DE102017124546A1 - microscope - Google Patents

Abstract

A microscope with an observation beam path (2), an observation beam path (2), over which an eye (4) to be treated is observable, a wavefront measuring device (11) for measuring the refraction of the eye (4) to be treated, a treatment laser device (13 ), which has a treatment laser beam path through which treatment laser radiation can be focused into the eye to be treated (4) as a treatment laser spot, and a control unit (32), which is supplied with at least one measured value of the wavefront measuring device (11), wherein the control unit ( 32) adjusts the beam diameter and / or the beam shape of the treatment laser spot based on the at least one supplied measured value.

Description

The present invention relates to a microscope. In particular, it relates to a surgical microscope that can be used in eye surgery for interventions on the anterior and / or posterior chamber of the eye. Common procedures in the anterior chamber are cataract and glaucoma treatments. At the posterior chamber, interventions on the retina, e.g. Membrane peeling and macular hole procedures are performed.

In these procedures (especially on the retina), treatment lasers (which may also be referred to as therapeutic lasers) are used for photocoagulation. In addition to these thermally-acting lasers, ultrashort pulse lasers with pulse lengths in the fs range have also been clinically introduced for eye surgery in recent years. In particular, these ultrashort pulse lasers use refractive corrections in the cornea or support cataract surgery in the lens. The use for vitreous and retinal surgery has already been described.

Further, in recent years, in the field of ophthalmic surgery, wavefront measurement for e.g. intraoperative measurement of eye refraction and optical coherence tomography (OCT) for e.g. intraoperative visualization of retinal structures has been introduced.

Proceeding from this, it is therefore an object of the invention to provide a microscope that uses the described known technologies for a microscope with improved properties.

The invention is defined in claim 1. Advantageous developments are specified in the dependent claims.

The microscope according to the invention can observe an observation beam path over which an eye to be treated (preferably enlarged), a wavefront measuring device for measuring the refraction of the eye to be treated, a treatment laser device which focuses a treatment laser beam path, via the treatment laser radiation into the eye to be treated as a treatment laser spot can, has, and a control unit, which is supplied to at least one measured value of the wavefront measuring device. The control unit may adjust the beam diameter and / or the beam shape of the treatment laser spot based on the at least one supplied measured value.

This advantageously makes use of the measurement of the wavefront measuring device in order to be able to individually adjust properties of the treatment laser spot to the eye to be treated. Thus, an extremely high accuracy is achieved, since the defocusing and / or deformation of the treatment laser spot caused by the individual eye to be treated can be well compensated.

With the treatment laser device, pulsed laser radiation (eg ps- or fs-pulses) can be delivered into the eye to be treated. The treatment laser device may include a corresponding treatment laser (eg, fs / ps treatment laser). For connecting the treatment laser or for transmitting the laser radiation of the treatment laser to the microscope, a flexible fiber may be provided, which is designed in particular as a hollow core fiber or photonic crystal fiber. With such a fiber, the high pulse peak powers of the laser pulses emitted by the treatment laser can be easily transmitted. With the flexible fiber, the (pulsed) treatment laser radiation can be guided to a free jet of the microscope.

The wavefront measuring device can measure the spherical aberration of the eye to be treated. Furthermore, the wavefront measuring device can measure the astigmatism of the eye to be treated. This is possible with the desired accuracy so quickly that this measurement can be evaluated in real time and used for setting the beam diameter and / or the beam shape of the treatment laser spot.

In particular, the control unit can control the treatment laser device in such a way that a defocusing and / or a deformation is impressed on the treatment laser radiation, which is opposite to the defocusing and / or deformation caused by the eye to be treated.

The treatment laser device can have collimating optics for collimating the treatment laser radiation, wherein the control unit activates the collimation optics for setting the beam diameter and / or the beam shape of the treatment laser spot.

In particular, the collimating optics may have an axially displaceable lens. The control unit may adjust the axial position of the lens to adjust the beam diameter of the treatment laser spot.

Furthermore, the collimating optics may have a liquid lens, which is controlled accordingly by the control unit for setting the beam diameter and / or the beam shape of the treatment laser spot.

Furthermore, the collimating optics can have an adaptive mirror, which the control unit controls to adjust the beam diameter and / or the beam shape of the treatment laser spot.

The observation beam path may have a main objective. Furthermore, the main objective may be part of the treatment laser beam path and / or part of a detection beam path of the wavefront measuring device. Furthermore, the main objective can be part of the illumination beam path of the wavefront measuring device.

The microscope may have a lighting device. The illumination device comprises an illumination beam path, which may have the main objective. The illumination device can be designed as coaxial illumination and in particular as coaxial stereo illumination (SCI = stereo coaxial illumination). In particular, it can in the same way as the illumination device 120 of the EP 1 918 756 B1 be educated. It is here in particular 1 to 5 with associated description.

The microscope may be formed as a stereomicroscope with two observation beam paths (e.g., observation optical beam paths). Both observation beam paths can contain as lens the main objective. The microscope can also have an eyepiece in the observation beam path (or in each observation beam path). The microscope is designed in particular as a surgical microscope.

Furthermore, the microscope can have an OCT device, which has an OCT illumination beam path, via which OCT illumination radiation can be focused into the eye to be examined (or treated) as an OCT spot. The control unit may set the beam diameter and / or the beam shape of the OCT spot based on the at least one supplied measured value. In this case, the wavefront measuring device can measure the spherical aberration and / or the astigmatism of the eye to be treated

The OCT device may include a deflection unit (or scanning unit) in order to move the OCT illumination radiation in the eye. The microscope may in particular be designed so that the laser radiation of the treatment laser is deflected and moved via the same scanning unit.

The control unit can control the OCT device in such a way that a defocusing and / or a deformation is impressed on the OCT illumination radiation, which is opposite to the defocusing and / or deformation caused by the eye to be treated.

The OCT device can have collimating optics for collimating the OCT illumination radiation, wherein the control unit controls the collimation optics for setting the beam diameter and / or the beam shape of the OCT spot. In this case, the collimating optics of the OCT device can have an axially displaceable lens whose axial position is adjusted by means of the control unit for adjusting the beam diameter of the OCT spot.

Furthermore, the collimating optics of the OCT device can have a liquid lens, which is controlled by the control unit for setting the beam diameter and / or the beam shape of the OCT spot.

The collimation optics of the OCT device can have an adaptive mirror, which the control unit controls to set the beam diameter and / or the beam shape of the OCT spot.

The main objective of the observation beam path can also be part of the OCT illumination beam path. Since the OCT measurement beam path runs opposite to the OCT illumination beam path, the main objective can also be part of the OCT measurement beam path.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the specified combinations but also in other combinations or alone, without departing from the scope of the present invention.

The invention will now be described by way of example with reference to the accompanying drawings 1 , which is a schematic representation of an embodiment of the microscope according to the invention and discloses the features also essential to the invention, explained in more detail. These embodiments are merely illustrative and are not to be construed as limiting. For example, a description of an embodiment having a plurality of elements or components is not to be construed as requiring all of these elements or components for implementation. Rather, other embodiments may include alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of various embodiments may be combined with each other unless otherwise specified. Modifications and modifications described for one of the embodiments may also be applicable to other embodiments.

At the in 1 the embodiment shown is the microscope according to the invention 1 as a stereo surgical microscope 1 formed with two optical observation beam paths, of the in 1 only one observation beam 2 is schematically illustrated. The beam path 2 runs from an object to be observed 4 through a main lens 5 , then through a first beam splitter 6 , a zoom lens 7 and an eyepiece 8th , so that an observer with his eye A, the object to be observed 4 can perceive enlarged.

The microscope 1 further includes an OCT device 10 (OCT = optical coherence tomography), a wavefront measuring device 11 , a lighting device 12 and a treatment laser device 13 ,

As described in detail below, the beam paths of these devices become 10 - 13 superimposed and by means of the first beam splitter 6 to the lens 4 redirected. These are a second, third, fourth and fifth beam splitter 15 . 16 . 17 . 18 , a diverting spigot 19 , a scanning unit 20 with a first and second deflection mirror 21 . 22 intended. The OCT facility 10 includes a first collimator optics 23 , a first light guide 24 and an OCT module 25 , During operation, the OCT module generates 25 the necessary coherent illumination radiation, which may for example have a wavelength of 1060 mm. The coherent illumination radiation is transmitted through the first light guide 24 directed and by means of the first collimator optics 23 collimated. The scanning unit 20 leads by means of the first and second deflection mirrors 21 . 22 the desired deflection in the x-direction and y-direction through, so by the scanning unit 20 coherent illumination radiation via the third, second and first beam splitter 16 . 15 . 6 to the lens 4 steered and by means of the objective 5 to the desired location in the object 4 is focused to thereby generate detection radiation which is directed opposite to the coherent illumination radiation to the OCT module. To simplify the illustration, further optically imaging elements known to the person skilled in the art are provided between the first collimator optics 23 and the lens 5 In order to realize the described focusing of the scanned coherent illumination radiation, not shown.

The generated detection radiation passes through the illumination beam path of the OCT device 10 in the opposite direction and is over the first light guide 24 to the OCT module 25 passed, in which the detection is carried out in a known manner.

The treatment laser device 13 includes a second optical fiber 26 and a second collimator optics 27 , The laser radiation of the illumination laser device 13 for the treatment of the object 4 which, for example, may be an eye (especially a human eye), is placed in the second light guide 26 coupled and up to the second collimator optics 27 which collimates the laser radiation, which then passes through the fourth beam splitter 17 to the scan unit 20 is steered and thus then passes through the same beam path as the illumination radiation of the OCT device 10 , A treatment laser emitting the laser radiation 28 may be part of the treatment laser device 13 his. The treatment laser 28 In particular, it emits pulsed laser radiation in the femtosecond or picosecond range and can therefore be referred to as an fs laser or as a ps laser. The wavelength of the emitting laser radiation can in the infrared range, for. B. in the range of 800-900 nm or in the range of 1000-1100 nm, or even in the visible wavelength range. Typical wavelengths are here 532, 561, 577, 660 or 670 nm.

The wavefront measuring device 11 includes a lighting laser 29 For example, which emits laser radiation having a wavelength in the range of 750-850 nm, via the fifth and second and first beam splitter 18 . 15 . 6 to the lens 5 is directed towards. Furthermore, the wavefront measuring device comprises 11 a wavefront sensor 30 (eg a Shack-Hartmann camera 23 ) for detection, wherein the radiation to be detected on the main objective 5 , the first, second and third beam splitters 6 . 15 and 16 to the wavefront sensor 30 is directed towards.

The lighting device 12 includes a light source 31 , which emits illumination radiation in the range of 400-700 nm, which exceeds the deflection mirror 19 as well as the fifth, second and first beam splitter 18 . 15 . 6 to the main lens 5 is directed towards.

To simplify the illustration are next to the main lens 5 further optically imaging elements of the wavefront measuring device 11 and lighting device 12 not shown, since these are known in the art.

Further, a control unit 32 provided, inter alia, with the wavefront sensor 30 , the scanning unit 20 , the treatment laser 28 , the OCT module 25 as well as the two collimator optics 23 and 27 connected and the microscope 1 , as will be described below, can control.

To the described superposition of the beam paths of the devices 10 - 13 to realize are the first to fifth beam splitter 6 . 15 - 18 formed as a dichroic beam splitter. The reflection and transmission values for the beam splitters 6 . 15 - 18 are given as percentages in Tables 1 to 5 below. Similarly, the values for the first and second deflecting mirrors 21 and 22 as well as for the redirection seal 19 in Tables 6 and 7 below. SCI stands for the radiation of the light source 31 , OCT for the radiation of the OCT module, WFS for the radiation of the illumination laser and LASER for the radiation of the treatment laser 28 , Table 1 (first beam splitter 6, VIS = visible wavelength range, IR = infrared range): Reflection [in%] Transmission [%] SCI 30 70 OCT 100 0 WFS 100 0 LASER 30 (VIS) / 100 (IR) 70 (VIS) / 0 (IR) Table 2 (second beam splitter 15): Reflection [in%] Transmission [%] SCI 50 50 OCT 0 100 WFS 50 50 LASER 50 50 Table 3 (third beam splitter 16): Reflection [in%] Transmission [%] OCT 0 100 WFS 100 0 LASER 0 100 Table 4 (fourth beam splitter 17): Reflection [in%] Transmission [%] OCT 0 100 LASER 100 0 Table 5 (fifth beam splitter 18): Reflection [in%] Transmission [%] SCI 0 100 WFS 100 0 Table 6 (first and second deflecting mirrors 21, 22): Reflection [in%] Transmission [%] OCT 100 0 LASER 100 0 Table 7 (deflection mirror 19): Reflection [in%] Transmission [%] SCI 100 0

These specifications are based on the following considerations. The OCT beam path has to be optimized in terms of illumination and the OCT detection has to be optimized in terms of transmission since a reduction of the image quality is undesirable. The wavefront beam path is not as critical in terms of transmission as the OCT beam path. Therefore, the wavefront beam path is optimized for detection because of losses in wavefront illumination via a stronger illumination laser 29 can be compensated. At the radiation of the treatment laser 28 must have losses at the first and second beam splitter 6 . 15 be accepted. However, these can be achieved by means of a higher output power of the treatment laser 28 be compensated. The same applies to the light source 31 the lighting device 12 , The second beam splitter 15 can with respect to the 50/50 values of reflection and transmission for the beam path of the illumination device 12 , the beam path of the wavefront measuring device 11 and the beam path of the treatment laser device 13 adapted to the respective light source.

When using the microscope according to the invention 1 In the field of eye treatment, the quality of the OCT image data is from the lateral diameter of the illumination beam on the retina of the eye to be photographed (and, if necessary, to be treated) 4 dependent. Likewise, the efficiency of the photocoagulation, the photodisruption and / or the photoablation depends on the diameter of the laser spot of the laser radiation of the treatment laser 28 on the fundus.

According to the invention in the microscope 1 by means of the wavefront measuring device 11 the refraction of the eye 4 measured. Parallel or separately, then, the spot diameter of the laser radiation of the OCT module and / or the spot diameter of the laser radiation of the treatment laser 29 be adjusted taking into account the measured refraction. The setting can be for the spot diameter of the laser radiation of the OCT module 25 through the first collimation optics 23 be performed. The adjustment of the spot diameter of the laser radiation of the treatment laser 28 can by means of the second collimation optics 27 respectively. This can be achieved, for example, by axial displacement of a lens of the corresponding collimation optics 23 . 27 be performed. It is also possible that the collimation optics 23 . 27 have an adaptive mirror and / or a liquid lens with electrically variable focal length.

Especially in the measurement and / or treatment of the retina, the eye can 4 the laser spot of the laser radiation of the OCT module 25 and / or the laser spot of the laser radiation of the treatment laser 28 defocus and / or deform (so that it is no longer round, for example). The measurement by means of the wavefront measuring device 11 can be done quickly and with high accuracy. The measurement results can then, as already described, be used for this purpose by means of the corresponding collimation optics 23 . 27 to perform a defocusing exactly opposite to that through the eye 4 conditional defocusing. Of course you can perform in the same way an opposite deformation of the laser spot to those through the eye 4 compensate for conditional deformation of the laser. This is achieved in an advantageous manner that the laser spot of the laser radiation of the OCT module 25 and / or the laser spot of the treatment laser 28 in the eye to be treated 4 For example, focused on the retina and is round.

Of course, the laser spot of the laser radiation of the treatment laser 28 not only minimized, it is also possible to adjust it to a desired diameter. This may be particularly advantageous in photocoagulation and / or photodisruption.

In the microscope according to the invention 1 can thus based on the measurement by means of the wavefront measuring device 11 the diameter of the laser spot of the laser radiation of the OCT module 25 and / or the diameter of the laser spot of the laser radiation of the treatment laser 28 specifically controlled or adjusted in terms of diameter and / or shape.

Furthermore, with the microscope according to the invention 1 a treatment mode can be realized in which by means of the OCT device 10 B-scans and / or volume data (hereinafter referred to as OCT data). The OCT data may include, for example, blood vessels and other retinal structures. These structures can be determined by evaluating the OCT data. This evaluation can be done, for example, in real time (or online). On the basis of this evaluation, then the treatment laser 28 including scan unit 20 be controlled so that specifically the desired locations are coagulated.

This treatment mode can be realized, for example, as a sequential or as a parallel treatment mode. In the sequential treatment mode, the OCT data is first measured and, based thereon, the desired locations with the laser radiation of the treatment laser 28 coagulated or cut. In the parallel treatment mode, the OCT data is permanently and continuously measured and evaluated. The treatment laser 28 is then turned on only at those times at which by means of the scanning unit 20 the laser beam of the OCT module 25 as well as the laser beam of the treatment laser 28 cover the desired places.

The connection of the treatment laser 28 to the microscope 1 as a portable surgical microscope 1 can be formed is difficult, since the second light guide 26 can not be realized by a conventional quartz glass fiber. So would the high pulse peak power of the treatment laser 28 emitted laser pulses lead to destruction of the coupling surface of the second light guide. Therefore, as the second optical fiber, a photonic crystal fiber (also called a microstructured hollow core fiber) is used. The hollow core diameter may be, for example, about 40 microns, using a so-called "Kagome" structure (Benabid et al., Laser Focus World, Vol. 50, September 2014, "Fiber for Fiber Lasers: Kagome PC Fails to Extreme for Ultrashort Pulses lasers "). In such a hollow core fiber, for example, the ultra-short pulse radiation of the treatment laser 28 be coupled with about <20 mrad half angle. The transmission losses are very low (a few percent) with such a fiber and the beam quality at the end of the fiber 26 Remains almost stable with a beam quality parameter product of M ² <1.3. Furthermore, this is flexible fiber 26 able to transmit even larger power of about 500 W easily. Since in medicine, and in particular in the treatment of eyes a maximum of about 10 W are needed, such a fiber is very well suited to the treatment laser 28 to the microscope 1 to tie. Further, in photonic crystal fibers, as compared with quartz glass fibers, no remarkable dispersion effects occur, which would cause undesirable changes in the temporal pulse shape. Thus, the described hollow core fiber is a flexible fiber, which is particularly suitable for the transmission or the transmission of fs and ps laser pulses.

For photodisruption in the posterior section of the eye, the focusing of the ultrashort pulsed laser radiation with a comparatively small aperture is necessary. For example, fs laser pulses with pulse energies in the nJ and μJ range are usually focused at NA> 0.8 apertures in order to produce a plasma at the focal point which causes photodisruption and thus formation of no bubbles in the mostly transparent tissue. These sites of photodisruption can be detected by means of the scanning unit 20 be placed side by side so that thereby the fabric can be perforated and / or cut. This is also done at apertures NA> 0.25 in the anterior segment of the eye. With scanned ultrashort pulse laser radiation with a numerical aperture of less than 0.25, autofocusing increasingly occurs with fs laser pulses, which causes filamentation of the laser beam and thus jitter in the focus position and thus inaccurate cutting by photodisruption. Therefore, for positionally precise cuts in the posterior segment of the eye and at apertures of less than 0.25, in particular ps laser pulses (0.7-20 ps and in particular 1 -3 ps), which have pulse energies in the μJ range and are used repetitively in the kHz range. If the treatment laser 28 operates repetitively in the MHz range, smaller pulse energies in the lower μJ range or nJ range can also be used.

The inventive flexible connection of the ultrashort pulse treatment laser 28 to the surgical microscope 1 by means of the microstructured hollow core fiber 26 with preservation of pulse quality and beam quality, the transmission within the microscope 1 with comparatively large beam diameter without intermediate focus points (especially on optical surfaces to avoid laser damage) and in particular the use of ps laser pulses thus allows a jitter-free focusing in the rear eye section for exact cutting of structures of the retina and the vitreous body of the eye to be treated 4 ,

In an alternative embodiment, the laser radiation of the treatment laser 28 and the laser radiation of the OCT module 25 in the same fiber 24 or 26 be guided, if this can be tolerated for wavelength reasons and requirements for the beam profile of the laser radiation.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• EP 1918756 B1 [0016]

Claims (10)

Microscope with an observation beam path (2) over which an eye (4) to be treated can be observed, a wavefront measuring device (11) for measuring the refraction of the eye (4) to be treated, a treatment laser device (13), which has a treatment laser beam path over which treatment laser radiation can be focused in the eye to be treated (4) as a treatment laser spot, and a control unit (32), to which at least one measured value of the wavefront measuring device (11) is fed, wherein the control unit (32) adjusts the beam diameter and / or the beam shape of the treatment laser spot based on the at least one supplied measured value. Microscope after Claim 1 in which the wavefront measuring device (11) measures the spherical aberration of the eye (4) to be treated. Microscope after Claim 1 or 2 in which the wavefront measuring device (11) measures the astigmatism of the eye (4) to be treated. Microscope according to one of the preceding claims, wherein the control unit (32) controls the treatment laser device (13) so that the treatment laser radiation a defocusing and / or deformation is impressed, which is opposite to the defocusing caused by the eye to be treated (4) and / or deformation. Microscope according to one of the preceding claims, in which the treatment laser device (13) comprises collimating optics (27) for collimating the treatment laser radiation, wherein the control unit (32) controls the collimating optics (27) for adjusting the beam diameter and / or the beam shape of the treatment laser spot. Microscope after Claim 5 in which the collimating lens (27) has an axially displaceable lens whose axial position is adjusted by means of the control diameter (32) for adjusting the beam diameter of the treatment laser spot. Microscope after Claim 5 or 6 in which the collimating optics (27) has a liquid lens which is actuated by the control unit (32) for setting the beam diameter and / or the beam shape of the treatment laser spot. Microscope after one of the Claims 5 to 7 in which the collimating optics (27) has an adaptive mirror, which the control unit (32) controls to adjust the beam diameter and / or the beam shape of the treatment laser spot. Microscope according to one of the above claims, wherein the treatment laser device (13) comprises a hollow core fiber (26) via which the treatment laser radiation emitted by a treatment laser (28) is guided to an open beam path of the microscope (1). Microscope according to one of the above claims, wherein the observation beam path (2) has a main objective (5) and the main objective is part of the treatment laser beam path and / or part of a detection beam path of the wavefront measurement device.

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