JPH0767909A - Photo-coagulator - Google Patents

Abstract

PURPOSE:To provide a photo-coagulator capable of clearly and expansively displaying a fundus image on a monitor in a wide visual field, easily aiming a portion for a photo-coagulation treatment, and efficiently carrying out a treatment. CONSTITUTION:The laser beam of an observation laser light source 1 is radiated to the fundus 10a of an eye 10 to be checked, it is two-dimensionally deflected and scanned, and the reflected beam from the fundus 10a is received and photoelectrically converted to obtain a fundus image in a scanning laser ophthalmoscope. Laser beams of an aiming laser light source 21 and therapeutic laser light sources 31, 32 are guided on the same optical path, a spot image is formed on the fundus 10a, and this structure is combined with the scanning laser ophthalmoscope. The position of the spot image on the fundus 10a of the aiming laser beam matched with the therapeutic laser beam is displayed on a monitor 19 overlappingly with the fundus image. The position of the spot of the aiming laser beam on the fundus 10a can be optionally moved by the action of a scan mirror 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocoagulation apparatus for observing a fundus with an observation laser beam and for coagulating a desired part of the fundus with a therapeutic laser beam.

[0002]

2. Description of the Related Art Conventionally, there is known a technique of observing a fundus of an eye to be examined and photocoagulating a desired portion of the fundus with a therapeutic laser beam by a laser photocoagulation device combined with a slit lamp microscope. ing.

[0003]

In the conventional photocoagulation apparatus as described above, because of corneal reflection due to illumination light, etc.,
The field of view of the fundus that can be observed is almost slit-shaped and fairly narrow.

For this reason, it is difficult to quickly identify a diseased site obtained from a color fundus photograph or a wide-range photograph by fluorescence angiography, and it is necessary to move the visual field one after another according to the spread of the affected area. Yes, it required considerable skill and skill to operate.

Therefore, an object of the present invention is to solve the above-mentioned problems and to display a fundus image in a wide field of view in a wide and clear manner on a monitor without frequently moving the field of view, and a diseased part of the fundus can be easily specified. At the same time, it is another object of the present invention to provide a photocoagulation device capable of easily aiming a region to be photocoagulated and efficiently performing the treatment.

[0006]

In order to solve the above problems, according to the photocoagulation apparatus of the present invention, a photocoagulation apparatus for observing the fundus of an eye to be inspected and photocoagulating treatment by using a laser beam is provided. By irradiating the fundus of the eye to be inspected with a laser beam for observation and performing two-dimensional deflection scanning by the deflection scanning means, the reflected light from the fundus is received through the deflection scanning means and the pinhole and photoelectrically converted. Having a scanning laser ophthalmoscope to obtain a fundus image, and an aiming laser light source that oscillates an aiming laser light having a different wavelength from the observation laser light, and a therapeutic laser having a different wavelength from the aiming laser light And a therapeutic laser light source that emits light.

Further, a lens system that guides the aiming laser light and the therapeutic laser light through an optical fiber in the same optical path and forms a spot of the laser light at the exit end of the fiber on the fundus of the eye to be examined. The lens system is disposed at a position substantially conjugate to the pupil of the eye to be inspected, and moves the spot images of the aiming laser light and the therapeutic laser light formed on the fundus to an arbitrary position. A scan mirror is provided for this purpose.

Then, the reflected light of the aiming laser light from the fundus is guided to the pinhole through an optical path common to the reflected light of the observation laser light and detected by a light receiving element, and a signal from the light receiving element is signaled. It is input to the processing device, and the position of the spot image of the laser light for aiming by the signal is synthesized so as to be superimposed on the fundus image and is displayed on the monitor.

[0009]

According to this structure, the scanning laser ophthalmoscope can enlarge and clearly display the fundus image on the monitor with a wide field of view without frequently moving the field of view. Then, the position of the spot image of the fundus of the aiming laser light that perfectly matches the therapeutic laser beam is displayed on the monitor in superimposition with the fundus image, and the position of the spot image is arbitrarily moved by the scan mirror to aim. It can be easily performed, and photocoagulation treatment with a therapeutic laser beam can be efficiently performed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment, the observation laser light is applied to the fundus of the eye to be inspected, and this is two-dimensionally deflected and scanned, and the scanning laser ophthalmoscope obtains a fundus image by photoelectric conversion by receiving reflected light from the fundus, A configuration is used in which a laser photocoagulator using an aiming laser beam having a different wavelength from the observation laser beam is combined.

<First Embodiment> FIG. 1 shows the arrangement of a photocoagulator according to the first embodiment of the present invention. In FIG. 1, a laser light source for observation (eg, argon laser)
The laser beam 2 emitted from 1 is a perforated mirror 11
The light passes through the hole 11a and is condensed by the lens 3 (the perforated mirror 11 may be replaced with a half mirror).

Further, the laser light is reflected by the horizontal scanning polygon mirror 4. The polygon mirror 4 is directly connected to the motor 5 and scans the laser light in the horizontal direction (direction perpendicular to the paper surface) by the high speed rotation of the polygon mirror 4.

Further, the laser light passes through the lens 6, is reflected by the vertical scanning mirror 7 driven by the galvanometer 8, and is transmitted through the half mirror 26. At this time, the horizontal scanning polygon mirror 4 and the vertical scanning mirror 7 are arranged in an optically substantially conjugate relationship with respect to the lens 6.

The high speed rotation of the motor 5 and the vibration of the galvanometer 8 are both driven and controlled by the signal processing device 18.

The laser light transmitted through the half mirror 26 passes through the objective lens 9 and the iris (pupil) 10b of the eye 10 to be inspected.
And is focused on the fundus 10a.

At this time, the vertical scanning mirror 7 and the iris (pupil)
10b and the objective lens 9 are arranged in an optically substantially conjugate relationship. Therefore, the laser light always enters through the center of the pupil 10b and scans the fundus 10a.

The laser light reflected by the fundus 10a spreads to the pupil 10b as much as possible, passes through the objective lens 9 and the half mirror 26, and passes through the vertical scanning mirror 7, lens 6,
The horizontal scanning polygon mirror 4 and the lens 3 travel in the same optical path as the incident light in the reverse direction, and the hole 11 of the perforated mirror 11
It is reflected on the outside of a and is focused on the pinhole 13 by the lens 12.

Since the lens system is arranged as described above, the laser beam 2 of the observation laser light source 1 passes through the two-dimensional deflection scanning device, is focused on the fundus 10a, and is scanned two-dimensionally. While the reflected light retains the information from the fundus, it travels in the same optical path as the incident light in a state where it spreads outward from the incident light, changes its direction by the perforated mirror 11, and always converges on the pinhole 13.

Since harmful light such as scattered light generated from other than the condensing point of the fundus 10a cannot pass through the pinhole 13, such a lens system can obtain a good fundus image.

At this time, the eye to be inspected 10 also constitutes a part of the above-mentioned lens system, so that it is naturally necessary to adjust diopter correction, interval, and optical axis alignment for the eye to be inspected.

The reflected light from the fundus passing through the pinhole 13 is separated by the dichroic mirror 14. The mirror 14 is configured to transmit an aiming laser beam described later and reflect an observing laser beam (and a therapeutic laser beam described later). The aiming laser beam is received by the light receiving element 15 via the mirror 14. Then, the observation laser light is received by the light receiving element 17 and detected.

The amount of light received by the light receiving element 17 is converted into an electric signal and input to a signal processing device 18 constituted by using a computer system or the like, and drive control of the motor 5 and the galvanometer 8 used for scanning the observation laser light. An image signal is processed based on the signal and output to the monitor. As a result, a clear fundus image is enlarged and displayed on the monitor 19.

A shutter 16 is arranged in front of the pinhole 13 and is normally opened. However, the shutter 16 is closed when the therapeutic laser light is oscillated to protect the light receiving element 17 from the strong therapeutic laser light. . Therefore, during this period, the fundus image disappears from the monitor 19.

On the other hand, the aiming laser light source 21 for oscillating the aiming laser light used for aiming at the photocoagulation position oscillates a laser light having a wavelength different from that of the observation laser light. The aiming laser light source 21 is constantly oscillating, and the aiming laser beam 22 passes through the dichroic mirror 36, is condensed by the condenser lens 37, and is guided by the optical fiber 38.
Incident on.

As the therapeutic laser light source, for example, only an argon laser having the same wavelength as the observation laser light, or a plurality of therapeutic laser light sources including the argon laser and a DYE laser having a different wavelength from the argon laser are provided. . Here, two therapeutic laser light sources 31,
32 are arranged. When the operator turns on a fire button (not shown) after aiming, the therapeutic laser light source 31 or 32 oscillates laser light.

The therapeutic laser beam 35 from the laser light source 31 or 32 is transmitted through the dichroic mirror 34, or the mirror 33 and the dichroic mirror 34.
And is reflected by the dichroic mirror 36 arranged in the optical path of the aiming laser light source 21, and is condensed by the condenser lens 37 at the incident end of the optical fiber 38.

That is, the therapeutic laser light is introduced into the same optical path as the aiming laser light, and in particular, after entering the optical fiber 38, the therapeutic laser light travels in the completely same optical path.

The aiming laser light and the therapeutic laser light that have passed through the optical fiber 38 pass through the telescope 23, are reflected by the scan mirror 24 and the half mirror 26, and are reflected by the objective lens 9 to the fundus 10a of the eye 10 to be examined. After being condensed, the spots of the two laser lights at the exit end of the optical fiber 38 are imaged. Since the aiming laser light and the therapeutic laser light travel in exactly the same optical path, it goes without saying that the image forming positions (focusing positions) of the spots of the two laser lights on the fundus 10a are perfectly aligned with each other. .

In the above-mentioned condenser lens system, the telescope 23 has a function of focusing the spot of the laser light (for aiming and treatment) at the exit end of the optical fiber 38 on the fundus 10a through the objective lens 9, It has a function of changing and adjusting the size of the spot image formed on the fundus 10a by moving a part of the lens group forming the scope 23 in the optical axis direction by a cam (not shown) or the like.

The spot size is changed, for example, in photocoagulation treatment of diabetic retinopathy (proliferative type), the spot size is 200 μm in the posterior pole part excluding the macula and its surroundings.
Further, the peripheral middle portion is changed to 500 μm and the outermost peripheral portion is changed to 500 to 1000 μm, which is useful for efficient treatment.

The scan mirror 24 is connected to the micromanipulator 25, and by operating the operating lever 25a of the manipulator 25, the scan mirror 24 is swung in the two-dimensional direction so that the spot image is formed on the fundus 10a. Can be moved to a position.

The scan mirror 24 and the iris (pupil)
10b is arranged at a position which is optically conjugate with respect to the objective lens 9. Therefore, the aiming laser light and the therapeutic laser light always pass through the center of the pupil 10b and irradiate the fundus.

The laser light for aiming reflected by the fundus 10a spreads through the pupil as shown by the thick broken line in FIG. 1, passes through the objective lens 9, passes through the half mirror 26, and reflects the laser light for observation. Follow the same optical path as the light,
Reach pinhole 13.

However, when the focusing position of the observation laser light and the position of the spot image of the aiming laser light are different, the aiming laser light is pinhole 13 as shown in the figure.
It does not pass through the hole of (1) but passes through the hole of the pinhole 13 only when the converging position of the observation laser light and the position of the spot image match.

That is, the spot image of the aiming laser light that has been moved to an arbitrary position by the swing of the scan mirror 24 and the converging position of the scanning laser light for scanning coincide with each other. The position will be detected. At the same time, the size of the spot image can be known by detecting the coincidence of time.

With the above configuration, the light receiving element 17 detects the reflected light of the observation laser light, and the light receiving element 15 detects the reflected light of the spot image of the aiming laser light passing through the pinhole 13. Signal processing device 18
To enter. Then, the input signal is processed into an image signal based on the drive control signals of the motor 5 and the galvanometer 8 used for scanning the observation laser light, and is output to the monitor 19 so as to be superimposed on the fundus image. The position and size of the spot image of the laser light for use can be displayed on the monitor 19.

On the other hand, the therapeutic laser light oscillated after aiming travels along the same optical path as the aiming laser light, and the converging positions of both laser lights at the fundus 10a are completely coincident with each other. The light is focused on the part of the fundus that has been aimed, and photocoagulation is performed.

With the above structure, at the time of observing and aiming the fundus, the observing laser beam and the aiming laser beam are oscillated, and the fundus image is widened by the scanning laser ophthalmoscope without frequently moving the field of view. It can be enlarged and displayed on the monitor, and a clear image of the fundus can easily identify the disease site. At the same time, the position of the spot image of the aiming laser light can be displayed in color by superimposing it on the fundus image, and the examiner can operate the lever 25a of the manipulator 25 while looking at the spot image of the aiming laser light. Aiming can be easily performed by arbitrarily moving the position of the spot image.

The position of the spot image is adjusted to the part of the fundus where the photocoagulation treatment is desired, and a fire button (not shown) is turned on to close the shutter 16 and
The treatment laser light source 31 or 32 oscillates, and a spot of the treatment laser light is focused on the aimed portion of the fundus to perform photocoagulation treatment. Then, after a predetermined time, the oscillation of the therapeutic laser light source 31 or 32 is stopped and the shutter 16 is opened.

As described above, the fundus image disappears from the monitor 19 while the shutter 16 is closed, but the image immediately before the shutter 16 is closed is temporarily stored and displayed as a still image, and the shutter 16 is opened. At the same time, it is possible to restore the current image by the observation laser light and the aiming laser light.

As described above, the photocoagulation treatment can be efficiently performed.

By the way, in the above configuration, the monitor 1
If a color monitor is used for 9 and the color of the spot image of the aiming laser light displayed on the monitor 19 so as to be superimposed on the fundus image is the same color as the therapeutic laser light More convenient.

The reason is that the fundus (retina) has a cross section composed of several layers such as the retinal surface layer, the retinal nerve fiber layer, the retinal pigment epithelium layer, and the choroid. Different layers reach depending on the wavelength. Therefore, laser light is selected according to the condition to be treated. In the case of the present embodiment, assuming that a He-Ne laser (wavelength 633 nm) is used as the laser light source for aiming, argon blue (488 nm), which has a wavelength sufficiently different from that of the He-Ne laser, is used as the therapeutic laser light.
Argon green (514 nm), DYE yellow (577 nm), DYE orange (590 nm), etc. are provided in a plurality of types (two types of reference numerals 31 and 32 in FIG. 1),
Select and use. As the laser light source for observation, one of the above-mentioned plurality of laser light sources is used. It is desirable that the wavelength of one laser beam of the therapeutic laser light source be the same as that of the observation laser beam, because the layers (or the reflecting surface) that both laser beams reach at the fundus coincide.

The position and size of the spot image of the aiming laser light is displayed on the monitor 19 at the same time, and its color is displayed in the same system color as the therapeutic laser light selected at that time. The type of the therapeutic laser beam used is known on the monitor 19, which is convenient for operation.

Next, FIG. 2 shows a modification of the above-described embodiment, in which a half mirror 27 for reflecting the aiming laser light and the therapeutic laser light is arranged in front of the objective lens 9 (on the side of the eye 10 to be examined). The case is shown.

In this case, as shown in the figure, a lens 40 is provided instead of the objective lens 9 in the optical paths of the aiming laser light and the therapeutic laser light. That is, the telescope 23 and the lens 40 have a function of forming a spot at the exit end of the therapeutic laser light source on the fundus and changing the size of the spot image.

Further, the scan mirror 24 and the iris (pupil) 10b are arranged at positions substantially optically conjugate with the lens 40. Therefore, in the configuration of FIG. 2, the laser light always passes through the center of the pupil and forms an image on the fundus even if the scan mirror 24 swings.

According to the above configuration, the laser photocoagulator can be attached and detached without impairing the function of the scanning laser ophthalmoscope behind the objective lens 9. Therefore, the laser photocoagulator can be easily and inexpensively configured based on the existing scanning laser ophthalmoscope, and the laser photocoagulator part to be supplied as an option can be easily attached and detached. .

Moreover, in the configuration of FIG. 2 as well, as described above, it is possible to easily identify the diseased part with the clear fundus image, and at the same time, the position of the spot image of the therapeutic laser light can be displayed in color by overlapping with the fundus image. Can be treated efficiently.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. In the following, description of the same parts as those in the first embodiment will be omitted.

In this embodiment, as will be described later, in order to adjust the focus by detecting the matching state between the focal plane of the aiming laser light and the image plane of the fundus, the aiming laser and the therapeutic laser are adjusted. The optical system is different from that of the first embodiment as shown in FIG.

That is, in the present embodiment, the disc shown by reference numeral 28 is provided so that it can be inserted into and retracted from the optical path between the telescope 23 and the scan mirror 24. As shown in FIG. 4, the disc 28 is formed with two small holes 28a and 28b. The disk 28 is rotated by driving the motor 41. Further, in order for the examiner to adjust the position of the focal plane of the aiming laser light (the position of the focal plane of the therapeutic laser light), the focus lens 42 is arranged in the optical path between the scan mirror 24 and the half mirror 27. It is possible to make fine movements along the optical path.

In the structure shown in FIG. 3, a laser beam 22 emitted from a laser light source for aiming (for example, He-Ne laser) 21 passes through a telescope 23, and two small holes 28a and 28b of a disk 28 form two laser beams. The beam becomes a thin beam, is reflected by the scan mirror 24, passes through the focus lens 42, is further reflected by the half mirror 27, passes through the objective lens 9 and the central portion of the pupil 10b of the subject's eye, and forms an image on the fundus 10a.

The disc 28 is inserted in the optical path when aiming with the aiming laser light, and retracts immediately before the oscillation of the therapeutic laser light source. That is, by turning on a fire button (not shown), after the shutter 16 is closed, the disc 28 withdraws from the optical path, the treatment laser light source oscillates, and the treatment laser light entirely passes through the treatment. Done. After a predetermined time, the oscillation of the therapeutic laser light source stops and the disc 28 returns to the optical path. Subsequently, the shutter 16 is opened, the fundus image is displayed on the monitor 19, and the detection of the aiming laser light is restarted.

Similar to the first embodiment, other functions, for example, the position and size of the spot image can be displayed on the monitor 19 so as to be superposed on the fundus image to improve the aiming and displaying performances.

Next, detection of the focused state of the therapeutic laser light (the focused state of the aiming laser light) will be described.

In the present embodiment (or the first embodiment), the focal plane of the scanning laser ophthalmoscope and the focal plane of the aiming and therapeutic laser light are adjusted so as to coincide with each other. Since the beam of the laser light for observation is narrowed and irradiated, the depth of focus is deep and a sharp fundus image can be obtained even in rough focusing.

However, it is necessary to focus the therapeutic laser light. The reason is that the therapeutic laser light concentrates energy on the focal plane where photocoagulation is performed and disperses the energy before and after the focal plane so that photocoagulation does not reach outside the treatment site. Usually, a cone angle of about 10 degrees is provided as shown in FIG. Therefore, when the therapeutic laser beam is imaged on the front side of the focal plane, the spot size naturally increases, and the energy of the laser beam is dispersed according to the area ratio,
The desired energy density cannot be obtained and photocoagulation becomes insufficient. Thus, if the therapeutic laser beam is out of focus, the energy is dispersed and the desired photocoagulation is not performed.

Therefore, in order to focus the therapeutic laser light more precisely on the fundus image which is roughly focused by the observation laser light, the focal plane of the therapeutic laser light is the image plane of the fundus. It is necessary to have a means for detecting the matching state of matching or deviation.

Therefore, in this embodiment, instead of detecting the matching state of the focal plane of the therapeutic laser light, the aiming laser light whose optical path completely matches that of the therapeutic laser light and whose focus is completely matched. Detects the matching state of the focal plane.
It is done as follows.

That is, in FIG. 3, the plurality of aiming laser beams 21a and 21b that have passed through the small holes 28a and 28b of the disc 28 are focused by the focus lens 42, the objective lens 9 and the subject's eye 10 by the fundus 10 itself.
Form an image on a. At this time, the image plane (for example, the surface layer of the retina)
And the focal plane coincide with each other, the spot image is displayed as one spot image on the monitor with a plurality of beams completely overlapping as shown in FIG.

On the other hand, as shown in FIG. 6, when there are image planes in front of the focal points 21 'of the plurality of aiming laser beams 21a, 21b, the spot images are 21a', 21b.
They are separated as shown in b'and displayed as two spot images on the monitor.

At this time, when the disk 28 is rotated at a speed of about 1 rotation / 2 seconds by the motor 41 of FIG. 3, two spot images are formed when the focal plane and the image plane are displaced back and forth. It rotates on the monitor, and when the focal plane and the image plane coincide with each other, the spot images become one, and the rotation appears to the examiner to stop.

While observing the in-focus state on the monitor 19, the examiner adjusts the focus lens 42 or the objective lens 9 to move the position of the focal plane so as to coincide with the image plane. In FIG. 6, the laser beam 2 of the laser light for observation is focused on the fundus 10a as indicated by reference numeral 2 '.

With the above-mentioned structure, the aiming laser beam can detect the deviation of the spot image of the therapeutic laser beam from the focal plane, avoid coagulation failure due to energy dispersion, and reliably carry out the treatment. be able to.

[0066]

As is apparent from the above, according to the photocoagulation apparatus of the present invention, a fundus image can be enlarged and displayed on a monitor with a scanning laser ophthalmoscope in a wide field of view without frequently moving the field of view. The diseased site can be easily identified with a clear fundus image. At the same time, the position of the spot image on the fundus of the aiming laser light that perfectly matches the therapeutic laser light can be displayed on the monitor in a superimposed manner with the fundus image, and the position of the spot image can be displayed via the scan mirror. An excellent effect that the aiming can be easily performed by arbitrarily moving it and the photocoagulation treatment can be efficiently performed is obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a first embodiment of a photocoagulation device adopting the present invention.

FIG. 2 is a configuration diagram showing a modified example of the apparatus of FIG.

FIG. 3 is a configuration diagram showing a second embodiment of a photocoagulation device adopting the present invention.

4 is a plan view of a disc used in the apparatus of FIG.

5A and 5B are explanatory views showing a cone angle of a therapeutic laser beam of the apparatus of FIG. 3 and a shift between a focal plane and an image plane.

6 is an explanatory diagram showing a focusing function of a therapeutic laser beam in the apparatus of FIG.

[Explanation of symbols]

 1 Laser light source for observation 4 Horizontal scanning polygon mirror 5, 41 Motor 7 Vertical scanning mirror 8 Galvanometer 9 Objective lens 10 Eye to be examined 11 Perforated mirror 13 Pinhole 14, 34, 36 Dichroic mirror 15, 17 Photodetector 16 Shutter 18 Signal processing device 19 Monitor 21 Laser light source for aiming 23 Telescope 24 Scan mirror 25 Micromanipulator 26, 27 Half mirror 28 Disc 31, 32 Laser light source for treatment 37 Condenser lens 38 Optical fiber 42 Focus lens

Claims (5)

[Claims] 1. A photocoagulation apparatus for observing a fundus of an eye to be inspected and performing photocoagulation treatment by using a laser beam, wherein the fundus of the eye to be inspected is irradiated with two-dimensional deflection scanning by a deflection scanning means. Then, a scanning laser ophthalmoscope that obtains a fundus image by receiving reflected light from the fundus through the deflection scanning means and a pinhole and performing photoelectric conversion, and an aiming laser having a different wavelength from the observation laser light. Aiming laser light source that oscillates light, a therapeutic laser light source that oscillates a therapeutic laser light having a wavelength different from that of the aiming laser light, and the same aiming laser light and therapeutic laser light are passed through the same optical fiber. A lens system which guides the light through an optical path and forms an image of the spots of the two laser lights at the exit end of the fiber on the fundus of the eye to be examined; In this system, a scan mirror for arranging the spot image of the aiming laser light and the therapeutic laser light formed on the fundus of the eye is disposed at a position substantially conjugate to the pupil of the eye to be inspected. Having a reflected light from the fundus of the aiming laser light is guided to the pinhole in a common optical path with the reflected light of the observation laser light and detected by a light receiving element, and a signal from the light receiving element is a signal processing device. The photocoagulation device is characterized in that the position of the spot image of the laser light for aiming by the signal is synthesized so as to be superimposed on the fundus image and is displayed on a monitor. 2. The photocoagulation apparatus according to claim 1, wherein the therapeutic laser light source oscillates a therapeutic laser light having the same wavelength as the observation laser light. 3. A detection means for detecting the matching state of the position of the imaging plane of the fundus of the aiming laser light and the focal plane, and an adjusting means for adjusting the position of the focal plane of the aiming laser light. Claim 1 or 2 characterized by the above.
The photocoagulation device according to. 4. The lens system for forming the spots of the aiming laser light and the therapeutic laser light on the fundus of the eye to be inspected is provided with means for changing the size of the spot. The photocoagulation device according to any one of 3 above. 5. The color display of the spot position of the aiming laser light imaged on the fundus in the same system color as the therapeutic laser light on the monitor. The photocoagulation apparatus according to item 1.