Procedures for functional testing and calibration of an ophthalmic laser therapy device

Abstract

The present invention relates to a method for functional testing of a laser device (110) of an ophthalmological laser therapy device (100). The task is solved by a method comprising: providing (F1, K3) test signals representing a plurality of spaced laser pulses of the laser device (110) into a working area (160, 260) within a test volume (150, 250) containing hyaluronic acid, acquiring (F2, K4) a spatially resolved data set to detect an interaction between the laser pulses and the test volume (150, 250), and spatially resolving (F3, K5) checking the data set for interaction. The task is further solved by a suitable calibration procedure, a calibration unit (K), an ophthalmic laser therapy device (100), a computer program product and a suitable testing device (200).

Description

[0001] The present invention relates to a method for functionally testing a laser device and a calibration method for generating calibration data for a laser device of an ophthalmic laser therapy device. The invention further relates to a corresponding calibration unit, an ophthalmic laser therapy device, a computer program product with program code, and a test device.

[0002] Refractive errors of the human eye have long been corrected with lenses in the form of eyeglasses. However, for some years now, various approaches have been developed to correct refractive errors by modifying the cornea. This modification alters the curvature of the cornea and thus the refractive power of the eye. This is typically achieved by removing tissue from the cornea. By removing corneal tissue, the refractive power of the cornea is altered in such a way that—taking into account the overall optical properties of the eye—the refractive error is reduced or even completely corrected (see, for example, US 6110166 A).

[0003] Carl Zeiss Meditec AG has developed a particularly gentle corneal modification procedure called SMILE. In this procedure, a femtosecond laser is used to create large incisions in the cornea, enclosing a lenticule-shaped piece of corneal tissue. This lenticule is then removed from the cornea through a small access incision. This alters the curvature of the anterior surface of the cornea (the interface between the cornea and air). This change in curvature alters the cornea's refractive power, thereby correcting refractive errors.

[0004] To create the large incisions in the cornea, laser radiation is focused within the tissue—that is, below the tissue surface—to create optical breakthroughs. Various processes, initiated by the laser radiation, occur sequentially within the tissue. If the power density of the radiation exceeds a threshold, an optical breakthrough occurs, generating a plasma bubble within the material. This plasma bubble grows after the optical breakthrough due to expanding gases (in a cavitation bubble). If the optical breakthrough is not maintained, the gas generated in the plasma bubble is absorbed by the surrounding material, and the bubble disappears. However, this process takes much longer than the formation of the bubble itself. When a plasma bubble separates previously fused layers of material, this is usually referred to as photodisruption.For the sake of simplicity, the processes mentioned are summarized here under the term optical breakthrough (or breakthrough), meaning that this term includes not only the actual optical breakthrough but also the resulting effects in the material. If a large number of optical breakthroughs are created next to each other in the fabric, a planar cut (cut surface) can be produced in this way.

[0005] In laser-assisted refractive correction, the laser energy delivered to the eye during treatment should be kept as low as possible, while still exceeding a disruption threshold to ensure that an optical breakthrough can be achieved. Besides the laser energy level, the focusing of the laser beam is crucial for generating an optical breakthrough. This follows from the physical properties of the corneal tissue (such as its band gap) and the wavelength of the femtosecond laser: An optical breakthrough only occurs if the conditions for multiphoton absorption are met. For example, at a laser wavelength of approximately 1000 nm, this requires a high probability of at least four photons being absorbed. The probability P MP applies: PMP=#p / (VP⋅tP)

[0006] Here, #p describe the number of photons, V P the volume of the focus and t P the pulse duration. From this, it follows that both the laser energy (via #p) and the focus quality (V) P ) as well as the pulse duration (t P ) influence whether an optical breakthrough is achieved.

[0007] To verify the functionality of the laser device of an ophthalmic laser therapy device, enucleated pig eyes are currently used because pig eyes are similar to the human eye in terms of geometry, structure, and the biomechanical properties of their components. The pig eye is positioned in front of the laser therapy device (in the position where a human eye would be during laser eye surgery), and the laser device emits laser pulses into the cornea of ​​the pig eye. Subsequently, a visual (subjective) check is performed to determine whether an optical breakthrough has occurred. This can be done by creating a cross-sectional area in the cornea of ​​the pig eye; the proportion of the treated area exhibiting a blistering film is then visually (subjectively) assessed.

[0008] The use of enucleated pig eyes has several disadvantages: Firstly, there is a risk of infection for the person performing the functional test; adhering to the necessary hygiene regulations is time-consuming and costly. Secondly, pig eyes can only be used for functional testing for approximately two days after removal, as the tissue changes—despite refrigeration—to such an extent that its use does not yield reliable results. Furthermore, the logistical effort must be considered. In addition, pig eyes are not always available, so there is a risk of supply disruptions. Since pig eyes are biological tissue, consistent quality cannot be guaranteed, meaning that functional verification of the laser device or even calibration of the laser power is prone to errors.Finally, there are ethical or religious aspects that argue against the use of enucleated pig eyes.

[0009] The object of the present invention is therefore to provide a method for functional testing of a laser device of an ophthalmological laser therapy device, a calibration method for generating calibration data of a laser device of an ophthalmological laser therapy device, a calibration unit, an ophthalmological laser therapy device, a computer program product and a test device that overcome the aforementioned disadvantages and enable reproducible, objective and temporally flexible functional testing or calibration.

[0010] According to the invention, the problem is solved by the features of the independent claims. Preferred embodiments and configurations are the subject of the dependent claims.

[0011] A first aspect of the invention relates to a method for functionally testing a laser device of an ophthalmic laser therapy device. An ophthalmic laser therapy device is understood to be a device designed to create optical breakthroughs in a human eye—particularly in its cornea—by means of (pulsed) laser radiation, so that, for example, refractive correction of the eye can be achieved. For this purpose, the laser therapy device includes a laser device. The laser device may be or include a femtosecond laser (fs laser); however, other pulsed infrared lasers are also conceivable.

[0012] The procedure for functional testing includes the following steps: a) Providing test signals representing a plurality of spaced laser pulses from the laser device into a working area within a test volume containing hyaluronic acid.

[0013] The signals can be provided via an interface through which they are made available to the laser therapy device. The laser therapy device can have a control unit that receives the test signals via the interface, converts them into control signals, and forwards them to the laser device. When the test signals are executed, the laser device is controlled to emit a large number of laser pulses. A large number of laser pulses is defined as at least 1,000, 10,000, or 100,000.

[0014] The working area describes the three-dimensional volume into which the laser pulses are delivered. The working area may be predefined by the laser therapy device—for example, by the maximum displacement / deflection into which a laser pulse can be delivered relative to a central position. The working area can have an axial extent (i.e., in a direction along the propagation direction of the laser radiation; e.g., the z-axis) of at least 10 µm, 100 µm, or 500 µm. A maximum axial extent may be 2 mm or 1 mm. The working area can also have a lateral extent (i.e., in directions perpendicular to the propagation direction of the laser radiation; e.g., x-axis, y-axis) of at least 1 mm, 2 mm, or 3 mm. A maximum lateral extent may be 8 mm, 7 mm, or 6 mm. Thus, the laser pulses have a laser focus (or laser spot) located within the test volume.

[0015] Spacing out laser pulses means that the laser pulses are not all emitted to the same location within the working area. There can be at least 5 different locations or at least 50 different locations. The number of (paired) different locations can additionally or alternatively correspond to at least 50%, at least 80%, at least 90%, or at least 98% of the total number of laser pulses.

[0016] According to the invention, the test volume in which the working area is located contains hyaluronic acid. The molecular formula of the repeating unit of hyaluronic acid is C 14 H 21 O 11 N.

[0017] b) Acquisition of a spatially resolved data set to detect an interaction between the laser pulses and the test volume.

[0018] Data acquisition can be performed, for example, via an interface. The spatially resolved data set can consist of measurement data from a measuring unit such as a camera or other sensor, whose measurement data allows for the spatially resolved detection of information about the occurrence of an interaction between the laser pulses and the test volume. The detected interaction preferably involves the detection of an optical breakthrough. The plasma bubble associated with the breakthrough and the remaining gas bubble (cavitation bubble) can, for example, be detected optically.

[0019] The acquisition of the spatially resolved data set can be preceded by the transmission of a trigger signal (for example via an interface), which is suitable for initiating the recording of the spatially resolved data set.

[0020] The recorded data set may consist of measurement data generated, for example, by a measuring unit that is part of the ophthalmic laser therapy device.

[0021] c) Spatially resolved check of the data set for interaction.

[0022] The test can be performed on a computer that has a processor and memory. The computer can include at least one processor or processing element, such as 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 computer can include computer memory, optionally a semiconductor memory chip. The processor can be configured to execute a computer program. The computer program can be stored in the computer memory.

[0023] Testing for the interaction preferably involves detecting optical breakthrough. The result of the test is spatially resolved information about whether an interaction is detectable (or whether and where optical breakthrough could be detected by the multitude of laser pulses).

[0024] The testing process can also include providing the test result. This provision can be done via an interface.

[0025] The described method is based on the inventive finding that the use of a test volume containing hyaluronic acid can overcome the disadvantages of the prior art: Hyaluronic acid is a synthetically produced substance (for example, through bacterial fermentation). It is stable (for up to a year or more). This allows for consistent properties as a test material for detecting breakthroughs—unlike porcine eyes. Reproducible results can thus be guaranteed. At the same time, hyaluronic acid is transparent (in the visual spectral range as well as for typical wavelengths of a femtosecond laser) and has a viscous consistency. This has proven to be easy to handle, as the test material conforms to the shape of any contact lens used and retains its shape even after docking. Overall, this simplifies the functional verification process compared to the time-consuming process using porcine eyes.Furthermore, it was demonstrated that there is a correlation between the interaction of femtosecond laser radiation with hyaluronic acid and the interaction of the radiation with the cornea of ​​the human eye. Specifically, it was shown that at similar laser energies, an optical breakthrough occurs, forming a detectable cavitation bubble. This is because hyaluronic acid has a similar band gap to the cornea of ​​the human eye.

[0026] Furthermore, capturing and verifying the data set to demonstrate the interaction allows for more reliable results than with a visual (subjective) inspection. Spatially resolved testing also enables the detection of any spatial variations in optical penetration, which may be caused, for example, by changes in focus quality within the working area.

[0027] The method according to the invention thus allows a time- and resource-saving method for functional testing of the laser device of an ophthalmological laser therapy device.

[0028] A second aspect of the invention relates to a calibration method for generating calibration data for a laser device of an ophthalmic laser therapy device.

[0029] The calibration procedure includes the procedural steps for functional verification according to the first aspect described above.

[0030] The calibration process further includes the following steps: d) Selecting a first laser energy E1.

[0031] The selection can be performed by a person (user) or a program. It can involve choosing from a list of possible laser energies. The selection can be random or according to a predefined logic or algorithm. Preferably, the first laser energy E1 is greater than zero. The selected laser energy E1 is provided in the process step of generating the test signals (see step a) of the test procedure). The selected laser energy E1 is part of the test signals.

[0032] e) Calculating a laser energy-dependent quality factor to evaluate a spatially resolved distribution of the tested interaction between the laser pulses and the test volume.

[0033] The calculation can be performed on a computer (as described above). The calculation is based on the data set, which has been checked for interactions.

[0034] The quality factor can comprise or consist of one or more numbers. A single quality factor number can describe different magnitudes and / or properties of the interaction. For example, it could represent the presence of a breakthrough (yes / no – exemplified by 1 / 0) or the size of a cavitation bubble (diameter or volume).

[0035] This process step thus provides one or more quality values ​​for the laser energy used previously (in step b)) (e.g., the first laser energy E1). The quality value is a measure of the spatially resolved distribution of the tested interaction between the laser pulses and the test volume.

[0036] The quality factor can be defined for each laser pulse of the multitude of laser pulses mentioned in step b) and recorded in step c). Such a quality factor could, for example, be a "map" marking where a breakthrough was detected. Alternatively, the quality factor could be defined for only a fraction of the laser pulses—preferably for at least 10, at least 20, or at least 50 different locations within the working area of ​​the test volume. Such a quality factor could, for example, be a "coarse" map with at least 10 (or 20 or 50) regions, for which a breakthrough was detected is marked as a representative example.

[0037] Additionally or alternatively, the quality can be expressed as a value derived from the entirety or spatially resolved distribution of the tested interaction. Such a quality can, for example, be a number describing the proportion of the multitude of laser pulses for which an interaction (breakthrough) was detected. The "entirety" comprises at least 50% of the multitude of emitted (and tested) laser pulses, preferably at least 80% or 90%.

[0038] The calculation of the laser energy-dependent quality can be done using artificial intelligence (AI).

[0039] f) Checking (K7) a termination criterion.

[0040] The check can be performed on a computer (as described above). The termination criterion can be for which and / or how many laser energies the laser energy-dependent quality has already been calculated. The termination criterion can also be one or more limit values ​​that have been exceeded (or fallen below, or reached) by the previously calculated laser energy-dependent quality. Alternatively, the termination criterion can be one or more limit values ​​that are derived (calculated) from the quality.

[0041] g) Selecting a laser energy E i , which differs from the previously selected laser energies, and repeat steps a), b), c), e) and f) if the termination criterion is not met. Here, i > 1.

[0042] The selection can be made from a variety of continuous or discrete values ​​of laser energies E. iThis is to be carried out. The selected laser energy is preferably different from all previously selected laser energies (E). i ≠ E j with i > 1 for all j < i). An energy difference ΔE between the chosen energy E i and the energies selected immediately beforehand E i-1 This can correspond to the minimum energy difference that can be set using the laser source of the laser device. The energy difference ΔE between successively tested laser energies is advantageously constant; however, the energy difference ΔE can also be chosen to be non-constant.

[0043] When repeating steps a), b), c), e) and f), a pattern assigned in step a) to the multitude of laser pulses (using the first laser energy E1) can be repeated in step a) (using the laser energy E i) exhibit a similar or even identical pattern. The similarity can refer to the spatial extent of the pattern as well as, additionally or alternatively, to the minimum, maximum, and / or mean distances between the spaced laser pulses. A similar or identical pattern is advantageous for comparing the laser energy-dependent quality factors.

[0044] The selection can be made on a computer (as described above).

[0045] h) Determining a marginal energy E G the laser device, if the termination criterion is met.

[0046] The determination is based on the laser energy-dependent quality factor for evaluating the spatially resolved distribution of the tested interaction between the laser pulses and the test volume. The limiting energy E G This describes a value for the laser energy required to ensure optical breakthrough. The limiting energy E GThis can vary spatially, i.e., show different values ​​for different locations within the test volume.

[0047] Determining the marginal energy E G can be done in a computer (as described above).

[0048] i) Determining calibration data for the laser device.

[0049] The determination is based on the previously determined marginal energy E G The limit value E G This defines the lowest value for the laser energy required to perform a continuous, planar incision. From a surgical perspective, however, there are application advantages to using a laser energy that is lower than the limiting energy E. Gslightly increased. This increased laser energy can be determined by multiplying by a factor (greater than one) or by adding a constant value. This increased laser energy is a value in the calibration data of the laser device.

[0050] In the event that it is desired to remain below the breakthrough threshold, the calibration data can be determined from the limiting energy E. G Energy can also be subtracted, or the marginal energy E can be determined. GThe calibration data can be multiplied by a factor less than one. The calibration data can be defined on a computer (as described above). The factor, or the constant additive (or subtractive) energy value, can be determined empirically. Alternatively, it can be determined using artificial intelligence (AI). Preferably, the method also includes the step of providing the calibration data to the ophthalmic laser therapy device. This can be done, for example, via an interface.

[0051] The advantages of the functional testing method described above (first aspect) also apply to the calibration method according to the invention presented here (second aspect).

[0052] In addition, the presented calibration method allows for an objective and reproducible calibration of the laser device, which was not possible according to the prior art.

[0053] In one embodiment of the method for functional testing and the calibration method, these are characterized in that the hyaluronic acid has a concentration between 10 mg / ml and 40 mg / ml, preferably between 20 mg / ml and 35 mg / ml, particularly preferably between 30 mg / ml and 32 mg / ml.

[0054] The product Z-HYALCOAT serves as an example. ® Carl Zeiss Meditec AG. The hyaluronic acid used there has a concentration of 30 mg / ml.

[0055] When hyaluronic acid is used in the aforementioned procedures within the limits mentioned above, both the similarity of the laser energies between the test volume and the human cornea for an optical breakthrough and easy handling due to the viscosity of the material in the test volume are ensured.

[0056] According to one embodiment, the process is characterized in that the hyaluronic acid has an intrinsic viscosity between 10 dl / g and 40 dl / g, preferably between 10 dl / g and 20 dl / g, and particularly preferably between 10 dl / g and 12 dl / g. Handling is particularly simplified with hyaluronic acid having such intrinsic viscosities.

[0057] In a further embodiment of the procedure for functional testing and the calibration procedure, these are characterized by the fact that the acquisition of the spatially resolved data set for demonstrating the interaction includes measurement data from reflection imaging (or digital photography).

[0058] In the context of this application, reflection imaging refers to imaging methods that are not based on interference but allow a two-dimensional view (perpendicular to an optical axis of the imaging system) of a sample, where the detected radiation is light reflected from the sample. This can involve a camera whose observation optics are designed to observe the eye—in particular, its cornea. Preferably, the camera also includes illumination for lighting the eye. The illumination optics and the observation optics may be partially identical.

[0059] Reflectance imaging is particularly suitable for detecting cavitation bubbles by evaluating contrast in the image. It thus enables a highly reliable and reproducible spatially resolved check of the data set for the occurrence of interaction between the laser pulses and the test volume.

[0060] According to one embodiment of the method, the spatially resolved examination of the data set for interaction includes contrast-based image processing. Such processing of the data set is particularly well suited for demonstrating the interaction.

[0061] In one embodiment of the functional testing and calibration methods, these are characterized in that the test signals are provided such that the laser pulses have a minimum distance of no more than 10 µm from each other, preferably no more than 3 µm or no more than 1.5 µm. In other words, the distance of each laser pulse to the nearest adjacent laser pulse is no more than 10 µm, 3 µm, or 1.5 µm.

[0062] Additionally or alternatively, the method is characterized in that adjacent laser pulses have a maximum distance of at most 10 µm, preferably at most 3 µm or at most 1.5 µm. The aforementioned maximum distances apply to at least 50% of the plurality of laser pulses, preferably at least 80% or 95%. In two dimensions, the maximum distance of adjacent laser pulses means that if the area surrounding a laser pulse is divided into four equal segments, the aforementioned maximum distances for a nearest neighbor are maintained in at least two of these equal segments. In three dimensions, the maximum distance of adjacent laser pulses means that if the area surrounding a laser pulse is divided into eight equal solid angles, the aforementioned maximum distances for a nearest neighbor are maintained in at least two of these equal solid angles.

[0063] If test signals are provided as described above, the interaction between the laser pulses and the test volume can be demonstrated particularly well. Furthermore, the distribution (pattern) of the laser spots is similar to patterns that can occur in applications on the human eye, so that function and calibration can be performed not only on the scale of individual breakthroughs, but also on the scale of surgically relevant dimensions.

[0064] According to a further development of the procedure for functional testing and the calibration procedure, these are characterized in that the provision of the test signals is carried out in such a way that the multitude of the rejected laser pulses has the shape of an intersection.

[0065] In other words, when the test signals are executed by the laser device of the ophthalmic laser therapy unit, the pattern of cavitation bubbles generated by the numerous laser pulses in the test volume has the shape of a cross-sectional surface. A cross-sectional surface is a collection of laser pulses that forms a two-dimensional surface in three-dimensional space. When a cross-sectional surface is generated in the human eye, it serves to cut tissue; any existing tissue bridges act as "weak points" when the tissue volume is removed.

[0066] The cut surface can correspond to a cap cut in terms of geometry and arrangement of the laser spots. This is a cut surface that, when used in a human eye, is used to delineate a lenticule in the cornea, facing the anterior surface of the cornea. The cut surface can also correspond to a lenticule cut in terms of geometry and arrangement of the laser spots. This is a cut surface that, when used in a human eye, is used to delineate a lenticule in the cornea, facing away from the anterior surface of the cornea.

[0067] If test signals are provided that represent an interface, the procedure for functional testing or calibration reproduces the conditions occurring during application on the human eye particularly well.

[0068] In a further embodiment of the calibration method, it is characterized in that the method additionally comprises receiving a measurement of the actual emitted laser energy for at least one laser pulse of the plurality of laser pulses. Preferably, measurements of the actual emitted laser energies are received for at least 20% of the plurality of laser pulses, particularly preferably at least 50% or 80%. The measurement can be received via an interface.

[0069] To measure the actual laser energy, a (known) fraction of the laser radiation can be coupled out of the beam path and directed onto a measuring device that converts the measurement signal into a measured value for the laser energy.

[0070] The process can include storing the actual laser energy emitted. This storage can be done, for example, in an electronic memory.

[0071] In addition, the calibration procedure is designed in such a way that the determination of the marginal energy E G the laser device using the actual emitted laser energy.

[0072] Taking into account the actual emitted laser energy when determining the limiting energy E G improves the robustness of the calibration procedure.

[0073] According to a further development of the calibration procedure, this also includes the acquisition of a spatially resolved reference dataset. This acquisition can be performed via an interface.

[0074] A reference dataset is defined as a dataset acquired in the same manner as a dataset used to demonstrate an interaction between laser pulses and the test volume. However, unlike the latter, no laser pulses were emitted into the test volume. Instead, only laser pulses with a laser energy below a threshold value were emitted into the test volume. This threshold value is set at a maximum of 80% of a previously determined threshold energy E. G,früher The concentration should be no more than 50% or 20%. No interaction should be detectable in the reference dataset.

[0075] Preferably, the calibration procedure is designed such that the reference data set is taken into account when checking the data set for interaction (process step d)).

[0076] Using the reference dataset can improve the quality of spatially resolved interaction testing, as it reduces the risk of misinterpreting the dataset due to impurities in the test volume, ambient light and / or background disturbances.

[0077] In a further embodiment of the calibration procedure, it is characterized in that the selection of the laser energy E iAdditionally, a further working area is selected that differs from the previously selected working areas. Preferably, the further working area is disjoint from all previously selected working areas. The further working area can be laterally and / or axially displaced relative to the previously selected working areas. If the further working area is axially displaced relative to the previously selected working areas, it is preferably located closer to an optical aperture through which the laser pulse exits the ophthalmic laser therapy device than the previously selected working areas. In other words, the further working area is positioned less deeply within the test volume than the previously selected working areas.

[0078] Selecting an additional working area can be achieved by adjusting the test signals to select a different subvolume as the additional working area within the application volume accessible by the ophthalmic laser therapy device. Additionally or alternatively, the test volume can be shifted relative to the ophthalmic laser therapy device. For this purpose, control signals (via an interface) can be provided to actuate an adjustment unit designed to move the test volume relative to the ophthalmic laser therapy device. This adjustment unit could, for example, be a motorized sliding table. Alternatively, a signal (e.g., visual or audible) can be provided indicating that the subvolume should be shifted manually relative to the ophthalmic laser therapy device.

[0079] By selecting a wider working range, it can be advantageously ensured that for each laser energy E i Within the test volume, a working area can be irradiated with laser pulses into which no laser pulses were previously emitted. This prevents cavitation bubbles already present in the working area from affecting the result of a test for the occurrence of interactions for the newly selected laser energy E. i distort.

[0080] According to a further development of the calibration procedure, this is characterized in that after selecting the further working range and before providing test signals for laser pulses with laser energy E i Another location-resolved reference dataset is captured.

[0081] By using the reference dataset for each additional work area, the quality of spatially resolved interaction testing can be improved, as the risk of incorrect interpretation of the dataset due to impurities in the test volume, for example, can be reduced.

[0082] In a further embodiment of the calibration procedure, it is characterized by the fact that the selection of the laser energy E i such that the selected laser energy E i is greater than all previously selected laser energies E j In other words: E i > E j with i > 1 for all j < i.

[0083] By selecting increasing laser energy, the quality of spatially resolved interaction testing can be improved, as it is also possible to check whether, in areas within the working area where interaction has already been demonstrated for lower laser energies, it also occurs at higher energies.

[0084] Conversely, due to the aforementioned plausibility, the selection of increasing laser energies eliminates the need to choose a new working area for each laser energy. Additionally or alternatively, it is possible to forego providing test signals for areas within the working volume where an interaction has already been detected. Both of these factors contribute to accelerating the calibration process.

[0085] If the laser energy-dependent quality is taken into account when checking the termination criterion, the calibration procedure can also be accelerated by selecting increasing laser energies.

[0086] According to a further embodiment of the calibration method, it is characterized in that the laser energy-dependent quality factor corresponds to a proportion of the multitude of spaced laser pulses in the test volume for which an interaction is detectable. For example, it can be checked for each laser pulse (or a predefined fraction thereof) whether an interaction has occurred (for example, by checking whether a cavitation bubble can be detected in the spatially resolved data set). The proportion then corresponds to the ratio of the number of laser pulses with a detected interaction to all laser pulses tested. Additionally or alternatively, the interaction test can also be performed for several sub-regions (at least 10, 20, or 50) of the working area, for which it is checked whether an interaction is detectable.The proportion then corresponds to the ratio of the number of sub-areas with proven interaction to all tested sub-areas. Preferably, the sub-areas are all the same size and / or evenly distributed within the work area. The entirety of the sub-areas can correspond to a "map" that represents a spatial distribution of evidence of interaction.

[0087] This map can describe an overlay of the work area with cavitation bubbles.

[0088] If the laser energy-dependent quality factor is calculated as described above, the use of artificial intelligence for the calculation is particularly suitable. Furthermore, contrast-based image processing is also particularly well-suited for determining the laser energy-dependent quality factor, either additionally or as an alternative.

[0089] Preferably, the calibration procedure is designed such that the termination criterion is met when the proportion of detectable interaction is at least 80%, 90%, 95% or 99%.

[0090] If the laser energy-dependent quality factor is calculated as described above, a spatially resolved limiting energy E can be determined particularly well. G calculate or define spatially resolved calibration data.

[0091] According to one embodiment of the calibration procedure, it is characterized by the fact that the determination of the limiting energy E G by means of a modified sigmoid function.

[0092] The modified sigmoid function for describing the laser energy-dependent quality factor can have the following form: A(E)=Amax−1exp(E−μc)+1Amax−Amin

[0093] Here, µ and c are fitting parameters. A min and A maxdescribe a minimum and a maximum quality that were calculated for the different laser energies E.

[0094] If the laser energy-dependent quality factor is, for example, the proportion (in percent) of laser pulses for which an interaction is detectable, then in ideal measurements A min = 0 and A max = 100.

[0095] If the function A(E) is inverted (formation of A -1 (.)), thus it can easily be deduced for which laser energies E a given proportion of detectable interaction can be achieved; for example E 50 = A -1 (50%) or E 95 = A -1 (95%).

[0096] Preferably the marginal energy E G selected so that it corresponds to an energy for a quality (or proportion) of at least 80%, preferably at least 90%, 95% or 99%.

[0097] The described use of a modified sigmoid function allows for a particularly robust determination of the limiting energy. Other functions that describe a functional relationship between the laser energy and a component of the detected interaction are also conceivable.

[0098] In a further embodiment of the calibration procedure, it is characterized by the fact that the determination of the limiting energy E G The laser device is spatially resolved. In other words, different limiting energies E can be determined for different locations among the multitude of laser spots. G be determined.

[0099] Due to the properties of the laser device and / or the optical beam paths and / or any scanning device used to shift the laser beam focus within the working area, the laser energy for which an interaction between the laser pulse and the test volume can be detected may vary spatially. Such spatial variation can, for example, provide information about focus quality.

[0100] A spatially resolved limiting energy has the advantage that, when applied to the human eye, only enough laser energy needs to be applied to generate a cavitation bubble at the respective location. The total energy delivered to the eye during laser surgery can thus be reduced.

[0101] For this purpose, the calibration procedure is preferably designed such that the calibration data of the laser device is determined with spatial resolution. The calibration data are therefore preferably determined taking into account the spatially resolved limiting energy E. G determined.

[0102] According to one embodiment of the calibration procedure, it is characterized by the fact that it further includes the storage of the last spatially resolved data set or all spatially resolved data sets and / or the marginal energy E. G and / or calibration data and / or measurements of the actual laser energy delivered. Furthermore, the procedure may include storing intermediate results or so-called metadata such as a time, date, or serial number of the ophthalmic laser therapy device.

[0103] Storing the aforementioned data increases the reproducibility of the results and allows the results to be checked at a later time.

[0104] A third aspect of the invention relates to a calibration unit for an ophthalmic laser therapy device. This unit comprises a computing device configured to perform a calibration procedure according to one of the embodiments mentioned above. The computing device is further configured to receive the spatially resolved data set(s) for detecting an interaction, to provide test signals, and to provide calibration data.

[0105] The computing device may include or consist of a computer with a processor and memory. The computer may include at least one processor or processing element, such as a CPU (optionally in the form of a microprocessor), a GPU, a TPU (and / or an FPGA). The computer may include 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.

[0106] Furthermore, the calibration unit has a first interface for receiving the spatially resolved data set (or sets) for verifying the interaction and forwarding it to the calculation unit, a second interface for providing the test signals, and a third interface for providing the generated calibration data. Two or three of these interfaces may be identical.

[0107] The calibration unit can be part of the ophthalmic laser therapy device.

[0108] A fourth aspect of the invention relates to an ophthalmic laser therapy device. This device comprises a calibration unit as described above (according to the third aspect). Furthermore, the ophthalmic laser therapy device includes a control unit for controlling the device, the control unit being connected to the calibration unit via the second interface and the third interface for receiving test and calibration data. The calibration unit may also be part of the control unit. The control unit may include or consist of a computer as described above. The control unit is connected to the devices of the ophthalmic laser therapy device described below in order to control them. This is typically done by means of signal data transmitted from the control unit to the various devices via signal data lines or wirelessly.The signal data is generated in the control unit, taking the calibration data into account.

[0109] The control unit can typically access all controllable devices of the ophthalmic laser therapy device. It can be a single unit or a multi-part unit, and it can communicate with the controllable devices of the ophthalmic laser therapy device via wired or wireless communication channels.

[0110] The ophthalmic laser therapy device further comprises a laser device for providing a laser beam with laser pulses. 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 penetrating the tissue of a patient's eye by means of optical breakthrough due to non-linear absorption.

[0111] The laser device can, for example, include a femtosecond laser or a picosecond laser.

[0112] A femtosecond laser, for example, has a wavelength in the range of 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 the pulse energy range of 20 nJ to 2 µJ. A pulse energy of approximately 130 nJ is particularly preferred. Typically, the 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.

[0113] The ophthalmic laser therapy device further comprises a focusing device for focusing the laser beam at a focus within the working area of ​​the test volume. The focusing device is designed to focus the laser beam in the tissue of a patient's eye as well as in the working area of ​​the test volume, so that an optical breakthrough can be 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, at the cornea – or the refractive indices of the irradiated tissue). Furthermore, the focusing device can be designed to create a focus of the laser beam in the tissue of the patient's eye as well as in the working area of ​​the test volume, with a contact lens (contact element) positioned upstream of the patient's eye (or working area) in the beam path.The contact lens is used to fixate a patient's eye. For hygienic reasons, a contact lens can only be used once during therapy. It is conceivable that a contact lens could be reused for functional testing or calibration, and / or that a special contact lens with less stringent requirements could be used. Both approaches allow for cost savings.

[0114] In addition, the ophthalmic laser therapy device includes a scanning device for moving the focus of the laser beam within the working area of ​​the test volume.

[0115] The scanning device of the ophthalmic laser therapy system allows the focus of the laser beam to be shifted or scanned within the tissue of the eye or within the working area of ​​the test volume. Scanning the laser beam should be possible without restriction in all three spatial directions: x, y, z. Accordingly, the scanning device should be designed to perform lateral scans in the x and y directions as well as z-scans along the optical axis of the pulsed laser beam. The scanning device may incorporate galvo scanners and / or MEMS scanners. The scanning device may also be configured to shift a lens – for example, radially and azimuthally.

[0116] Furthermore, the ophthalmic laser therapy device includes a measuring device for acquiring the spatially resolved data set to demonstrate the interaction. The measuring device can be configured to acquire measurement data from optical coherence tomography and / or reflection imaging. For this purpose, the measuring device can, for example, include a camera with camera optics designed to detect light emitted from the working area and convert it into an electrical signal to obtain the spatially resolved data set. The detected light can be, for example, visible light or infrared light. The measuring device can additionally include a light source (such as a lamp, an LED, or a laser) and illumination optics. The illumination optics are designed to direct the light from the light source into the working area. The illumination optics and camera optics can be partially identical.Additionally or alternatively, the illumination optics and / or camera optics can be section by section identical to the optics through which the laser radiation of the laser device is guided to the working area.

[0117] The ophthalmic laser therapy device according to the invention allows the laser device to be calibrated efficiently, resource-savingly, objectively and reproducibly.

[0118] A fifth aspect of the invention relates to a computer program product which, when executed on an ophthalmic laser therapy device as described above, is configured to perform a calibration procedure according to one of the embodiments described above. The computer program product comprises program code that can be loaded into a computer to execute the calibration procedure.

[0119] A fifth aspect of the invention relates to a test device for calibrating a laser device of an ophthalmic laser therapy device. The test device comprises a test volume containing hyaluronic acid. Furthermore, the test device comprises a housing designed to accommodate the test volume. For this purpose, the housing has a base and preferably a lateral boundary. The housing is shaped such that a laser beam emitted by the laser device can be focused into the test volume. For this purpose, the housing may have an opening through which the laser beam can enter the test volume. The opening is designed such that collisions between the housing and the ophthalmic laser therapy device cannot occur when the test device and the laser therapy device are positioned relative to each other such that the focus of the laser beam lies within the test volume.The opening can be large enough to allow a contact element (also called a contact lens), which couples the laser therapy device to the human eye during laser surgery, to be immersed in the test fixture. Preferably, the housing is designed so that the contact element can come into contact with the test volume. The housing can be a flat shell open at the top (towards the contact element). Alternatively, the housing can have a window that is transparent to the radiation from the laser device.

[0120] Furthermore, the housing is shaped in such a way that a measuring beam can leave the test volume to detect an interaction between the laser beam and the test volume. This ensures that a measurement can be performed to verify the interaction. For this purpose, the housing can have an opening through which the measuring beam can leave the test volume to be detected by a measuring device. Alternatively, the housing can have a measuring window that is transparent to a specific wavelength of the measuring beam and through which the measuring beam can be detected by the measuring device.

[0121] The described test device is particularly well suited for a functional test or a calibration procedure according to one of the described configurations.

[0122] According to one embodiment, the test device is characterized in that the base has a barrier layer, wherein the barrier layer is configured to block the wavelength of the measuring beam and / or visible light, and wherein the barrier layer is in contact with the test volume. To block the measuring beam and / or visible light, the barrier layer can have a transmission of at most 1%, preferably at most 0.01%, 0.0001%, or 0.000001%. Additionally, to block the measuring beam and / or visible light, the barrier layer can have a reflection of at most 10%, preferably at most 1%, 0.1%, or 0.01%. The barrier layer can be configured as a neutral density filter (also called an ND filter) and have values ​​such as ND = 2, ND = 4, ND = 6, or ND = 8.

[0123] By using a barrier layer as described above, the proportion of detected light from outside the test volume is reduced, so that the measuring beam carries largely only information about the interaction. In this way, the detection of interactions can be carried out with particular reliability. This is especially true for detection using contrast-based image processing.

[0124] A barrier layer for visible light simplifies a visual inspection to determine whether an interaction of the laser radiation with the test volume has occurred.

[0125] In a further embodiment, the test device is characterized in that the lateral boundary has a first and a second lateral access through which the test volume can be inserted into or removed from the housing.

[0126] A test device designed in this way allows the test device and laser therapy device to be aligned once for a functional test or calibration. Between individual measurements to demonstrate the interaction for different laser energies, the test volume can be exchanged via the two lateral access points. This can be done automatically, for example. In this way, the test device enables particularly convenient testing or calibration.

[0127] According to a further embodiment, the test device is characterized in that the housing is designed to be connected to a contact element. The connection can be achieved, for example, by means of a thread, a clamp (such as a bead), or a clamp. Alternatively, the housing has a contact element. Both variants simplify handling during functional testing or calibration of an ophthalmic laser therapy device that uses a contact element during operation (during a laser surgical procedure). This embodiment is particularly advantageous if the lateral edge has two lateral access points, as described above.

[0128] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations given, but also in other combinations or on their own, without leaving the scope of the present invention.

[0129] The invention is explained in more detail below with reference to exemplary embodiments and illustrations, which also disclose essential features of the invention. The exemplary embodiments serve for illustration purposes and are not to be interpreted as limiting. Unless otherwise stated, elements or components from different exemplary embodiments may be combined. If variations or modifications are given for one exemplary embodiment, they may also be applicable to other exemplary embodiments. To avoid repetition, identical or corresponding elements in different figures are marked with the same reference numerals and are not explained multiple times. The figures show: - Fig. 1 a scheme of an embodiment of an ophthalmic laser therapy device according to the invention; - Fig. 2 an example of a method for functional testing of a laser device of an ophthalmic laser therapy device; - Fig. 3 an example of a calibration procedure for generating calibration data of a laser device of an ophthalmic laser therapy device; - Fig. 4 measurements obtained during a calibration procedure; - Fig. 5 measurements for different laser energies, which were calculated to obtain spatially resolved limiting energies; - Fig. 6 a section through a test device according to a first embodiment; - Fig. 7 a section through a test device according to a second embodiment; - Fig. 8 a section through the test device according to the second embodiment and a contact element of a laser device; - Fig. 9 a section through a test device according to a third embodiment; - Fig. 10 a section through a test device according to a fourth embodiment.

[0130] In Fig. Figure 1 schematically depicts an embodiment of an ophthalmic laser therapy device 100 (enclosed by a dashed box). During operation of the ophthalmic laser therapy device 100, a laser device 110 emits a pulsed laser beam 115. The laser beam 115 is deflected axially (in the z-direction) by a scanning device 130 and laterally (in the x- and y-directions) by another scanning device 135. A focusing device 120 concentrates the pulsed laser beam 115 into a focus 125 (when the laser therapy device 100 is used to correct the refraction of a human eye) in the cornea of ​​the eye being corrected. Any advantageous fixation of the eye relative to the ophthalmic laser therapy device 100 by means of a contact element is not shown.

[0131] In Fig. 1. The laser beam 115 is directed by the focusing device 120 into a test device 190, which is not part of the laser therapy device 100. The test device 190 comprises a test volume 150 containing hyaluronic acid. Within the test volume 150, a working area 160 is schematically marked by dotted lines. The focus 125 of the laser beam 115 is located within the working area 160. The ophthalmic laser therapy device 100 is designed to move the focus 125 within the working area 160. This is made possible by the scanning devices 130 and 135.

[0132] During operation, the laser device 110 and the scanning devices 130 and 135 are controlled fully automatically via signal data transmitted from a control unit 140 to the respective devices 110, 130, and 135. This is indicated by arrows pointing from the control unit 140 to the devices 110, 130, and 135, respectively. The control unit 140 ensures appropriately synchronized operation of the laser device 110 and the three-dimensional scanning devices 130 and 135. The focusing device 120 could also be controlled by the control unit 140. The signal data can be transmitted via signal data lines or wirelessly. The signal data required for operation is determined in the control unit 140 based on control data.

[0133] During a functional test or calibration of the laser device 110, the control unit 140 receives test signals and, if necessary, calibration data from a calibration unit K via unspecified communication paths such as a calibration data line (in Fig. (1 shown as a solid line between the calibration unit K and the control unit 140). Calibration data can also be transmitted using memory chips (e.g., via USB or memory stick), magnetic storage media (e.g., floppy disks), wirelessly via radio (e.g., WLAN, UMTS, Bluetooth), or via wired connections (e.g., USB, FireWire, RS232, CAN bus, Ethernet, etc.). Alternatively, instead of direct communication, the calibration unit K can be located physically separate from the control unit 140, and a corresponding data transmission channel can be provided.

[0134] The calibration unit K comprises a computing unit C, which is a computer with a processor and memory. Furthermore, the calibration unit K has a second interface S2 and a third interface S3, via which test signals and calibration data can be provided to the control unit 140. In the present embodiment, the second and third interfaces are identical.

[0135] Furthermore, the calibration unit K has a first interface S1, via which a spatially resolved data set can be received to detect an interaction in the working area 160 between the laser pulses of the laser beam 115 of the laser device 110 with the test volume 150.

[0136] In the illustrated embodiment, the spatially resolved data set is provided by a measuring device M. In the present example, this is a camera having camera optics that view the working area 160 in the test volume 150 of the test device 190 in the direction (coaxially) of the incident laser beam. The ability of the measuring device M to acquire measurement data (as a spatially resolved data set) is described in Fig. 1 is represented by a dashed double arrow. A light source that is also present is not shown.

[0137] The calculation unit C of the calibration unit K is designed to generate and provide test signals, acquire spatially resolved data sets, and perform spatially resolved interaction testing. The interaction is tested using a contrast-based method. Additionally, the calculation unit C can calculate a laser energy-dependent quality factor to evaluate the spatially resolved distribution of the tested interaction and can also check a termination criterion.

[0138] If the termination criterion is not met, the calculation unit C selects a laser energy E. i from, which is different from all other laser energies already used. In addition, the steps of providing test signals, acquiring a spatially resolved data set (for the last selected laser energy E) are described. i ), repeatedly checking for an interaction and checking a termination criterion.

[0139] If the termination criterion is met, the calculation device C is set up to select a marginal energy E. G to determine, as well as to define calibration data and to provide this via the third interface S3.

[0140] The calibration unit K also has an input device (not shown) which is connected to the calculation unit C. A first laser energy E1 can be input via this input device.

[0141] The calibration unit K does not have to be part of the ophthalmic laser therapy device. Alternatively, it can be a separate unit that can be connected to the laser therapy device via the interfaces mentioned. The calibration unit K can have a measuring device; it can also be additionally or alternatively connected via interface S1 to a measuring device that is neither part of the calibration unit K nor of the laser therapy device.

[0142] In Fig. Figure 2 is a schematic example of a procedure for functional testing of a laser device of an ophthalmic laser therapy device. The individual procedure steps are shown schematically in the blocks labeled F1 to F3.

[0143] Process step F1 involves providing test signals representing a multitude of spaced laser pulses from the laser device within a working area contained in a test volume filled with hyaluronic acid. These test signals are then provided to the ophthalmic laser therapy device whose laser mechanism is undergoing functional testing. There, the test signals can be converted (for example, by a control unit) into control signals that trigger execution. During execution, the multitude of laser pulses is generated, corresponding to a multitude of spaced laser foci within the working area of ​​the test volume.

[0144] Process step F2 is performed after the emission of the numerous laser pulses. Here, a spatially resolved data set is acquired to detect an interaction between the laser pulses and the test volume. A corresponding data set is generated after the laser pulses are emitted (e.g., by a measuring unit) and made available to the process.

[0145] Procedure step F3 is performed after procedure step F2. In step F3, a spatially resolved check of the data set for interactions is carried out. In the functional verification procedure shown here, check F3 also includes providing the result of the check.

[0146] The in Fig. The two methods described can be found in the Fig. The calibration unit K shown in Figure 1 is used. The test result is then made available to the control unit 140 via the S2 / S3 interface. The control unit 140 is configured to perform various actions based on the test result, such as issuing a warning if the test result is negative.

[0147] In Fig. Figure 3 is a schematic example of a calibration procedure for generating calibration data for a laser device of an ophthalmic laser therapy device. The individual procedure steps are shown schematically in the blocks labeled K1 to K13. The sequence of steps is indicated by the arrows connecting the blocks.

[0148] In process step K1, a spatially resolved reference data set is acquired. In the present calibration procedure, no laser pulses are emitted into the working area before acquisition. However, laser pulses could also be emitted beforehand, preferably well below an expected threshold energy E. G lay.

[0149] K1 is an optional procedure step that allows the quality of spatially resolved interaction testing to be improved in step K5, as the risk of incorrect interpretation of the data set due to impurities in the test volume, ambient light and / or background disturbances of the test volume can be reduced by taking the reference data set into account when testing the interaction.

[0150] Process step K2 comprises selecting a first laser energy E1. In the calibration procedure shown here, this is a laser energy that is significantly below an expected limiting energy E. G lies - for example at 20% to 30% of the expected (e.g. previously determined) marginal energy E G However, the election could also deviate from this.

[0151] In process step K3, test signals are provided that represent a multitude of spaced-apart laser pulses from the laser device into a working area within a test volume containing hyaluronic acid. This step corresponds to step F1 in the process described in Fig. Figure 2 shows that the provided test signals also include information about the selected laser energy. For the first iteration of the loop, this is the first laser energy E1; in subsequent iterations, it is the laser energy E selected in step K8. i .

[0152] Procedure step K4 comprises the acquisition of a spatially resolved data set to detect an interaction between the laser pulses and the test volume. This step corresponds to step F2 in the procedure described in Fig. 2 is shown.

[0153] In process step K5, the data set is checked for interactions at a spatial resolution. This step corresponds to step F3 in the procedure described in Fig. 2 is shown.

[0154] In process step K6, a laser energy-dependent quality factor is calculated to evaluate a spatially resolved distribution of the tested interaction between the laser pulses and the test volume.

[0155] Process step K7 involves checking a termination criterion. If the termination criterion is not met, process step K8 follows, which involves selecting a laser energy E. i , which differs from the previously selected laser energies. Subsequently, process step K13 is executed, which includes reacquiring a spatially resolved reference data set. Step K13 is advantageous when selecting the laser energy E i In step K7, an additional work area is selected, which differs from the previously selected work areas. Procedure step K13 is optional. The procedure then continues with step K3.

[0156] If the termination criterion is met, process step K9 follows, which involves determining a marginal energy E. G the laser device. This is followed by process step K10, which involves defining calibration data for the laser device.

[0157] In process step K11, the last spatially resolved data set or all spatially resolved data sets and / or the marginal energy E are stored. G and / or the calibration data and / or the measurements of the actual emitted laser energy. This procedure step is not mandatory for the calibration procedure, but it improves the reproducibility of the calibration.

[0158] In process step K12, the calibration data is provided.

[0159] The method according to the invention thus enables a time- and resource-saving method for calibrating the laser device of an ophthalmic laser therapy device. The method is objective and reproducible.

[0160] Is Fig. Figure 4 shows measurements obtained during a calibration procedure according to the invention. The first row (row a)) schematically shows, in a cross-sectional plane, where the foci of the plurality of laser pulses were placed in the test volume. The lower, hemispherical element represents the test volume. Above it, a contact element is shown with thicker lines. In this example, the contact element and the test volume are in direct contact.

[0161] The second line (line b)) shows measurement data from a camera. The camera records measurement data along the optical axis of the pulsed laser beam; this corresponds to a top view of the working area. The measurement data was recorded after the laser pulses were emitted into the working area of ​​the test volume. These correspond to the spatially resolved data sets for different laser energies. The measurements show an increased signal at locations where cavitation bubbles were formed by the laser pulses, as shown in line b). Fig. 4 appears as a lighter gray. Areas without cavitation bubbles produce a weak signal (or no signal) and remain dark gray. The circular structure in all five camera images shown represents the outer edge of the contact element used in the calibration procedure.

[0162] The third line (line c)) shows an evaluation of the camera measurement data displayed in line b). The individual images from line b) were subjected to contrast-based image processing. In each image, wherever the contrast is increased due to the generated bubbles, the corresponding location in the image is marked white. Conversely, locations without bubbles exhibit low contrast against the background and are marked black in the image.

[0163] The first column (marked "E = 0") contains data acquired as a reference. The laser energy was set to zero (E = 0). No cavitation bubbles are visible in the spatially resolved dataset (row c). This is the spatially resolved reference dataset.

[0164] The following columns show data obtained for non-zero laser energies. The second column corresponds to a first laser energy E1; the last column to a final laser energy E n During the calibration procedure, data were acquired using increasing laser energy (E i < E i+1 ). In line a) it can be seen that for the laser energies E1 to E n The foci of the numerous laser pulses in the test volume describe a curved surface, which is shown as a curved line in the cross-sectional view. In this example, the surface runs parallel to the surface of the contact lens and corresponds to a cap section. The top view of the working area in row c) shows that with increasing laser energy, the proportion of locations where cavitation bubbles are visible also increases. The last column shows the last laser energy E. n The area of ​​the cap cut is almost entirely white.

[0165] Fig. Figure 4 shows an example with a reference measurement (reference data set) and four measurements with different laser energies. To determine a limiting energy E G Since the data is not spatially resolved, the available number of iterations and measurements may be sufficient. In this case, the quality factor for the different laser energies can be determined, for example, by the proportion of detectable interaction—that is, what percentage of the cut surface is shown as whitish in the measurements shown in row c). For the data shown in row c), values ​​of approximately 0% (for the reference measurement with E = 0), approximately 15%, approximately 45%, approximately 80%, and approximately 95% (for the measurement with laser energy E) are obtained. n ).

[0166] If a spatially resolved calibration is desired, the limiting energies must be determined with spatial resolution. For this purpose, a higher number of iterations is recommended to incorporate measurement data from a wider range of laser energies into the calibration. Fig. Figure 5 shows how to extract a data set from a series of spatially resolved data sets (in Fig. Figure 5 (four measurements are shown on the left as examples) combines the measurements (long arrow on the left) and calculates a spatially resolved distribution of the limiting energy (large arrow in the middle of the figure). The result is shown on the right. The different shades of gray represent different limiting energies. Different limiting energies can occur, for example, if the focus quality varies spatially. In the example shown, the limiting energies are used to calculate spatially resolved calibration data for the laser device.

[0167] In Fig. Figure 6 shows a section through a test device according to a first embodiment. The test device 200 has a housing 210 with a base 215. The base 215 comprises a barrier layer 240, which is Fig. 6 is shown in black. In the example shown, this is an ND filter with ND > 6. On the base 215 and in direct contact with the barrier layer 240 is a test volume 250, shown as a dotted line. The test volume 250 contains hyaluronic acid. In the example shown, this is present at a concentration of 31 mg / ml and has an intrinsic viscosity of approximately 11 dl / g. In the embodiment shown, the laser radiation from the laser device, whose function is to be tested or which is to be calibrated, can penetrate the test volume 250 from above. Measurement radiation leaving the test volume 250 to detect an interaction can also be emitted upwards. By using a barrier layer 240 (which is not strictly necessary), the quality of the spatially resolved data set (the measurement data) can be improved, thus simplifying the quality check. The in Fig. 4 and Fig. The measurements shown in section 5 were carried out using a test device according to this embodiment.

[0168] In Fig. Figure 7 shows a section through a test device according to a second embodiment. In addition to the features shown in Fig. In this embodiment, the housing 210 has a lateral edge 220, as shown in Figure 6. Such an edge 220 can simplify the handling of the test device 200, for example, if the test volume 250 is to have a greater thickness than in the first embodiment (according to Figure 6). Fig. 6).

[0169] In Fig. Figure 8 shows a section through a test device according to the second embodiment and a contact element of a laser device. If the ophthalmic laser device has a contact element 290 (shown with oblique hatching) to fix the patient's eye during laser surgery, the contact element 290 is in direct contact with the eye. Therefore, it is advantageous if a functional test or calibration is also carried out in such a way that the contact element 290 is in direct contact with the test volume 250 – as is the case in Figure 8. Fig. 8 is shown.

[0170] In Fig. Figure 8 shows an additional work area 260 and a further work area 206.i (outlined with dotted lines and filled with white). Laser pulses with an initial energy E1 can be emitted into work area 260. After a measurement (of an initial spatially resolved data set), the work area can be shifted so that laser pulses with a laser energy E can be emitted into a further work area (260.i). i can be handed in.

[0171] It should be noted that the first embodiment also follows Fig. 6. Suitable for use with a laser therapy device with a contact element. This is due to the intrinsic viscosity of hyaluronic acid.

[0172] In Fig. Figure 9 shows a section through a test device according to a third embodiment. In addition to the features shown in Fig. In the second embodiment, as shown in Figure 7, the rim 220 has two lateral access points 260. The test volume 250 can be introduced into the test device via an applicator 270 through the access point 260 shown on the right. The test volume 250 can be removed through the access point 260 shown on the left. The insertion and removal processes are schematically illustrated by corresponding arrows in the lateral access points 260.

[0173] In Fig. Figure 10 shows a section through a test device according to a fourth embodiment. In addition to the features shown in Fig.In accordance with the features shown in the third embodiment, the housing 210 is designed to accommodate a contact element 290, which is not part of the test device 200. For this purpose, a bead is provided around the entire circumference of the lateral edge 220, by means of which the contact element can be clamped to the test device 200. Other connection options are also conceivable.

[0174] The test device could also be designed such that the contact element is part of the test device. The test device could then be mechanically and optically coupled to the ophthalmic laser therapy device, whose laser mechanism is to be tested, via the contact element.

[0175] The features of the invention mentioned above and described in various embodiments can be used not only in the exemplary combinations given, but also in other combinations or alone, without leaving the scope of the present invention.

[0176] A description of a device relating to process characteristics applies analogously to the corresponding process with respect to these characteristics, while process characteristics represent corresponding functional characteristics of the described device. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 6110166 A

[0002]

Claims

[1] Method for functional testing of a laser device (110) of an ophthalmic laser therapy device (100), comprising: a) Providing (F1, K3) test signals representing a plurality of spaced laser pulses from the laser device (110) into a working area (160, 260) within a test volume (150, 250) containing hyaluronic acid, b) Acquisition (F2, K4) of a spatially resolved data set to detect an interaction between the laser pulses and the test volume (150, 250), c) Spatially resolved check (F3, K5) of the data set for interaction. [2] Calibration method for generating calibration data of a laser device (110) of an ophthalmic laser therapy device (100), comprising the method according to claim 1, further comprising: d) Selecting (K2) a first laser energy E1, e) Calculating (K6) a laser energy-dependent quality factor to evaluate a spatially resolved distribution of the tested interaction between the laser pulses and the test volume (150, 250), f) Checking (K7) a termination criterion, g) Selecting (K8) a laser energy E i , which differs from the previously selected laser energies, and repeat steps a), b) c), e) and f) if the termination criterion is not met, h) Determining (K9) a marginal energy E G the laser device (110) when the termination criterion is met, i) Determining (K10) calibration data of the laser device (110). [3] Method according to claim 1 or 2, characterized by that the hyaluronic acid has a concentration between 10 mg / ml and 40 mg / ml, preferably between 20 mg / ml and 35 mg / ml, particularly preferably between 30 mg / ml and 32 mg / ml. [4] Method according to any of the aforementioned claims, characterized bythat the hyaluronic acid has an intrinsic viscosity between 10 dl / g and 40 dl / g, preferably between 10 dl / g and 20 dl / g, particularly preferably between 10 dl / g and 12 dl / g, [5] Method according to any of the aforementioned claims, characterized by , that the spatially resolved check (F3, K5) of the data set for interaction includes contrast-based image processing. [6] Method according to any of the aforementioned claims, characterized by , that the provision (F1, K3) of the test signals is carried out in such a way, - that the laser pulses have a minimum distance of no more than 10 µm from each other, preferably no more than 3 µm or no more than 1.5 µm, and / or - that adjacent laser pulses have a maximum distance of 10 µm, preferably a maximum of 3 µm or a maximum of 1.5 µm. [7] Method according to any of the aforementioned claims, characterized by, that the provision (F1, K3) of the test signals is carried out in such a way that the multitude of the rejected laser pulses has the shape of an intersection surface. [8] Calibration method according to any one of claims 2 to 7, characterized by , that the procedure continues to include: - Capture (K1) a spatially resolved reference dataset. [9] Calibration method according to any one of claims 2 to 8, characterized by , that by selecting (K7) the laser energy (E i ) additionally, another workspace (260.i) is selected, which is different from the previously selected workspaces. [10] Calibration method according to any one of claims 2 to 9, characterized by , that the selection (K7) of the laser energy (E i ) such that the selected laser energy (E i ) is greater than all previously selected laser energies E j . [11] Calibration method according to any one of claims 2 to 10, characterized by , that the laser energy-dependent quality corresponds to a proportion of the multitude of spaced laser pulses in the test volume (150, 250) for which an interaction is detectable, and preferably that the termination criterion is met when the proportion of detectable interaction is at least 80%, 90%, 95% or 99%. [12] Calibration method according to any one of claims 2 to 11, characterized by , that determining (K9) the marginal energy E G the laser device (110) is spatially resolved, and preferably that the setting (K10) of the calibration data of the laser device (110) is spatially resolved. [13] Calibration unit (K) for an ophthalmic laser therapy device (100), comprising - a computing device (C) that is designed to, ◯ to perform a calibration method according to any one of claims 2 to 12, ◯ to receive the spatially resolved data set to demonstrate an interaction, ◯ to provide test signals, and ◯ To provide calibration data, - a first interface (S1) for receiving the spatially resolved data set to prove the interaction and for forwarding it to the computational unit (C), - a second interface (S2) for providing the test signals, and - a third interface (S3) for providing the generated calibration data. [14] Ophthalmic laser therapy device (100), comprising - a calibration unit (K) according to claim 13, - a control unit (140) for controlling the ophthalmic laser therapy device (100), wherein the control unit (140) is connected to the calibration unit (K) via the second interface (S2) and the third interface (S3) for receiving the test data and the calibration data, - a laser device (110) for providing a laser beam (115), - a focusing device (120) for focusing the laser beam (115) at a focus (125) in the working area (160, 260) of the test volume (150, 250), - a scanning device (130, 135) for moving the focus (125) of the laser beam (115) in the working area (160, 260), and - a measuring device (M) for recording the spatially resolved data set to demonstrate the interaction. [15] Computer program product which, when implemented on an ophthalmic laser therapy device (100) according to claim 14, is configured to perform a method according to any one of claims 2 to 12. [16] Test device (190, 200) for calibrating a laser device (110) of an ophthalmic laser therapy device (100), comprising - a test volume (250) containing hyaluronic acid, - a housing (210) designed to accommodate the test volume (250), with a base (215) and preferably with a side rim (220), wherein the housing (210) is shaped such that a laser beam (115) emitted by the laser device (110) can be focused into the test volume (250), and wherein the housing (210) is shaped such that a measuring beam can leave the test volume (250) to detect an interaction between the laser beam and the test volume (250). [17] Test device (190, 200) according to claim 16, characterized by , that the floor (215) has a barrier layer (240), wherein the barrier layer (240) is configured to block the wavelength of the measuring beam and / or to block visible light, and wherein the barrier layer (240) is in contact with the test volume (240). [18] Test device (190, 200) according to claim 16 or 17, characterized by, that the lateral boundary (220) has a first and a second lateral access (260) through which the test volume (250) can be inserted into or removed from the housing (210).

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