JP2001149403A - Photocoagulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocoagulator by which uniform coagulation spots with no burning unevenness are obtained and an appropriate therapy can be performed. SOLUTION: In the photocoagulator wherein photocoagulation is performed by introducing a therapeutic laser light from a laser light source into the eyegrounds, a laser irradiating optical system in which the therapeutic laser light from the laser light source is formed into a small spot and is irradiated on the eyegrounds, a scanning means arranged in the laser irradiating optical system and scanning the laser light of a small spot on the eyegrounds, a setting means for setting a laser irradiating condition on coagulation size and coagulation time for performing photocoagulation and a control means for controlling scanning of the above described scanning means based on the set condition are provided.

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 performing photocoagulation by irradiating a fundus or the like with laser light from a laser light source.

[0002]

2. Description of the Related Art There is known a photocoagulation apparatus which coagulates by irradiating a treatment site with a treatment laser beam while observing a patient's eye with an observation optical system such as a slit lamp. BACKGROUND ART A photocoagulation device is a device that causes a tissue such as a fundus to coagulate protein by using a thermal action of laser light, and is used for treatment of proliferative diabetic retinopathy or the like.

At the time of laser irradiation, coagulation conditions such as coagulation size (area of laser irradiation region), coagulation time (laser irradiation time), and laser output are changed according to treatment contents. The change in the solidification size has generally been performed by moving a zoom lens disposed in the laser light guiding optical system to increase the spot diameter of the laser beam.

[0004]

However, in photocoagulation, due to the non-uniformity of the energy distribution of the laser beam,
The center part is over-coagulated compared to the spot periphery, and the laser irradiation site does not solidify smoothly and uneven burning occurs.
Coagulation spots were not always formed as expected at each irradiation site. In particular, this tendency becomes more conspicuous as the spot diameter of the laser beam is increased.

If the spot diameter of the laser beam at the fundus is increased by the zoom optical system, the angle of incidence on the eye is reduced, and the laser beam having a high power density passes around the cornea. , Energy is absorbed in that portion, and the effect of heat is likely to appear.

[0006] In view of the above prior art, it is an object of the present invention to provide a photocoagulation apparatus capable of obtaining uniform coagulation spots without burning unevenness and performing appropriate treatment.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) In a photocoagulation apparatus for conducting photocoagulation by guiding therapeutic laser light from a laser light source to the fundus or the like, a laser for forming the therapeutic laser light from the laser light source into small spots and irradiating the light onto the fundus. Irradiating optical system, scanning means arranged on the laser irradiating optical system for scanning a small spot of laser light on the fundus, setting means for setting laser irradiation conditions of coagulation size and coagulation time for photocoagulation, and the setting Control means for controlling scanning by the scanning means based on conditions.

(2) In the photocoagulation apparatus of (1), an aiming light irradiating means for irradiating aiming light from an aiming light source using the scanning means is provided. The scanning of the scanning means is controlled so as to be different from the time when the treatment laser light is emitted.

(3) In the photocoagulation apparatus of (2), when only the aiming light is irradiated, the control means controls the scanning area of the aiming light by the scanning means based on the setting of the coagulation size, and the treatment laser. The scanning of the aiming light is controlled at a different speed from the scanning of the light.

(4) In the photocoagulation apparatus of (3), the scanning area by the aiming light scans only the outline of the laser irradiation area.

(5) The photocoagulation apparatus according to (1), further comprising a spot diameter changing means for changing the setting of the spot diameter of the laser beam applied to the fundus, wherein the control means performs the scanning based on the setting of the spot diameter. The scanning by means is controlled.

(6) The photocoagulation apparatus according to (1), further comprising a shape changing means for changing the shape of the laser irradiation area scanned by the scanning means.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external view of a laser photocoagulation device according to the present invention.

Reference numeral 1 denotes an apparatus main body, which houses a laser light source and an optical system for making laser light incident on the optical fiber 2. Reference numeral 3 denotes a control unit for setting laser irradiation conditions such as laser output and irradiation time and necessary settings of the apparatus. Reference numeral 4 denotes a slit lamp delivery for irradiating the affected part of the patient's eye with laser light while observing the patient's eye, a laser irradiator 5 for irradiating the laser light guided to the optical fiber 2, and an illuminator for slit illuminating the patient's eye. 6. Equipped with a binocular microscope unit 4a. 7
Is a cable for transmitting a signal between the apparatus main body 1 and the slit lamp delivery 4. Reference numeral 8 denotes a foot switch for transmitting a trigger signal for laser irradiation.

FIG. 2 is a view for explaining a schematic optical system of the apparatus. Reference numeral 10 denotes a treatment laser light source that emits treatment laser light. In this embodiment, a treatment laser light source that obtains, from a Nd: YAG laser that oscillates a fundamental wave of 1064 nm, green light that is a second harmonic thereof (532 nm linearly polarized light) is used. are doing. Reference numeral 14 denotes a beam splitter that transmits most of the laser light from the laser light source 10 and partially reflects the laser light. The laser light reflected by the beam splitter 14 passes through the diffusion plate 15, and
6 is incident. The output sensor 16 detects the output of the laser light from the laser light source 10.

Reference numeral 17a denotes a first safety shutter for blocking laser light, which is inserted into and removed from the optical path by a driving device 17b. Reference numeral 18 denotes a dichroic mirror. The red aiming laser light from the visible semiconductor laser 19 passes through the collimator lens 20 and is made coaxial with the treatment laser light by the dichroic mirror 18. A second safety shutter 21a is inserted into the optical path by the driving device 21b when the aiming laser light from the semiconductor laser 19 is not emitted. Each laser beam that has passed through the second safety shutter 21a is condensed and incident on the incident end face 2a of the optical fiber 2 by the condenser lens 22.

Reference numeral 5 denotes a laser irradiating unit. The treatment laser light and the aiming light guided by the optical fiber 2 are used for changing the spot size of the laser light and the slit 23 having a hexagonal opening, the relay lens 24, and the like. An axially movable zoom lens 25, a collimating lens 39,
After passing through the galvano first mirror 37, the galvano second mirror 38, and the objective lens 26, the light is reflected by the movable mirror 27, and irradiates the affected part of the patient's eye E via the contact lens 28. Thus, the laser irradiation optical system and the aiming light irradiation optical system are configured.

The galvano first mirror 37 and the galvano second mirror 38 have a motor 37 as shown in FIG.
a, 38a are attached, and the motors 37a, 38
By controlling the rotation of a by the signal from the control unit 50, the irradiation spot shaped into a hexagon is scanned on the fundus. The zoom lens 25 is moved by the spot diameter changing knob 55 shown in FIG. 1 to change the spot diameter of the treatment laser light and the aiming light applied to the fundus.

Reference numeral 6 denotes an illumination unit for projecting slit light,
The illumination light from the illumination light source 30 is a condenser lens 31,
After passing through the slit 32 and the projection lens 33, the light is reflected by the split mirrors 35 a and 35 b and illuminates the patient's eye through the contact lens 28. Reference numeral 34 denotes a correction lens for correcting the optical path length of the illumination light reflected by the split mirror.

Reference numeral 4a denotes a binocular microscope section, in which an objective lens 40, a variable power optical system 41, a protection filter 42,
An erect prism group 43, a field stop 44, and an eyepiece 45 are provided.

The control unit 50 controls the treatment laser light source 10 and the motors 37a and 37 for scanning the laser light based on the laser irradiation conditions set by the control unit 3 and the change knob 55.
b, etc., to control each drive unit.

FIG. 4 is a diagram showing details of the control unit 3. As shown in FIG. Reference numeral 60 denotes a counter display unit for displaying the number of irradiation scans of the treatment laser beam, and reference numeral 61 denotes a spot diameter display unit for displaying the spot diameter. The spot diameter can be changed in 10 μm increments between 50 and 100 μm by a change knob 55.
The setting signal of the spot diameter by the change knob 55 is transmitted to the control unit 50.
Is input to Reference numeral 72 denotes an irradiation diameter display unit for displaying an irradiation size (solidification size).
It can be changed in 10 μm increments between 0 μm. The irradiation size is set by the irradiation diameter setting switch 73. Reference numeral 62 denotes a time display section for displaying an irradiation time required to irradiate the entire set irradiation size. The irradiation time is set by an irradiation time setting switch 64. Reference numeral 63 denotes an output display unit for displaying the irradiation output of the treatment laser light. The setting of the irradiation output is performed by an output setting switch 65. The aiming switch 66 is used for adjusting the brightness of the aiming light.
Reference numeral 67 denotes an INTERVAL switch for setting a laser beam irradiation interval time during continuous irradiation while the foot switch 8 is used.
It can be changed from 0.2 second to 1.0 in units of 0.2 seconds. 71
Switches between possible and impossible treatment laser beam irradiation S
TATUS switch.

In the apparatus having the above configuration,
The operation will be described.

The operator observes the fundus illuminated by the illumination light from the illumination unit 6 through the microscope unit 4a. Also,
The aiming light is turned on by the aiming switch 66. When the aiming light is set to be emitted, the control unit 50 causes the second safety shutter 21a to leave the optical path.

Next, the operator sets the laser irradiation size, irradiation time, output, and irradiation interval time with various switches of the control unit 3 in order to determine the laser light irradiation conditions. The setting conditions are set based on the experience of the operator depending on the condition of the affected part of the patient and the like.

The operator operates the joystick 56 for moving the slit lamp delivery 4 and the manipulator (not shown) for oscillating the movable mirror 27 while observing the aiming light irradiated to the fundus, so as to operate the affected part. Perform positioning. The control unit 50 controls the angles of the galvano first mirror 37 and the galvano second mirror 38 to scan the aiming light emitted from the semiconductor laser 19 on the fundus. The scanning of the aiming light when the treatment laser light is not emitted is performed by, for example, scanning a contour portion of an irradiation area of the treatment laser light with a spot shaped into a hexagon as shown in FIG. I do. This outline is determined by the control unit 50 based on the set spot diameter and irradiation size. FIG. 5A shows that the spot diameter is 5
This is an example when the irradiation size is 500 μm with a small spot of 0 μm. When only the aiming light is emitted, the control unit 50 scans the aiming light at such a speed that the outline of the irradiation area looks like one connected outline (1).
If the cycle is scanned at a speed faster than 1/30 second, one contour appears due to the residual phenomenon.) This allows the surgeon to determine the laser irradiation region by observing the aiming light, as in the related art.

When the surgeon can specify the laser irradiation position by observing the aiming light, the operator depresses the foot switch 8 and
A trigger signal for laser irradiation is sent to the control unit 50. Control unit 5
When the trigger signal is inputted, the first safety shutter 17a is opened to irradiate the laser beam from the therapeutic laser light source 10 and the laser beam is set on the basis of the laser irradiation condition set by the control unit 3. The scanning of the galvano first mirror 37 and the galvano second mirror 38 is changed to scanning for laser irradiation. The scanning of the laser irradiation at this time is performed by the control unit 50 based on the set spot diameter and irradiation size so that the hexagonal spots are continuously arranged over the entire irradiation area as shown in FIG. 5B. It is calculated and determined. At each spot position, the control unit 50 irradiates the laser light only when the galvano first mirror 37 and the galvano second mirror 38 are stopped, and does not irradiate the laser light during the movement of the laser irradiation spot.
To control the drive of.

The irradiation time of one spot is determined by the switch 6
The irradiation time (coagulation time) set by 4 is determined according to the number of spots so that the irradiation time of the entire area of the irradiation size becomes the irradiation time. For example, if the irradiation time is set to 0.5 seconds and the number of spots is 100, it is 5 msec at one spot position. As a result, in one small spot, the same energy as in the case of performing coagulation by enlarging the conventional spot diameter is given, and by arranging the photocoagulation of these small spots, even in a large irradiation area. Burn unevenness is reduced, and a uniform solidified spot is formed.

When the period of emission / stop of the treatment laser beam is short and it is difficult to control the laser light source 10 in a few milliseconds, as shown in FIG. 6, a light-shielding disk having a large number of openings 101 at regular intervals. 100 is provided in the optical path where the treatment laser light is guided, and this is rotated by a motor 102,
Intermittent laser irradiation may be obtained. At the time of laser irradiation, the control unit 50 controls the movement / stop of the laser irradiation spot and the rotation of the light-shielding disk 100 in synchronization.
Controls.

Even in the case where continuous irradiation is performed without performing intermittent laser irradiation, the irradiation time at one spot position may be determined in consideration of the moving speed.
Furthermore, scanning of a small spot may be performed at a constant speed so that the entire irradiation time is equal to the set irradiation time.

In the case of scanning in which laser irradiation is performed continuously, the scanning pattern is such that a small spot (preferably a circular spot) is scanned spirally from the center to the outside as shown in FIG. There is also a way to do it. in this case,
The irradiation energy increases in the center locus of the small spot, and the laser irradiation amount decreases in the peripheral portion of the small spot. Therefore, the circular small spots overlap as the trajectory spreads in the first and second laps of the spiral scan. To make the dose uniform.

As shown in FIG. 7 (b), a method of scanning linearly with a small circular spot may be used. In this case, the first and second rows are partially overlapped with each other. It is preferable to minimize non-uniformity due to the scanning trajectory.

As described above, a small spot of laser irradiation is scanned at the time of irradiation with the therapeutic laser, so that one irradiation size is increased to 500 μm or more as in pan-retinal photocoagulation treatment for proliferative diabetic retinopathy. Even in the case of performing the method, unevenness in power density is eliminated, and uniform photocoagulation can be performed.

In the scanning of a small spot as described above, when the time at the irradiation position of one spot becomes too short, the size of the spot diameter is increased to 100 μm by the change knob 55, so that one spot is irradiated. (If the spot diameter is changed by the change knob 55, the control unit 50 calculates the irradiation time at each spot position according to the spot diameter.) If the spot diameter is about 100 μm,
Since burn unevenness in one spot is not so large, by scanning the spot diameter within the set irradiation size, a uniform solidified spot can be obtained at least as compared with the related art.

If the laser output for the spot position is too high in one scan, the laser output per scan can be divided by performing multiple scans within the set coagulation time. Can be reduced. For example, if the laser output is set to 400 mW and scanning is performed 10 times, the output may be controlled so that laser irradiation of 40 mW is performed in one scanning.

As described above, by performing scanning of a small spot for photocoagulation of a large irradiation size, the following advantages can be obtained. That is, as shown in FIG.
When the image magnification between the exit end of the optical fiber 2 and the fundus is low,
The incident angle θ1 of the laser beam to the eye is large. On the other hand, when the image magnification is increased by the zoom optical system,
As shown in FIG. 8B, the incident angle θ2 of the laser beam to the eye decreases. Angle of incidence θ of laser beam on eye
If 2 is small, the energy density of the laser beam passing around the cornea and the crystalline lens increases, and if there is an opaque element of the therapeutic laser light due to turbidity or the like around the cornea and the crystalline lens, the thermal effect on that part is likely to appear. . This effect can be reduced by increasing the incident angle of the laser beam.

In the above, an example has been described in which the shape of the laser irradiation area is substantially circular as in the conventional case. However, the apparatus of the present embodiment changes the shape pattern of the laser irradiation area by pressing the FORM button 70 of the control unit 3 to form a triangle. Or squares. The shape pattern selected by the FORM button 70 can be confirmed by turning on one of the graphic patterns on the display unit 70a. The changeable shape pattern is stored in a memory of the control unit 50, and the control unit 50 controls the scanning of the spot position of the laser irradiation according to the changed shape. Thereby, the solidification shape can be properly used according to the condition of the solidification position, and the shape of the solidification spot can be appropriately set.

[0039]

As described above, according to the present invention,
Even when the solidification size is increased, it is possible to reduce burn unevenness and obtain a more uniform solidified spot. In addition, it is not necessary to increase the thermal effect of the laser beam on the cornea and the crystalline lens where opacity is present.

[Brief description of the drawings]

FIG. 1 is a diagram showing an appearance of a laser photocoagulation device.

FIG. 2 is a diagram showing an optical system and a control system.

FIG. 3 is a diagram illustrating an optical path of a galvanomirror.

FIG. 4 is a diagram showing details of a control unit.

FIG. 5 shows an aiming scanning pattern in a laser irradiation area,
It is a figure showing a treatment scan pattern.

FIG. 6 is a diagram showing a light-shielding disk for emitting / stopping laser light.

FIG. 7 is a diagram showing a method of continuously scanning laser irradiation.

FIG. 8 is a diagram showing a laser beam passing around the cornea.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Apparatus main body 3 Control part 4 Slit lamp delivery 5 Laser irradiation part 10 Laser light source 19 Visible semiconductor laser 37 Galvano first mirror 38 Galvano second mirror 50 Control part 55 Spot diameter change knob

Claims (6)

[Claims] In a photocoagulation apparatus for performing photocoagulation by guiding therapeutic laser light from a laser light source to a fundus or the like, laser irradiation for forming the therapeutic laser light from the laser light source into small spots and irradiating the light onto the fundus. An optical system, a scanning unit arranged on the laser irradiation optical system to scan a small spot of laser light on the fundus, a setting unit for setting a laser irradiation condition of a coagulation size and a coagulation time for performing photocoagulation, and the setting condition Control means for controlling the scanning of the scanning means based on the image data. 2. The photocoagulation apparatus according to claim 1, further comprising an aiming light irradiating means for irradiating aiming light from an aiming light source using said scanning means. A photocoagulation device, wherein the scanning of the scanning means is controlled so as to be different from the time when the laser light is emitted. 3. The photocoagulation apparatus according to claim 2, wherein when irradiating only the aiming light, the control means controls the scanning area of the aiming light by the scanning means based on the setting of the coagulation size and treats the treatment laser light. A photocoagulation device which controls the scanning of the aiming light at a different speed from the scanning of the image. 4. The photocoagulation apparatus according to claim 3, wherein the scanning area by the aiming light scans only the outline of the laser irradiation area. 5. The photocoagulation apparatus according to claim 1, further comprising: a spot diameter changing unit for changing a setting of a spot diameter of a laser beam applied to a fundus, wherein said control unit controls said scanning unit based on the setting of the spot diameter. A photocoagulation device, characterized in that the scanning by means of is controlled. 6. The photocoagulation apparatus according to claim 1, further comprising a shape changing means for changing a shape of a laser irradiation area scanned by said scanning means.