EP4041151A1 - Arrangement for laser vitreolysis - Google Patents

Abstract

The present invention relates to an arrangement for the laser treatment of vitreous floaters. According to the invention, the arrangement for the laser vitreolysis of an eye consists of an OCDR system, a laser system having a deflection unit, optical elements for coupling the OCDR system and the laser system, a display unit and a central control and operating unit, wherein the OCDR system is designed to localize the position of a floater along the optical axis of the OCDR system. The laser system is designed to destroy the floaters by means of laser pulses, and the central control and operating unit is designed to focus the laser system onto the position of the floater and to activate it, in particular when the position of the laser focus and the floater match in a sufficient manner. The present invention relates to an arrangement for the gentle, low risk and painless laser treatment of vitreous floaters, which allows in particular a partially or fully automated therapy.

Description

Arrangement for laser vitreolysis

The present invention relates to an arrangement for the laser treatment of vitreous opacities.

The vitreous body consists of a mostly clear, gel-like substance located in the interior of the eye between the lens and the retina. At a young age, the vitreous is completely transparent and has contact with the retina. In the course of life, the vitreous liquefies and increasingly separates from the retina, which is referred to as posterior vitreous detachment. This is a normal aging process that usually happens after the age of 50.

The detached vitreous parts collapse inside the eye and the structural substances, which liquefy at different rates, and the densification of the vitreous humor become visible to the patient. Since they can move across the field of vision as a result of eye movements, they are also known as floaters. Often, the cause of floaters after the detachment of the vitreous body is also membrane-like structures on the posterior side of the vitreous body, in some cases even blood residues if retinal injuries occurred during the detachment of the vitreous body. In rarer cases, floaters can be present as crystal-like precipitates in the vitreous body, even with metabolic problems.

Even if floaters usually have no pathological cause, they are not as harmless as generally assumed, because they can in some cases significantly impair the quality of life and also the productivity of those affected.

Especially against a light background, e.g. B. when working on the computer, when reading or looking at the blue sky or snow, these opacities are perceived and disturb the eyesight. Floaters that are thrown into and out of the central viewing area as a result of reading movements can be particularly disturbing. Because they often have the perceived shape of “flying mosquitos”, they are described - from French - using the technical term “Mouches-Volantes”. However, the opacities can also have other forms, e.g. B. be ring- or star-shaped branch or as point clouds. In the following, the term “floater” is used for the vitreous opacities to be treated, regardless of its type or shape.

Floaters generally do not go away without treatment because the immune system does not recognize them as abnormal and therefore does not degrade. They can hardly be ignored or overlooked by those affected. Certain types of floaters, such as those caused by blood residues after retinal bleeding, are partially absorbed by the body, even if this often takes weeks or months.

In a so-called vitrectomy, after opening the eye with cutting instruments, the vitreous humor is partially (nuclear vitrectomy) or completely shredded, suctioned off and removed. Such an operation is routinely carried out in the event of retinal detachment or peeling of epiretinal membranes, but is usually viewed as a disproportionate therapy to remove the circumscribed vitreous opacities. In addition, vitrectomy is invasive, it requires hospitalization and carries the risks associated with surgical intervention, in particular often the induction of a cataract, less often a detachment of the retina and very rarely, but possible, endophthalmitis.

The so-called laser vitreolysis is now a low-risk treatment alternative. The laser vitreolysis is a gentle, low-risk and painless laser treatment with which vitreous opacities can be atomized or va porized without opening the eye.

With laser vitreolysis, short laser light pulses are directed at the vitreous opacities in order to achieve an optical breakthrough or photodisruption there due to the high laser intensity in the focus area. The floaters and the glass body surrounding them absorb the laser energy and it is formed a cutting and / or expanding laser plasma, as a result of which the floaters are vaporized and / or comminuted and can therefore dissolve better or at least be removed from the central field of vision. The treatment is painless and there is no risk of infection. Laser vitreolysis is a safe method for the gentle treatment of troublesome glass opacities if it can be ensured that important and sensitive eye structures are not damaged by the laser, such as the capsular bag, the crystal lens or areas of the retina, in particular the macula.

However, the success of the treatment depends on the type of floater. The treatment is particularly successful for so-called white rings or floaters, which form around the optic nerve head due to vitreous detachment, but can also move in the central visual area in a disruptive manner. Strands of tissue can be severed and the densities of tissue, which are responsible for the disturbing shadows, can be eliminated or removed from the field of vision.

For over 3 decades (Brasse, K., Schmitz-Valckenberg, S., Jünemann, A. et al. Ophthalmologe (2019) 116: 73. https://doi.Org/10.1 QQ7 / sQQ347-018- 0782-1) floaters are treated with YAG lasers (for example Nd: YAG at 1064nm), this laser treatment being much less common than the known laser staring treatment to remove cell growth on the back of the IOL or retinal treatments for local coagulation of retinal areas by means of a frequency-doubled YAG laser (532nm), for example in diabetic retinopathy or for attaching and securing detached retinal areas or the securing repositioning of retinal holes (foramen). In addition to green, red and yellow laser versions (VISULAS Trion) are used for retinal treatments, depending on the desired depth of penetration into the retina (green for treatment close to the surface; yellow and red for deeper or pigmented retinal layers, IR for the choroid). The lower prevalence of laser vitreolysis is mainly one Uncertainty regarding possible retinal, lens or capsular bag damage from the treatment laser, as well as the rather time-consuming, manual treatment itself. For this reason, laser vitreolysis has so far mainly been carried out by quite experienced ophthalmologists who specialize in it.

Examples of laser systems that are used for laser vitreolysis are the MERIDIAN Microruptor II, the Laserex LQP4106 laser or the Ellex Ultra-Q-Reflex.

According to the known state of the art, numerous solutions for laser surgery of tissue of the eye, in particular in the vitreous body, already exist.

DE 102011 103 181 A1 describes a device and a method for femtosecond laser surgery on tissue, in particular in the vitreous humor of the eye. The device consists of an ultrashort pulse laser with pulse lengths in the range of approx. 10fs-1ps, in particular approx. 300fs, pulse energies in the range of approx. 5nJ-5pJ, in particular approx. 1-2pJ and pulse repetition rates of approx. 10kHz-10 MHz, especially 500 kHz. The laser system is coupled with a scanner system, which enables the spatial variation of the focus position in three dimensions. In addition to this therapeutic laser scanner optics system, the device continues to consist of a navigation system coupled to it.

US 2006/195076 A1 describes a system and method for producing incisions in eye tissue at various depths. The system and method focus light, possibly in a pattern, onto different focal points located at different depths within the eye tissue. With a segmented lens, several focal points can be created at the same time. Optimal incisions can be achieved by focusing the light sequentially or simultaneously at different depths, creating an expanded plasma column and a beam with an elongated waist. The techniques described here can, inter alia, also be used to carry out new ophthalmological procedures or improve existing procedures, including dissection of tissue in the posterior pole, such as floaters, membranes, and the retina.

US 2014/257257 A1 also describes a system and its method for treating target tissue in the vitreous humor of an eye, comprising a laser unit for generating a laser beam and a detector for generating an image of the target tissue. The system also includes a computer that defines a focal point path for emulsifying the target tissue. A comparator connected to the computer then controls the laser unit to move the focus of the laser beam. This focus point movement is performed in order to treat the target tissue, while deviations of the focus point from the defined focus point path are minimized.

US 2015/342782 A1 likewise relates to a system and a method for using a computer-controlled laser system provided in order to carry out a partial vitrectomy of the vitreous body in an eye. First of all, an optical channel is surgically defined through the vitreous humor. Glass-like and suspended deposits (floaters) in the optical channel are then abgetra conditions and, in some cases, removed from the optical channel (e.g. suctioned off).

In some cases, a clear liquid can be introduced into the optical channel to replace the ablated material and thereby create unhindered transparency in the optical channel. In general, the present invention relates to systems and methods for ophthalmic laser operations. In particular, the present invention relates to systems and methods for using pulsed laser beams to remove so-called floaters.

US 2018/028354 A1 also describes a method and a system for an ophthalmological intervention on an eye. An image of at least a part of the eye is used to identify undesirable features. Undesirable features in the vitreous cavity are vitreous opacities that impair vision, such as floaters. After the floaters have been identified and localized, they are sighted by a doctor "shot at" manually with laser pulses. The laser energy vaporizes at least part of a vitreous opacity. This process is repeated until the opacity of the vitreous is removed. The entire process is repeated for each opacity of the vitreous until the liquid in the vitreous is deemed to be sufficiently clear.

A method described by ELLEX (product brochure from Ellex Medical Pty Ltd .; "Tango Reflex - Laser Floater Treatment"; PB0025B; 2018; (http://www.ellex.com)) provides for the use of a pulsed nanosecond laser (YAG) to break down vitreous opacity or to completely eliminate it by converting it into gas. The target area (floater) is sighted with a pilot laser beam and then “shot at” with one or more therapy laser pulses. Both the pilot laser beam and the therapy laser pulses are triggered manually by the user. Such a manual laser treatment typically consists of two individual treatments, each lasting 20-60 minutes.

The use of laser energy in the context of laser vitreolysis is not in vasive and avoids the disadvantages of surgical interventions, but is also associated with disadvantages and risks.

So aiming the laser can be difficult. Because the doctor looks at the vitreous along the path of the beam, it can be difficult to determine the depth of the position of the retina, the depth of opacity of the vitreous, or other relevant features. As a result, there is a risk of missing the opacity of the vitreous and / or injuring the eye.

In particular, the treatment of position-changeable and difficult to recognize, largely transparent floaters, which, as phase objects, can nevertheless generate disturbing shadows on the retina, proves to be difficult.

The application of laser energy can also result in additional movement of the opacities of the vitreous humor, which makes the treatment even more difficult. Thus, the doctor realigns the laser after each application of laser energy. This can take a long time. Treatment with laser energy is therefore expensive and burdensome for both the patient and the doctor.

Another possible problem is incomplete vitreous detachment, which can lead to local vitreous tractions and even retinal detachments. A laser treatment in the vitreous body can lead to changes in the balance of forces in the vitreous body due to the shock waves propagating as a result and thus, for example, cause tension in the retina.

Ultimately, the treatment of such floaters also proves to be particularly difficult that are located close to sensitive structures of the eye.

The laser radiation can damage the retina (especially macula), the lens of the eye or the capsular bag. Sensitive areas can also be the vicinity of vitreous tractions, i.e. areas where a vitreous body that is not completely detached exerts tension on the retina, which harbors the risk of retinal rupture in the event of mechanical stress. Such zones can be identified in the OCT, for example, by local, pointed elevation of the retinal layers.

The present invention is based on the object of developing a solution for the laser treatment of vitreous opacities that eliminates the disadvantages of the known technical solutions. With the solution, a simpler, faster and, above all, safer treatment of troublesome vitreous opacities by means of laser vitreolysis should be possible. In addition, the solution should be easy to implement and economically cost-effective and ideally only require little getting used to with today's laser treatments.

This task is achieved with the proposed arrangement for laser vitreolysis, consisting of an OCDR system, a laser system with a focus unit, optical elements for coupling the OCDR and laser system, egg ner display unit and a central control and operating unit solved that the OCDR system is designed to localize the position of a floater along the optical axis of the OCDR system, that the laser system is designed to destroy the floater by means of laser pulses, and that the central control and operating unit is designed to operate the laser system to focus and activate the position of the floater, especially if the position of the laser focus and the floater coincide sufficiently.

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

The term OCDR (= Optical Coherence Domain Reflectometry) refers to the entirety of the methods for the interferometric determination of the position or distances of scattering structures in the eye.

The OFDR (Optical Frequency Main Reflectometry) method is particularly preferred, and the so-called swept-source OFDR method, as described in DE 1020080632252, the full content of which is hereby incorporated by reference, is particularly preferred. Versions as spectrometer-based SD-OCDR or a TD-OCDR are possible, but not preferred.

It is particularly advantageous if the laser beam and the measuring beam of the OCDR system are collinearly superimposed, are of the same or almost the same wave length and are focused in the same or almost the same way. When using other wavelengths of the OCDR system such as approx.

780 - 840 nm or 1320 nm compared to the YAG laser wavelength of 1064 nm, a comparison of the measurement signals of the OCDR system with regard to the position of the retina and posterior capsular bag membrane with the focus position of the YAG laser is required and provided. This calibration can be carried out in advance with an artificial test eye. It is preferred if the OCDR system works at a wavelength of 1060nm and with a frequency of at least 100 Hz, better 1..10 kHz, A-scans at least the entire eye length (ideally up to 30 of the 40mm in tissue) and with a axial measurement resolution of preferably 20 pm, better 10 pm or 5 gm in tissue.

Furthermore, the system is preferably set up to evaluate such an A-Scan with approximately the same frequency and the position of eye structures (cornea, lens, retina) and possible floaters with low latency in the range of a few milliseconds (<100ms, ideally <20ms, < 10ms or even <5ms) and trigger the laser if the safety criteria are met. These safety criteria can be, for example, minimum distances from sensitive eye structures. These distances can depend on the type of eye structure, for example greater in the case of the sensitive macula than in the case of less sensitive or critical peripheral areas of the retina. In particular, the minimum distances should be designed in such a way that cutting, vaporising or atomising plasma effects, acoustic shock waves and thermal tissue coagulation do not change the tissue or only change it to an acceptable extent. Exemplary minimum distances of the laser focus from the macula can be around 2 ... 3 mm for a YAG laser at 1064 nm and 1.5 ... 2 mm from the capsular bag and peripheral retinal areas. This procedure also makes it possible to move floaters temporarily out of the sensitive areas (anterior to the macula), for example into the area anterior to the temporal retinal periphery, or to atomize them there by means of the rapid laser vitreolysis according to the invention.

The minimum distances can also be made dependent on the laser energy used, the number of pulses (burst), the pigmentation state of the retina, the state of the lens (natural lens or IOL) or a variable focal length. In particular, it is also possible for the doctor to define blocked or processing zones himself by means of manual, for example, experience-based setting, for example by cursor lines in an OCDR display.

Furthermore, according to the invention, a focusing unit is provided which can set the laser focus on a detected floater or can sweep over the floater with the laser focus. With the solution according to the invention, this focusing can take place quickly (for example scanning or also tracking), i.e. in a few 10ms to 100ms, but it can even be done manually and slowly while maintaining a high level of precision in the laser processing of the floater.

According to a further embodiment, the central control and operating unit is designed to be triggered automatically within a time of <50 ms, better <20 ms, preferably <10 ms, particularly preferably <5 ms, taking into account the derived exclusion criteria for the treatment.

Advantageous refinements relate to the central control and operating unit, which is designed in particular to determine not only the position of the localized floaters but also their distance from structures of the eye and to derive exclusion criteria for the treatment.

The central control and operating unit is advantageously able to determine changes in the structure of the eye closest to the localized floater during the treatment and to derive termination criteria for the treatment. Scan as a new, clearly scattering, but also absorbing structure (“shadow” suddenly attenuates the OCDR signal of posterior structures) in front of the retina or an increasing retinal elevation during treatment during a vitreous traction or an increase in the length of the axis (cornea to retina ) as a result of increasing intraocular pressure. The present invention relates to an arrangement which is intended for gentle, low-risk and painless laser treatment of opacities of the vitreous body. A partially or fully automated therapy device (system) is proposed in which an OCDR system is used for navigation and therapy control in order to localize the floaters in the course of the treatment and to support the treatment by means of OCDR when a floater is detected at least one laser pulse is triggered essentially automatically when the laser is focused sufficiently well on the floater. This focusing can be done by focus tracking (iterative reduction of the axial distance between the focus position and the floater position, ie "tracking") or a periodic focus scan that sweeps over the floater position, or manual focusing on the floater. Sufficiently good focusing of the laser on the floater is understood to mean that with this deviation there is no noticeably worse floater treatment (atomization and / or vaporization), which is generally the case if the positional deviation is smaller than the laser focus dimension in this direction, especially if the deviation is less than 75%, <50%, <25% or <10% of the laser focus dimension.

The invention also relates to a method for controlling a laser for vitreolysis, in which floaters in the vitreous humor of the eye are detected by means of OCDR and, when a floater is detected, the laser is focused on the floater and at least one laser pulse is emitted on the floater.

In an alternative method for controlling a laser for vitreolysis, the laser focus is guided through the vitreous body of the eye and at the same time OCDR detects whether there are floaters at time-dependent laser focus positions, and if a floater is detected at such a position, at least one laser pulse is triggered if the Laser focus reaches the floater position.

Previous solutions provide that a (more or less) complete picture of the vitreous body is obtained, the floaters by the doctor (ELLEX Tango Reflex) or automatically localized and then the treatment laser is aligned to these localizations and the laser radiation is triggered. However, due to the human reaction time or the time required for automatic laser alignment, but also due to the time required for image acquisition and automatic localization of the floater, it is not certain that when the laser is triggered, the floater will still be at the suspected location and there with it Focus of the laser is located. With a typical eye movement of 1 mm / s, a floater can move around 20 pm in 20 ms and thus move out of a laser focus of 10 pm, for example. In addition, devices known per se for tracking eye movements (eye trackers) would often fail here because the floaters (according to their designation) are usually located opposite the eye structures (“landmarks” such as the iris, retinal structures such as the optic nerve head, macula or vessels ) move.

The system preferably also has electromechanical (galvo scanners), electro-optical (acousto-optical modulators) or motorized (lens displacement) deflection units for automated beam deflection (scanning) in up to three dimensions.

When focusing the laser system, a programmed focus shift between the target position and the localized floater is preferably taken into account.

In order to take advantage of the sound pressure wave generated by the laser beam, an anterior position to the floater is preferred and set in the user settings of the central control and operating unit.

The distances between the localized floaters and structures of the eye determined by the central control and operating unit are used to derive exclusion criteria for laser processing, namely if the distance between the localized floaters and the retina, fovea, lens or the like is too small, see above that laser treatment can lead to bleeding, retinal lesions or even a retinal tear. Processing and restricted zones can also be determined from the coordinates of the localized floaters.

On the one hand, these serve to implement an automated optimization of the positioning of the processing laser focus. On the other hand, processing is only permitted if the processing laser focus is outside the restricted zone or within the processing zone.

While a distance of> 15mm is sufficient as a restricted zone in relation to the expected optical and acoustic wave exposure, a distance of> 2 - 3mm is to be used for sensitive areas of the eye.

The user can be warned (acoustically and / or optically) when the processing laser focus approaches the exclusion zone. In addition, it is possible to recognize, display or report acoustically the approach to sensitive structures. But it is also possible to abort the laser processing or to deactivate the laser as long as the laser is in a restricted area.

There are different forms of vitreous opacities, which can be treated differently well.

The so-called white ring floaters are relatively large, fibrous ring-shaped floaters that are usually located a safe distance from the lens and retina of the eye. As a result, these floaters can be safely and effectively treated with laser vitreolysis.

Floaters in the form of fiber-like strands are common in younger people and are perceived as a collection of dots or as thread-like tissue. Depending on the size and position, these floaters can also be treated with laser vitreolysis. In contrast, diffuse (cloud-like) floaters are the result of natural aging. This type of floater can also be treated with laser vitreolysis, but several treatments are often necessary to achieve a satisfactory result.

According to a preferred embodiment, the central control and operating unit is also designed to determine the type of localized floater (for example white ring or blood residue) before laser treatment and to derive processing criteria such as suitable laser energy, laser wavelength or laser pulse number. The type of floater can be determined via the OCDR signal strength (i.e. backscattering capacity), absorption (for example by determining an increased reduction in the signals of posterior structures behind a blood clot), size (especially axial extent), position (for example proximity to the optic nerve head), mobility or the reaction to laser processing.

According to a preferred embodiment, the central control and operating unit is also designed to determine changes or changes in position of the structure of the eye closest to the localized floater during the treatment and to derive termination criteria for the treatment. This closest structure can be, for example, the capsular bag or the vitreoretinal interface.

According to the invention, a decision to terminate or continue the treatment is derived.

Preferred criteria for this are:

• exceeding a limit value of a relative change in position within the retinal layers (eg local displacement of a retinal region in an anterior direction) or • Exceeding a threshold value for the change in intraocular pressure as a result of the laser effect

• bleeding as a criterion for discontinuation that starts during treatment.

The detection of the positions of the floaters in relation to the sensitive structures of the eye from the OCDR results is particularly preferably carried out automatically. For this purpose, the distance between the posterior capsular sac and retinal structures is determined by means of the OCDR system and used to decide which is the more sensitive structure that is to be followed by means of OCDR.

If the treatment is continued, OCDR is used to track whether the treatment can be continued or whether it has to be discontinued.

By deriving a termination criterion, the aim is in particular to prevent the mechanical stress conditions at the vitreoretinal interface from developing unfavorably as a result of the vitreous treatment and later retinal lesions or even a retinal tear becoming more likely.

In order to prevent the localized floater from moving out of the focal area of the processing laser, the processing laser is triggered according to the invention within a period of <10 ms after a floater is superimposed with the laser focus.

According to the invention, the optical elements for coupling OCDR and laser systems are based on dichroic or polarization-sensitive optical components (for example wavelength-sensitive splitters, polarization splitter cubes or also wavelength-independent splitters, which for example direct 30% of the OCDR measurement light to the eye and 70% of the processing laser) or use a geometric combination (pupil division). With the latter, small angles can also be accepted between the OCDR and the processing laser beam if, for example Floaters that are too small should not be treated and a sufficient overlap between the two beams is achieved, at least in the processing zone.

The beam cross-sections of the OCDR and laser are preferably selected before the superposition in such a way that the numerical aperture of the OCDR beam in the eye is smaller than that of the processing laser. One advantage of this setting is that the signal strengths in the OCDR signal with axial focus positions change less than with other configurations of the numerical aperture.

Mirrors introduced into the beam path at very short notice are not preferred, but are possible in order to enable very rapid switching between the processing laser and the OCDR beam, for example by means of a rapidly rotating mirror with transmission windows.

The coupling by means of dichroic optical components is preferably carried out by means of a notch filter which, for example, transmits a narrow-band Nd: YAG processing laser and reflects the broader band OCDR beam.

The display unit used is eyepieces with a mirrored display, a head-mounted display and / or a separate display (screen).

According to a further preferred embodiment, the OCDR system, the laser system with deflection unit, the optical elements for coupling the OCDR and laser system, the display unit and the central control and operating unit are integrated in a slit lamp.

This has the advantage that the user can look at the back of the eye with the slit lamp and localize the opacities of the vitreous in advance, as well as any other diseases that might be an exclusion criterion for treatment (for example a peripheral retinal detachment). The invention will be described in more detail below with reference to exemplary embodiments. To show

FIG. 1: the symbolic representation of the arrangement according to the invention for OCDR-supported laser vitreolysis which is integrated into a slit lamp.

FIG. 2: a schematic representation of a preferred variant of the invention.

FIG. 3: an illustration of an A-scan with restricted zones and processing zone

Figure 4: a schematic representation of an eye with attached contact glass

In addition, FIG. 1 shows the symbolic representation of a slit lamp in which the arrangement according to the invention for OCDR-supported laser vitreolysis is integrated.

In the slit lamp 1 (only shown as a box) the OCDR system 2, the laser system 3, the beam combiner 4 (here designed as a dichroic optical element) for coupling the OCDR and laser system, a display 5 and a central control and control unit 6 as well as a focus unit 14 with a deflection unit integrated.

As is known, the slit lamp 1 is arranged on a base unit 7 and can be positioned in 2 or 3 axes in relation to the eye 9 by means of a joystick 8.

In the eye 9, in addition to the eye lens 10, a localized floater 11 and the laser focus 12 are shown. Since in the present case the retina is the closest structure of the eye 9 to the localized floater 11, during the Treatment of at least this area (identified by position number 13) examined more closely using OCDR.

In addition to the localized floater 11, the display 5 can also display application-specific irradiation patterns, exclusion criteria or termination criteria for the treatment, or also defined processing and restricted zones, for example.

In Figure 2, a preferred embodiment of the invention is tert erläu. The representation concentrates on the interaction according to the invention of laser 3 and OCDR system 2. FIG. 2a shows the relationships at a point in time ti when there is no floater 11 in laser focus 12, F (t) stands for a focus position of the laser in Dependence on the time. The measuring beam 15 of the OCDR system 2 is brought together by means of the beam combiner 4 with the (not active here) laser beam 16 of the laser 3 and directed onto the eye 9. Before combining the beams, the beam cross-sections were selected so that the numerical aperture of the OCDR signal in the eye is smaller than that of the laser. The OCDR system 2 is able to measure complete A-scans of the eye 9 at 100 Hz, preferably 1 kHz or faster. Such an A-Scan 17 is shown here with an example. In a manner known per se, it contains the reflections from the cornea, the front side of the lens, the rear side of the lens 18 and the retina 19. In addition, the A-scan has a reflex 20 of a floater 11, the position of which in the eye is thus detected. The laser focus 12 is not in the area of the floater 11, and the laser is not triggered. By means of the focusing system 14, the laser focus 12 is shifted into the area of the floater 11 (FIG. 2b, point in time b. If the position of the laser focus 12 and the floater 11 match (reflex 20 and laser focus 12 essentially match), the laser pulse is triggered ( shown schematically with control pulse 21), preferably in a time <5 ms.Since the position of the floater 11 is updated in less than 10 ms per A-scan, it is ensured that it does not move out of the laser focus 12 in this short time could. For fast focusing the laser focus 12 by means of the focusing unit 14, in addition to lenses that can be moved mechanically on a linear slide with a position measuring system, electrically adjustable lenses such as the EL-10-30-C or -Ci are particularly suitable, which achieve a target focus in less than 10 ... 15 ms (Optotune Switzerland AG | Bernstrasse 388, CH-8953 Dietikon). Alternatively, a classic lens can be periodically shifted axially back and forth towards the eye by means of a magnetically driven oscillator in order to vary the focus position with a fixed focal length. The lens position can also be recorded here by means of a displacement encoder and easily calibrated with respect to the OCDR signal. A manual or motorized movement of the entire slit lamp in the direction of the eye in order to change the focusing is possible, but not preferred.

A calibration of the focus position to the OCDR can be achieved in various ways. One variant is scanning through the joint focusing of OCDR and laser focus and detection of signal increases depending on the focus position on the cornea, lens, capsular bag, vitreous scattering or retinal structures, since the OCDR signal is at its maximum when the focus is on a structure. Alternatively, calibration over the focus position to the OCDR can be achieved by determining the axial position of the beam waist with fixed focus settings, for example using a screen or a beam profiler, and then determining the position of the screen or the beam profile via OCDR, possibly also in one liquid-filled test eye.

With this arrangement, a method for handling floaters can be implemented, which is characterized by the following steps:

- Measurement of an A-scan

- Detection of a reflex of a floater (if available) in the A-Scan

- Optional detection of the back of the lens / capsular bag and retina in the A-scan - Optional verification of the permissibility of the laser treatment at the location of the floater

- Optional check of the permissibility of the laser treatment depending on the floater signatures (floater type)

- Shifting the laser focus onto the floater

- Optionally check whether the floater is still at this point

- Triggering of the laser pulse directed at the floater

This method is particularly preferred if the adjustment of the laser focus can be realized in the millisecond ... sub-second range, for example with an electrically adjustable lens with corresponding properties, but in principle also works with slow, possibly even manual, focusing , although in this case the probability of the floater running away during focusing increases, ie the treatment efficiency decreases, although the advantage of blocking and treatment zones is retained.

It is also possible to shift the laser focus to the side by means of a deflection unit (e.g. galvo scanner), i.e. scanning floater processing at a constant depth in the eye.

In an alternative method, the laser focus is moved along the A-scan and the laser pulse is triggered within milliseconds when a floater is detected in the area of the laser focus (by evaluating the A-scan). Slower focusing units would also be suitable for this (for example a few Hz to a few 10 Hz).

The displacement of the A-scan relative to the eye axis for the treatment of further floaters can take place either manually (by means of the joystick 8) or by motor. In the manual variant, the doctor can aim at the floater (s) and start the treatment. Only when the OCDR system detects a floater in the A-scan and the laser focus is directed to the floater will (without further Interaction) triggered a laser pulse. This means that the success of the treatment is no longer dependent on the skill and speed of reaction of the doctor.

In the motor-controlled variant, it is advisable to first create an overview image of the glass body in a manner known per se by means of an OCT system and to roughly detect the position of floaters. These position coordinates are then controlled one after the other, the actual position of the floaters being checked with the OCDR system and one (or more) laser pulse (s) being emitted only for actually detected floaters.

The verification of the permissibility of the laser treatment can be done in different ways. First of all, it must be ruled out that the laser treatment is carried out too close to sensitive structures of the eye such as the back of the lens / capsular bag or the retina / macula. Appropriate evaluation of the A-scan can be used to define permissible areas (> 1.5 mm from the back of the capsular bag, <2 ... 3 mm from the retina). FIG. 3 shows a corresponding example of an A-scan with the boundaries between restricted zones and processing zones. The anterior restricted zone is located anterior to the anterior border 22 of the processing area, and the posterior restricted zone is located posterior to the posterior border 23 of the processing area. In particular, the rear side of the lens 18 is located sufficiently deep in the anterior restricted zone and the retina 19 is located sufficiently deep in the posterior restricted zone, so that the desired minimum distances between these structures and the laser processing can be achieved.

Laser treatment is only permitted in the processing area enclosed by the borders 22, 23.

Furthermore, further parameters can be checked during the treatment, in which case monitoring of the intraocular pressure is preferred.

This can be done in different ways: 1. By checking for a change in eye length along the A-scan. The corresponding data are available for this from the evaluation of the A-Scan, if an extension is found here, this can be used as a termination criterion (e.g. an eye length enlargement of 4.5 pm to limit a pressure increase to 2 mmHg, see Leydolt et al , "Effects of change in intraocular pressure on axial eye length and lens position", Eye (2008) 22, 657-661).

2. By measuring the change in intraocular pressure using an appropriately equipped contact lens (will be explained in more detail below with reference to FIG. 4).

3. On the basis of ultrasound, as detailed in EP 3 173013 A2, the content of which is hereby incorporated by reference.

If a difference in intraocular pressure of, for example, 2 or 5 or 10 mmHg is exceeded, further treatment is interrupted in order to avoid damage to the eye. The choice of the termination criterion with regard to pressure can be made dependent on possible illnesses of the patient, e.g. greater caution must be applied with regard to pressure increases in glaucoma patients.

The proposed arrangement provides for the use of an OCDR system which is based on a spectral domain or preferably a swept source method. It would also be possible to use a time domain system with a repetition rate of several hundred Hz over a limited scanning depth of 2-3 millimeters.

According to the invention, an axial scan depth> 1mm, preferably 4mm in tissue, with an axial resolution <100pm, preferably 5pm FWHM in tissue, and a focal wavelength of 840nm, and an A scan rate of 10 to 100kHz. Preferably this has System via z-tracking of the retina or capsular bag depending on which structure of the eye is closer to the localized floater. Because of the low scan depth, the use of several parallel reference arms is possible, so that relevant eye structures and a posterior vitreous area can be detected together outside the simple scan depth. This approach is also conceivable for a time domain system. However, the latter has deficits in sensitivity (typ. 85dB). Spectral domain systems, on the other hand, can still have 90dB sensitivity at repetition rates of a few 10kHz, which means that normal, non-disruptive vitreous structures can also be detected. In contrast, swept-source systems in the kHz range with over 100 or even 110dB sensitivity still have sensitivity reserves that even make measurements through cataracts possible.

For a swept-source system, a focal wavelength in the range of 1000-1070 nm, in particular 1050nm or 1060nm, and scan rates of 1kHz to 100MHz (e.g. by means of a Fourier Domain Mode Locked laser (FDML) or VCSEL laser) and At least 90dB sensitivity in the processing zone is preferred. According to the invention, the system is combined with an Nd: YAG laser or fs laser, notch layer system filter and covers the entire eye with its OCDR scan depth. The axial resolution of the SS-OCDR is preferably selected so that it corresponds to the Rayleigh length of the machining laser or is greater than twice to three times the Rayleigh length. A higher axial resolution is possible, but hardly allows a better floater treatment. If changes in axis length are to be detected in order to determine changes in pressure, axial resolutions below 30 pm, preferably below 10 pm or even around 5 pm, are favorable.

According to the invention, a time domain system with a scanning reference arm can also be used. With the exception of the A-scan rate, the preferred parameters correspond to those for SD-OCT. In this case, the A scan rates are in the range of a few kHz, in particular 2 to 4 kHz. For all OCDR variants, the respective parts of the path in air and eye must be taken into account and a corresponding position determination correction and, if necessary, a group speed dispersion correction may be necessary.

In order to be able to detect floaters well, the systems according to the invention have a sensitivity of 85dB, preferably at least 90dB, in at least part of the A-scan. In a further preferred variant, the A-scans have at least a sensitivity of 90dB and more preferably sensitivities of more than 100dB over the entire scan depth. From approx. 90 dB, the normal scattering on the glass body and also on the crystal lens can be detected even in areas without floaters, thus allowing the differentiation of lens and glass body structures from fluid-filled pockets or eye areas.

Regardless of the variants just mentioned, the OCDR system can be part of an OCT system, which is designed as a two- or three-dimensional scanning system; It is important that the floater is localized in relation to variable focusing and the triggering of the laser pulse on the basis of the evaluation of an A-scan (and thus not on the basis of image information).

One-dimensional OCDR scans (A-scans) can be used to determine the position of the floater in the eye (coordinate system of the patient's eye) and to calculate its distance to the retina or other interfaces, and this very quickly and with little effort. They are therefore used to aid navigation and to increase safety when handling the floaters manually. Due to the possible very high sensitivity of the OCDR to all non-interferometric imaging methods, floater detection and visualization can be implemented much more reliably. The use of interferometric methods, in particular in the NIR spectral range, can also significantly reduce the exposure to light compared to methods based on VIS light, including resulting glare or pupillary contraction if the drug has not been dilated sufficiently. In addition, a distance display for the user is possible through the implementation of a machining zone that is only allowed during machining. When the treatment laser is activated within the restricted zone, the user is warned and / or the delivery of therapy radiation is blocked

According to the invention, the OCDR system has a sensitivity of 90 dB, at least in part of the A-scan.

The proposed arrangement provides for the use of a laser system which is based on a ps to ns YAG laser, a ps or an fs laser.

While a pulse duration of 1-5 ns is preferred according to the invention for a YAG laser, this is between 1 and 1000ps for a ps laser and between 50 and 10OOfs for an fs laser.

Instead of YAG lasers, such as the Nd: YAG laser at 1064nm, 946nm, 1320nm wavelengths, similar lasers such as the Nd: YLF 1047 to 1053nm and other similar parameters as with the YAG laser can also be used. The use of frequency-doubled lasers are possible in principle, although the unfavorable increased absorption by blood, especially in vessels, must be taken into account.

According to a further advantageous embodiment, the laser system has, in addition to a treatment beam, at least one pilot beam for checking the correspondence of the treatment beam focus and the target area. Laser diodes in the VIS are suitable for this, for example in the red spectral range at 635 nm.

In particular, the pilot beam can be continuous or quasi-continuous.

In the event that a visual check is to be carried out by the user, it is advisable to use a pilot beam in the visible spectral range. In addition, a pilot beam in the visible or infrared spectral range can be used in order to have its scattered radiation generated on the floater detected by the detection system and display it.

According to another advantageous embodiment, the difference between the wavelengths of the OCDR and laser systems is less than 50 nm, preferably less than 5 nm, so that common beam guiding and focusing elements can be used in the therapy device, but also the refraction of light from both systems into the eye in through corneal and lens refraction do not differ significantly from one another.

Furthermore, it is advantageous according to the invention if the arrangement has an additional fixation mark for the patient in order to achieve a favorable or known positioning of the patient's eye.

Furthermore, a changeable fixation mark offers the patient the possibility of editing while the eye movements are stimulated with it. This can also be necessary, for example, in order to bring floaters into the area accessible for processing in the first place. Also, a moving target mark can cause the patient to move the eye to move floaters in or out of an area. For example, the degree of subjective disturbance by a floater can be checked by moving the floater into the central viewing area (e.g. in front of the macula), but then moving it into an area that is less critical for laser treatment, for example in front of the retinal periphery there is laser therapy.

According to a further advantageous embodiment, the use of an additional vacuum contact glass for additional fixation of the eye is seen. An optional vacuum supply and a coupling to the therapy laser are provided during the treatment. This is particularly advantageous for high-precision laser treatment of floaters using fs lasers with focus diameters below 20pm, 10pm or even 5pm. For the higher lateral resolutions, pupil dilation and possibly also beam shaping by means of adaptive optics, such as deformable mirrors or liquid crystal SLMs, are advantageous.

The contact lens can be equipped with a device for determining the intraocular pressure or its change during the laser treatment. Such a contact glass 24 is shown in FIG. The cause of the change in intraocular pressure can be the generation of gas bubbles by the effect of the laser pulses. If this rises above a certain level, the eye could be damaged. The measured intraocular pressure is transmitted via a control line 25 to the control unit 6 (not shown here) which, for example, interrupts the further laser treatment if a difference in intraocular pressure of, for example, 2, 5 or 10 mm Hg is exceeded. Fundamentals for the determination of the intraocular pressure with a contact lens are for example in Leonardi et al; First Steps toward Noninvasive Intraocular Pressure Monitoring with a Sensing Contact Lens. Invest. Ophthalmol. Vis. Be. 2004; 45 (9): 3113-3117. doi: 10.1167 / iovs.04-0015.

The solution according to the invention provides an arrangement for the OCDR-assisted laser treatment of opacities of the vitreous body, which eliminates the disadvantages of the known technical solutions.

With the arrangement, a simpler, faster and, above all, safer treatment of troublesome vitreous opacities by laser vitreolysis is possible. The solution is also easy to implement and economical.

The present invention relates to an arrangement which is provided for the gentle, low-risk and low-pain laser treatment of opacities of the vitreous body. A partially or fully automated therapy device (system) is proposed, in which an OCDR system is used for navigation, to the To locate floaters in the course of the treatment and thereby support the treatment.

The proposed arrangements also enable the safe treatment of variable-position and difficult to recognize, largely transparent floaters, the effort for positioning the machining laser beam can be reduced and a visible target laser beam is no longer mandatory.

The risk of retinal damage due to incorrect focus positions or too small a distance between the laser focus and sensitive structures of the eye could be eliminated by defining exclusion criteria for the treatment.

In addition, the risk of retinal damage in the event of incomplete glass body detachment could be reduced by locally increasing the tension on the retina by adapting the treatment or terminating the treatment based on derived termination criteria.

Claims

Claims

1 . Arrangement for laser vitreolysis of an eye, consisting of an OCDR system, a laser system with deflection unit, optical elemen th for coupling the OCDR and laser system, a display unit and a central control and operating unit, the OCDR system being formed from floaters to localize, the laser system is designed to destroy the floater by means of laser pulses, the central control and operating unit is designed to activate the laser system based on the localization of the floater (s) in relation to the focus position of the laser system and in relation to eye structures.

2. Arrangement according to claim 1, characterized in that the central control and operating unit is designed to determine changes in the structure of the eye that is preferably closest to the localized floater during the treatment and to derive termination criteria for the treatment.

3. Arrangement according to claims 1 or 2, characterized in that the central control and operating unit is designed to automatically activate the laser system within a time of <10 ms, taking into account the derived exclusion criteria for the treatment and the application-specific radiation pattern generated or to be selected triggered after the detection of a floater.

4. Arrangement according to claims 1, 2 or 3, characterized in that the OCDR system, the laser system with deflection unit, the optical elements for coupling the OCT and laser system, the display unit and the central control and operating unit in a slit lamp or an operating microscope are integrated.

5. Arrangement according to claim 1, characterized in that the OCDR system is based on a spectral domain or a swept source method.

6. The arrangement according to claim 1, characterized in that the laser system is based on a ps, an ns, a ps or an fs laser or combinations thereof.

7. Arrangement according to claim 1, characterized in that the difference between the wavelengths of the OCDR and laser system is <50 nm.

8. The arrangement according to claim 1, characterized in that the OCDR system has an axial resolution which is better than the smallest Rayleigh length that can be set in the eye of the laser system used.

9. A method for controlling a laser for vitreolysis, preferably with an arrangement according to claim 1, in which floaters in the glass body of the eye are detected by means of OCDR and when a floater is detected, the laser is focused on the floater and at least one laser pulse is emitted on the floater becomes.

10. A method for controlling a laser for vitreolysis, preferably according to claim 1, in which the laser focus is guided through the glass body of the eye and detected promptly by means of OCDR whether there are floaters in the laser focus, and at least one laser pulse when a floater is detected is triggered.

11. Arrangement according to Claim 1, characterized in that an operator can fix or change a processing area in relation to distances to eye structures in which laser processing can be activated.

12. The arrangement according to claim 1, characterized in that laser parameters, such as laser energy, laser focus shift compared to OCDR, laser wavelength or laser pulse number depending on the focus position changed over the common focus unit and / or the distance from eye structures is varied.

13. The arrangement according to claim 1, characterized in that the OCDR has a smaller numerical aperture than the laser.