WO2022223690A1

WO2022223690A1 - Device for automatically laser-treating the trabecular meshwork

Info

Publication number: WO2022223690A1
Application number: PCT/EP2022/060550
Authority: WO
Inventors: Martin Hacker; Manfred Dick; Gerald Kunath-Fandrei
Original assignee: Carl Zeiss Meditec Ag
Priority date: 2021-04-23
Filing date: 2022-04-21
Publication date: 2022-10-27
Also published as: DE102021204066A1

Abstract

The invention relates to a device for automatically laser-treating the trabecular meshwork, said device being based on the ab externo trabeculoplasty or trabeculectomy approach. The device consists of a laser unit comprising a laser source and a focusing unit, a deflecting unit for changing the emission direction of the laser beam onto the trabecular meshwork in a controlled manner, and a control unit which is designed to control the laser unit or an ab externo laser treatment of the eye and the deflecting unit. According to the invention, a contact glass is provided which is designed to allow multiple deflections of the laser treatment beam into the anterior chamber angle of the eye when the contact glass is positioned in front of the eye, thus allowing an up to 360° treatment of the trabecular meshwork. The invention relates to a device which is designed for an automatic 360° treatment of glaucoma in particular. The device preferably additionally has an illumination unit for projecting an illumination beam into the anterior chamber angle of an eye and an image processing unit such that the device can also be used for examination and diagnostic purposes.

Description

Device for automated laser processing of the trabecular structure

The present invention relates to a device for automated laser processing of the trabecular meshwork, the device being based on ab-externo laser trabeculoplasty or trabeculotomy, in particular “selective laser trabeculoplasty” (SLT for short). Another frequently used variant of an ab-externo laser trabeculoplasty is the argon laser trabeculoplasty (ALT),

In addition to ab-externo laser trabeculoplasties, there are also ab-internal variants, such as excimer laser trabeculotomy or trabeculostomy (ELT), in which the trabecular meshwork is ablated with a laser using an endoscopic optical fiber. However, the ab interno variants are invasive procedures that can usually only be carried out in the context of other surgical interventions with a sensible risk/benefit ratio.

Trabeculoplasty and trabeculomomy are treatments of the trabecular meshwork. For the sake of simplicity, the term trabeculoplasty will also include trabeculotomy (removal of trabecular tissue) and trabeculostomy (creation of a hole in the trabecula). The trabecular meshwork is a spongy network in the region of the chamber angle and also includes the juxtacanalicular tissue opposite to Schlemm’s canal. Through the network of the trabecular meshwork, most of the outflow of the constantly produced aqueous humor takes place in a regulated manner, which supports, among other things, the maintenance of healthy eye structures such as the cornea and the lens. A smaller part of the outflow, especially in younger people, also takes place via the so-called uveoscleral outflow path,

Most of the outflow resistance in the trabecular outflow path is created by the juxtacanalicular tissue. If the trabecular meshwork in the eye hardens due to age or illness and regular drainage is no longer possible, the aqueous humor builds up in the eye and leads to an increase the intraocular pressure, which in turn can cause damage to the ocular nerves and even blindness - glaucoma,

The various trabeculoplasties have different mechanisms of action (mechanical, cellular, biochemical), but some are not yet fully understood.

With ELT, for example, tissue is ablated in a hole-shaped manner using UV light at 308 nm, which is intended to achieve a direct increase in the permeability of the trabecular meshwork through the resulting openings. With ALT, continuous laser radiation generated by means of an argon laser or laser diodes at e.g. 514 nm is used to create drainage openings through thermal interactions with the tissue, which tend to close again through scarring and through healing processes. US 2020/0016002 A1 now also proposes using laser pulses in the femtosecond range at 1030 nm for athermal trabecular meshwork processing in order to cut drainage channels with it.

In contrast, SLT is a simple and highly effective laser therapy in the area of the trabecular meshwork, which has been shown to reduce intraocular pressure in glaucoma (glaucoma). It is assumed that the treated tissue is stimulated at the cellular and biochemical level, which leads to tissue regeneration and/or release of endogenous substances, which in turn increase tissue permeability and aqueous humor outflow.

In addition to the selective absorption, especially of the wavelength 532nm in the pigment melanin, the SLT laser therapy uses very short light pulses with low energy and thus primarily affects only the pigmented cells of the trabecular meshwork and extracellular pigment grains (https://doi.org/10.1155/2015/ 476138). Such pigment particles or cells may have previously become detached from the iris, for example in the case of a pigment dispersion syndrome, and then the trabecular meshwork to become clogged, as in pigmentary glaucoma. Depending on their energy density, these cells are either stimulated or destroyed and then renewed or broken down via a regenerative, endogenous self-healing process. Pigment grains can be broken up into smaller grains, particularly at higher laser energies. These regeneration processes improve the drainage of the aqueous humor and lower the intraocular pressure.

It should be noted that although melanin has an absorption coefficient that increases evenly towards shorter wavelengths, the ratio of its absorption to that of other substances occurring in the eye, such as hemoglobin, sometimes changes considerably, so that favorable wavelength bands result for selective absorption. For example, the absorption of melanin in the range of 480 - 520 is about a factor of 10 higher than that of hemoglobin.

In the regeneration processes mentioned above, the release of cytokines as a result of the laser treatment also seems to contribute to improving aqueous humor drainage, for example by increasing the permeability of tissues such as Schlemm's canal and supporting the breakdown of cell debris (Garg and Gazzard, "Selective laser trabeculoplasty; past, present, and future", doi: 10.1038/eye.2017.273).

With the SLT, it is advantageous to have such a large laser treatment zone that the approx. 300 μm wide TM viewed from the direction of the laser beam can be safely covered, for example by means of a 400 μm laser treatment zone. ZEISS creates this 400 μm laser treatment zone from 52 individual spots, each approx. 50 μm in size. The actual thermal damage zones are defined by the pigmented TM cells, since the absorption mainly only takes place there

The basic features of an SLT method, also referred to as selective laser trabeculoplasty, are described in the documents US Pat. No. 5,549,596 A, for example. In this method for the treatment of glaucoma, intraocular melanoma and macular edema, the relevant area is irradiated with laser radiation of between approximately 0.01 and approximately 5 Joules/cm ² .

The solution described in US Pat. No. 8,568,393 B2 also relates to an SLT method, in which the treatment has been optimized through the use of scanners.

A laser system that can be used for SLT processes is described, for example, in a device brochure from Ellex (http://www.ellex.com/de/). The SLT treatment takes place at a wavelength of 532nm, with a pulse length of 3ns and a pulse energy of approx. 1mJ on a spot diameter of 400 μm in the trabecular meshwork of the eye, whereby the treatment is carried out over a circumference of 180° or even 360° can.

Due to the fact that the selectively working laser systems known from the prior art have so far only been based on a fixed, unchangeable pulse length, they cannot be used universally. A system with a pulse length that can be selected, in particular intraoperatively, for a selectable selectivity of the damage to the entire cell or only to cell components is not known to date.

A further disadvantage of the known, selectively operating laser systems is that no patterns (spot patterns) are used which, in a structured manner, allow intracellular or cellular destruction.

So far, with a laser that covers the approx. 300 μm wide trabecular meshwork sufficiently wide (e.g. by means of a 400 μm wide laser irradiation zone composed of 50 μm individual spots), the thermal damage zones (treatment zones) are only covered by the occurrence of pigmented cells and extracellular pigment grains fixed. In addition to spot sizes, pulse lengths, energy densities and thermal damage zones, different pigmentation levels of the trabecular network would also have to be taken into account in order to be able to assess the therapeutic effect of the laser treatment or adjust it by adjusting laser parameters or patterns.

What all known systems for ab-externo laser trabeculoplasty have in common is that the laser beam and the eye fixation and alignment have always been carried out using a hand-held contact glass, which is cumbersome and severely limits the treatment speed. In particular, the use of a gonioprism as a contact lens requires sufficient training. Pattern scanning laser trabeculoplasty (PSLT) represents a certain advance, in which at least one pattern of a number of laser shots are applied together when the hand-held contact lens is in a position, which In particular, if a large part or the entire circle of the chamber angle is to be treated with adjacent or slightly separated laser spots, a method using beam guidance using a hand-held contact glass is very time-consuming, error-prone and tedious.

The object of the present invention is to develop a device for automated laser processing of the trabecular meshwork, which device can significantly simplify the rather cumbersome and time-consuming laser trabeculoplasty with contact glass. Furthermore, the device should be suitable for enabling a 360° treatment and better predictability of the achievable or evaluation of the currently achieved therapeutic effect.

According to the invention, the object is achieved by the features of the independent claims. Preferred developments and configurations are the subject matter of the dependent claims, This object is achieved with the present device for automated laser processing of the trabecular meshwork, consisting of a laser unit with a laser source and a focusing unit, a deflection unit for the controllable change in the irradiation direction of the laser beam onto the trabecular meshwork and a control unit that is designed to be the laser unit for an ab-externo laser trabeculoplasty of the eye and to control the deflection unit, solved by the fact that a contact glass is present, which is designed, when the contact glass is positioned opposite the eye, several deflections of the laser treatment beam in its anterior chamber angle and thus one up to To enable 360° treatment of the trabecular meshwork.

First configurations relate to the laser unit, consisting of a laser source and a focusing unit, which is preferably designed as an autofocus.

In particular, the laser unit is designed to enable laser trabeculoplasty using thermally stimulating, SLT or ALT treatment (i.e. femtosecond or picosecond laser) or a nanosecond laser (ns laser).

The ns laser can be focused anterior to the trabecular meshwork in order to produce a photodisruption in the aqueous humor there. According to the invention, the resulting pressure waves should stimulate the trabecular meshwork and reduce the intraocular pressure with a treatment that is gentle on the trabecular meshwork.

This treatment variant using photodisruption in the aqueous humor is independent of the absorption in the pigments and can therefore also take place at other wavelengths, for example the YAG laser wavelength of 1064 nm. As with SLT, this treatment is also planned over 360° with a spot arrangement that is as equidistant as possible. Furthermore, the laser unit is preferably designed to enable pattern-based laser trabeculoplasty treatment, with the treatment pattern being able to be generated in different ways.

The treatment pattern is preferably generated from individual spots with the aid of a scanner. However, it is also possible to use a diffractive optical element (DOE) in order to generate a plurality of laser treatment beams radiating in at the same time. Not preferred, but possible, is the generation of several such simultaneously radiating laser beams by optical beam splitters (splitting mirrors, dichroic mirrors, polarization splitters or fiber-optic splitters), which are then aligned by means of one or more scanners, for example realized by rotating mirrors or prisms , galvo mirrors, MEMS scanners, acousto- or electro-optical modulators or liquid crystal modulators,

In particular, the laser unit can also be designed to generate laser pulses with pulse lengths in the range of 50 ns-50 μs. The laser unit is preferably further designed to generate a spot pattern with an outer, approximately octagonal shape from square spots placed directly next to one another. The laser unit is also designed to provide light in particular with at least one wavelength in the range of 480-590 nm , for example 515 nm or 532 nm (for example using an InGaN laser diode or a frequency-doubled Nd;YAG laser),

A second group of configurations relates to the deflection unit for the controllable change in the irradiation direction. According to the invention, this is designed to change the position of the laser treatment beams in such a way that they are guided in different directions into the anterior chamber angle of an eye by the multiple deflections in the contact lens in order to to enable up to 360° treatment of the trabecular meshwork. Furthermore, the deflection unit is preferably designed to change not only the irradiation direction of the laser treatment beams but also the irradiation direction of the illumination radiation and the observation beam path.

Further configurations relate, for example, to the contact glass. Several facet mirrors or a rotating mirror are arranged in the contact glass for the deflection of the laser treatment beams into different parts of the trabecular meshwork.

The surfaces present for the deflection of the laser processing beam have coatings which have a sufficiently high reflectivity for the processing laser and a spectral range suitable for illumination and observation.

According to a preferred embodiment, the surfaces present for the deflection of the laser processing beam have a coating whose reflectivity for incidence conditions with s- and p-polarization at the laser wavelength are approximately the same.

The facet mirrors can use the total reflection at the interface between the contact glass and air or other media with a low refractive index, which offers the advantage of realizing high reflectivity over a large spectral bandwidth. The disadvantage, however, is that the total reflection is sensitive to contamination of the total reflecting surface (for example fingerprints), so that the contact glass would then have to be suitably enclosed against contamination. Alternatively, dielectric layers or layer systems can also be used in order to achieve high reflectivity. In this case, however, it must be ensured that the layer system is designed in such a way that the reflectivity for incidence conditions with s- and p-polarization does not differ too much, since otherwise the laser power would vary during the treatment of different sections of the chamber angle. ren differences in reflectivity of less than 1%, favorable <5% and mandatory <10%. Alternatively, metal-coated mirrors can also be used. Depending on the laser wavelength, gold (NIR), silver (VIS-NIR) or aluminum (VIS) is used, but these are often soft or degrade easily, so that here too protection against contact and, if necessary, oxidation must be implemented, for example by a protective dielectric layer on the back of the reflective metal layer.

It would be possible, but somewhat more difficult, to adjust the laser polarization in the laser unit in order to enable uniform laser power when reflected from the different facets. It is possible, for example, to use a λ/4 wave plate to generate circular laser polarization from linear laser polarization or to use a rotatable λ/2 wave plate to adjust the alignment of a linear laser polarization direction depending on the facet used , Alternatively, fiber optic polarization adjustment means such as motorized fiber paddles can also be used in fiber lasers. Electro- or magneto-optical means for polarization adjustment can also be used.

It is also possible to realize the polarization-dependent transmission losses of the laser power during the transmission into the different chamber angle ranges by adapting the power, for example by adapting the laser current or attenuation. To determine transmission-dependent power variations, the laser power can be titrated to the desired one Tissue processing takes place (bubble formation or tissue discoloration) or the intensity of the backscattering of the processing laser is determined and evaluated. For this purpose, the processing laser can also be activated in a defined weakened manner. If the pilot beam and the processing laser are calibrated to one another, the backscatter signal of the pilot laser can also be used to adjust the power of the processing laser. It is also possible to carry out direction-dependent calibration of the power adjustment of the treatment beam in order, for example, to implement adjusted laser power values for the mirror facet used in each case. It is for that it is necessary for the contact glass with its mirror facets to have a specified or known position in relation to the treatment device, for example by means of a suitably designed recording device for the contact glass on the treatment device or also by recognizing the position of the contact glass, for example by marking recognition,

At least one opto-acoustic sensor is preferably arranged on the contact glass, which is connected to the control unit for the transmission of signals for a dosimetric control of the laser unit. Preference is given to using piezoelectric sensors,

For signal generation independent of the deflection, the contact glass has either a ring-shaped sensor or a sensor for each facet mirror,

Furthermore, the contact glass preferably has a liquid- or gel-filled contact chamber and/or a suction device.

According to a particularly advantageous embodiment, it is provided that the device also has an illumination unit for projecting an illumination beam into the anterior chamber angle of an eye and an image processing unit in order to generate images from the light backscattered from the anterior chamber angle, which provide additional information for the Deliver SLT treatment.

According to the invention, the image processing unit is based on an imaging or scanning optical method. It is also possible to use an image processing unit based on interferometry, such as an OCT system. Since this is image processing in the anterior chamber, it is possible in addition to the usual ones OCT wavelengths such as 780 ... 860nm or 1040 ... 1060nm to use longer-wave light, for example in the range from 1300 ...1550nm, since the short beam paths in the eye also make relatively strong absorption in the eye media acceptable.

The last configurations relate to the control unit, which has connections to the illumination unit and to the image processing unit and is designed to detect feature points in the images from the anterior chamber angle and to determine their position and to include them in the control of the laser processing of the trabecular meshwork.

Such characteristic points can be eye structures, such as Schwalbe's line, or also pigmentation variations in the trabecular meshwork, or reflux blood in Schlemm's canal, but also missing parts of the trabecular meshwork or scarring due to previous treatments or artificial trabecular meshwork implants (e.g. the iSTENT or the HYDRUS) , which are to be spared during trabeculoplasty. When using OCT for imaging, the cross-section of Schlemm's canal or the aqueous humor collection vessels behind Schlemm's canal can also be used as feature points, since drainage improvement at the trabecular meshwork is particularly effective there where Schlemm's canal still has a sufficient cross-section in the connection to the nearest aqueous humor collection vessels.

It is possible to process feature points recorded by the image processing unit together with image and measurement data obtained pre-operatively in the control unit in order to control the laser processing of the trabecular meshwork. For this purpose, the image data recorded by the image processing unit are preferably registered with the image data obtained preoperatively.

Furthermore, the control unit is designed to use the signals from the opto-acoustic sensor and the image processing unit to carry out a titration algorithm for controlling the laser unit in order to achieve an optimal treatment result. For this purpose, the control unit is also designed based on of the signals from the image processing unit to take into account the degree of pigmentation of the trabecular meshwork to be treated when controlling the laser unit, for example by adjusting the energy, duration or number of laser pulses,

It is also possible to determine the intraocular pressure (IOP) before, during and after the laser treatment in order to record a direct pressure reduction effect of the laser treatment and, if necessary, to include it in the laser processing control, for example when a target is reached. to end the print area. For this purpose, the contact lens can preferably be equipped with a force sensor system in order to determine IOR values, similar to Goldmann tonometry, on the basis of the defined or measured contact surface from the contact forces. Transpalpebral tonometry is also very suitable, i.e. through the lid. The use of other alternative tonometry methods is not preferred, but possible, such as airpuff, rebound or shock wave tonometry.

It is very advantageous if the system is equipped with a device to limit the contact force of the contact lens on the patient's eye. It is possible to use a spring-loaded holder for the contact glass or to control a motorized device displacement in such a way that force values continuously recorded by the force sensors do not exceed certain limits. Also, for example, an electromechanical retraction of the contact glass away from the patient's eye to limit the force is possible. In addition, acoustic or optical warning signals for the operator can be implemented.

Moderate, force-compensating changes in position of the contact lens in relation to the beam paths of illumination, observation, pilot and treatment lasers can be largely compensated for via the autofocusing and the deflection units, so that the treatment does not have to be interrupted as a result. The present invention relates to a device which is intended in particular for the manual and/or automatic 360° treatment of open-angle glaucoma (90% of all glaucoma) and the rarer pseudoexfoliative glaucoma or pigmentary glaucoma. According to an advantageous embodiment, the device also has an illumination unit for projecting an illumination beam into the anterior chamber angle of an eye and an image processing unit. Thus, the proposed device can be used not only for automated laser processing of the trabecular meshwork, in particular for “selective laser trabeculoplasty”, but also or only for examination and diagnostic purposes.

The invention is described in more detail below using exemplary embodiments. to show

FIG. 1: the device according to the invention with a contact glass with facet mirrors,

FIG. 2: the device according to the invention with a contact glass with facet mirrors and an opto-acoustic sensor and

FIG. 3: the device according to the invention with a contact glass with a rotating mirror.

The proposed device for manual and/or automatic 360° treatment of open-angle, pseudoexfoliation or pigment glaucoma consists of a laser unit with a laser source and a focusing unit, and a control unit that is designed to use the laser unit for SLT treatment of an eye to control.

According to the invention, a movement unit for changing the irradiation direction of the laser treatment beam and a contact lens for the deflection of the laser treatment beam into the anterior chamber angle of the eye.

The proposed device for automated laser processing of the trabecular meshwork consists of a laser unit with a laser source and a focusing unit, a deflection unit for controllably changing the direction of irradiation of the laser beam onto the trabecular meshwork, and a control unit that is designed for the laser unit to control an ab-externo laser trabeculoplasty of the eye and the deflection unit.

Furthermore, there is a contact lens which is designed to allow multiple deflections of the laser treatment beam in its anterior chamber angle when the contact lens is positioned opposite the eye and thus allow up to 360° treatment of the trabecular meshwork.

According to the invention, the contact glass is only positioned once in relation to the eye and allows the laser treatment beam to be deflected several times into the anterior chamber angle of the eye without changing the positioning.

In particular, the contact glass is designed to allow the laser treatment beam to be deflected into the anterior chamber angle of the eye in at least two of the following quadrants without changes in positioning: superior, temporal, inferior and nasal.

The proposed device for automated laser processing of the trabecular meshwork consists of a laser unit with a laser source and a focusing unit,

Furthermore, the laser unit is designed to enable laser trabeculoplasty by means of a thermally stimulating, an SLT or an ALT treatment. However, it is also provided that the laser source of the laser unit is a laser for predominantly athermal laser processing of the trabecular meshwork, for example an ultra-short pulse laser or an ns laser.

In order to ensure improved uniformity of the laser power that can be applied in different chamber angle areas, the laser unit has means for adjusting the polarization and/or power of the laser,

This is particularly favorable if reflective deflections in the contact glass for s- or p-polarized laser treatment beams have strongly differing reflectivities depending on the incidence conditions, which can be compensated for by this power or polarization adjustment in order to ensure uniform treatment of different chamber angle sections to realize.

The laser unit preferably also has a unit for projecting a pilot beam onto the trabecular meshwork,

The pilot beam is preferably also a laser beam which is aligned collinearly with the treatment laser beam and has the same focal position.

The pilot beam can be visible (for example red, yellow, green, possibly also blue), or invisible, for example with a wavelength in the NIR range, such as 780-1550 nm, when it is tracked with a camera. However, shorter wavelengths have the advantage that the penetration depth into the tissue is lower than with longer wavelengths, so that the pilot beam spot is scattered less strongly in the depths of the tissue.

Ideally, the pilot laser beam should sufficiently overlap the trabecular meshwork band, but if possible not hit the neighboring structures such as the Schwalbe line, the scleral spur and the ciliary body band. A correct one Positioning can be easily controlled by the image processing and control unit.

Only if this position of the pilot beam point is correct, the laser emission of the SLT treatment is activated via the control unit. A centered positioning of the pilot beam point on the trabecular meshwork band is ideal,

According to an advantageous embodiment, the laser unit is designed to enable a pattern-based laser trabeculoplasty treatment.

For this purpose, the laser unit has either a diffractive optical element (DOE), with which several laser treatment beams are generated simultaneously for a treatment pattern for laser trabeculoplasty,

Or the laser unit has a scanner that is fast enough to generate a treatment pattern for laser trabeculoplasty using a laser treatment beam.

For example, in order to generate a treatment pattern consisting of 52 individual spots within 280ms, a scanner is required that works with a line deflection frequency of at least 20Hz ... 25Hz. For this purpose, the spot application must be carried out in a synchronized manner during the individual line scans of the scanner without stopping.

In contrast, a spot-to-spot positioning operation of the 20Hz scanner would result in a processing time of 2.6 s for the specified treatment pattern.

According to the invention, a frequency-doubled, continuously working solid-state laser is provided for the laser unit, which generates pulse lengths in the range of 50 ns-50 μs, in particular 150 ns to 1 μs. In the case of a continuously working solid-state laser, the pulse length is achieved by means of clocking by means of a switch-on and switch-off regime.

A spot pattern with an outer, approximately octagonal shape and a diameter of approx. 400 μm is preferably generated by the laser unit from square, directly adjacent individual spots with an edge length of 50 μm. The individual spots have a pulse energy of 2-130 μJ, in particular 25-65 mϋ.

The diameter of the laser treatment zones preferably exceeds the width of the trabecular meshwork (of approx. 300 μm, viewed from the direction of incidence of the treatment laser, otherwise approx. 550 ... 750 μm wide), so that spot patterns or alternatively used large individual spots have an outer diameter of approx. 400μm.

The existing focusing unit is intended to focus the laser treatment beams onto the trabecular meshwork and is preferably designed as an autofocus unit. For example, a confocal detection of light from the pilot laser or the weakened processing laser can be used for autofocusing, which light is backscattered at the trabecular meshwork surface (possibly also other surfaces). For this purpose, the laser focus can be brought closer to the trabecular meshwork, for example, until a backscatter signal threshold is exceeded. Alternatively, an auto-focusing of the observation for contrast-maximizing "sharpening" of feature points or the minimization of the pilot beam laser spot size can be used to optimize the focussing of the processing laser on the target area. Autofocusing based on the location of the trabecular meshwork surfaces in OCT data is also possible. However, the OCT scan position and the focus position of the treatment laser must be calibrated to each other.

According to the invention, the device has a deflection unit for the controllable change in the irradiation direction, which is designed to change the position of the laser to change the treatment beams in such a way that they are directed in different directions into the anterior chamber angle of an eye by the multiple deflections in the contact glass, in order to enable up to 360° treatment of the trabecular meshwork. The deflection unit is preferably also designed to also change the direction of incidence of the illumination radiation.

According to the invention, the contact glass has several facet mirrors or a rotating mirror in the contact glass,

The surfaces present in the contact gas for deflecting the laser processing beam preferably have a coating whose reflectivity for incidence conditions with s- and p-polarization at the laser wavelength differs by <10%, preferably <5% and particularly preferably <1% .

Furthermore, it is advantageous in this connection if the surfaces present in the contact gas for the deflection of the laser processing beam are totally reflecting for the incident laser processing beam, i.e. with an angle of incidence greater than the critical angle for total reflection.

The surfaces present in the contact gas for deflecting the laser processing beam preferably have coatings which have a high reflectivity of preferably >90% for the wavelength of the processing laser and a spectral range suitable for observation.

It is known from 360° gonioscopy to use an automatically aligned contact glass with a gel as a contact connection to the cornea, which is in principle also possible for laser applications.

However, with laser therapy, care must be taken to ensure a stable contact connection. For this purpose, the contact glass preferably has a liquid- or gel-filled contact chamber. With this comparatively gentle contacting of the cornea, opacities and streaks in the cornea, such as those in a direct mechanical contact of a contact glass can be avoided. This improves the transmission and focusability of the laser radiation.

An even better and more secure fixation of the patient's eye can be achieved if the contact lens also has a suction device.

To deflect the laser treatment beams, the contact glass has several faceted mirrors or a mirror rotating around the device axis. This enables a very compact design, despite the flat angle of entry into the anterior chamber of the eye,

The use of flat faceted mirrors or a flat rotating mirror in the contact lens has clear advantages over the use of a conical or possibly torically curved mirror in the contact lens in that the processing laser, illumination and observation beam paths do not have to be optically rectified in a complex manner . This is possible in principle, but expensive. Correction would be somewhat easier if spherical or certain aspherically curved mirrors were used, but would still be more complex than using flat mirrors for deflection,

Especially when using a rotating mirror, the contact glass should have a suction device, since the rotation can cause vibrations. Alternatively, the vibrations can be suppressed by "balancing", i.e. using co-rotating balancing weights.

According to a particularly advantageous embodiment, the contact lens has at least one opto-acoustic sensor that is connected to the control unit connected is. Accordingly, the control unit is designed to use the signals from the sensor for dosimetric control of the laser unit.

The contact glass preferably has a ring-shaped sensor or a sensor for each facet mirror, which makes it possible to obtain a signal that is independent of the deflection.

The sensor detects the pulse amplitude of the incident laser beam through direct contact with the facet mirror of the contact glass and, with a certain time delay due to the speed of sound, the smaller opto-acoustic signal from the laser spot (with possible bubble formation) within the trabecular meshwork. Both signals can be used for further evaluations can be compared with one another or used for calibration or also for regulating the laser processing.

According to a further advantageous embodiment, the device also has an illumination unit for projecting an illumination beam into the anterior chamber angle of the eye and an image processing unit for generating images from the light backscattered from the anterior chamber angle. The control unit has corresponding connections to the lighting unit and to the image processing unit for controlling them and is designed to detect feature points in the images from the anterior chamber angle and to determine their position.

In this case, the image processing unit is based on an imaging or scanning optical method. In particular, however, it is also possible here to use an image processing unit that is based on an OCT method.

Devices and methods for gonioscopy, ie examination of the chamber angle and in particular of the trabecular meshwork, are known from the prior art. A gonioscope is described in EP 3329839 A1, which 360° imaging of the trabecular meshwork, including visualization of the level of pigmentation.

According to the invention, on the other hand, the movement unit and the contact glass are designed in such a way that the irradiation direction of a processing laser for automated processing of the trabecular meshwork can also be changed or redirected and focused onto or into the trabecular meshwork.

It is advantageous if there is a fixation unit for projecting a fixation beam along the optical axis of the device into the eye.

For this purpose, FIG. 1 shows a first variant of the device according to the invention with a contact glass with facet mirrors,

On the one hand, the eye 1 is illuminated by the illumination unit 2, with the illumination beam 2' being directed into the chamber angle 6 via the deflection unit 3 and a facet mirror 4 of the contact lens 5.

Starting from the laser unit 7, the treatment beam 7' is focused via the scanning unit 8, the deflection unit 3 and also via a facet mirror 4 of the contact glass 5 in the chamber angle 6 onto the trabecular meshwork. Focusing units for the observation and processing laser beam path are not shown here. Focusing for the treatment beam 7' is preferably implemented in the laser unit 7, i.e. before the laser beam is deflected by the scanning unit 8. The focusing unit for the observation beam path can be integrated into the image processing unit. In the case of an OCT system, the illumination and observation beam paths can be identical.

The illumination light backscattered by the chamber angle 8 is imaged on the image processing unit 9 . The existing control unit 10 has connections fertilize to the lighting unit 2, to the image processing unit 3 and to the laser unit 7 for their control or for signal evaluation.

The fixation unit 11 projects a fixation beam 11' along the optical axis 15 of the device into the eye 1. A contact gel 12 is used here as a connection between the contact lens 5 and the eye 1,

FIG. 2 shows an embodiment of the variant of the device according to the invention with a contact glass with facet mirrors according to FIG.

FIG. 3 shows a second variant of the device according to the invention, in which a contact glass with a flat, rotating mirror is used.

In contrast to the solutions according to FIGS. 1 and 2, in the solution according to FIG rotating mirror 14 in the contact lens 5 is focused in the chamber angle 6 onto the trabecular meshwork.

In this case, the deflection unit 3 is synchronized to the movement of the rotating mirror 14 by the control unit 10 . The movement of the rotating mirror can take place continuously or in steps.

The contact glass 5 preferably has a ring-shaped opto-acoustic sensor (not shown), which makes it possible to obtain a signal that is largely independent of the direction of deflection.

As an alternative to an illumination and observation beam, a

OCDR or an OCT beam with the SLT treatment beam path directly superimposed and focused and scanned together. The OCT signals obtained in this way can not only be used to control and focus the treatment laser, but also to visualize the anterior chamber angle. In this context, it is advantageous if OCT scans are registered and aligned with one another in corresponding chamber angle directions (for example 0° and 360°) in order to compensate for movement artifacts in such an OCT representation. Furthermore, the OCT scan can be registered to a color image of the chamber angle. The locations of the laser treatment can then be displayed in the color and/or OCT visualization, since these locations correspond to the positions of the OCT scans that were recorded at the respective activation moments of the treatment laser. 1D, 2D or 3D scans are possible as OCT scans, ie A scan, B or volume scans, preferably for displaying the trabecular meshwork and Schlemm's canal cross section).

In order to protect the image sensor of the image processing unit from high-intensity treatment laser radiation reflected by the patient and the system, a corresponding filter can be arranged in front of the image sensor.

This filter should selectively block the therapeutic laser radiation (e.g. 532nm) but have a high transmission for the wavelength of the pilot laser beam and all other wavelengths used in the system.

Furthermore, a fully automated system uses an OCDR or OCT scan overlaid with the SLT laser beam to detect whether the SLT laser beam is aimed at the trabecular meshwork and the SLT treatment can be triggered.

As already described, the control unit is designed to detect feature points in the images from the anterior chamber angle and to determine their position. In the present case, this is the trabecular meshwork in order to align and focus the pilot and/or treatment beam on it. For automatic steering of the pilot and/or treatment beam along the parts of the trabecular meshwork to be treated, the trabecular meshwork and the laser beam position are preferably detected in the images and their position determined. A treatment pattern along the trabecular meshwork can then be calculated and executed by the control unit.

According to a last advantageous embodiment, the control unit is designed to use the signals from the opto-acoustic sensor and the image processing unit to carry out a titration algorithm for controlling the laser unit in order to achieve an optimal treatment result.

In this case, the laser dosimetry can be carried out by a plurality of feedback signals, for example by;

- opto-acoustic signals via Grüneisen coefficients correlated to temperature signals (temperature-controlled laser coagulation)),

- Occurrence of blisters (endpoint of photodisruption or selective photothermolysis treatment),

- Color changes in visual imaging or scatter signals, as well as

- Speckle structure or position changes of tissue layers in OCT signals,

This is known from retina photocoagulation and selective retina therapy (according to US Pat. No. 7,863,894 B2) and can be used accordingly in the case of opto-acoustic dosimetry in laser trabeculoplasty.

For this purpose, the contact glass is provided with at least one opto-acoustic sensor in order to continuously detect the changing reflection point on the facet mirrors or the rotating mirror element. However, the proposed solution does not use ring-shaped sensor elements, such as those used in dosimetric retinal laser treatments.

Instead, the sensors are placed directly on the facet mirrors or the rotating mirror element, which allows the sensors to detect the direct acoustic amplitude from the laser point on the trabecular meshwork and thus receive a better and more clearly defined opto-acoustic signal, Bei During selective laser trabeculoplasty with this system, the opto-acoustic signal clearly shows a bubble formation threshold in order to adjust the laser energy for reliable laser therapy.

For a complete (i.e. a 360°) SLT treatment of the trabecular meshwork of the eye, it is necessary to line up around 100 individual laser treatment zones or spot patterns with an outer diameter of 400 μm.

When using a contact glass with 16 facet mirrors, for example, it is therefore necessary to set about 6 laser beam positions and/or angles of incidence from the XY scanner per facet mirror.

A contact glass known from gonioscopic imaging devices is preferably used for this purpose, in which facets are incorporated and mirrored.

In contrast, when using a contact glass with a mirror element rotating around the patient's visual axis, an XY scanner can sometimes be dispensed with. However, this requires that only relatively large individual spots with a diameter of 400 μm are used, or that the corresponding treatment pattern of smaller individual spots is generated by several laser beams radiating in at the same time. As already described, a diffractive optical element can be used for this, for example (DOA), This variant has the advantage that a continuous change of the reflection point is possible.

According to a last advantageous embodiment, the control unit is further designed to take into account the degree of pigmentation of the trabecular meshwork to be treated when controlling the laser unit using the signals from the image processing unit.

It has been shown that technical variations or configurations can be expedient for the proposed device.

For example, it is expedient to use the focusing unit of the laser unit for the image processing unit to visualize the structures of the trabecular meshwork.

Furthermore, when using a contact glass with facet mirrors, it can be advantageous to modify the device in such a way that the laser beam for the treatment and the illumination light for the imaging system are not focused into the trabecular meshwork via the same facet mirror.

For example, consecutive or opposing facet mirrors can be used. In this way, for example, the light exposure caused by processing lasers and illumination for observation can be distributed spatially. However, for a sufficiently precise processing of a trabecular meshwork area, the time interval between the observation (i.e. illumination and image processing) and the laser processing of this trabecular meshwork area activated on the basis of this observation must be limited to Δt<treatment zone diameter*2E-4 s/m, For example, 80 ms for a treatment zone diameter of 400 μm. For treatment zones below 300 μm, a general limit of 60 ms can be acceptable if a certain disturbance of the pattern due to patient eye movements that cannot be completely avoided is acceptable. This can be technically implemented, for example, by using a relatively fast line scan camera with line frequencies of, for example, 50 kHz as the image processing unit, which scans the chamber angle, for example, using a rotating deflection unit in combination with the facet mirror according to the invention or the rotating deflection mirror. The image signals obtained in this way can then be evaluated, for example, using fast computers, FPGAs or DSPs with low latency, so that the laser can be activated within the set time frame. It is also possible to track the treatment laser optimally on the trabecular meshwork using control signals obtained from the image data.

In order to keep the light exposure of the patient as low as possible, the use of laser radiation in the NIR range is suggested. For example, wavelengths of 1310 - ISSOnm are conceivable for imaging and 700 - 1064nm for laser treatment.

With the solution according to the invention, a device is made available with which manual and/or automatic 360° treatment of open-angle, pseudoexfoliative or pigmentary glaucoma is made possible.

The device is based on the automated laser processing of the trabecular meshwork, in particular the "selective laser trabeculoplasty".

The particular advantage of the proposed solution can be seen in the fact that the device is suitable for enabling a 360° treatment and a more precise prediction of the therapeutic effect that can be achieved or is currently being achieved.

Furthermore, it is advantageous to supplement the device with an illumination unit for projecting an illumination beam into the anterior chamber angle of an eye and an image processing unit. This allows the device not only for the automated laser processing of the trabecular meshwork, in particular the "selective laser trabeculoplasty", but also or only for examination and diagnostic purposes.

This also offers the possibility of auto-titrating the laser energy and/or taking into account the degree of pigmentation when controlling the laser unit

Claims

patent claims

1. Device for automated laser processing of the trabecular meshwork, consisting of a laser unit with a laser source and a focusing unit, a deflection unit for controllably changing the direction of incidence of the laser beam on the trabecular meshwork, and a control unit that is designed to use the laser unit for a to control ab-externo laser trabeculoplasty of the eye and the deflection unit, characterized in that a contact glass is present, which is designed, when the contact glass is positioned relative to the eye, several deflections of the laser treatment beam in its anterior chamber angle and thus an up to 360° to allow treatment of the trabecular meshwork,

2. The device according to claim 1, characterized in that the existing contact glass is designed to enable several deflections of the laser treatment beam into the anterior chamber angle of an eye at the same time when the contact glass is positioned in relation to the eye,

3. Device according to claim 1, characterized in that the contact glass is designed to enable deflections of the laser treatment beam into the anterior chamber angle of the eye at least in two of the following quadrants when positioned opposite the eye: superior, temporal , inferior and nasal,

4. Device according to claim 1, characterized in that the laser unit is designed to enable laser trabeculoplasty by means of a thermally stimulating, an SLT or an ALT treatment.

5. The device according to claim 1, characterized in that the laser source of the laser unit is a laser for predominantly athermal laser treatment processing of the trabecular meshwork, for example an ultra-short pulse laser or an ns laser,

6. Device according to claim 1, characterized in that the laser unit has means for polarization and/or power adjustment of the laser in order to ensure improved uniformity of the laser power that can be applied in different chamber angle ranges,

7. The device according to claim 1, characterized in that the laser unit also has a unit for emitting a pilot beam,

8. Device according to claims 1 and 4, characterized in that the laser unit is designed to enable a pattern-based laser trabeculoplastic treatment,

9. The device as claimed in claim 8, characterized in that the laser unit has a diffractive optical element (DOE) for generating a plurality of laser treatment beams that are radiated in at the same time for a pattern-based laser trabeculoplasty treatment,

10. The device according to claim 8, characterized in that the laser unit additionally has a scanner for generating a treatment pattern for a pattern-based laser trabeculoplasty treatment,

11. The device according to claim 10, characterized in that the scanner operates at a frequency of at least 20 Hz in order to generate a treatment pattern consisting of 52 spots within 280 ms,

12. Device according to claims 1 and 4, characterized in that a frequency-doubled, continuously operating solid-state laser is provided for the laser unit.

13. Device according to claims 1 and 4, characterized in that the laser unit is designed to generate pulse lengths in the range of 50 ns - 50 μs, in particular 150 ns - 1 s.

14. Device according to claims 1 and 4, characterized in that the laser unit is designed to produce a spot pattern with an outer, approximately octagonal shape and a diameter of approx .400 m to generate.

15. Device according to claims 1 and 4, characterized in that the laser unit is designed to generate individual spots with a pulse energy of 2-130 μJ, in particular 25 μJ-65 μJ.

16. Device according to claim 1, characterized in that the focusing unit is designed to focus the laser treatment beams onto or into the trabecular meshwork.

17. The device according to claim 1, characterized in that the deflection unit for the controllable change in the irradiation direction is designed to change the position of the laser treatment beams in such a way that they are guided in different directions into the anterior chamber angle of an eye by the multiple deflections in the contact lens, to allow up to 360° treatment of the trabecular meshwork.

18. Device according to claim 1, characterized in that the deflection unit is designed to also change the direction of incidence of the illumination radiation and/or the pilot laser.

19. Device according to claim 1, characterized in that the contact glass has several faceted mirrors or a rotating mirror in the contact glass.

20. Device according to claims 1 and 19, characterized in that the surfaces present in the contact gas for the deflection of the laser processing beam have a coating whose reflectivity for incidence conditions with s- and p-polarization at the laser wavelength is <10% , preferably <5% and particularly preferably <1% differ.

21. Device according to claims 1 and 19, characterized in that the surfaces present in the contact gas for the deflection of the laser processing beam are totally reflecting.

22. Device according to claims 1 and 19, characterized in that the surfaces present in the contact gas for the deflection of the laser processing beam have coatings which have a high reflectivity of preferably >90% for the processing laser and a spectral range suitable for observation. having.

23. Device according to claims 1, 4 and 19, characterized in that the contact lens has at least one opto-acoustic sensor and the control unit is designed to use the signals of the sensor for dosimetric control of the laser unit.

24. The device as claimed in claim 23, characterized in that the contact glass has a ring-shaped sensor or a sensor for each facet mirror to enable signal acquisition independent of the deflection.

25. Device according to claims 1 and 19, characterized in that the contact glass has a liquid- or gel-filled contact chamber and/or a suction device.

26. The device according to claim 1, characterized in that an illumination unit for projecting an illumination beam into the anterior chamber angle of an eye and an image processing unit in order to generate images from the light backscattered from the anterior chamber angle are additionally present and that the control unit, connections to the - Has the lighting unit and the image processing unit for controlling it and is designed to detect feature points in the images from the anterior chamber angle and to determine their position.

27. Device according to claim 26, characterized in that the contact glass is used for the projection of the illumination beam into the anterior chamber angle of an eye.

28. Device according to claim 26, characterized in that there is a fixation unit for projecting a fixation beam along the optical axis of the device into the eye.

29. Device according to claim 26, characterized in that the image processing unit is based on an imaging or scanning optical method.

30. Device according to claim 26, characterized in that the image processing unit is based on an OCT method.

31. Device according to claims 1, 23 and 26, characterized in that the control unit is designed to use the signals of the opto-acoustic sensor and/or the image processing unit to calculate a titration algorithm for controlling the laser unit in order to achieve an optimal to carry out the result of the action.

32. Device according to claims 1 and 26, characterized in that the control unit is further developed, based on the signals of the image processing processing unit to take into account the degree of pigmentation of the trabecular meshwork to be treated when controlling the laser unit.

33. Device according to claim 1, characterized in that there is a tonometry device for determining the intraocular pressure.

34. Device according to claim 33, characterized in that the tonometry device is designed to determine the intraocular pressure without interrupting the laser treatment.

35. Device according to claim 34, characterized in that the control unit is designed to take into account the intraocular pressure values recorded in the course of the laser treatment when controlling the treatment.

36. The device as claimed in claim 35, characterized in that the contact glass has a sensor for determining a force effect of the eye on the contact glass and the control unit uses its transmitted measurement values to determine the intraocular pressure and/or limit the contact force on the eye.

37. The device as claimed in claim 1, characterized in that there is an image processing unit which is designed to deliver image signals to the control unit which processes them in order to activate the laser unit.

38. Device according to claim 37, characterized in that the image processing unit, control unit and laser unit are designed in such a way that the maximum time Δt between image acquisition of a trabecular meshwork zone and activation of the laser unit by the control unit for processing the trabecular meshwork zone is Δt<treatment zone diameter*2E- 4 s/m is limited.