UV laser based system for impaired vision correction and method for centration thereof

Abstract

This invention relates to a UV laser-based system, specifically a UV laser-based system (100) for correcting impaired vision in a patient's eye (10), a UVL-LVC system (100). The UVL-LVC system (100) comprises: a UV laser source (102) designed to emit laser radiation to treat the patient's eye (10); and an imaging optics (124) for focusing the laser radiation onto the cornea (12) of the patient's eye (10), wherein the imaging optics (124) is designed such that it detects the reflection (126) of radiation at a receiving angle χMαχ of at least 2.5°, the radiation being incident on the cornea (12) of the patient's eye (10) through the imaging optics (124) and at least partially reflected from the cornea (12) of the patient's eye (10). The invention also relates to a method for centering the UVL-LVC system (100).

Description

Technical Field

[0001] This invention relates to a laser vision correction (LVC) system based on ultraviolet laser (UVL), i.e., a system for correcting impaired vision by means of laser radiation, wherein the corresponding therapeutic laser is emitted in the ultraviolet range, i.e., an excimer laser or solid-state laser having a wavelength between approximately 193 nm and 213 nm. The system is typically a pulsed system, i.e., a system that does not emit a continuous wave (cw). This UVL-LVC system is configured to treat a volume of the cornea of ​​a patient's eye, starting from its surface, by means of photoablation (e.g., PRK, LASEK), or, in the case of flipping up the surface of the cornea of ​​the patient's eye (LASIK), starting from the exposed surface. The invention also relates to a corresponding method for a UVL-LVC system. Background Technology

[0002] Traditional UVL-LVC systems, such as the MEL system from Carl Zeiss Medite AG, the Amaris system from Schwindeye-tech Solutions LLC, or the Micron system from Excelsius Medical LLC, have been successfully used for the correction of refractive errors for a long time. Further improvements to such systems are proposed and explained in this disclosure.

[0003] Traditional UVL-LVC systems typically feature a rigid laser beam guidance system. While this simplifies and ensures safe laser beam guidance, it requires the patient to be positioned on a patient bed within a fixed system aperture in the x, y, z coordinates until the patient's eye is correctly positioned relative to the system's optical axis for treatment. An exception is US2013 / 0226157A1, in which the inherently rigid laser arm is positioned as a whole above the patient, but in a manner and method that requires the patient to be positioned on a patient bed as before. The latter, for safety reasons, typically requires an electrical and / or mechanical connection between the patient bed and the laser base unit, which in turn necessitates system approval and a large placement space.

[0004] In traditional UVL-LVC systems, eye alignment with rotation is typically achieved manually and statically by rotating the patient's head while lying on a couch under visual control. This significantly reduces the achievable precision and thus leads to undesirable deviations when the patient's head is rotated during treatment without correction for the resulting rotation.

[0005] Furthermore, in some conventional UVL-LVC systems, a contact U-interface is known for securing the eye. Here, the contact interface in such UVL-LVC systems, as described, for example, in US2013 / 0226157A1 and US9592156B2, is implemented solely to stabilize the eye and does not play an active role. Conversely, in many systems, operation occurs without any contact interface whatsoever.

[0006] A large working distance between the laser exit aperture and the eye is achieved using a UVL-LVC system that incorporates point scanning. This is done in the context of a microkeratome used with a patient on the system's patient bed to cut a LASIK flap, i.e., a flapable opening in the cornea. This likely also necessitates a large working distance. Subsequently, an eye tracker is introduced to register and compensate for eye movements, and further, to compensate for eye movements during ablation, since the eye is not annotated. The resulting overall optical system design—which is substantially similar across different systems—is also considered disadvantageous.

[0007] In applications, various technical challenges arise for eye tracking. Generally, the registration speed of eye movements is finite, and the time available for adjusting the scanning mirror to correct pulse coordinates is limited. In the context of system performance, the response time to eye movements is typically slow, thus limiting its accuracy. In the case of conventional, fast eye tracker systems (repetition frequency of approximately 1000 Hz), this is sufficient for lateral correction (x, y displacement; "first and second eye tracking dimensions"). Of course, even the fastest conventional systems will impose limitations, especially when the eye tracker speed is below the scanning frequency limit. In some systems, prediction is based on the eye's previous motion trajectory: where the eye will move ("seventh eye tracking dimension"). However, this is only feasible within an approximate range, as saccades / nystagmus correspond to statistical eye movements in the broadest sense. This also indicates that with conventional techniques, increasing the repetition rate is associated with technical challenges, although such repetition rates may be of interest for specific applications and within specific ablation time windows (thermal control / mild ablation).

[0008] Furthermore, lateral tracking can be a constraint because the eye's rotation around the z-axis ("dynamic cyclic rotation"; the 6th eye-tracking dimension) and rolling motion around the horizontal and vertical eye axes (the 3rd and 4th eye-tracking dimensions) need to be considered to achieve the best possible accuracy. Additionally, the distance from the laser exit aperture (z-distance) can also vary, which can also be compensated for through corresponding tracking (the 5th eye-tracking dimension).

[0009] Despite the availability of all the technical refinements and corrective options, traditional systems are limited in certain situations: they respond precisely to changes in eye position; registration quality is limited; and the speed of registration and correction can have a significant impact. However, the impact on refractive outcomes is usually very small and almost impossible to verify.

[0010] However, in the context of eye tracking, further challenges arise in cases of uncooperative patients who are unstable, tense, cognitively impaired, or have difficulty perceiving the fixation target. In some cases, ophthalmic surgeons need to ensure that the patient's eye is manually fixed during ablation using clamps and / or foam scrapers to achieve precise ablation. This can be used to avoid eye movements outside the so-called (limited) "eye-tracking hot zone," as this would otherwise require stopping the system.

[0011] In UVL-LVC systems, it is also crucial to consistently ensure that prism errors are avoided via the eye tracker. Failure to do so can result in undesirable situations where the ablation profile is not applied to the correct plane, i.e., not along the surface normal, i.e., perpendicular to the visual axis. Consequently, this can be advantageous, as the patient may prefer to fixate on a largely fixed, but "incorrect," direction, i.e., permanently looking in a fixed direction that does not correspond to the center of the "fixed cloud" (during surgery, the patient may no longer be able to clearly see the fixed target due to refractive errors and treatment time).

[0012] Figure 1 The diagram illustrates the principle of prism correction error (Tip / Tilt) that occurs when the patient is not fixed at the center of the "fixed cloud" due to insufficient precision in using the eye tracker. Here, in Figure 1 The image shows a patient's eye 10 with a cornea 12 and a fovea 14, as well as an optical axis 16 or visual axis 16 of the patient's eye, an ablation profile 18, a scanning system 20, and a fixation element 22 on which the patient fixes their gaze.

[0013] If the patient does not fix the eye 10 in the center, but instead fixes it, for example, to the edge region of the fixation element 22, this will result in the ablation profile 18 being incorrectly applied along the desired treatment axis (e.g., the visual axis 16; which is defined by the ophthalmic pole (OP) and the patient fixation) and thus not in the normal direction to the visual axis. Figure 1 The relationship is shown in a highly exaggerated manner.

[0014] Eye trackers do not work equally reliably in all eyes because some eyes have insufficient color contrast. If an eye tracker is unavailable, the eye surgeon may halt the procedure or continue without it, which places higher demands on the surgeon's skill and / or may compromise the quality of the treatment outcome.

[0015] In conventional systems, it is often impossible or only very difficult to set constant environmental conditions for the surgical site. However, it is known that varying environmental conditions, such as air humidity and the resulting changes in corneal hydration, air composition (in the case of solvent evaporation), or temperature, can have significant effects on refractive outcomes. It is also known that it is advantageous to ensure that the cornea remains hydrated during ablation or to prevent it from drying out (see, for example, RR Krueger, M. Campos, XW Wang, M. Lee, PJ McDonnell, “Corneal Surface Morphology Following Excimer Laser Ablation With Humidified Gases,” Arch Ophthalmol. 111, 1993). Hydration is typically distinguished between two effects: a) physiological differences in corneal hydration as scattering between different patients, and b) maintaining hydration during the ablation itself. Both of these effects lead to increased scattering in refractive outcomes (e.g., via increased scattering predicted in “try and achieve”). Various studies exist on this topic in the professional literature. Therefore, the effect on corneal hydration is particularly significant.

[0016] Another factor influencing refractive outcomes is related to the amount and accumulation of ablation product (“debris”) on the ablated cornea, i.e., the surgical site. It is well known that incident UV ablation pulses are absorbed and scattered in the debris. Consequently, the effective pulse volume, which largely controls the ablation process, can be modified in an uncontrolled manner and method. This can lead to significant volume deviations in the ablation pulse sequence. In the case of myopia treatment, this can result in the undesirable formation of a central corneal bulge (so-called a central island) postoperatively. Therefore, conventional systems typically have a suction device for debris or a combination of air delivery and suction devices. However, large gaps in delivery or extraction can hinder effective debris removal. In principle, for this purpose, it would be advantageous to exchange the entire air volume on the treated cornea between successive pulses at a pulse repetition rate of 500Hz to 1000Hz. Otherwise—in the case of suboptimal ablation product or directional suction—"bending" ablation, leading to, for example, induced coma or SIA (surgical induced astigmatism), should be avoided.

[0017] Aseptic and secure placement of the flap is crucial for LASIK procedures. The flap is typically only 100 micrometers thick and is secured to the cornea via a very narrow "hinge" after the LASIK incision. Maintaining flap hydration is critical for pathological reasons, but it is equally important for preserving flap shape, as a dehydrated flap will shrink within seconds. A shrinking flap may lose its fit to the stromal bed post-treatment (this could also be due to changes in the stromal surface shape caused by ablation), which, if not carefully considered, can lead to postoperative complications such as "ingrown epithelium." The flap should also be kept as free as possible from folding, stretching, or otherwise compressing. Therefore, the "Calzone technique," once used, is now rarely employed by specialists. Furthermore, it should be avoided to leave the flap in potentially non-sterile areas of the eye. This can still occur despite aseptic preparation of the eye, such as through the tear film or contact with non-sterile parts of the eyelid.

[0018] In the absence of solutions integrated into traditional systems, users sometimes cut their own flap supports from a sterile foam scraper (or similar material), which are then wetted and used as a safe and sterile support for sensitive flaps. Therefore, solutions are sought to improve this situation.

[0019] Because the working pitch Δ of conventional UVL-LVC systems is relatively large, there is almost no difference in the focal plane. Therefore, the ULV-LVC system can be considered almost telecentric on the image side. In conventional UVL-LVC systems, the beam typically hits the cornea at a significant angle because the typical radius of curvature RC of the human eye is approximately 7.86 mm, and conventional ULV-LVC systems typically have a working pitch of approximately 250 mm (the distance from the device exit aperture profile to the eye). This has a further disadvantage: the optical receiving angle used to guide reflections from the cornea back into the optical system is very small, which leads to significant limitations in current systems and often excludes or minimizes the use of corneal reflections.

[0020] Other drawbacks of conventional UVL-LVC systems are now described, most of which arise directly from the optical design and the geometry derived from ablation.

[0021] In conventional systems, the oblique incidence of laser radiation onto the cornea results in a loss of flux, i.e., the energy density of the laser pulse, which is crucial for ablation. Two effects must be considered here: losses arising from deviations in the ablation footprint caused by the local geometry of the cornea at the ablation pulse location (“geometric factor”), and Fresnel losses when light incident at boundary surfaces with different refractive indices (air, cornea), which can be calculated using Fresnel equations. These effects have long been known in the art.

[0022] The pulse ablation shape (corresponding to the effective fluence distribution of the incident ablation laser pulse on a plane perpendicular to the incident direction) is deformed into a "pulse ablation footprint on the cornea" by the geometry of the incident pulse on the cornea, thereby changing the fluence distribution relative to the incident "pulse ablation shape".

[0023] Fresnel loss can be calculated using the Fresnel equations, given the refractive indices of air and the cornea (or matrix) and the angle of incidence, where the polarization of the laser radiation must be taken into account.

[0024] Because traditional UVL-LVC systems have a large working distance from the patient's eye, resulting in a small receiving angle for the focusing optics, it is either only feasible or completely infeasible to use the patient's corneal refraction for analysis and centering. The effects of imprecise centering are known and have been extensively discussed in the literature. It is generally considered that spherical aberration correction is only satisfactory on certain tilts, such as spherical corneas, namely, the centering error, i.e., the deviation between the ablation center and the target position on the cornea, which typically has no effect on spherical aberration correction due to deviations caused by the "eye pole" used for centering on the visual axis; this centering error is referred to as eccentricity below. However, visual physiology has not been considered here. Eccentricity typically leads to a displacement of the physiological visual axis. When visual impressions are processed in the brain, the eye "rotates" through the eye muscles so that light is still incident on the point of clearest vision, which essentially compensates for prism shift ("tip / tilt"). This causes problems, for example, in binocular vision (stereoscopic vision), problems known, for example, from studies of poorly centered spectacle lenses. Especially in the case of non-spherical aberration correction on elliptical corneas, which corresponds to real-world scenarios, decentering can physically prevent the desired correction from being achieved. Therefore, decentering significantly impacts the results of "custom ablation" because it causes higher aberrations (such as "night vision problems"), thus affecting refractive outcomes. Therefore, precise centering is crucial for good results in both orthographic and wavefront correction.

[0025] Aberrations (or optical modes) are coupled under eccentricity. Eccentricity is critical in real eyes, but also in pure spherical and cylindrical corrections, due to the coupling between spherical and cylindrical surfaces at higher-order aberrations (coma, spherical aberration, higher-order astigmatism) and in natural (aspherical) eyes. For example, coma is coupled under eccentricity at astigmatism and defocus, or spherical aberration is coupled at coma, astigmatism, and defocus. Several examples are provided here, initially focusing only on the effects of major aberrations (up to order 4). Calculations are performed from the coordinate transformation of the optical modes:

[0026] A coma of 0.25 μm with a Z(3,1) shift of 0.3 mm results in approximately -1 / 8D defocus.

[0027] A coma of 0.25 μm with a Z(3,1) shift of 0.3 mm (horizontal / vertical) results in a 1 / 8D fundamental astigmatism (Z(2,2) / Z(2,-2)).

[0028] A coma of 0.5 μm with a Z(3,1) shift of 0.5 mm results in approximately -0.3D defocus.

[0029] A coma of 0.4 μm Z(3,1) shifted by 0.5 mm (horizontal / vertical) results in a fundamental astigmatism of 0.3D (Z(2,2) / Z(2,-2)).

[0030] A spherical aberration of 0.6 μm with a Z(4,0) displacement of 0.4 mm results in approximately -1 / 8D defocus.

[0031] A spherical aberration of 0.6 μm Z(4,0) shifted by 0.4 mm (horizontal / vertical) results in approximately 1 / 8 D of fundamental astigmatism (Z(2,2) / Z(2,-2)).

[0032] So far, only the optical patterns manifested in the ablation profile of the optical region have been considered. The transition zone has not been mentioned. However, in this context, eccentricity also means that the transition zone can reach the optically active zone, especially in the case of hyperopia correction. This can lead to interference (known as "postoperative night vision complaints," which does not imply nighttime myopia), particularly in intermediate to low light conditions, and consequently, patient dissatisfaction.

[0033] In refractive surgery, pupil centering (towards the CSC, "corneal aiming center") can be achieved reliably and well using an eye-tracking system ("eye tracker") as an integrated pupil recognition device. However, this type of centering is not the preferred choice because it is currently undisputed in the field that centering towards the ocular pole (visual axis, coaxial visual membrane light reflection, "CSCLR", condition, see below) or apex will be correct and preferred over pupil centering. Experience shows that this is very unimportant for minor or medium myopia correction. It becomes more difficult in cases of larger astigmatism and myopia correction, and especially hyperopia correction. Therefore, hyperopia is typically characterized by a non-negligible angle ("angle kappa") between the pupillary axis and the visual axis. The corneal aiming center and the ocular pole are no longer sufficiently close to each other, resulting in a difference between angle λ ("angle lambda") and angle κ ("angle kappa"). Typically, the angle λ represents the angle between the pupillary axis (or pupillary axis) and the line of sight, while the angle κ (kappa) represents the angle between the pupillary axis and the visual axis. See "Handbook of Visual Optics Vol. 1," CRC Press Taylor & Francis Group, Ed. Pablo Artal, Vol. 1, Chapter 17 (written by DA Atchison), or "Investigation of the isoplanatic patch and wavefront aberration along the pupillary axis compared to the line of sight in the eye," M. Nowakowski, M. Sheehan, D. Neal, AVGoncharov, Biomedical Optics Express, Vol. 3, 2. Furthermore, the pupil and its center are not fixed points and can be clearly marked. Both the pupil and its center can vary with illumination conditions. Summary of the Invention

[0034] Therefore, the object of the present invention is to describe an apparatus and method for solving the aforementioned problems of currently used UVL-LVC systems. In particular, the object of the present invention is to describe an apparatus and method for simply and reliably centering a patient's eye relative to a UVL-LVS system.

[0035] A first embodiment of the present invention relates to a UV laser-based system, namely a UVL-LVC system, for correcting impaired vision in a patient's eye. The UVL-LVC system includes a UV laser source designed to emit laser radiation to treat the patient's eye; and an imaging optics device for focusing the laser radiation onto the cornea of ​​the patient's eye. Here, the imaging optics device is designed such that it achieves a receiving angle χ of at least 2.5°. Mαx The backscattering of radiation is detected, which is incident on the cornea of ​​the patient's eye through an imaging optics device and is at least partially reflected from the cornea of ​​the patient's eye.

[0036] Another embodiment of the invention relates to a method for centering a UVL-LVC system used for correcting impaired vision in a patient's eye. Here, the method includes: incident a centering ray onto the cornea of ​​the patient's eye using an imaging optics device; and detecting, by means of the imaging optics device, a retroreflection of a portion of the incident radiation reflected from the cornea, wherein the retroreflection is detected within an angle range of at least 2.5°. Furthermore, the method includes determining the positioning and / or orientation of the UVL-LVC system relative to the patient's eye based on the detected retroreflection. Centering can optionally be performed manually, partially automatically, or fully automatically.

[0037] Here, the imaging optics used to focus laser radiation onto the cornea of ​​a patient's eye perform the function of a focusing optics, which can focus the laser beam to be incident on the patient's eye onto the eye, and at least partially collect the reflection from the cornea, making it usable by a UVL-LVC system. Focusing by the imaging optics does not necessarily have to be achieved with a point-like or Gaussian focal point; other focal fields can also be produced. Optionally, the imaging optics can be designed to generate a curved focal field.

[0038] Here, the backscattering of radiation from the cornea may optionally be radiation reflected from the corneal surface toward the UVL-LVC system and projected back at least partially toward the UVL-LVC system. The backscattering of radiation may optionally be one of a first Purkinje reflection and / or another Purkinje reflection.

[0039] However, the radiation incident on the patient's cornea as a retroreflection via the imaging optics does not necessarily correspond to the laser radiation provided by a UV laser source. Alternatively or additionally, the incident radiation can also be provided as a centering beam and / or a scanning beam, wherein the centering beam and / or scanning beam is provided by a separate laser source, possibly in a spectral range other than the ultraviolet spectral range, such as the visible or infrared spectral range. Alternatively or additionally, the incident radiation can also be provided by a UV laser source and substantially correspond to a laser beam used for treatment at reduced power.

[0040] The imaging optics achieve a receiving angle χ of at least 2.5°. Max Detecting backlighting here means detecting the receiving range of backlighted rays using an angle relative to the optical axis of the imaging optics. Therefore, an imaging optics device with a 2.5° receiving angle can, for example, detect backlighted optical rays reflected from the cornea to the imaging optics in a light cone having an angle of 5° relative to the incident direction (i.e., an angle of 2.5° between the side surfaces of the light cone and the midline of the light cone), such that the optical rays can be collected by the imaging optics and used by the UVL-LVC system.

[0041] The advantage of this invention is that it enables the detection of reflected radiation incident on the patient's eye via the imaging optics over a significantly larger angular range than is feasible with conventional UVL-LVC systems. Conventional UVL-LVC systems have a receiving angle of only about 2° or less. In contrast to conventional UVL-LVC systems, this invention therefore allows the use of reflected radiation to center the UVL-LVC system relative to the patient's eye, because the reflected radiation can also be collected and analyzed by the imaging optics for centering even when the UVL-LVC system is not yet in a centered position or is very close to it.

[0042] Therefore, the present invention offers the following advantages: a more reliable method for automatic centering and / or manual alignment can be performed using the UVL-LVC system according to the invention, which utilizes retroreflection from the cornea. Thus, instead of employing the pupil midpoint for automatic centering and alignment of the UVL-LVC system relative to the patient's eye, which only achieves limited accuracy, other methods utilizing retroreflection can be considered, which offer greater accuracy and / or higher reliability compared to centering using the pupil midpoint. Therefore, the present invention improves reliability and accuracy, especially in automatic centering, when centering the UVL-LVC system relative to the patient's eye.

[0043] The UVL-LVC system according to the invention includes a UV laser source that emits preferably pulsed laser radiation in the UV range. For example, this can be an excimer laser or a solid-state laser with wavelengths between approximately 193 nm and 213 nm. Furthermore, the UVL-LVC system optionally includes a scanning system for laterally scanning the laser radiation at least in the x and y directions and preferably also in the z direction, and imaging optics for focusing the preferably pulsed laser radiation onto the cornea of ​​a patient's eye (at least with respect to its lateral extension). This can induce a photoablation process of the cornea, which is a desired treatment or is included therein. Optionally, the UV laser source is designed to emit pulsed laser radiation. Alternatively or additionally, the UV laser source is configured as or includes an excimer laser.

[0044] Optionally, the UVL-LVC system includes a control unit for controlling all or some of the system's units, such as the UV laser source, scanning system, and movable components of the imaging optics. Furthermore, the control unit can also control movable components, such as the application arm and positioning contact interfaces. The control unit can be configured as a central control unit, or it can consist of multiple interconnected sub-units. A dedicated planning unit for surgical planning can also be part of or connected to the control unit.

[0045] The imaging optics may optionally include a microscopic optics device for focusing preferably pulsed laser radiation onto the cornea of ​​a patient's eye, the optical aperture of which is designed to achieve a receiving angle χ for the retroreflection detectable by the UVL-LVC system according to the invention, greater than 2.5°, optionally greater than 5°, optionally greater than 10°, optionally greater than 15°, optionally greater than 25°, and optionally greater than or equal to 37°. Max Here, compared to the existing UVL-LVC system, the imaging optics are characterized by a very small working pitch and a large optical aperture. This allows for particularly efficient return of corneal reflection to the UVL-LVC system. Optionally, the imaging optics has an optical aperture and a preset working pitch, such that the diameter of the formed optical aperture is greater than or equal to the preset working pitch. This provides an imaging optics with a particularly large receiving angle and correspondingly achieves a particularly large range within which the reflection can be collected and used for centering. Optionally, the imaging optics has an optical aperture with a diameter of at least 50 mm, optionally at least 60 mm, and a working pitch of less than 50 mm and optionally less than or equal to 40 mm. Therefore, the working pitch is significantly smaller than that of conventional UVL-LVC systems, meaning that a significantly larger receiving angle can be achieved compared to conventional UVL-LVC systems.

[0046] The UVL-LVC system optionally includes a contact interface for coupling the patient's eye to the UVL-LVC system. This simplifies the stabilization of the patient's eye at the UVL-LVC system. Optionally, the UVL-LVC system also includes a scanning system for lateral scanning of the laser radiation in the x and y directions and optionally in the z direction.

[0047] Optionally, the UVL-LVC system is designed to couple the echo of the radiation detected by the imaging optics out of the ray path of the laser radiation between the imaging optics and the scanning system. This provides the advantage that the echo does not need to be guided through the scanning system and that potential losses can be avoided. For example, a suitable sensor for detecting the echo of the coupled output can be arranged in the area between the imaging optics and the scanning system. Alternatively, the UVL-LVC can be designed to couple the echo of the radiation detected by the imaging optics out of the ray path of the laser radiation. For this purpose, the imaging optics can, for example, have a corresponding coupling output optics. This provides the advantage that the UVL-LVC can be configured in a particularly compact manner.

[0048] Optionally, UVL-LVC includes a detection system for returning rays, which are formed by the detected back reflection of radiation incident on the cornea of ​​the patient's eye via an imaging optics device and at least partially reflected from the cornea of ​​the patient's eye, wherein the returning rays are optionally formed by centering rays.

[0049] Here, a centering ray can be formed by setting the laser beam used for treatment in an attenuated form. Specifically, the centering ray is configured such that it acts non-therapeutically on the patient's eye, but only provides a reflection from the cornea detectable by the UVL-LVC system. Alternatively or additionally, a centering ray can be provided in other spectral ranges, such as the visible and / or infrared spectral ranges. For this purpose, for example, the UVL-LVC system can have an additional laser source. This provides the advantage that a centering ray can be provided when necessary, which can be detected by conventional CCD and / or CMOS detectors and / or is even visible to the human eye. Accordingly, the centering ray has a spectrum in the infrared and / or visible spectral range or consists of a spectrum in the infrared and / or visible spectral range. Alternatively, the centering ray has a spectrum in the ultraviolet spectral range or consists of a spectrum in the ultraviolet spectral range. Optionally, it is provided by laser radiation emitted by a UV laser source in an attenuated form.

[0050] Optionally, the UVL-LVC system includes a control unit, which is optionally designed to execute scanning and positioning evaluation algorithms and / or reflection analysis algorithms. This provides the feasibility of automatic centering based on detected backscatter.

[0051] Optionally, the imaging optics are designed to provide a focal field. To this end, the imaging optics optionally include an objective lens for imaging laser radiation within the focal field, wherein the objective lens includes lenses constituting the focal field. The advantage of a focal field is that it improves the uniformity of the incident angle of the laser beam onto the curved cornea, and thereby also improves the uniformity of the injection volume acting on the corneal portion to be treated. Thus, depending on the corneal centering position of the UVL-LVC system, the need for injection volume correction can be selectively eliminated.

[0052] The focal field may optionally have a focal field diameter of at least 6 mm, at least 8 mm, or at least 10 mm. This provides the advantage that the focal field diameter is on the same order of magnitude as the corneal area to be treated.

[0053] Optionally, each location of the focal field has a local midpoint of curvature located on a side opposite to the imaging optics, and wherein each location of the focal field preferably has a radius R. s The focal field curvature is within the range of 6mm to 60mm, optionally within the range of 7mm to 55mm, optionally within the range of 8mm to 50mm, optionally within the range of 10mm to 30mm, and optionally within the range of 12mm to 20mm. This provides the advantage that the focal field curvature is similar in size to the corneal curvature and accordingly enables the delivery of injection volume for corneal treatment with high uniformity.

[0054] Optionally, the imaging optics are designed to: enable laser radiation to be applied perpendicularly to a curved surface, wherein the curved surface has a local midpoint of curvature at each location, the local midpoint of curvature being located on a side opposite to the imaging optics, and wherein the curved surface has a diameter and / or radius R of at least 6 mm. F The surface curvature ranges from 8 mm to 50 mm. This provides the advantage that the laser radiation is incident as perpendicularly as possible at each point in the area to be treated, and accordingly provides a uniform injection volume for uniform treatment.

[0055] Optionally, the UVL-LVC system also includes a spacing determination unit designed to determine the spacing between the imaging optics and the curved surface of the patient's eye or cornea. This provides the feasibility of precisely directing the curved focal field onto the patient's cornea, especially when the patient's eye is not secured by a contact interface or contact lens.

[0056] Optionally, the UVL-LVC system is designed to detect Purkinje reflections within an angular range of at least 2.5° by detecting the reflection of radiation incident on and at least partially reflected from the cornea of ​​the patient's eye via imaging optics. This provides the advantage of being able to use Purkinje reflections within a large angular range to center the UVL-LVC system relative to the patient's eye. Thus, it eliminates the need for other types of centering, such as centering based on the midpoint of the pupil. Optionally, the UVL-LVC system is designed to detect a first Purkinje reflection within an angular range of at least 2.5°. Alternatively or additionally, it is also possible to detect one or more other Purkinje reflections within an angular range of at least 2.5°.

[0057] Optionally, the UVL-LVC system is designed to use detected Purkinje reflections for fully automatic and / or partially automatic and / or manual alignment of the UVL-LVC system, wherein automatic and / or manual alignment (if necessary, by means of visualization of the reflections to the user) is optionally performed according to CSCLR conditions. Here, the UVL-LVC system can be designed to use an algorithm for calculating the fluence loss function for centering correction during automatic centering by the lead of the scan position. This provides the advantage of achieving particularly simple and reliable centering.

[0058] The UVL-LVC system is optionally designed to determine the detected position of the Purkinje reflex as an offset position, where the offset position represents the deviation from the centering condition of the CSCLR condition. Here, for example, the UVL-LVC system can achieve precise treatment while remaining at the offset position using a scanning device, even when centered at an offset position that deviates from the CSCLR condition.

[0059] Optionally, the centering ray is incident on the cornea of ​​the patient's eye through an imaging optics device, such that the centering ray has a radius of curvature of R. S The reflex focal field. Here, determining the position and / or orientation of the UVL-LVC system relative to the patient's eye optionally includes analyzing the detected retroreflections, wherein the radius of curvature R of the reflex focal field is used. S The patient's pre-set corneal curvature radius R C The axial distance between the cornea and the imaging optics is used to position and / or orient the UVL-LVC system relative to the patient's eye. Furthermore, the incidence of the centering ray involves lateral scanning of the centering ray in the x and y directions, and optionally in the z direction, using a scanning system, and determining the appropriate settings of the scanning system.

[0060] Optionally, the centering ray has a parallel beam, and the detection of backscattering includes detecting a first Purkinje reflection of the parallel beam. This provides advantages in detecting and evaluating Purkinje reflections compared to the incident beam.

[0061] Optionally, the method includes determining the offset position based on detected Purkinje reflections, where the offset position characterizes the deviation from the centering according to CSCLR conditions. Here, the method can also include determining the lead amount of the UVL-LVC system to the offset position. Furthermore, the method can optionally determine the appropriate coordinates for the laser radiation to be incident on to treat the patient's eye, taking into account the offset position and the deviation of the centering according to CSCLR conditions associated with the offset position. This provides the advantage of enabling precise treatment even when the centering deviates from CSCLR conditions.

[0062] Optionally, the method may include continuously monitoring the displacement position using an eye tracker, and optionally tracking the displacement position in the event of a change in displacement position determined by continuous monitoring. In particular, continuous monitoring can also be performed during treatment to continuously ensure the accuracy of the treatment.

[0063] Conventional systems typically use a first Purkinje reflection, either a fixed or centered laser, to fix the patient on the visual axis (“target”) of the patient’s eye. The recommended CSCLR condition is met when the Purkinje reflection is centered on the system’s optics and the optical system axis and visual axis are vertically and horizontally coaxial. Due to the optical geometry of conventional systems, the first Purkinje reflection can only be found when it is already on or minimally deviated from the optical system axis, where the conventional system has a very small receiving angle for the reflection to enter the optical ray path. However, even with a small deviation from correct centering (e.g., starting at 0.2 mm), the Purkinje reflection cannot be used for alignment in conventional systems because the optical aperture is so small that even a small deviation is undetectable. Therefore, larger deviations cannot be corrected using the Purkinje reflection in conventional systems because the reflection cannot be detected by the system when it deviates significantly from the system’s optical axis. This is further complicated by cases with immobilized or uncooperative patients, where the Purkinje reflex may be lost again even after the patient has been immobilized. Furthermore, the "parallax error" of the surgical microscope—the difference in the direction of the reflection in the observer's left and right eyes due to binocular alignment—makes accurate alignment difficult in conventional systems. Automatic centering based on the CSCLR using the Purkinje reflex is absent in conventional systems and is not feasible using them due to limitations arising from the optical geometry of the conventional systems.

[0064] Optionally, the UVL-LVC system also includes a radiation source and a control unit. The radiation source provides a centering beam in the form of one or more circles to be incident on the cornea of ​​the patient's eye via imaging optics. The control unit is designed to detect and analyze the return radiation of the incident radiation in the form of one or more circles. Optionally, the UVL-LVC system also includes a scanning system, wherein the centering beam in the form of one or more circles is provided by means of a point-shaped centering beam and deflection motion is provided by the scanning system. This provides the advantage that circles can be used to center the UVL-LVC system onto the patient's eye.

[0065] Optionally, analyzing the retroreflection of one or more circles includes analyzing the deviation of the shape of the retroreflection from the shape of the incident radiation of one or more circles. This provides the advantage that the deviation from the centering position can be identified based on the shape deviation of the retroreflection from the incident circles and / or their arrangement relative to each other and / or their position relative to the optical axis. Optionally, the control unit is designed to determine the alignment of the system axis of the UVL-LVC system with the corneal curvature axis of the patient's eye when the deviation of the shape of the retroreflection from the shape of the incident radiation of one or more circles is minimal or equal to zero. Deviations can exist in particular from circular to elliptical shapes, equidistant arrangements of circles or ellipses, and / or concentric arrangements of circles or ellipses around a common center of symmetry. Optionally, when the deviation of the shape of the retroreflection of one or more circles from the shape of the incident radiation of one or more circles is below a preset threshold or equal to zero, the system axis of the UVL-LVC system extends through the apex of the patient's eye and is coaxial with the corneal curvature axis. This provides the possibility of easily and reliably centering the UVL-LVC system to the apex of the patient's eye. Optionally, multiple circles may have different diameters.

[0066] The control unit is optionally designed to execute an algorithm for calculating the injection loss function for centering correction. This provides the advantage of using centering information to precisely adapt the injection settings in order to achieve the most accurate treatment results possible.

[0067] Optionally, the incident centering rays, which are in the form of one or more circles, are incident by means of point-like centering rays, wherein deflection motion is provided by a scanning system. Furthermore, the method may optionally include analyzing the return of the centering rays, which are incident as one or more circles, wherein the positioning and / or orientation of the system axis of the UVL-LVC system relative to the patient's eye is determined based on the deviation of the shape of the one or more returned circles from the shape of the one or more incident radiation circles and / or their arrangement relative to each other and / or their position relative to the optical axis and / or based on the symmetry between the incident circles and their return.

[0068] Optionally, when the deviation between the shape of the reflected radiation and the shape of one or more circles of the incident radiation is less than a preset threshold or equal to zero, the consistency between the system axis of the UVL-LVC system and the corneal curvature axis of the patient's eye is determined. Similarly, the method may optionally include: when the deviation between the shape of the reflected radiation and the shape of one or more circles of the incident radiation is less than a preset threshold or equal to zero, determining that the system axis of the UVL-LVC system extends through the apex of the patient's eye.

[0069] The method may optionally further include automatically centering the system axis of the UVL-LVC system to the apex of the patient's eye or automatically centering the system axis of the UVL-LVC system to a point on the patient's eye that deviates from the apex, and determining the point of deviation of the patient's eye as the offset position. Furthermore, the method includes determining appropriate coordinates for the laser radiation to be incident on the patient's eye, taking into account the offset position and the deviation associated with the centering according to CSCLR conditions.

[0070] It is known in the prior art that manual centering to a vertex is performed by inputting displacement coordinates, which typically represent the reference center of the topography (usually measured along the corneal curvature axis). This is commonly used for topography-guided correction, but also in standard spherical correction, although the correct reference axis can be the visual axis in this case. The latter is feasible because, for a normal eye, the CV (“corneal vertex,” i.e., the point on the cornea where the corneal curvature axis penetrates with the patient fixed) is sufficiently close to the ocular pole, i.e., the visual axis. This is also because the midpoint of the corneal curvature roughly coincides with the optical nodal point on the second image side of the eye (see the Gullstrand, Liou-Brennan eye model). Typically, the user manually moves the treatment center based solely on a visual comparison with the topography measurement. Alternatively, the user inputs displacement coordinates into the system, which are given in that direction relative to the pupillary center (CSC), and these displacement coordinates are, for example, taken from the topography measurement. In both cases, a disadvantage is that, due to illumination differences, the pupil diameter during the topography measurement is not necessarily consistent with the pupil diameter under laser. The frequent shifts in pupil center due to pupil size result in suboptimal centering because the corneal apex is not correctly determined.

[0071] Furthermore, alternative embodiments of the present invention also provide the feasibility of performing automatic centering relative to vertices, which is not known from the prior art and is not feasible by means of conventional systems.

[0072] Hereinafter, the features and implementations mentioned above and explained below should be considered not only as disclosed in the separately expressly presented combinations, but also as included in other technically meaningful combinations and implementations.

[0073] Now, with reference to the accompanying drawings, further details and advantages of the invention, as well as the technical background, will be explained in more detail with reference to the following examples and alternative embodiments. Attached Figure Description

[0074] Hereinafter, without departing from the scope of the invention, the features of the invention described above and in various embodiments can be used not only in the exemplary combination described herein, but also in other combinations or individually.

[0075] The attached diagram shows:

[0076] Figure 1 A schematic diagram showing the ablation profile of an improperly positioned structure;

[0077] Figure 2 A schematic diagram of a UVL-LVC system according to an alternative implementation is shown;

[0078] Figure 3A The ray path of a UVL-LVC system according to an alternative implementation is shown;

[0079] Figure 3B An exemplary receiving angle of a conventional UVL-LVC system is shown;

[0080] Figure 3C An exemplary receiving angle of a UVL-LVC system according to an alternative implementation is shown;

[0081] Figure 4 An exemplary view showing the patient's eye and the centered imaging optics of the UVL-LVC system;

[0082] Figure 5 The differential curvature radius R is shown. Δ Explanation;

[0083] Figure 6 This illustrates the principle behind the non-coaxial alignment of the patient during fixation;

[0084] Figure 7 This demonstrates an explanation of the principle behind the Purkinje reflector.

[0085] Figure 8 The explanation of incident centering to the vertex via the ring mark is shown;

[0086] Figure 9 A schematic diagram showing the ray path of a UVL-LVS system according to an alternative implementation is provided.

[0087] Figures 10A to 10I An exemplary view showing the reflection of a ring incident on a vertex.

[0088] In the following figures, for simplicity, the same or similar elements are denoted by the same reference numerals in different embodiments. Detailed Implementation

[0089] Figure 1 The diagram illustrates the principle of prism correction error (Tip / Tilt) formed using a conventional centering method with insufficient precision when the patient is not fixed to the center of a fixed object or "fixed cloud". Here, the patient's eye 10, with cornea 12 and fovea 14, is... Figure 1 The image shows the optical axis 16 or visual axis 16 of the patient's eye, the ablation profile 18, the scanning system 20, and the fixation element 22 on which the patient fixes their gaze. The visual axis 16 intersects the cornea 12 at the ophthalmic pole 24.

[0090] If the patient does not fix their eye 10 at the center of the fixation element 22 as intended, but instead fixes it, for example, at the edge region of the fixation element 22, this will cause the ablation profile 18 to not be correctly applied along the necessary treatment axis (e.g., along the visual axis 16; which is defined by the ocular pole (OP) and the point on the fixation element 22 where the patient's eye 10 is fixed, and therefore not orthogonal to the visual axis 16). To better illustrate, in Figure 1 The relationship is shown in a highly exaggerated manner.

[0091] Therefore, when treating a patient's eye using a UVL-LVC system, it is essential to ensure that such prismatic errors are avoided. Failure to do so can result in an undesirable situation where the ablation profile 18 is not applied to the correct plane, i.e., not to the surface normal, i.e., perpendicular to the visual axis 16. This can be facilitated by the patient preferably fixing themselves in a largely fixed, but "incorrect," direction, i.e., permanently looking in a fixed direction that does not correspond to the center of the fixation element 22 (during surgery, depending on the refractive error and treatment duration, the patient may no longer be able to clearly see the fixed target).

[0092] Figure 2A schematic diagram of a UVL-LVC system 100 according to an alternative embodiment of the present invention is shown. The UVL-LVC system 100 includes a UV laser source 102, a scanning system 104, a control unit 106, and a planning unit 108. For data exchange between the control unit 106 and the UV laser source 102, the scanner 104, and the planning unit P, the control unit 106 has an interface (shown as a box at control unit S) through which data lines can be transmitted via cables. The planning unit 108 also has an interface for data exchange with the control unit 106 (shown as a box at planning unit P). Wireless transmission is also possible. The planning unit 108 has a computing unit (not shown) through which planning data is calculated. The terms scanner and scanning system are used synonymously within the scope of this disclosure.

[0093] exist Figure 3AThe diagram exemplarily illustrates the principle arrangement of the optical beam path in one embodiment of a UVL-LVC system 100, particularly an application component of the UVL-LVC system 100. A laser beam 110 is provided as a UV laser source by an excimer laser 112. The laser beam 110 is attenuated by an (optional) optical attenuator 114, deflected by a deflector 116, and enters an aperture (or pinhole) 118, and then enters a beam shaper 120. The beam shaper is used to shape the raw excimer laser beam into a Gaussian or super-Gaussian pulse fluence distribution. The laser beam 110 is capable of being deflected laterally in the x and y directions (indicated by curved arrows) via a scanning system 104. From here, the laser beam 110 is guided into a first hinged arm. In the illustrated embodiment, the laser beam is movably connected to a basic unit (not shown) via a first rotating hinge 122 (indicated by a rotation axis and rotation arrow symbol). The basic unit includes a laser source 102 or excimer laser 112, an optical attenuator 114, an aperture 118 (and a deflector 116 located in the ray path between the optical attenuator 114 and the aperture 118), a ray shaping element 120, and a scanning system 104. On the side opposite to the basic unit, a first hinge arm is movably connected to a second hinge arm via a second rotary hinge 122 (shown via a rotation axis and rotation arrow symbol). Optionally, one or more additional rotary hinges (not shown) can also be configured. The laser beam 110 is guided into the second hinge arm via the second rotary hinge 112 through two additional deflectors 116. From there, the laser beam 110 is deflected toward the patient's eye 10 via another deflector 116. Here, the laser beam 110 is focused onto the cornea 12 of the patient's eye 10 via a focusing optics device or an imaging optics device 124. Here, the imaging optics device 124 is configured in two pieces. The deflector 124c is located between the first lens group 124a and the second lens group 124b in the ray path. The required lenses for the two lens groups 124a and 124b are shown only schematically. Here, the imaging optics 124 is configured such that it has a receiving angle of at least 2.5°, which is used to detect the reflection of radiation incident on the cornea through the imaging optics.

[0094] Figure 3B and Figure 3C A schematic diagram illustrates a conventional UVL-LVC system with a receiving angle of approximately 1° for a retroreflection of 126. Figure 3B Comparison with a ULV-LVC system having a receiving angle of approximately 30° according to an alternative embodiment of the present invention.

[0095] Hereinafter, methods according to alternative embodiments of the invention are described by way of example, which can be performed using a UVL-LVC system as described with reference to the preceding drawings.

[0096] Radiation, particularly the laser beam and / or centering rays used to treat the patient's eye 10, is incident on the cornea 12 via the imaging optics 124 and produces a backscatter, as at least a portion of the incident radiation is reflected from the cornea 10. Here, the backscatter is projected back towards the UVL-LVC system and detected by the imaging optics due to the large receiving angle. From the position of the backscatter, the eccentricity of the UVL-LVC system according to the invention relative to the corneal apex can be determined using suitable sensing devices by means of knowledge of the geometry of the device, the corneal curvature (K-value), and optical imaging. Therefore, it is feasible to determine the first-order Purkinje reflection and center the UVL-LVC system 100, for example, toward the visual axis 16 by the advance of the scanning system 104. For the UVL-LVC system 100 according to the invention, this provides various options for automatic centering, for example, at the apex or at an offset position away from the apex, and precise coaxial alignment between the visual axis 16 and the system axis becomes unnecessary. By combining scanner lead with imaging optics, the system can achieve centering according to CSCLR conditions. These imaging optics can be configured as microscopic optics or can incorporate microscopic optics. Here, the centering process requires fixing the patient to a fixed target.

[0097] According to an alternative implementation, the UVL-LVC system 100 uses Purkinje reflection for centering. This allows for the detection of the reflected light through the imaging optics 124 at the exit aperture and a large receiving angle, and enables the location of reflections belonging to the CSCLR by means of Purkinje reflection.

[0098] This is an example in Figure 4 The diagram illustrates the patient's eye 10 and the centered imaging optics 124 of the UVL-LVC system 100. It can be identified that the optical opening 1000 of the imaging optics has approximately the same order of magnitude as the working distance 1002 from the cornea 12 of the eye. Therefore, the imaging optics has a large receiving angle for collecting the reflection from the cornea 12, which is approximately 37° in the illustrated embodiment. Note that in… Figure 4 In the image, the UVL-LVC system is shown in a manner that is not centered relative to the corneal curvature axis (the line connecting the apex and the fixed target when the patient is fixed). Figure 4Also shown is an exemplary laser beam 110 incident on the cornea 10 via an imaging optics device 124 (solid line), and a retroreflection 126 (dashed line) reflected from the cornea 10, the retroreflection being reflected at an angle χ relative to the ULV-LVC system and collected by the imaging optics device 124.

[0099] The advantageous imaging optics of the UVL-LVC system 100 thus bring about an optimization and significant simplification of the manual method according to the prior art UVL-LVC system, and additionally achieves automatic centering using Purkinje reflections. For this purpose, the UVL-LVC system according to the invention detects and visualizes Purkinje reflections that return to the system at a specific eye position. Due to the large receiving angle, the Purkinje reflections are visible even when the eye is significantly displaced from the CSCLR condition. In the case of manual centering, the user displaces the application component until the visible reflection reaches the center of the system optics, thereby satisfying the CSCLR condition (coaxial alignment).

[0100] Furthermore, when the scanning ray direction and the reflection direction are symmetrical about the axis parallel to the optical system, the UVL-LVC system 100 can determine the corneal point where its normal is parallel to the optical axis. For this, the scanning ray must be changed by the system. This allows the treatment center to be automatically shifted to this point using corresponding scan offset coordinates (automatic centering via scan lead). The user therefore no longer needs to manually move the application components to place the Purkinje reflection at the optical center (or the system can optimize this through the user's suboptimal manual centering), but instead moves it to its corresponding coordinates ("approximate CSCLR centering").

[0101] Furthermore, in the UVL-LVC system 100, corneal coordinates belonging to or approximating the discovered CSCLR can be optionally registered to the simultaneously detected pupil and / or iris and / or limbus. This means that once corneal coordinates belonging to the CSCLR (also applicable to vertex positions) have been found and registered, retroreflection detection is no longer required. This also allows for compensation for moderate slippage of the contact interface used in the UVL-LVC system according to the invention during docking, or for safe and automatic recentering in the event of contact interface detachment (“suction loss”) after interface reapplication.

[0102] Another alternative embodiment of the invention based on Purkinje reflection is described below by way of example. The principle of the solution determined by Purkinje reflection should be explained above, see [link to relevant documentation]. Figure 4 Further background information will be explained below.

[0103] The Purkinje reflex is essentially nonexistent. A reflection always occurs upon incident light onto the cornea, and in the case of a first-order Purkinje reflex, this reflection is determined in front of the cornea by the law of reflexes. In ophthalmology, the Purkinje reflex is commonly used to refer to the reflex corresponding to the Purkinje reflex under CSCLR conditions. Essentially, this is because, in conventional, existing UVL-LVC systems, this reflex is only observed when the patient is almost always correctly positioned; it is sometimes referred to as "Purkinje centering."

[0104] refer to Figure 5 This explains the differential radius of curvature R associated with precision treatment. Δ Here, the difference radius of curvature R Δ From the radius of curvature R of the focal field S (Scanning radius of curvature) and corneal radius of curvature R C The difference is formed. Here, the calculation is a good approximation based on the spherical function method (spherical model) of the cornea or focal field.

[0105] Here, Figure 5 The patient's eye 10 is shown on the left side of the diagram, where the focal field curvature radius R is shown. S and corneal curvature radius R C The right side shows an enlarged view of the radius of curvature in a spherical coordinate system.

[0106] Here, the coordinate z depends on the radial variable r and the radius of curvature R (Equation 1). From this, the differential radius of curvature R is obtained. Δ Mathematical descriptions (Formulas 2 to 4):

[0107]

[0108] Δz(R C ,R S ,r)=z C (R C ,r)-z S (R S ,r)=z(R Δ ,r) (2)

[0109]

[0110] According to one alternative implementation, it is advantageous that the UVL-LVC system is designed such that the focal field curvature radius R S Located on the order of magnitude of a typical cornea. In particular, it is advantageous to accordingly construct imaging optics. This provides the following advantage: a significantly reduced volume loss can be achieved. (Reference) Figure 5 The calculation of the interpretation determines the radius of curvature R of the difference. ΔThe differential radius of curvature corresponds to the “effective” corneal curvature of light incident from the z-direction. In other words, the cornea is imaginarily bent into a focal field radius of curvature by difference calculation—figuratively speaking. Therefore, for a focal field radius of curvature with a value between approximately 8 mm and approximately 16 mm, using R… C A typical corneal curvature radius of 7.86 mm is obtained for the effective corneal curvature from approximately R. Δ ≈450mm to approximately R Δ The value is approximately 15 mm. This parameter is determined by the law of reflection to influence the direction of rays reflected from the cornea. For example, if the reflection of the incident pulsed laser beam itself is used for retroreflection detection (see below), it is immediately apparent how the reflection angle relates to the incident direction and the corneal normal at the point of reflection on the cornea (equal to the incident position), which is also related to the displacement of the eye below the application component.

[0111] A key feature of the interaction between the imaging optics and the remaining system optics of the UVL-LVC system is that, since the optics delivering the laser beam to the eye are identical, light reflected from the cornea (e.g., Purkinje reflection) can be effectively “collected” by the system and, when needed, guided back through the optical system to the basic unit. This is particularly simplified by integrating the scanning system at the starting point of the ray path (observed from the UV laser source). The light collected by the eye can then be deflected or redirected at appropriate points in the ray path of the optics and delivered to the detector, for example, before reaching the scanning system. Here, optionally, the receiving angle for collecting the light projected back from the cornea is particularly large, and imaging in the remaining system optics is specifically optimized for this.

[0112] according to Figure 6 The explanation is based on an approximate determination of the reflection angle in a UVL-LVC system according to an alternative implementation. Figure 6 The left side shows a comparison between non-coaxial fixation (dashed line) and coaxial fixation (solid line) at the apex according to the CSCLR condition for the patient's eye. Note that this view is simplified, particularly in terms of corneal shape. Here, the superscript "MB" indicates a description of a system according to an alternative embodiment of the invention, and the superscript "M90" indicates a description of an exemplary conventional system according to the prior art. On the right side, according to pupil coordinates r... MB ≈r M90 This shows the incident angle α of the ray on the cornea in the UVL-LVC system. MB The estimated value. Then, using the lateral displacement Δ LS The reflection angle 2α is obtained. MB +γ. Here, angle γ is the radial vector R between the system axis and the focal field. SThe angle between them, the radial vector indicating the incident position of the laser radiation (see...) Figure 6 (See the right-hand diagram). Here, Δ LS Used for pupil coordinates r in calculation M90 The eye pole (OP) and corneal apex (CV, also called vertex) are equivalent here without loss of generality. For angles γ and α... MB Applicable to the following:

[0113]

[0114] With the help of the focal field curvature radius R S The aforementioned values ​​also provide a suitable environment for this application to detect rays reflected from the cornea. To demonstrate this, Figure 6 The left side illustrates the principle of non-coaxial alignment of the patient under fixed conditions. Although the target is fixed (note: the directional laser beam is used as the target (green)), the patient is not coaxially aligned with the optical system, which corresponds to correct centering according to the CSCLR condition (solid line). Assume the displacement of the system axis (optical axis) of the UVL-LVC system relative to the CSCLR condition is Δ. LS = 2mm (i.e., the displacement of the dashed ray path relative to the solid ray path, with the scanning system at zero position) and assuming a focal field curvature radius R of 12mm. S When the scanner is at zero position, the dashed ray is achieved by a suitable ray, such as an alignment ray, guided by the scanning system. Then, the reflection angle 2α... MB The calculation of +γ is aided by Figure 6 The formula on the right and r M90 =Δ LS We get approximately 2α MB A reflection angle of +γ = 20°. This angle can be detected without problems by the imaging optics and can be processed in the UVL-LVC system.

[0115] A system structure with the interaction of imaging optics and the remaining system optics is advantageous because light projected back from the cornea can be effectively “collected,” detected, and processed by the system.

[0116] For better understanding, the focal field curvature radius R will be used in the following explanation. S and corneal curvature radius R C Equivalent. The precise optical ray path preceding the imaging optics (observed from the ray source) is no longer important for the following considerations.

[0117] The patient was fixed, but the CSCLR criteria were not met (see Δ). LS of Figure 6(and description). When scanning the eye using appropriate rays deflected by a scanner, different paths are obtained for the incident and reflected rays. Figure 7 ).

[0118] according to Figure 7 The principle of the Purkinje reflector (or ocular reflector) is explained according to an alternative implementation method, namely, a method for centering a UVL-LVC system based on the Purkinje effect. For this purpose, it is assumed that the focal field radius of curvature and the corneal radius of curvature are equal, i.e., R... S =R C In the left figure, the CSCLR condition is met. In the right figure, it is not met. The patient's eye is fixed, but shifted to the left relative to the system axis of the UVL-LVC system (see apex). The focal field curvature radius is shown as a semicircle 1004 (dashed line on the right). The dashed double arrow 1006 in the right partial figure indicates that if telecentric incidence is possible, the incident ray will be reflected.

[0119] Under CSCLR conditions (left-hand diagram), the ray is projected back upon its own reflection, where R is applicable. S =R C If this is not the case, then a symmetrical deviation is thus obtained around the system axis (and therefore in the figure when scanning to the left or right), which can be obtained from R. S and R C The difference is calculated (and this is also true in the case of aspherical or ellipsoidal corneas). The CSCLR reflex, or ocular pole belonging to the axis mentioned above, typically appears very close to the corneal apex CV. Therefore, in medical practice, the Purkinje reflex of the CSCLR condition usually determines the apex, and vice versa.

[0120] If the CSCLR condition is no longer met, the ray will no longer self-reflect (R S =R C ), or there is no longer a symmetrical ray orientation (R). S Not equal to R C Instead, the ray trajectory is shown as in the right-hand section of the diagram. The only applicable scanning direction guiding the ray to the corneal point (eye pole) belonging to the CSCLR (actually the apex) is: the reflected rays are symmetrically (“symmetrical ray pairs”) reflected back to the axis of movement (see Δ). LS (Approximate CSCLR condition). All other rays show reflections to the right, i.e., an increase in deviation in the same direction.

[0121] Manual positioning and automatic centering are achieved through alignment:

[0122] In manual centering, the user moves the imaging optics (or an application component with integrated optics) laterally in the x,y plane (application component) above the eye until the corneal reflection (Purkinje reflection) of the centering ray entering along the optical system axis returns to the system center (i.e., coaxial with the system axis). With the patient fixed, the CSCLR condition is thus satisfied, and the visual axis and system axis are coaxial. Automatic system-controlled displacement (x / y displacement) achieves the same effect.

[0123] Both methods require a suitable visualization for the user. For example, this could be an auxiliary circle and a reflected "vector" display as an overlay for visual perception. Various suitable display options can be considered, up to a purely numerical display of the appropriate values. Furthermore, the measurement process must be permanently repeated through alignment during manual positioning and, advantageously, automatic centering, with the display updated accordingly at a specific repetition rate.

[0124] This centering also advantageously allows for registration relative to the simultaneously detected pupil and / or iris and / or limbus (i.e., determining the eye position relative to the system, the "reference position"), in order to compensate for possible slippage of the contact interface during docking or to enable reliable recentering (e.g., in the case of "suction loss"), which is feasible by means of the reference position. In solutions without a contact interface, an eye tracker system, which can be implemented, is preferably used for registration.

[0125] For example, a fixed laser can be used as the scanning beam entering during manual and automatic centering via alignment, the fixed laser extending coaxially with the system optics. Alternatively, a suitable beam guided by the scanner can be used, such as the alignment beam at the scanner's zero position. Other separate, preferably monochromatic, beam sources can also be considered. Even pulsed laser beams can therefore be used with appropriate attenuation (see also below). The direction of the scanning beam can be calculated given that the dispersion and imaging geometry of the optics are known. If the scanning beam and the therapeutic beam (UV) have the same wavelength, the therapeutic beam and the scanning beam extend in the same direction.

[0126] Automatic centering via scanner lead time:

[0127] With the aid of the known geometry of optical imaging in the UVL-LVC system according to an optional implementation and in understanding R S and R CIn this case, the "symmetric ray pair" (i.e., also the position of the detected echo) and its corresponding scan position ("offset position") can be determined, thereby also determining the position of the corneal point belonging to the "symmetric ray pair". This gives the "offset position" of the corneal point (the ocular pole used for ablation centering on the cornea according to the CSCLR condition) relative to the optical axis of the system.

[0128] This enables automatic centering, which can be achieved to the offset position using a scanner with lead time.

[0129] In practice, due to the radius of curvature R of the focal field S and corneal curvature radius R C The differences are usually significant, making the situation more difficult in automated programs. Given the patient's corneal curvature radius R... C (or, in the case of ellipsoidal cornea, the corneal curvature k-value (or its principal radius of curvature)) and the focal field radius of curvature R S In this case, the effective radius of curvature can be determined. Using this value and geometric data (optical imaging in the UVL-LVC system according to the invention), the reflection angle can be calculated, which matches an approximate CSCLR condition with the patient fixed. This angle can also be found by scanning the cornea.

[0130] The Purkinje reflections or their corresponding scanner positions (“offset positions”) that are found to be in the CSCLR condition can now be used to: convert the scan coordinates of the ablation pulses so that the scan coordinates are adapted for ablation of the eye under the contact interface in a separate case, i.e., just when the system is not coaxially positioned relative to the CSCLR condition.

[0131] The problem is, of course, two-dimensional, and requires two-dimensional scanning and corresponding analysis. For automatic centering, an "offset position" is used for all pulse coordinates to move the treatment center to the corneal coordinates belonging to the CSCLR case during ablation. The user therefore does not need to manually apply the displacement component to align the Purkinje reflex.

[0132] It should be noted that in this case, the volume loss compensation function should be corrected using the UVL-LVC system. This is possible by understanding the optical geometry, R... S R C (or corneal curvature data, see above) and the determined “offset position” are taken into account.

[0133] Of course, this is only a limited feasibility and does not preclude the advantages gained through improved volume loss compensation. Other limitations must also be considered regarding automatic centering so that the accuracy of ablation is not affected. Therefore, the eye must already be positioned "relatively" well, i.e., "close to the CSCLR standard."

[0134] Advantageously, the “offset position” can also be advantageously registered relative to the simultaneously detected pupil to compensate for possible slippage near the interface during docking or to achieve reliable recentering (e.g., in the case of “suction loss”).

[0135] In another embodiment, the offset position is simultaneously detected using the tracking signal from an eye-tracking system. Here, the eye tracker continuously probes the position of the pupil at a high repetition rate. Preferably, the eye tracker also probes the limbus and / or the iris. At the moment the offset position is determined by the above method, the current tracking position of the eye tracker is also evaluated.

[0136] Therefore, during treatment, in cases where the eye does not dock with the contact interface, the offset position can be continuously tracked via the output signal of the eye-tracking system. In eyes that cannot dock for medical or anatomical reasons, this allows for maintaining correct treatment focus at least for a small number of eye movements. The only drawback is that continuously recalculating the injection loss compensation with timely eye-tracking data is currently too costly and cannot fully retain the advantages of docked eyes.

[0137] The implementation of this process requires a suitable, preferably monochromatic, centering beam for scanning. For this purpose, a coupled input laser or a aligning beam laser can be used, for example. The latter, which passes through the scanner, is particularly suitable. Therefore, no additional scanner is required; instead, the scanner can be used to deflect the ablation laser beam. For sufficient accuracy, it is advantageous that the incident centering beam passes through the focal point of the optics within a range of approximately 0.5 mm or less. For this, the precise wavelength for which the microscopic optics are designed must be considered. Preferably, the centering beam is designed such that, after reflection at the eye (which corresponds to the effect when passing through a scattering lens based on curvature) and through the focusing optics of the therapeutic beam and the detection optics of the reflected light, it is focused onto the detector.

[0138] Therefore, a fast and intelligent scanning method is advantageous. Static scanning is unnecessary. Instead, efficient and fast scanning algorithms (e.g., extended Newton's method) can be implemented based on the problem geometry. Furthermore, this solution requires fast position assessment algorithms and detection systems, such as cameras. For example, deflectors or beam splitters can be used to image incident and / or outgoing rays onto the detection system. Software for visualizing user support functions, such as direction indicators or proximity indicators for manual centering, is also advantageous, as are algorithms for calculating the "flux loss function for centering correction."

[0139] For completeness, it should be mentioned that reflectance detection methods can be used preoperatively, but also during treatment, within the realm of scattering on rough, treated (i.e., ablated) stromal surfaces. This can be used as an online morphology method and for ablation control. For this purpose, it is advantageous to accurately determine the distance between the cornea and the focusing optics, which can also be determined optically using suitable measurement mechanisms, such as OCT, fringe projection, or sensing devices, based on spectral processing of reflectance in optics with longitudinal chromatic aberration.

[0140] In one particular design, the ablation laser beam itself (as the "incident ray") can be used for Purkinje reflection detection during ablation.

[0141] It is also possible to consider using ablation rays as Purkinje reflection signals before actual ablation, provided that this is done with highly attenuated therapeutic rays.

[0142] Therefore, and optionally for other implementations, it is advantageous not only to reduce the UV laser energy below a threshold acceptable for laser safety, but also preferably to spatially filter the UV laser, which can have a large spatial spread in the relevant part of the ray path, otherwise it would negate the high position resolution in detection.

[0143] Therefore, according to an alternative embodiment of the invention using Purkinje reflection, there are the following three options for centering:

[0144] - Manual positioning / centering, for example, outputting the image of the Purkinje reflection to the user graphically.

[0145] - The system automatically centers the object based on CSCLR conditions.

[0146] - Automatic centering at offset points outside of CSCLR conditions by using the advance of the scanning system.

[0147] Different implementation methods exist in the first two variations. Therefore, according to one alternative implementation, only the imaging optics can be moved. Alternatively, the entire internal optics can be moved together with the imaging optics, which is advantageous in that the optical system axes move together. This can be achieved, for example, by moving the application components (where the optical axes of the system automatically move together, i.e., move together) and / or by moving the entire optical beam guide of the laser system via x / y displacement units.

[0148] For example, during manual positioning / centering, the user moves the application component or imaging optics above the patient's eye until the (visualized) reflection reaches the center of the system optics, thereby satisfying the CSCLR condition (coaxial alignment).

[0149] With the aid of suitable software (analyzing the retroreflection direction from the detected reflection position on a suitable detector) and hardware (x / y displacement units for the application component or (part of) the laser system), it is also possible for the system to automatically perform alignment (automatic centering through alignment). For this purpose, it is preferable to detect the retroreflection with the center of incidence on the optical axis of the system (therefore the reflection direction is also known from the geometry of the device). The adjustment signal for the displacement of the x / y displacement unit can optionally be derived from the deviation of the reflection direction from the scanning ray. The system (directly or via (part of) the laser system) then moves the application component or microscopic optics in a direction that makes the reflection coaxial with the central scanning ray. This achieves the CSCLR condition. This is preferably done in a control loop, wherein the system continuously performs reflection detection and displacement of the application component at a suitable repetition rate until perfect alignment of the eye with respect to the application component is achieved.

[0150] Furthermore, when the scanning ray direction and the reflection direction are symmetrical about the parallel lines of the optical system axis, a UVL-LVC system according to an optional embodiment can determine corneal points whose normals are parallel to the optical axis. For this purpose, the scanning ray or centering ray can be changed by the system. Points on the cornea belonging to (approximately, see above) CSCLR conditions or near-CSCLR conditions can be determined by analyzing the reflections. In this way, the treatment center can also be moved fully automatically to the point using the corresponding scanner offset coordinates (automatic centering via the advance of the scanning system). The user therefore no longer needs to manually move the application components to place the Purkinje reflection at the optical center (or the system can optimize through the user's suboptimal manual centering), but instead moves to the corresponding coordinates ("approximate CSCLR centering").

[0151] The following explains other alternative embodiments of the UVL-LVC system and method according to the invention, the subject of which is the centering of the UVL-LVC system at vertices. Here, in particular, such alternative embodiments are represented by a manual method of inputting displacement coordinates and an automatic centering option relative to the vertex.

[0152] Here, there are three methods similar to CSCLR conditions:

[0153] 1. Manual positioning

[0154] 2. Automatic centering via alignment

[0155] 3. Automatic centering via scanner lead time

[0156] Here, multiple rings arranged concentrically with equal spacing are incident on the cornea through an imaging optics device, and the retroreflection from the cornea is detected within an angle range of at least 2.5° by means of the imaging optics device. According to option 1, the user moves the application component such that the retroreflection of the rings incident through the imaging optics device is as circular and symmetrical as possible (the ring spacing is equal in all directions) and centered relative to the optical axis. Furthermore, the ring pattern moves in the direction of the optical system axis. In the case where the system axis is off-center relative to the vertex (more precisely relative to the corneal curvature axis), the reflection pattern (shown at the system's entry aperture) becomes a displaced ellipse, and the spacing of the reflection pattern along the ellipse is no longer circular. That is, three criteria must be met for centering. Then, centering along the corneal curvature axis ("vertex centering") is achieved. Optionally, the vertex is found by the UVL-LVC system, visualized by the user, and the user can move the treatment center to the vertex by lateral displacement of the application component of the UVL-LVC system according to the invention (i.e., placing the vertex at the center of the system optics device, or aligning the corneal curvature axis coaxially with the system axis).

[0157] In Option 2, the displacement of the applied component is automatically achieved through the system via x / y displacement units. Therefore, an algorithm is needed to evaluate the elliptical shape and / or its position in order to derive the adjustment signal for the automatic displacement direction. The system can then check for symmetry conditions (primarily circular, centered retroreflections), which can be visually verified by the user. Optional output for user visualization is also feasible but not mandatory.

[0158] In option 3, the determination of the corneal vertex location is performed from the scanning pattern (i.e., an ellipse, ring, or circle) and the geometry of the cornea and the system's geometry (which may require modeling the shape of the cornea, for example, as an elliptic ring). Therefore, the determined vertex is approximate.

[0159] The UVL-LVC system determines vertex positions from a known incident ring pattern, i.e., based on the incident circle, the resulting retroreflection pattern, the system geometry, the eye model, and its associated eye model parameters (measured or average values, e.g., R). C The treatment center (Q value) is determined. Therefore, the treatment center can be optionally set automatically by the system using the corresponding scanner offset coordinates (coordinates of the vertex position used for addressing calculations), such that the treatment center of the ablation pattern is centered relative to the point position (the user therefore no longer necessarily needs to manually move the application component to place the vertex at the optical center, but rather moves the application component to the vertex to make the scanned pattern “symmetrical” (see above)). Advantageously, the automatically detected vertex can be optionally registered to the pupil simultaneously detected by co-observation or by a dedicated eye tracker. Therefore, when using a contact interface to couple the patient's eye to the ULV-LVC system, moderate slippage of the contact interface can be compensated during docking, or safe and automatic recentering can be achieved after reapplying the contact interface in the event of contact interface detachment (“suction loss”).

[0160] This principle is similar in some respects to that of the Placido disk topography apparatus—with a key difference, of course: while the Placido disk topography apparatus evaluates the imaging (non-directional radiation) of an illuminated ring such that each point of the cornea is illuminated by a different ring and each point of the cornea produces Purkinje reflections at each point on the illuminated ring, the evaluation is still performed via directional incident radiation in the UVL-LVC system according to the alternative implementation explained herein, which produces only the reflections of rays oriented towards the cornea. In contrast, in the conventional Placido disk topography apparatus, only reflected rays arriving at (entrance pupil) through the nodes of the camera system are detected. The corneal shape is calculated from this and the associated reflection conditions via (typically iterative) reconstruction.

[0161] According to the explained alternative implementation, a ring or circle is scanned using a UVL-LVC system. Various situations arise here... Figure 8The following is exemplarily illustrated. Here, the exact situation depends on the geometry of the incident light, the geometry of the eye 10, and the geometry of the reflection detection device, and may thus deviate from the illustrated principle. If the patient's eye under the UVL-LVC system according to the invention is not aligned with the corneal curvature axis, i.e., not aligned with the line connecting the corneal apex and the fixed target when the patient's eye is coupled to the UVL-LVC system via the patient interface (left-hand image), and thus the corneal curvature axis is not coaxial with the optical axis of the UVL-LVC system according to the invention, then the loop traveled by the scanner will not produce a circular and symmetrical loop as a reflection due to the "tilt" of the eye, i.e., because the rays are incident at the point at different angles of incidence. This results in characteristic deformation of each circle and mutual displacement of the scanned circles with different diameters (as shown, see...). Figure 8 (Note that the deformation / displacement of this ring does not reflect the actual situation).

[0162] Conversely, if the system axis of the UVL-LVC system coincides with the corneal curvature axis, then... Figure 8 The situation shown on the right. This situation (as in the morphology) is characterized by the rings being as circular and symmetrical as possible (equal spacing between rings in all directions), and the circle being centered relative to the optical system axis. Thus, the vertices, serving as morphological landmarks of the cornea, lie precisely on the corneal curvature axis (“vertex centering”). This is because the human cornea, generally (without severe pathological changes or trauma), can be well modeled using an ellipse (or ellipsoidal ring shape). This is further facilitated by the ability to construct measurements of corneal parameters (morphology: R). C With a suitable corneal model (such as Q value) and knowledge of the optical geometry, the vertex position on the cornea can be determined, thereby enabling the determination of the corresponding scanner offset position, which belongs to the corneal vertex.

[0163] Hereinafter, the features of the present invention described above and explained in various exemplary embodiments can be used not only in the combinations illustrated by example, but also in other combinations or individually without departing from the scope of the present invention.

[0164] The device description associated with the method features is similarly applied to the corresponding method for those features, and the method features are corresponding to the functional features of the described device.

[0165] The following reference Figure 9 A further alternative implementation of the UVL-LVC system is described in detail.

[0166] According to an optional embodiment, the UVL-LVC system has an imaging optics device 124 configured as a microscopic optics device. The microscopic optics device consists of two parts (MO1 and MO2) and is designed such that ray shaping is optimal for properly focusing the UV laser beam used for treatment onto the cornea (approximately 0.7 mm FWHM), i.e., at an ablation wavelength of 193 nm. For example, the ray deflector 124c enables, for example, visual observation of the eye 10 using an appropriate camera. The microscopic optics device is also designed to focus on a focal field curvature radius RS of 20 mm (see also Figure 3). Here, the geometry is chosen (see above) such that the effective optical diameter of the microscopic optics device 124, i.e., the optical opening, corresponds to approximately 50 mm at the entrance aperture of the application component, and an operating pitch of approximately 47 mm is achieved (the distance between the image-side vertex of the microscopic optics device and the corneal vertex, having a working plane WP, and also referring to the operating pitch Δ). Figure 2 Both the therapeutic beam and the scanning beam are deflected (not shown) by a scanning system configured as a 2D scanner (x / y deflection, propagation direction z), and the scanner plane is appropriately advanced toward the direction of the microscopic optics 124 by a 4f optics device (relay-Optik, "extension tube", also not shown) such that said plane is the pupil plane of the microscopic optics 124 for focusing on the eye along the radius of curvature of the focal field. The laser beam 110 is exemplarily shown with focus for the center and periphery (green or blue dashed beams). Any scanning beam or centering beam is also exemplarily drawn. It has been explained that the UV laser beam can be used for treatment and that scanning beams or centering beams can be applied simultaneously (in situ scanning during ablation) or temporally separately (e.g., scanning beams determining a reflection pattern, see below, before or after treatment). Therapeutic beams (or the same source) can also be used directly for scanning or centering beams, where certain requirements must be considered, such as those presented below (attenuation or beam shaping). If the scanning beam is generated from a separate source, similar or other known methods can be used to define the beam. Thus, for example, wavelength dispersion in the optical device can be considered for the specific beam path and the incident direction of the scanning beam or the centering beam onto the cornea 12. In this case, it may also be necessary to adapt the beam divergence of the scanning or centering beam to produce a suitable focus in the working plane or focal field. Otherwise, in the case of infrared scanning beams, a clear focus will not be formed in the corneal plane (when the focal position at 193 nm is in the corneal plane, the focus is "deeper" in the image, i.e., below the working plane WP of the therapeutic beam or UV laser beam), because the refractive power of the microscopic optical device at that wavelength is lower than at 193 nm (assuming positive dispersion).

[0167] The direction of the retroreflection (reflection 126) is determined by the incident angle and the position of the scanning ray on the cornea and the corneal normal at the incident position, the latter in turn determined by the corneal shape. The retroreflection is deflected by MO (or only by MO1) as long as it enters the optical aperture and can be detected at the appropriate location (e.g., by coupling the output towards the scanning system at another beam splitter behind MO1 or directly before the scanning system). The retroreflection is derived in a known manner from the ray calculation / imaging formula via the microscopic optics and the precise ray path thereafter. The incident position (or focal field position) of the scanning ray in the working plane is unilaterally defined (e.g., as a function of the scanner angle). Therefore, the known geometry of the cornea 12 and the known working spacing, as well as the known imaging via the imaging optics 124, also define the precisely defined deflection of the retroreflection 126 (or the shape and size of the reflection pattern, e.g., in the case of circular scanning) on ​​the detector. It should be noted that the reflection pattern shown is derived from the reflection puncture point in the vertex plane of the optical device MO1, that is, without the specific inverse calculation from the optical device to the detector. This is irrelevant to the content being discussed, because within the calculable range, only the size of the pattern after passing through the optical device and the detector is changed, but the symmetry behavior and relationships in the pattern itself are not changed.

[0168] In the following text, see references Figures 10A to 10I The invention describes, by way of example, the method of centering the UVL-LVC system onto the apex of the patient’s eye by analyzing the reflection of radiation incident on the cornea in a circular form through the imaging optics, but is not limited thereto.

[0169] Here, in Figures 10A to 10I The left side shows the scanning pattern in the working plane (WP) in front of the eye, and the right side shows the reflection pattern, as shown in the vertex plane on the object side (i.e., before passing through the optical device). The axes on the right are intersected in mm. In the left figure, the loop shown in thick line represents the optical system axis, and the triangle drawn in thick line represents the corneal vertex. In the right figure, the circle around the origin of the coordinate system indicates the entry aperture of the imaging optics at the application point.

[0170] It is important to note that the same scanner angle (e.g., circular scan) was used in the calculations for different cases—even with different wavelengths (scanning beam wavelengths of 193nm and 840nm). Due to image dispersion in the optical system, different wavelengths will result in different illumination positions and angles on the cornea under the same scanner deflection! All calculations are based on the aforementioned optical systems (including the 4f optical system). A Q value of -0.25 was chosen. An elliptical corneal model with a central curvature radius of 7.86 mm and a polarity of 7.86 mm were used as the eye model for calculating reflection.

[0171] Figure 10A The scan involves multiple circles with different diameters (left image). The optical system axis of the applied component is shifted 1.5 mm horizontally ("left") and 0.5 mm vertically ("down") relative to the corneal apex (more precisely, the corneal curvature axis). In the retroreflected image, ellipses with characteristic shapes, arrangements, and positions are formed in the circular scan. It can be identified that reflections at the selected scan radius (the radius of the largest ring in the left image is 1.78 mm) cannot be completely returned to the system.

[0172] The scanning wavelength is 193 nm.

[0173] Figure 10B The scan involves multiple circles with different diameters (left image). The optical system axis of the applied component is not displaced relative to the corneal apex. In the reflected image, circles with midpoints around the optical system axis are also formed in the circular scan. It can be identified that reflections for the scan radius of the selected scan (the radius of the largest ring in the left image is 1.78 mm measured in the working plane) cannot be completely returned to the system.

[0174] The scanning wavelength is 193 nm.

[0175] Figure 10C Multiple circles with different diameters were scanned (left figure). The largest ring radius (left figure) was obtained from the image, compared to cases 1 and 2 (193 nm), with the same scanner deflection, due to changes in dispersion in the optics. The optical system axis of the applied component was shifted 1.5 mm horizontally ("left") and 0.5 mm vertically ("down") relative to the corneal apex (more precisely, the corneal curvature axis). In the reflected image, ellipses with characteristic shapes, arrangements, and positions were formed in the circular scan. It can be identified that reflections for the selected scan radius (the radius of the largest ring in the left figure is measured as 2.35 mm in the working plane) cannot be completely returned to the system.

[0176] The scanning wavelength is 840 nm.

[0177] Figure 10D The scan involves multiple circles with different diameters (left image). The optical system axis of the applied component is not displaced relative to the corneal apex. In the reflected image, circles with a midpoint around the optical system axis are also formed in the circular scan. It can be identified that reflections for the scan radius of the selected scan (the radius of the largest ring in the left image is 2.35 mm) cannot be completely returned to the system.

[0178] The scanning wavelength is 840 nm.

[0179] Figure 10E A line with a length of 5.94 mm is scanned in both the horizontal and vertical directions (left image). The optical system axis of the applied component is shifted 1.5 mm horizontally ("left") and 0.5 mm vertically ("down") relative to the corneal apex. In the reflected image, a "curved" line displaced relative to the system axis is formed. It can be identified that reflections of the deflected (line length) portion cannot be fully returned to the system.

[0180] The scanning wavelength is 193 nm.

[0181] Figure 10F A line is scanned in both the horizontal and vertical directions, each with a length of 5.94 mm (left image). The optical system axis of the applied component is not displaced relative to the corneal apex. In the reflected image, a straight line with the midpoint of the optical system axis is formed. It can be identified that reflections of a deflection (line length) cannot be fully returned to the system. This is the case up to a line length of 3.56 mm (see circular scan).

[0182] The scanning wavelength is 193 nm.

[0183] Figure 10G A line with a length of 7.82 mm is scanned in both the horizontal and vertical directions (left image). With the same scanner deflection, a longer line length is obtained from the image, compared to cases 5 and 6 (193 nm), in the altered image due to dispersion in the optics (left image). The optical system axis of the applied component is shifted 1.5 mm horizontally ("to the left") and 0.5 mm vertically ("downward") relative to the corneal apex (more precisely, the corneal curvature axis). In the reflected image, a "curved" "line" displaced relative to the system axis is formed. It can be identified that reflections with respect to the deflection (line length) cannot be fully returned to the system.

[0184] The scanning wavelength is 840 nm.

[0185] Figure 10HA line is scanned in both the horizontal and vertical directions, each with a length of 7.82 mm (left image). The optical system axis of the applied component is not displaced relative to the corneal apex. In the reflected image, a straight line with the midpoint of the optical system axis is formed. It can be identified that reflections of a deflection (line length) cannot be fully returned to the system. This is the case up to a line length of 3.56 mm (see circular scan).

[0186] The scanning wavelength was 840 nm. The scannable area on the cornea is smaller compared to 193 nm (see circular scan).

[0187] If the eye is in the working plane (in cases 1 to 8) relative to the application component or imaging optics (see, for example) Figure 10A The displacement causes the reflected pattern or retroreflection to change in a calculable and defined manner and method. From the scanned circle ( Figure 10A The left side (in the vertex plane of the optical device) becomes an ellipse ( Figure 10A (Right side). One feasible approach, currently feasible, is to "symmetrize" the reflection pattern by applying the component relative to the lateral displacement being studied. In the example above, only when the optical system axis and the corneal curvature axis become coaxial (vertex centered) can the reflection pattern (as in the Placido topography) be transformed from an ellipse without equidistant spacing and not centered relative to the optical axis (as in the Placido topography). Figure 10A (The right side) becomes a circle with radially equidistant spacing ( Figure 10B (Right side). Therefore, the midpoint of the circle is also located on the axis of the optical system. Note: For a real eye, one would obtain (more precisely) an approximate circle. This is due to the residual irregularities of the eye, or the deviation between the real corneal shape and the model shape, which is practically insignificant unless the morphology of the cornea itself is determined. However, here, the deviation from a circular shape would be below a preset threshold.

[0188] It can also be identified that the choice of scanning wavelength has no effect on general symmetry relationships, for example, with Figure 10A , Figure 10B and Figure 10C and Figure 10D This is in comparison to cases involving scanning or centering beam wavelengths of 193nm or 840nm. Of course, without further measures, a scanning beam wavelength close to or equal to the therapeutic beam wavelength is more advantageous because it allows for the capture of reflections from a larger corneal area. This assumes that the optics and focal position have been optimized for 193nm.

[0189] For line scan, an intuitive equivalent relationship is obtained (see...). Figure 10E , Figure 10F , Figure 10G and Figure 10H(The situation described above). In this situation, it can also be identified that the direction of the scanned lines is aligned as close as possible to the principal axis of the cornea, because otherwise, additional small distortions of the lines (corneal astigmatism) will occur. Typically, the input of the corneal k-value is performed in a refractive laser system, because the corneal k-value is also required for other purposes, such as optimizing the ablation profile. Conversely, additional distortions of the lines (or rotation of the line axis and analysis of the line shape) can also be used to determine or check the k-value by means of a simple ellipsoidal corneal model. This also allows for the determination or monitoring of eye rotation. This is of interest because specific baseline data must usually be determined by diagnostics for this purpose, and this baseline data must then be compared with, for example, current data from an eye tracker. According to an alternative embodiment of the invention, this can be omitted, because essentially only the corneal curvature value (see the k-value above, principal radius of curvature) must be known, which is typically known and considered as standard information at each corneal refractive surgical intervention.

[0190] Figure 10I Scan a circle for two different eye spacings. For better illustration, consider the case where the circle is already centered (see above). Figure 10B (The situation in the middle). The small circle on the right side of the figure corresponds to... Figure 10B The third ring (counting from the inside) in the middle has a precise working pitch. When the eye moves 2mm in the direction of the system's optical aperture, a circle that is exactly on the outside is formed at the same scanning angle.

[0191] The eye itself does not necessarily need to be at the optimal (i.e., accurate) working distance for centering. Nevertheless, the symmetry or shape of the reflection pattern is preserved, but variations in its size (or changes in the deflection of the reflection detected on the detector), such as those for... Figure 10I The case shown is illustrated below. For simplicity, only the centered case is shown. However, for the non-centered case, an equivalent relation is obtained. The centering of the eye itself in the working plane is achieved and defined only by symmetry conditions (e.g., equidistant circles centered on the optical system axis).

[0192] Given the corneal geometry (k-value, radius of curvature, e.g., derived from the morphology), it is also possible to determine the distance of the vertical displacement of the eye or cornea (or vertex) relative to the working plane, i.e., the deviation of the eye from the system's working distance, by the deviation from the desired shape or, in particular, size (extension) of the reflection pattern. Here, a suitable corneal model is a function of an ellipse or an ellipsoid. The latter is closer to the true corneal shape, which has different corneal curvatures (corneal astigmatism) along two mutually perpendicular meridians. Other models, such as those used in diagnostic devices, can also be considered. A morphology actually determined through preoperative diagnosis can also be used. The reflection is then calculated based on precisely said morphology (the basic shape of which can usually be described very well by an ellipsoidal model for non-pathological corneas). Therefore, in principle, this method can also be used to set the correct working distance. For this purpose, a reflection pattern determined according to the corneal geometry (e.g., vertex centering in cases where the application component is centered relative to the eye in other aspects) is determined relative to a predetermined pattern. The method can also be performed in cases of non-centered alignment. Therefore, the following algorithm is advantageous, particularly considering, for example, the "magnification" within the range of affine transformations such as parallel / shear stretching, and thereby determining the deviation of the eye from the working distance. It is possible to determine or monitor insufficient adjustment of the distance and display it together. For the case of centering, this is also clearly understood directly through the consideration of the three-angle function, since for the system, the reflection angle (already determined) and the opposite side (also already determined), as well as the distance to the intersection point with the optical system axis in the working plane (the geometry of the scanning ray deflection), are known in a manner calculated back to the object-side vertex plane of the lens. Therefore, the adjacent side defining the distance is also determined.

[0193] Optionally, the working spacing in the UVL-LVC system is actively set by the user, whereby, for example, a cross-interval laser is used and / or a clear image of the eye is evaluated on a camera. Various methods are employed here. However, if the working spacing is precisely set, the geometry of the corneal surface can be determined, in exactly the opposite way, from the reflection pattern, for example, based on an ellipsoidal model. For this purpose, for example, it is possible to use squared error minimization, where corneal model parameters are varied until the deviation between the measured and model-based calculated reflection patterns (where the corneal distance = working spacing is known) and in the case of known optical ray imaging / geometry becomes minimal. Other or similar known methods will be apparent to those skilled in the art, as the process is similar to, for example, in keratometers or other diagnostic systems and devices used for measuring the cornea (e.g., IOL-Master, Zeiss).

[0194] By combining measurements of the reflection pattern of the circular scan and the reflection of the central scan ray (the scan ray incident on the axis of the optical system), it may be possible to determine the difference between the vertex and the eye pole (or the deviation of the visual axis from the corneal curvature axis) when centered either relative to the vertex or relative to the CSCLR condition.

[0195] In addition, this disclosure also includes the following topics:

[0196] 1. UV laser-based systems for vision correction of impaired vision (UVL-LVC systems), including

[0197] - A UV laser source that emits preferred pulsed laser radiation.

[0198] - A scanning system for radiating laser radiation laterally in the x and y directions, and preferably also in the z direction.

[0199] -Control unit

[0200] - An imaging optical device, comprising a microscopic optical device, for focusing preferably pulsed laser radiation onto the cornea of ​​a patient's eye, wherein the optical aperture of the imaging optical device is designed such that the retroreflection χ detectable by the UVL-LVC system according to the invention is adequately focused. Max It can achieve a receiving angle of greater than 15°, preferably greater than 25°, and especially preferably greater than or equal to 37°.

[0201] 2. According to the UVL-LVC system of Subject 1, the optical aperture is greater than 50 mm, preferably greater than or equal to 60 mm, and the working pitch is less than 50 mm, preferably less than or equal to 40 mm.

[0202] 3. The UVL-LVC system according to subject 1 or 2, wherein its imaging optics includes an objective lens for imaging laser radiation in a focal field, wherein the objective lens includes a lens constituting a focal field for providing a focal field.

[0203] 4. The UVL-LVC system according to any one of topics 1 to 3 further includes a contact interface for coupling a patient's eye to the UVL-LVC system.

[0204] 5. A UVL-LVC system according to any one of topics 1-3, which is designed to: determine the axial spacing between the cornea and the optical system.

[0205] 6. The UVL-LVC system according to any one of topics 1 to 4, further comprising a detection system for incident and returned rays, preferably narrow-band scanning rays, scanning and position evaluation algorithms, and reflection analysis algorithms.

[0206] 6a. A UVL-LVC system according to any one of topics 1 to 4, wherein the scanning beam operates in the IR range or the visible spectrum.

[0207] 7. A UVL-LVC system according to any one of themes 1 to 4, wherein the scanning beam operates in the UV range and preferably corresponds to a strongly attenuated ablation laser beam (theme HV), and preferably is matched to the probe plane through an aperture plate and suitable refractive optical elements (theme CZM).

[0208] 7a. The UVL-LVC system according to topics 5-8 is designed to: detect the position of Purkinje reflection as the offset position.

[0209] 8. The UVL-LVC system according to Theme 7 is designed to: use the position of the Purkinje reflection for automatic centering or for manual alignment according to CSCLR conditions.

[0210] 9. The UVL-LVC system according to Topic 8 has an algorithm for calculating the injection loss function for centering correction in the case of automatic centering.

[0211] 10. A method for centering a UVL-LVC system, wherein,

[0212] - Understanding the geometry of optical imaging and the radius of curvature R of the focal field S and corneal curvature radius R C In this case, the positions of the "symmetrical ray pair" of the incident ray and the detected retroreflection (Purkinje reflection) and their corresponding scanner positions are determined, thereby giving the offset position of the corneal dot relative to the optical axis of the system under the CSCLR condition.

[0213] -This enables the scanner to automatically center at the offset position with a lead time.

[0214] -In this context, the axial distance between the cornea and the optical system is preferably considered together.

[0215] 11. The method for centering a UVL-LVC system according to Topic 10, wherein the offset position is used to: convert the scan coordinates of the ablation pulse such that the scan coordinates are correct for the ablation of the eye when the system is not aligned with the CSCLR condition.

[0216] 12. A method for centering a UVL-LVC system according to topic 10 or 11, wherein the offset position is continuously tracked during treatment by means of a corrective signal from an eye tracker.

[0217] 13. UV laser-based systems for the correction of impaired vision (UVL-LVC systems), including

[0218] - A UV laser source that emits preferred pulsed laser radiation.

[0219] - A scanning system for radiating laser radiation laterally in the x and y directions, and preferably also in the z direction.

[0220] -Control unit

[0221] - An imaging optical device, comprising a microscopic optical device, for focusing preferably pulsed laser radiation onto the cornea of ​​a patient's eye, wherein the optical aperture of the imaging optical device is designed such that the retroreflection χ detectable by the UVL-LVC system according to the invention is adequately focused. Max It can achieve a receiving angle of greater than 15°, preferably greater than 25°, and especially preferably greater than or equal to 37°.

[0222] 14. The UVL-LVC system according to Topic 13 has an optical aperture greater than 50 mm, preferably greater than or equal to 60 mm, and a working pitch less than 50 mm, preferably less than or equal to 40 mm.

[0223] 15. The UVL-LVC system according to topic 13 or 14, its imaging optics includes an objective lens for imaging laser radiation in a focal field, wherein the objective lens includes lenses constituting a focal field for providing a focal field.

[0224] 16. The UVL-LVC system according to any one of topics 13 to 15 further includes a contact interface for coupling a patient's eye to the UVL-LVC system.

[0225] 17. A UVL-LVC system according to any one of topics 13 to 16, further comprising a detection system for incident and returned rays, preferably radioactive rays, a scanning and position assessment algorithm, and a reflection analysis algorithm.

[0226] 18. The UVL-LVC system according to topic 17 is designed to: determine the offset position relative to the vertex by scanning a circle on the cornea of ​​a patient's eye and analyzing the reflection, i.e., the deformed ring detected by the UVL-LVC system according to the invention.

[0227] 19. The UVL-LVC system according to topic 18 is designed to: scan circles of different diameters and determine their displacement and deviation (deformation) from the shape of the circle, wherein, when no displacement or deformation is determined, the system axis of the UVL-LVC system according to the invention coincides with the corneal curvature axis and thus with the position of the vertex.

[0228] 20. According to topic 18 or 19, the UVL-LVC system is designed to: use the position of the vertex (or the offset position to it) for automatic centering of treatment coordinates or for manual alignment of the UVL-LVC system.

[0229] 21. The UVL-LVC system according to Topic 20 has an algorithm for calculating the injection loss function for centering correction in the case of automatic centering.

[0230] 22. The UVL-LVC system according to topic 20 or 21, which has an eye-tracking system and is able to evaluate the coordinates of the tracked eye position relative to the determined vertex position.

[0231] 23. A method for centering a UVL-LVC system, wherein,

[0232] The position of the vertex (or its offset) is determined by scanning a circle on the patient's cornea and analyzing the reflection, i.e., the deformed ring detected by the UVL-LVC system according to the invention.

[0233] - By using the offset position, automatic centering to the offset position or manual centering can be achieved by using a scanner with lead time.

[0234] 24. The method for centering a UVL-LVC system according to topic 23, wherein the offset position is used to: convert the scan coordinates of the ablation pulses such that the scan coordinates are correct for the ablation of the eye when the system is not aligned with the CSCLR condition.

[0235] 25. The method according to topic 23 or 24, wherein, preferably, the determined offset position is simultaneously aligned with the tracking coordinates of the eye tracked by an eye tracker, such that even if the eye is not fixed, the determined vertex position and the treatment position centered thereon remain unchanged in the coordinate system that moves with the eye.

[0236] List of reference numerals

[0237] 10 Patient's Eyes

[0238] 12. Cornea

[0239] 14 Center recess

[0240] 16. The visual axis / optical axis of the eye

[0241] 18 Ablation Profile

[0242] 20 Scanning System

[0243] 22 Fixing elements

[0244] 24 Eye Pole

[0245] 100 UVL-LVC System

[0246] 102 UV laser source

[0247] 104 Scanner or Scanning System

[0248] 106 Control Unit

[0249] 108 Planning Units

[0250] 110 laser beams

[0251] 112 excimer laser

[0252] 114 Attenuator

[0253] 116 Deflector

[0254] 118 aperture

[0255] 120 X-ray forming components

[0256] 122 Rotating hinge

[0257] 123 Application Components

[0258] 124 Imaging Optical Device

[0259] The first lens group of the 124a imaging optical device

[0260] The second lens group of the 124b imaging optical device

[0261] 124c deflector

[0262] 126 Retraces

[0263] Optical opening of 1000 imaging optical device

[0264] 1002 Working spacing of imaging optics

[0265] 2000 working pitch

[0266] 2002 Working Plane

[0267] 2004 Scanning System

[0268] χ Angle of reflection

[0269] χ max The maximum detectable angle of the reflected light or the receiving angle of the imaging optics.

[0270] R S Focal field curvature radius

[0271] R CCorneal curvature radius

[0272] R Δ Differential radius of curvature

[0273] CV vertices.

Claims

1. A UVL-LVC system (100), said UVL-LVC system being a UV laser-based system (100) for correcting impaired vision in a patient's eye (10), wherein, The UVL-LVC system (100) has: - A UV laser source (102) designed to emit laser radiation for treating the patient's eye (10); - An imaging optics (124) for focusing the laser radiation onto the cornea (12) of the patient's eye (10), wherein the imaging optics (124) is designed to achieve a receiving angle χ of at least 2.5°. Mαx The backscattering (126) of radiation is detected, which is incident on the cornea (12) of the patient's eye (10) through the imaging optics (124) and is reflected at least partially from the cornea (12) of the patient's eye (10).

2. The UVL-LVC system according to claim 1, wherein, The UVL-LVC system (100) and the imaging optics (124) are designed to enable the receiving angle X Mαx Greater than 5°.

3. The UVL-LVC system according to claim 1, wherein, The UVL-LVC system (100) and the imaging optics (124) are designed to enable the receiving angle X Mαx 37° or greater.

4. The UVL-LVC system (100) according to claim 1, wherein, The imaging optical device (124) is designed as a microscopic optical device or includes a microscopic optical device.

5. The UVL-LVC system (100) according to claim 1, wherein, The imaging optical device (124) has an optical opening and a preset working distance, wherein the diameter of the optical opening is designed to be greater than or equal to the preset working distance.

6. The UVL-LVC system (100) according to claim 1, wherein, The imaging optics (124) has an optical opening with a diameter of at least 50 mm, and wherein the imaging optics has a working pitch of less than 50 mm.

7. The UVL-LVC system (100) according to claim 1, wherein, The imaging optics (124) has an optical opening with a diameter of at least 60 mm, and wherein the imaging optics has a working pitch of less than 40 mm.

8. The UVL-LVC system (100) according to claim 1 further includes a contact interface for coupling the patient's eye (10) to the UVL-LVC system (100).

9. The UVL-LVC system (100) according to claim 1, wherein, The UV laser source (102) is designed to emit pulsed laser radiation, and / or wherein the UV laser source (102) is designed as an excimer laser (112) or includes an excimer laser.

10. The UVL-LVC system (100) according to claim 1 further includes a scanning system (104) for transversely scanning the laser radiation in the x and y directions.

11. The UVL-LVC system (100) according to claim 1 further includes a scanning system (104) for scanning the laser radiation laterally in the x and y directions and in the z direction.

12. The UVL-LVC system (100) according to claim 10, wherein, The UVL-LVC system (100) is designed to couple the retroreflection (126) of the radiation, detected by means of the imaging optics (124), out from the ray path of the laser radiation between the imaging optics (124) and the scanning system (104).

13. The UVL-LVC system (100) according to claim 10, wherein, The UVL-LVC system (100) is designed to couple the retroreflection (126) of the radiation detected by means of the imaging optics (124) out from the ray path of the laser radiation.

14. The UVL-LVC system (100) of claim 1 further includes a detection system for returning rays formed by the detected back radiation (126) of radiation incident on the cornea (12) of the patient's eye (10) via the imaging optics (124) and reflected at least partially from the cornea of ​​the patient's eye (10).

15. The UVL-LVC system (100) according to claim 14, wherein, The returning rays are formed by centering rays.

16. The UVL-LVC system (100) according to claim 15, wherein, The centering ray has a spectrum in the infrared and / or visible spectral range or is composed of a spectrum in the infrared and / or visible spectral range.

17. The UVL-LVC system (100) according to claim 16, wherein, The centering ray has a spectrum in the ultraviolet spectral range or is composed of a spectrum in the ultraviolet spectral range.

18. The UVL-LVC system (100) according to claim 17, wherein, The centering ray is provided in a weakened form by the laser radiation emitted by the UV laser source (102).

19. The UVL-LVC system (100) according to claim 1 further includes a control unit (106), wherein, The control unit (106) is designed to execute scanning and position evaluation algorithms and / or reflection analysis algorithms.

20. The UVL-LVC system (100) according to claim 1, wherein, The imaging optics (124) are designed to provide a focusing field.

21. The UVL-LVC system (100) according to claim 20, wherein, The imaging optics (124) includes an objective lens for imaging the laser radiation in a focal field, wherein the objective lens includes a lens configured to provide the focal field.

22. The UVL-LVC system (100) according to claim 20, wherein, The focal field has a focal field diameter of at least 6 mm.

23. The UVL-LVC system (100) according to claim 20, wherein, Each part of the focal field has a local midpoint of curvature located on the side opposite to the imaging optics (124).

24. The UVL-LVC system (100) according to claim 23, wherein, Each part of the coke field has a radius R s Focal field curvature in the range of 8mm to 50mm.

25. The UVL-LVC system (100) according to claim 1, wherein, The imaging optics (124) are designed to apply the laser radiation perpendicularly to the curved surface, wherein the curved surface has a local midpoint of curvature at each location on a side opposite to the imaging optics (124), and The curved surface has a diameter and / or radius R of at least 6 mm. F Surface curvature in the range of 8mm to 50mm.

26. The UVL-LVC system (100) of claim 25 further includes a spacing determination unit designed to determine the spacing between the imaging optics and the curved surface of the patient's eye or the cornea.

27. The UVL-LVC system (100) according to claim 1, wherein, The UVL-LVC system is designed to detect Purkinje reflections within an angle range of at least 2.5° by detecting the backscattering of the radiation incident on the cornea (12) of the patient's eye (10) through the imaging optics and reflected at least partially from the cornea (12) of the patient's eye (10).

28. The UVL-LVC system (100) according to claim 27, wherein, The UVL-LVC system (100) is designed to detect first Purkinje reflections within an angular range of at least 2.5°.

29. The UVL-LVC system (100) according to claim 27, wherein, The UVL-LVC system (100) is configured to use the detected Purkinje reflections for automatic centering and / or manual alignment of the UVL-LVC system (100).

30. The UVL-LVC system (100) according to claim 29, wherein, The automatic centering and / or manual alignment are performed according to CSCLR conditions.

31. The UVL-LVC system (100) according to claim 29, wherein, The UVL-LVC system (100) is designed to perform automatic centering by means of an algorithm for calculating the injection loss function for centering correction.

32. The UVL-LVC system (100) according to claim 27, wherein, The UVL-LVC system (100) is configured to determine the detected position of the Purkinje reflection as an offset position, wherein the offset position characterizes the deviation from the centering of the CSCLR condition.

33. The UVL-LVC system (100) according to claim 1 further comprises a radiation source and a control unit (106), the radiation source being configured to provide a centering ray in one or more circular forms to be incident on the cornea (12) of the patient's eye (10) through the imaging optics, and the control unit being configured to detect and analyze the backscatter (126) of the radiation incident in one or more circular forms.

34. The UVL-LVC system (100) according to claim 33 further includes a scanning system (104), wherein, The centering ray is provided in the form of one or more circles by means of a point-form centering ray, and deflection motion is provided by a scanning system.

35. The UVL-LVC system (100) according to claim 33, wherein, Analyzing the retroreflection (126) of one or more circles includes analyzing the deviation of the shape of the retroreflection from the shape of the one or more circles of the incident radiation.

36. The UVL-LVC system (100) according to claim 35, wherein, The control unit (106) is configured to determine the consistency between the system axis of the UVL-LVC system (100) and the corneal curvature axis of the patient's eye (10) when the deviation between the shape of the retroreflection (126) and the shape of one or more circles of the incident radiation is less than a preset threshold or equal to zero.

37. The UVL-LVC system (100) according to claim 36, wherein, When the shape of one or more circles of the retroreflection (126) deviates from the shape of one or more circles of the incident radiation from a preset threshold or equal to zero, the system axis of the UVL-LVC system (100) extends through the apex of the patient's eye (10).

38. The UVL-LVC system (100) according to claim 33, wherein, The multiple circles have different diameters.

39. The UVL-LVC system (100) according to claim 33, wherein, The control unit (106) is configured to execute an algorithm for calculating the injection loss function for centering correction.

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