JP7263726B2 - Ophthalmic laser therapy device and ophthalmic laser control program - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an ophthalmic laser treatment device and an ophthalmic laser control program for treating a patient's eye.

2. Description of the Related Art An ophthalmic laser treatment apparatus for treating a patient's eye by irradiating the patient's eye with a laser beam is known (see Patent Document 1).

JP 2015-006402 A

By the way, in an ophthalmic laser treatment apparatus, it has been proposed to determine an irradiation position not by a surgical microscope but by a photographed image. However, since there is aberration in the optical system for imaging, when imaging with light of a wavelength different from that of the therapeutic laser beam, even if the aiming position or irradiation position is appropriate, the image will be displayed out of alignment. There was something to be done.

In view of the above problems, the technical problem of the present disclosure is to provide an ophthalmic laser treatment apparatus and an ophthalmic laser control program that can accurately set an irradiation position even when imaging light and treatment light have different wavelengths. do.

In order to solve the above problems, the present disclosure is characterized by having the following configuration.

(1) An ophthalmologic laser therapy apparatus for treating a patient's eye, comprising laser irradiation means for irradiating the patient's eye with treatment light and aiming light, and imaging for obtaining a fundus image by photographing the fundus of the patient's eye. An optical system and a controller, wherein the controller detects the aiming light from the fundus image and corrects a positional deviation between the fundus image and the aiming light caused by aberration of the imaging optical system. By doing so, the position of the aiming light with respect to the fundus image is changed.
(2) An ophthalmic laser control program to be executed in an ophthalmic laser therapy apparatus for treating a patient's eye, the program being executed by a processor of the ophthalmic laser therapy apparatus to provide treatment light and aiming light to the patient's eye. an imaging step of imaging the patient's eye with an imaging optical system ; a detection step of detecting the aiming light from the fundus image of the patient's eye captured in the imaging step; and the imaging optical system and a changing step of changing the position of the aiming light with respect to the fundus image by correcting the positional deviation between the fundus image and the aiming light caused by the aberration of Characterized by

1 is a schematic diagram showing an internal configuration of a first embodiment; FIG. It is a figure which shows the shift|offset|difference of an observation image and aiming light. FIG. 4 is a diagram showing spectral sensitivity of a light receiving element; FIG. 4 is a block diagram showing the flow of positional deviation correction of aiming light; It is a figure which shows about the detection method of aiming light. It is a figure which shows about the acquisition method of an observation image. 4 is a flow chart showing a control operation; It is a block diagram which shows the modification of 1st Example. It is a schematic diagram showing the internal configuration of the second embodiment. FIG. 11 is a block diagram showing the flow of processing in the second embodiment;

<Embodiment>
An embodiment according to the present disclosure will be described. An ophthalmic laser treatment apparatus (for example, laser treatment apparatus 1) according to an embodiment treats a patient's eye. The ophthalmic laser treatment apparatus includes a laser irradiation unit (eg, laser irradiation unit 10), an imaging optical system (eg, observation optical system 20), and a control unit (eg, control unit 70). The laser irradiation unit, for example, irradiates the patient's eye with therapeutic light and aiming light. The imaging optical system acquires a fundus image by, for example, photographing the fundus of the patient's eye. The controller detects aiming light from the fundus image and changes the position of the aiming light with respect to the fundus image. As a result, the ophthalmic laser therapy apparatus can irradiate therapeutic light onto appropriate positions. For example, the control unit may correct the positional deviation between the fundus image and the aiming light caused by the aberration of the imaging optical system. Further, the control unit may correct the positional deviation between the fundus image and the aiming light caused by the optical axis deviation between the laser irradiation unit and the imaging optical system. When changing the position of the aiming light with respect to the fundus image, either the position of the fundus image or the aiming light may be used as a reference. In other words, the controller may change the relative positions of the fundus image and the aiming light.

Note that the control unit may cause the display unit (for example, the display unit 74) to display the fundus image in which the position of the aiming light is changed. That is, the display position of the aiming light with respect to the fundus image may be changed. Thereby, the control unit can present information suitable for setting the irradiation position to the operator. When changing the display position of the aiming light with respect to the fundus image, the control unit may change the position of the image of the aiming light and display it, or electronically display the position of the aiming light after the change. good too. For example, the controller may cause an electronic mark to be displayed at the changed position of the aiming light.

Note that the imaging optical system may include a light receiving element (for example, the light receiving element 29) having two or more types of spectral sensitivities. For example, the light receiving element may be an RGB color sensor or the like. For example, the light receiving element may acquire an image for each of multiple channels. In this case, the controller controls a first fundus image (eg, first channel image) acquired with the first spectral sensitivity and a second fundus image (eg, second channel image) acquired with the second spectral sensitivity. ) may be used to detect the aiming light. For example, the difference between the R-channel image and the G-channel image may be obtained. The light receiving element may have sensitivity in wavelength regions corresponding to red, green, blue, and infrared light.

The ophthalmologic laser treatment apparatus may include a plurality of light receiving elements, and the light receiving elements may receive light whose wavelengths are separated by a wavelength separation member (for example, a dichroic mirror, etc.).

The imaging optical system may include a light receiving element having one type of spectral sensitivity. In this case, the control unit controls lighting of the sighting light in synchronization with photographing of the photographing optical system, and a lighting image photographed with the sighting light turned on and an image photographed with the sighting light turned off Aiming light may be detected based on the difference from the off image.

Note that the therapeutic light and the aiming light may have the same wavelength. In this case, the deviation of the irradiation position between the aiming light and the treatment light due to the aberration of the laser irradiation unit is reduced.

Note that the control unit may detect the aiming light in the first image area. The first image area is, for example, a partial image area including a pre-designated therapeutic light irradiation position. Also, the control unit may correct the positional deviation of the aiming light in the second image area. The second image area is, for example, a partial image area including the detection position of the aiming light.

Note that the control unit may execute an ophthalmic laser control program stored in a storage unit (for example, storage unit 75). The ophthalmic laser control program is executed, for example, in an ophthalmic laser treatment apparatus that treats a patient's eye. An ophthalmic laser treatment apparatus includes, for example, a laser irradiation step, an imaging step, a detection step, and a change step. The laser irradiation step is, for example, a step of irradiating the patient's eye with therapeutic light and aiming light. The imaging step is, for example, a step of imaging the patient's eye. The detection step is a step of detecting aiming light from the fundus image of the patient's eye captured in the imaging step. The changing step is a step of changing the position of the aiming light with respect to the fundus image.

<Example>
A first embodiment according to the present disclosure will be described. The first embodiment is a laser treatment apparatus 1 that irradiates a patient's eye with laser light. For example, it mainly includes a laser irradiation unit 10 , an observation optical system 20 , and a control unit 70 .

<Laser irradiation part>
The laser irradiation unit 10 oscillates therapeutic laser light, for example, and irradiates the patient's eye E with the laser light. For example, the laser irradiation unit 10 includes a laser light source 11, an aiming light source 12, a beam splitter 13 (combiner), a lens 14, a driving unit 15, a scanning unit 16, and the like. The laser light source 11 emits therapeutic laser light. The wavelength of the laser light source 11 is, for example, 577 nm. The aiming light source 12 emits visible aiming light (aiming light). The wavelength of the aiming light source 12 is, for example, 635 nm. The beam splitter 13 multiplexes the therapeutic laser light and the aiming light. The beam splitter 13 reflects most of the treatment laser light and transmits part of the aiming light. The lens 14 is moved by the drive unit 15 to adjust the focus of the laser beam. The scanning unit 16 includes, for example, a mirror 16a and a driving unit 16b. The driving section 16b changes the angle of the reflecting surface of the mirror 16a.

The laser light and the sighting light combined by the beam splitter 13 are reflected by the scanning unit 16 and the dichroic mirror 40 via the lens 14 and condensed on the fundus oculi Ef via the objective lens 41 . At this time, the irradiation position of the laser beam on the fundus oculi Ef is changed by the scanning unit 16 .

A shutter 17 is provided between the laser light source 11 and the beam splitter 13 to block the therapeutic laser beam. The shutter 17 may be used to irradiate and block laser light. A shutter 18 is provided in the optical path along which the laser light or the aiming light is guided. Shutter 18 is a safety shutter that is closed in the event of an emergency. A shutter 18 may be used to illuminate and block the aiming light as the aiming light is scanned. Each shutter may be replaced with a galvanomirror having the function of switching the optical path.

<Observation optical system>
The observation optical system 20 acquires an observation image of the patient's eye. The observation image is, for example, a front image of the fundus oculi Ef. The observation optical system 20 of this embodiment is a so-called scanning laser ophthalmoscope (SLO). For example, the observation optical system 20 includes a light source 21, a lens 22, a driving section 23, a scanning section 24, a lens 25, and the like. The light source 21 is a laser diode light source that emits highly coherent imaging light. The wavelength of the light source 21 is, for example, 785 nm. That is, the light source 21 is an infrared light source. The lens 22 is movable in the optical axis direction according to the refractive error of the patient's eye. The scanning unit 24 includes a mirror 24a and a driving unit 24b. The mirror 24a is a combination of a galvanomirror and a polygon mirror capable of scanning the fundus in the XY directions at high speed. The driving section 24b drives the mirror 24a. The lens 25 relays the measurement light reflected by the scanning section 24 to the objective lens 41 .

A beam splitter 26 is arranged between the light source 21 and the lens 22 . In the reflecting direction of the beam splitter 26, a lens 27, a confocal aperture 28 placed at a position conjugated to the fundus, and a light receiving element 29 are provided. A sensor having two or more types of spectral sensitivity characteristics is used for the light receiving element 29 of this embodiment. The light receiving element 29 is, for example, a general RGB color sensor. In this case, the light receiving element 29 has three types of spectral sensitivity characteristics.

A laser beam (measurement beam) emitted from the light source 21 passes through the beam splitter 26, passes through the lens 22, reaches the scanning unit 24, and is reflected in a different direction by the mirror 24a. The laser beam reflected by the scanning unit 24 passes through the dichroic mirror 42 via the lens 25 and then is focused on the fundus of the patient's eye via the objective lens 41 .

The laser beam reflected by the fundus passes through the objective lens 41 , the lens 25 , the scanning unit 24 and the lens 22 and is reflected by the beam splitter 26 . After that, after being condensed by the lens 27 , the light is detected by the light receiving element 29 via the confocal aperture 28 . A light receiving signal detected by the light receiving element 29 is input to the control section 70 . The control unit 70 acquires a front image of the fundus of the patient's eye based on the light receiving signal obtained by the light receiving element 29 . The acquired front image is stored in the storage unit 75 . The acquisition of the SLO image is performed by scanning the laser light in the vertical direction (sub-scanning) with the galvano mirror provided in the scanning unit 24 and scanning the laser light in the horizontal direction (main scanning) with the polygon mirror.

<Fixation target projection part>
The fixation target projection unit 30 has an optical system for guiding the line-of-sight direction of the patient's eye E. FIG. The fixation target projection unit 30 presents a fixation target to the patient's eye E, for example. The fixation target projection unit 30 has, for example, a visible light source that emits visible light. The fixation target projection unit 30 may be of the internal fixation lamp type or the external fixation lamp type.

<Control section>
For example, the control unit 70 is realized by a general CPU (Central Processing Unit) 71, ROM 72, RAM 73, and the like. The ROM 72 of the control unit 70 stores an image processing program for processing observation images, various programs for controlling the operation of the laser therapy apparatus 1, initial values, and the like. The RAM 73 temporarily stores various information. Note that the controller 70 may be configured by a plurality of controllers (that is, a plurality of processors).

As shown in FIG. 1, the control unit 70 is electrically connected to, for example, a display unit 74, a storage unit (eg, non-volatile memory) 75, an operation unit 76, and the like. The display unit 74 may be a display mounted on the device main body, or may be a display connected to the main body. A display of a personal computer (hereinafter referred to as "PC") may be used. Multiple displays may be used together. Also, the display unit 74 may be a touch panel.

The storage unit 75 is a non-transitory storage medium that can retain stored content even when power supply is interrupted. For example, a hard disk drive, a flash ROM, a removable USB memory, or the like can be used as the storage unit 75 . Various operation instructions are input to the operation unit 76 by the examiner. The operation unit 76 outputs a signal to the CPU 71 according to the input operation instruction. At least one of user interfaces such as a mouse, a joystick, a keyboard, and a touch panel may be used for the operation unit 76, for example. When the display section 74 is a touch panel, the display section 74 functions as the operation section 76 .

<Position correction of aiming light>
Next, a method for correcting the position of the sighting light appearing in the observed image will be described. When the patient's eye is irradiated with imaging light and aiming light with mutually different wavelengths, even if the light is reflected at the same position on the fundus of the eye, the aberration of the optical system from the patient's eye to the light receiving element 29 (for example, chromatic aberration, etc.) , are received at different positions on the light receiving element 29 . For example, as shown in FIG. 2, even if the irradiation target T on the fundus and the aiming light A match on the actual fundus, they are recorded as being out of alignment on the observation image P. FIG.

Therefore, the control unit 70 detects the aiming light A from the observation image P and corrects its position. For example, the control unit 70 acquires information on the aiming light using the spectral sensitivity characteristics of the light receiving element 29 . FIG. 3 shows the spectral sensitivity characteristics of the RGB color sensor used for the light receiving element 29. As shown in FIG. Since the wavelength of the aiming light is 635 nm, the response of the R channel is large and the response of the other channels is small. Since the wavelength of the photographing light is 785 nm, the response difference between the RGB channels is relatively small. Using this relationship, the control unit 70 separates the shooting light and the aiming light.

For example, the control unit 70 subtracts the G channel value from the R channel value, as shown in the block diagram of FIG. For example, as shown in FIG. 5A, the fundus Ef and the aiming light A appear in the R channel observation image P1. On the other hand, as shown in FIG. 5B, the observation image P2 of the G channel shows the fundus oculi Ef, but does not show the aiming light A. As shown in FIG. Therefore, by subtracting the G channel value from the R channel value, a difference image P3 in which the aiming light A is extracted is generated as shown in FIG. 5(c).

When the aiming light A is extracted by taking the difference between the different channel images in this way, the control unit 70 detects the aiming light A based on the difference image P3. For example, the control unit 70 detects, as the aiming light A, a portion whose luminance value is equal to or greater than a threshold. Of course, the aiming light A may be detected by other image processing methods or signal processing methods.

Next, the controller 70 corrects the positional deviation of the detected sighting light A. FIG. For example, the control unit 70 corrects the positional deviation of the aiming light A based on the correspondence relation between each position on the fundus and each position on the observed image, which is obtained experimentally in advance. FIG. 6(a) shows a difference image P4 showing the sighting light A0 whose positional deviation has been corrected. Note that if the aberration information of the optical system is acquired, the shift for each wavelength can be known, so the control unit 70 may correct the positional shift of the aiming light A by calculation. Further, the positional deviation correction process may be performed only on the area where the aiming light A is detected, or may be performed on the entire difference image P3.

Subsequently, the control unit 70 synthesizes the difference image P4 in which the positional deviation has been corrected and the observed image P5 obtained from the G channel and the B channel (see FIG. 6B). As a result, an observation image P6 showing the aiming light A0 in which the aberration of the light receiving system is corrected can be obtained (see FIG. 6(c)).

<Control action>
The control operation of the laser treatment apparatus 1 as described above will be briefly described with reference to the flow chart of FIG. First, in step S1, the control unit 70 adjusts (aligns) the positional relationship of the laser treatment apparatus 1 with respect to the patient's eye by means of a driving unit (not shown). In step S<b>2 , the control unit 70 photographs the fundus of the patient's eye using the observation optical system 20 . In step S<b>3 , the control unit 70 causes the laser irradiation unit 10 to irradiate the patient's eye with aiming light. In step S4, the control section 70 corrects the positional deviation of the sighting light appearing in the observation image by the method of FIG. In step S5, the control unit 70 causes the display unit 74 to display the observation image after correcting the displacement of the aiming light. The operator operates the operation unit 76 while confirming the aiming light A0 of the observation image displayed on the display unit 74 . In step S6, the control unit 70 drives the scanning unit 16 and moves the irradiation position based on the operator's operation. After determining the irradiation position based on the displayed aiming light A0, the operator operates the operation unit 76 to start irradiation of the treatment light. In step S7, the controller 70 irradiates the set irradiation position on the fundus with therapeutic light.

As described above, the laser treatment apparatus 1 of the present embodiment, even when the wavelengths of the imaging light and the aiming light are different, the aiming light caused by the aberration of the light receiving system (for example, from the objective lens 41 to the light receiving element 29). By correcting the positional deviation of the light, the position of the aiming light can be accurately displayed on the observed image. This allows the operator to appropriately set the irradiation position of the therapeutic light. In addition, the laser treatment apparatus 1 of the present embodiment uses invisible light such as infrared light as imaging light, thereby reducing glare on the patient and reducing the burden on the patient.

<transformation example>
Next, a modified example of the first embodiment will be described. The laser treatment apparatus 1 of the modification differs from that of the first embodiment in the method of correcting the position of the aiming light reflected in the observed image. FIG. 8 is a block diagram showing the flow of correction processing in the modified example. In this modified example, the control unit 70 divides the R image (observation image of the R channel) into a plurality of regions. For example, the control unit 70 divides the R image and the G image into grids, concentric circles, or the like. Since the area of the aiming light is specified in advance and the irradiation light is sufficiently small, the area of the aiming light is separated from the R image and the G image in advance, and correction processing is performed only in the vicinity of the aiming light. As a result, redundant calculation processing can be reduced, and processing can be speeded up. Further, by synthesizing the area other than the aiming light in the divided R image together with the G image (observation image of G channel) and the B image (observation image of B channel), a high quality IR image (infrared observation image) can be obtained. can be improved.

In the first embodiment and the modified example, the RGB color sensor is used as the light receiving element 29, but a sensor having two types of spectral sensitivities may be used, or a sensor having four or more types of spectral sensitivities may be used. may The light-receiving element 29 may, for example, be capable of separating the photographing light and the sighting light.

In the first embodiment and the modified examples, as shown in FIG. 4 or FIG. 8, the value of the G channel is subtracted from the value of the R channel when detecting the sighting light, but the combination of channels is not limited to this. , and other combinations. The control unit 70 may subtract the value of the channel insensitive to the wavelength of the aiming light from the value of the channel sensitive to the wavelength of the aiming light. For example, the aiming light may be detected by subtracting the B channel value from the R channel value.

<Second embodiment>
A second embodiment will be described. As shown in FIG. 9, the laser treatment apparatus 2 of the second embodiment differs in the light-receiving elements used in the observation optical system 20 . Other configurations are the same as those of the first embodiment, so the same reference numerals are given and the description is omitted.

The light receiving element 29a of the laser therapy device 2 has one type of pixel. In other words, in the second embodiment, the photographing light and the sighting light cannot be split according to the spectral sensitivity characteristics. Therefore, as shown in the block diagram of FIG. 10, the control unit 70 of the laser treatment apparatus 2 controls the lighting image captured with both the imaging light and the aiming light turned on, and the lighting image with the aiming light turned off and only the imaging light turned on. Information on the sighting light is acquired by taking the difference from the light-off image taken in the state. Then, the control unit 70 corrects the positional deviation of the sighting light in the same manner as in the first embodiment, and synthesizes the corrected sighting light with an extinguished image (observation image) photographed using only the photographing light, thereby correcting the aberration. It is possible to obtain an observation image showing the aiming position in the state of being held down.

Note that the control unit 70 may obtain information on the aiming light by obtaining the difference between the lit image and the unlit image only in the area near the aiming light. This makes it possible to speed up the processing. In this case, the lit image and the unlit image from which the difference is taken may be obtained by photographing the entire fundus, or may be obtained by photographing the entire fundus and cutting them out. Also, either one of the turned-on image and the turned-off image may be obtained by photographing only the vicinity of the sighting light.

Note that the observation image for irradiating the therapeutic light is preferably real time. Therefore, the control unit 70 captures observation images while blinking the aiming light, sequentially obtains the difference between the lit image and the unlit image, and causes the display unit 74 to display the observation image after correcting the displacement of the aiming light. good too.

In addition, in the first and second embodiments, the wavelength of each light source is not limited to the above embodiments, and light sources with different wavelengths may be used.

In the first and second embodiments, the laser light source 11 and the aiming light source 12 have different wavelengths, but light sources with the same wavelength may be used. In the second embodiment, the light source 21 of the observation optical system 20 may also use a light source of the same wavelength.

In the first and second embodiments, the control unit 70 corrects the positional deviation between the observation image and the aiming light due to the aberration of the optical system from the patient's eye to the light receiving element 29, but the present invention is not limited to this. . For example, the control unit 70 may correct the positional deviation between the observed image and the sighting light due to deviation of the optical system other than aberration (for example, deviation of the optical axis).

Reference Signs List 1 laser treatment device 10 laser irradiation unit 20 observation optical system 30 fixation target projection unit 70 control unit 71 CPU
72 ROMs
73 RAM
74 display unit 75 memory 76 operation unit

Claims (4)

An ophthalmic laser treatment device for treating a patient's eye,
laser irradiation means for irradiating the patient's eye with therapeutic light and aiming light;
a photographing optical system for obtaining a fundus image by photographing the fundus of the patient's eye;
a control means;
The control means detects the aiming light from the fundus image and corrects the positional deviation between the fundus image and the aiming light caused by the aberration of the photographing optical system, thereby controlling the aiming light with respect to the fundus image. An ophthalmic laser treatment device characterized by changing its position. 2. An ophthalmic laser treatment apparatus according to claim 1 , wherein said control means corrects a positional deviation between said fundus image and said aiming light caused by an optical axis deviation between said laser irradiation means and said photographing optical system. . The control means controls lighting of the sighting light in synchronization with photographing by the photographing optical system, and a lighting image photographed with the sighting light turned on and a photographed image photographed with the sighting light turned off. 3. An ophthalmic laser treatment apparatus according to claim 1 , wherein said aiming light is detected based on a difference from the turned-off image. An ophthalmic laser control program to be executed in an ophthalmic laser treatment apparatus for treating a patient's eye, the program being executed by a processor of the ophthalmic laser treatment apparatus,
a laser irradiation step of irradiating the patient's eye with therapeutic light and aiming light;
an imaging step of imaging the patient's eye with an imaging optical system ;
a detection step of detecting the aiming light from the fundus image of the patient's eye photographed in the photographing step;
a changing step of changing the position of the aiming light with respect to the fundus image by correcting the positional deviation between the fundus image and the aiming light caused by the aberration of the imaging optical system;
is executed by the ophthalmic laser treatment apparatus.

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