20.

In the example ofFIG.10, the venting pocket P is cut adjacent to and surrounding the void volume R as an intermediary escape area. The venting pocket P ofFIG.10is fluidically directly connected to the void volume R. Further, the venting pocket P ofFIG.10is fluidically connected by the venting channel Ch to the opening incision Ci in the exterior surface A of the cornea20. The arrangement and configuration illustrated inFIG.10enable the venting of the gas from the void volume R to the adjacent, surrounding venting pocket P, and from the venting pocket P through the venting channel Ch and through the opening incision Ci to the exterior to the cornea20.