JP5861329B2 - Ophthalmic laser treatment device - Google Patents

Description

  The present invention relates to an ophthalmic laser treatment apparatus for performing treatment by irradiating a therapeutic eye to a patient's eye.

  2. Description of the Related Art An ophthalmic laser treatment apparatus that performs treatment by irradiating a patient's eye with treatment laser light is known (see, for example, Patent Document 1). In the apparatus of Patent Document 1, the treatment laser light is irradiated to the tissue of the fundus, the temperature of the irradiated part is increased, and the irradiated part is solidified by a thermal action. In such an apparatus, the surgical conditions such as the output of the therapeutic laser beam, the spot size, and the irradiation time are changed according to the operation (the purpose of treatment). Furthermore, in the apparatus of Patent Document 1, the beam profile (energy distribution, intensity distribution) of therapeutic laser light is changed according to the operation.

JP 2001-8945 A

  The degree of treatment of the treatment laser beam irradiated to the irradiation site, for example, the degree of diffusion of heat (energy) at the spot, varies depending on the surgical conditions. Taking photocoagulation treatment as an example, the energy of the therapeutic laser beam irradiated to the spot of the therapeutic laser beam and the diffusion of energy over time in the tissue at the spot are closely related, and It affects the degree of solidification. As a parameter that influences the diffusion of heat, it is considered that the influence of the energy density distribution (beam profile) of the laser beam at the spot and the irradiation time is large. However, no apparatus considering such a relationship has been found.

  An object of the present invention is to provide an ophthalmic laser treatment apparatus capable of performing a suitable treatment by setting a beam profile of a treatment laser beam corresponding to a surgical condition in view of the above-described problems of the prior art.

In order to solve the above-mentioned problems, the present invention has the following configuration.
A laser light source for emitting treatment laser light, an irradiation unit for irradiating the irradiation site of the patient's eye with the treatment laser light emitted from the laser light source as a spot of a predetermined size, and an irradiation time of the treatment laser light are set In the ophthalmic laser treatment apparatus, comprising: an irradiation time setting means for performing control; and a control means for controlling the irradiation of the therapeutic laser light based on the set irradiation time. A beam profile changing unit that changes a beam profile that is a distribution of energy density of the laser beam for use, and the control unit controls the beam profile changing unit according to the irradiation time set by the irradiation time setting unit. It is characterized by that.

  ADVANTAGE OF THE INVENTION According to this invention, a suitable treatment can be performed by setting the beam profile of the treatment laser beam corresponding to a surgical condition.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an optical system and a control system of the ophthalmic laser treatment apparatus of the present embodiment. In this embodiment, as an ophthalmic laser treatment apparatus, a photocoagulation apparatus for irradiating the fundus of a patient's eye with therapeutic laser light and performing thermal coagulation of the irradiated region is taken as an example.

  The ophthalmic laser treatment apparatus 100 includes an observation unit 10 having a binocular microscope, an illumination unit 20 that illuminates a patient's eye, a laser light source unit 30 that emits treatment laser light and aiming light (aiming light), and a laser light source unit 30. An optical fiber 40 for transmitting laser light (treatment laser light and aiming light) from the laser beam, and a delivery unit (laser irradiation optical system) 50 for irradiating the affected part such as the fundus of the patient's eye with the laser light emitted from the optical fiber 40 A control unit 70 that controls and controls the entire apparatus, and an operation unit 80 that sets and confirms surgical conditions and the like.

  The observation optical system arranged inside the observation unit 10 includes an objective lens 11 shared by the left and right observation optical paths, a variable power lens unit 12 arranged in each of the left and right optical paths, an operator protection filter 13, and an imaging lens. 14, an erecting prism 15, a field stop 16, and an eyepiece 17.

  The illumination unit 20 includes an illumination light source 21 that emits white light for illumination. The illumination light beam emitted from the illumination light source 21 passes through the condenser lens 22, and then the height is changed by the variable aperture 23. The width is determined by the plate 24 and is formed into a slit-like light beam. Thereafter, the slit illumination light that has passed through the variable slit plate 24 passes through the projection lens 25 and is then reflected by the prism mirror 26 to illuminate the patient's eye PE. When observing the fundus, illumination and observation may be performed through the contact lens CL.

  The laser light source unit 30 is a therapeutic laser light source 31 that emits therapeutic laser light, an aiming light (aiming light) is emitted as an aiming light source 32, and a beam splitter that combines (coaxial) the therapeutic laser light and the aiming light. 33, a lens 34 for allowing the combined laser light to enter the fiber 40.

  The therapeutic laser light source 31 emits laser light in a wavelength range suitable for treatment. In the present embodiment, the laser light source 31 is configured to emit visible range laser light suitable for photocoagulation treatment. In the laser light source 31, there is a pair that defines an excitation light source, a laser medium that absorbs excitation light and amplifies a specific wavelength (in this embodiment, an infrared wavelength), and a resonator for emitting laser light. It is comprised of a mirror and a wavelength conversion element that converts laser light in the infrared region into laser light in the visible region that is the second harmonic (all are not shown). Here, an Nd: YAG crystal is used as the laser medium. The wavelength of the infrared laser light amplified by the laser medium and the mirror is 1064 nm. The infrared laser light is wavelength-converted to a visible laser beam of 532 nm by a wavelength conversion element, and a treatment laser beam of 532 nm used for treatment is emitted from the laser light source 31.

  The laser light emitted from the laser light source 31 is configured to change the irradiation time (pulse width) of the therapeutic laser light emitted based on the setting signal. In this embodiment, the irradiation time can be varied in four stages. For example, the irradiation time can be switched between 10 μs (microseconds), 100 μs, 1 ms (milliseconds), and 10 ms.

  The aiming light source 32 is configured by a semiconductor laser (LD: Laser Diode), and in this embodiment, it is red laser light. Specifically, the beam splitter 33 is a dichroic mirror, and has a characteristic of transmitting the therapeutic laser beam and reflecting the red laser beam as the aiming beam.

  The fiber 40 is a single mode fiber having a core diameter of about 5 μm. The laser light emitted from the fiber 40 is a Gaussian beam with high beam quality.

  The delivery unit 50 includes a collimator lens 51 that expands the beam diameter of the laser light emitted from the output end 41 of the fiber 40 to about 10 mm and makes it parallel light, and a diffractive optical element (hereinafter referred to as a beam profile of the laser light). DOE unit (beam profile changing means) 60 including a disk 61 on which a plurality of 62 are arranged, a relay lens 52, a mirror 53, and a spot size of a laser beam on a target surface (for example, a fundus of a patient's eye). A zoom lens group 54 that is a zoom optical system for changing, a relay lens 55, a dichroic mirror 56 arranged on the illumination optical axis of the illumination unit 20, a projection lens 25 shared by the illumination unit 20, a prism mirror 26, Is provided. The dichroic mirror 56 substantially reflects 532 nm, which is the wavelength of the therapeutic laser light, reflects red aiming light to some extent, and transmits white light from the illumination light source 21 to some extent, that is, loses the therapeutic laser light as much as possible. And has the characteristic of being synthesized coaxially with the illumination light. Further, the dichroic mirror 56 is made as small as possible so that the illumination light reaches the prism mirror 26 from the outside of the dichroic mirror 56.

  A DOE unit 60 serving as a beam profile changing unit (means) is a turret in which a plurality of diffractive optical elements (DOEs) are arranged, and each DOE is arranged to be switched to the optical axis. A shaft 63 is fixed to the central axis of the disk 61 in which a plurality of DOEs 62 are arranged on the same circumference (see FIG. 2). The shaft 63 is attached to the stepping motor 65. The disk 61 can be rotated by a motor 65. The motor 65 rotates and positions the disk 61 according to a command from the control unit 70, and switches and arranges one of the plurality of DOEs 62 on the optical axis. Each DOE 62 has a different diffraction grating pattern in order to shape the beam profile of the laser light into different shapes. Such a pattern of the diffraction grating is a pattern for obtaining a uniform energy density (top hat) as a profile of the therapeutic laser beam, or in other words, the center of the laser beam is recessed with respect to the peripheral portion of the laser beam. A pattern for making the energy density non-uniform so that the intensity at the center is relatively lower than the intensity at the periphery is prepared.

  The zoom lens group 54 includes a plurality of lenses such as a concave lens and a convex lens, and continuously moves the spot size of the laser light by moving along the optical axis. The zoom lens group 54 is held by a lens cam (not shown) and is moved when the lens cam is operated (rotated) by an operator. The spot size of the laser beam is continuously deflected between 50 μm (micrometer) and 500 μm, for example. The zoom lens group 54 is provided with a sensor 54a for detecting the position of each lens.

  The operation unit 80 includes a foot switch 81 for inputting a trigger signal for triggering irradiation of therapeutic laser light, and an operation panel 82 for displaying and setting surgical conditions such as laser light irradiation time. The operation panel 82 has a touch panel function, and has a configuration in which surgical conditions can be set by selecting numerical values, conditions, and the like by touching items on the panel. The operation panel 82 includes an output setting field 83 for setting the output of the therapeutic laser beam, an irradiation time setting field 84 for setting the irradiation time of the therapeutic laser beam, and a beam profile for displaying a beam profile set based on the irradiation time. A display unit 85 and a spot size display column 66 for displaying the spot size of the laser beam are provided.

  Each of the output display field 83 and the irradiation time setting field 84 has a switch (key) for increasing / decreasing a numerical value, and an output and an irradiation time are set by input by the switch. The beam profile display unit 85 displays a beam profile corresponding to the set irradiation time based on the setting signal in the irradiation time setting field 84 (details will be described later). The spot size display unit 86 displays the spot size obtained based on the detection signal of the sensor 54a.

  The control unit 70 that controls and controls the apparatus 100 includes a protective filter 13, an illumination light source 21, a treatment laser light source 31, an aiming light source 32, a sensor 54a, a motor 65, an operation panel 80 (foot switch 81 and operation panel 82), Is connected. The control unit 70 is connected to a memory 71 for storing a control program and set surgical conditions. The control unit 70 obtains the spot size of the laser beam based on the detection signal of the sensor 54a and displays it on the spot size display unit 86 of the operation panel 82.

  Next, the beam profile of the DOE unit and the therapeutic laser beam will be described. FIG. 2 is a diagram illustrating the configuration of the DOE unit 60. FIG. 3 is a diagram showing the relationship between the irradiation time of the therapeutic laser beam and the beam profile.

  FIG. 2 shows a state in which the DOE unit 60 is viewed from the optical axis direction. In the present embodiment, four DOEs 62 (62a to 62d) are arranged on the concentric circle C of the disk 61. However, the present invention is not limited to this, and the number of DOEs may be determined as necessary. The disk 61 is rotated left and right around a shaft 63 fixed at the center of the disk 61, so that one of the DOEs 62a to 62d is switched (inserted / removed) to the optical axis (optical path). The DOEs 62a to 62d are optical elements in which innumerable microgrooves that cause diffraction are formed in a predetermined pattern in a light transmitting body such as glass, quartz, or resin. Each DOE is designed so that the laser beam that has passed through innumerable microgrooves that cause diffraction is superimposed on the target surface (on the affected area) to form an intended beam profile.

  Even if the beam profile at the exit end 41 of the optical fiber 40 has speckle noise or a Gaussian beam profile, the target surface becomes an image in which laser beams that have passed through innumerable minute grooves are superimposed. For this reason, the beam profile on the target surface is formed into the desired shape by this superposition. For this reason, the alignment of the optical axis of the DOE and the optical axis of the laser light incident on the DOE does not require strictness. Therefore, the optical fiber 40 may be a multimode fiber. For example, a multimode fiber having a core diameter of 50 μm is used as the optical fiber. In this case, the design of the lens group of the zoom optical system is changed so that the spot size of the laser light is 50 to 500 μm.

  Each DOE is designed corresponding to the irradiation time of the laser beam, and is designed so that treatment is suitably performed when the laser beam of the selected irradiation time is irradiated onto the target surface. In this embodiment, by changing the beam profile of the therapeutic laser beam according to the irradiation time of the therapeutic laser beam, the energy (heat) of the laser beam is appropriately diffused within the range of the laser spot. The inside can be uniformly heat-coagulated. Each DOE is designed so that such a beam profile of the therapeutic laser beam corresponds to the irradiation time of the therapeutic laser beam.

  Here, in the spot of the therapeutic laser beam, the energy of the therapeutic laser beam diffuses during the irradiation time of the therapeutic laser beam. For this reason, if the laser light irradiation time is short in the plurality of irradiation times selected, the heat diffusion time is short, and the degree of heat diffusion is small. On the other hand, if the irradiation time is long, the heat diffusion time becomes long, and the degree of heat diffusion increases. Each DOE is designed in consideration of these phenomena. At each point in the spot, heat diffuses in all directions. For this reason, when considering the central part and peripheral part of the beam profile, heat from all directions tends to concentrate in the central part. Conversely, in the peripheral part, there is no heat source outside the spot, so heat concentration hardly occurs. . Therefore, in this embodiment, the degree of thermal coagulation of the entire spot is adjusted by changing (relatively reducing) the intensity of the central portion with respect to the peripheral portion of the beam profile in accordance with the irradiation time of the therapeutic laser beam. It is configured.

  As shown in FIG. 3, when the irradiation time is 10 μs, the degree of thermal diffusion is the shortest in the four irradiation times and the influence of thermal diffusion is small, so a beam profile with a uniform energy density (top hat) is selected. It is. The DOE 62a corresponds to a therapeutic laser beam with an irradiation time of 10 μs. When the irradiation time is 100 μs, the degree of thermal diffusion is large with respect to the irradiation time of 10 μs. For this reason, the beam profile is slightly lower (adjusted so as to be lower) than the peripheral portion. The DOE 62b corresponds to a therapeutic laser beam with an irradiation time of 100 μs. When the irradiation time is 1 ms, the degree of thermal diffusion is large with respect to the irradiation time of 100 μs. For this reason, the beam profile at the center is lower than that at the periphery compared to the case where the irradiation time is 100 μs. The DOE 62c corresponds to a therapeutic laser beam with an irradiation time of 1 ms. When the irradiation time is 10 ms, the degree of thermal diffusion is large with respect to the irradiation time of 1 ms. For this reason, the beam profile at the center is lower than that at the periphery compared to the case where the irradiation time is 1 ms. The DOE 62d corresponds to a therapeutic laser beam with an irradiation time of 10 ms. Note that the setting of the beam profile for such irradiation time (selection of DOEs 62a to 62d) is stored in the memory 71 in a state of being associated in advance.

  In this way, when the irradiation time becomes longer, the DOE is designed so that the beam profile having a relatively low intensity at the center corresponds to the periphery, and each DOE is switched to the optical axis. ing. Here, in the settable irradiation time, the relatively short irradiation time is the first irradiation time, and the relatively long irradiation time is the second irradiation time.

  Next, the setting of irradiation time and control of the DOE unit 60 will be described. When one of the four irradiation times (10 μs, 100 μs, 1 ms, 10 ms) is set (selected) by operating the irradiation time setting field 84 of the operation panel 82, the control unit 70 sets the corresponding DOE from the memory 71. Information is read, the motor 65 is controlled based on the setting signal, and DOEs (62a to 62d) corresponding to the setting signal are arranged on the optical axis. At this time, the control unit 70 determines the drive amount of the motor 65 based on the correspondence between the irradiation time stored in the memory 71 and the beam profile (each DOE). Further, the control unit 70 causes the beam profile display unit 85 to display a schematic diagram of the beam profile corresponding to the setting signal based on the setting signal. In addition, the control unit 70 prepares to control the laser light source 31 so that the irradiation time of the treatment laser light is set (the standby state). Similarly, the control unit 70 prepares for control of the laser light source 31 based on the setting signal in the output setting field 83.

  The operation of the ophthalmic laser treatment apparatus having the above configuration will be described. The surgeon sets the operating conditions prior to treatment. The surgeon determines the irradiation conditions (output, irradiation time, spot size) of the therapeutic laser beam according to the treatment. The surgeon operates the output setting field 83 of the operation panel 82 to output the therapeutic laser beam. Further, the surgeon operates the irradiation time setting field 84 to set the irradiation time. The surgeon moves the zoom lens group 54 by operating a lens cam (not shown) to set the spot size of the therapeutic laser beam. The spot size is confirmed by the display in the spot size display field 87. The control unit 70 prepares for control of the laser light source 31 based on the output setting signal and the irradiation time setting signal set by the operation panel 82. At this time, the control unit 70 arranges any of the DOEs (62a to 62d) corresponding to the irradiation time on the optical axis based on the setting signal.

  The surgeon operates the operation panel 82 to turn on the aiming light. Further, the surgeon makes the contact lens CL abut on the patient's eye PE and observes the irradiated region with the observation unit 10. Then, the operator aligns a laser spot (aiming spot) with the irradiation site. When the operator operates (depresses) the foot switch 81, the control unit 70 controls the laser light source 31 obtained based on the trigger signal, and outputs the therapeutic laser beam with the set output for the set irradiation time. Only the patient's eye PE is irradiated. The spot irradiated with the therapeutic laser beam is uniformly heat-coagulated in the spot by a beam profile corresponding to the irradiation time of the therapeutic laser beam. In this way, photocoagulation treatment is performed.

  As described above, a suitable treatment can be performed by setting the beam profile of the therapeutic laser beam corresponding to the surgical condition. By irradiating the patient's eye with a therapeutic laser beam having a beam profile set in consideration of the thermal diffusion in the spot corresponding to the irradiation time of the therapeutic laser beam, uniform thermal coagulation in the spot can be achieved. . Thereby, the problem of uneven burning and excessive solidification can be reduced. Even when the order of irradiation time is different (in this embodiment, 1000 times), a suitable photocoagulation treatment can be performed. For example, when the irradiation time is long, a treatment that coagulates the entire retina in the spot, such as panretinal photocoagulation treatment, and a specific layer (part) in the retina such as the retinal pigment epithelium is selectively coagulated. Selective retinal treatment and surgery can be performed with the same device.

  In the above description, the beam profile of the therapeutic laser beam is configured to adjust the relative intensity of the central portion with respect to the peripheral portion, but is not limited thereto. Any configuration may be used as long as the thermal diffusion in the spot and the energy density distribution (beam profile) in the spot are associated with each other, and the inside of the spot is uniformly heat-coagulated in the set irradiation time. For example, a configuration may be adopted in which a plurality of minute spots having a minute diameter with respect to a laser beam spot set as a single irradiation region are formed using a DOE and arranged in the set spot. For example, the energy density distribution in the entire spot is changed (the uniformity of the beam profile is changed) by adjusting the spot diameter and the spot interval of the minute spots. The degree of thermal diffusion (here, uniformity) is controlled by changing the beam profile. The pattern of the DOE diffraction grating is set so that a large number of minute spots are arranged in the spot of the therapeutic laser beam. When a plurality of types of beam profiles in the spot of the therapeutic laser beam are used, a plurality of DOE diffraction grating patterns different from each other are formed as in the above-described embodiment. When the intended treatment laser beam is required, the DOE corresponding to the beam profile is arranged on the optical axis of the treatment laser beam k. In each DOE, the diffraction grating pattern is changed so as to change the size of the minute spots and / or the interval between the minute spots.

  In the above description, the spot size of the therapeutic laser beam is changed by the zoom optical system. However, the present invention is not limited to this. Any configuration that can change the spot size may be used. In addition to the zoom optical system, the spot size may be changed by inserting and removing a lens on the optical axis. Further, the spot size may be changed by DOE. Further, it is not always necessary to change the spot size.

  In the above description, the set irradiation time and the corresponding DOE (type of beam profile) are the same number, but the present invention is not limited to this. The configuration may be such that at least two types of beam profiles can be selected for the set irradiation time of the therapeutic laser beam. Further, the irradiation time of the set laser beam can be arbitrarily set, and a corresponding beam profile can be set for each predetermined irradiation time range.

  In the above description, the therapeutic laser beam is used for photocoagulation treatment. However, the present invention is not limited to this. As long as it is preferable that the thermal diffusion within the spot of the therapeutic laser beam is uniform, the structure may be used for other ophthalmic surgery. For example, it may be applied to selective trabeculoplasty.

  In the above description, the irradiation time of the treatment laser beam is set between 10 μs and 10 ms (here, four stages), but is not limited thereto. The irradiation time may be set and irradiated from nanosecond order to second order. Further, a plurality of therapeutic laser light sources may be provided with a laser light source unit according to the irradiation characteristics of the therapeutic laser light, and the therapeutic laser light to be irradiated may be switched according to the irradiation time.

  In the above description, the beam profile of the therapeutic laser beam is changed using the DOE. However, the present invention is not limited to this. Any configuration that can change the beam profile at the treatment site (target surface) may be used. For example, a configuration may be adopted in which a plurality of filters having different transmission densities in the laser light transmission region are provided and a specific filter is disposed on the optical axis. Moreover, it is good also as a structure which generate | occur | produces a distortion aberration in the lens of a laser irradiation optical system, and distorts the spot in a target surface.

  In the above description, the therapeutic laser beam is a visible laser beam, but the present invention is not limited to this. Any laser light having a wavelength suitable for the treatment site may be used, and infrared laser light may be used. In addition, as the treatment laser light source, either a continuous wave laser light source that emits a continuous wave or a pulse laser light source that emits a pulse laser beam may be used.

It is a schematic block diagram of the ophthalmic laser treatment apparatus of this embodiment. It is a figure explaining the structure of a DOE unit. It is the figure which showed the relationship between the irradiation time of a therapeutic laser beam, and a beam profile.

31 Therapeutic laser light source 50 Delivery unit 60 DOE unit 62 (62a-62d) DOE
DESCRIPTION OF SYMBOLS 70 Control part 82 Operation panel 84 Irradiation time setting column 85 Beam profile display part 100 Ophthalmic laser treatment apparatus

Claims (4)

A laser light source for emitting treatment laser light, an irradiation unit for irradiating the irradiation site of the patient's eye with the treatment laser light emitted from the laser light source as a spot of a predetermined size, and an irradiation time of the treatment laser light are set In an ophthalmic laser treatment apparatus comprising: an irradiation time setting unit that performs control, and a control unit that controls irradiation of a therapeutic laser beam based on the set irradiation time.
Beam profile changing means for changing a beam profile that is a distribution of energy density of the therapeutic laser beam in the spot of the predetermined size irradiated to the patient's eye;
The ophthalmic laser treatment apparatus, wherein the control means controls the beam profile changing means according to the irradiation time set by the irradiation time setting means. The ophthalmic laser treatment device according to claim 1.
The irradiation time setting means can set at least one of a first irradiation time and a second irradiation time which is an irradiation time shorter than the first irradiation time,
The beam profile changing means can change the beam profile of a plurality of types of treatment laser light corresponding to at least two of the irradiation times set by the irradiation time setting means,
When the first irradiation time is set by the irradiation time setting means, the control means sets the uniformity of the beam profile set by the beam profile changing means, and sets the second irradiation time by the irradiation time setting means. An ophthalmic laser treatment apparatus, wherein the beam profile changing means is set so as to be lower than the uniformity of the beam profile set by the beam profile changing means. The ophthalmic laser treatment apparatus according to claim 1 or 2,
The said beam profile change means changes the relative intensity | strength of the center part with respect to a peripheral part in the beam profile of a laser beam for treatment using a diffractive optical element, The ophthalmic laser treatment apparatus characterized by the above-mentioned. In the ophthalmic laser treatment apparatus according to any one of claims 1 to 3,
  An ophthalmic laser treatment apparatus, wherein the irradiation time range of treatment laser light that can be set by the irradiation time setting means includes 10 μs to 10 ms.