KR20100093327A - Ultrafast laser device for selective ablation of retinal blood vessels - Google Patents

Abstract

PURPOSE: A selective retina blood vessel eliminator is provided to enable a user to selectively remove the retina blood vessel corresponding to the structure and characteristic of the eyes blood vessel using a high speed laser. CONSTITUTION: A selective retina blood vessel eliminator includes: a laser system which generates laser beams; an optical system which focuses the laser beams from the laser light source; a stage which controls organs including retinal blood vessels; and a monitoring apparatus which monitors the organs including retinal blood vessel. The laser beam system includes a laser control unit which regulates the fluence of laser beam corresponding to the type of each blood vessel.

Description

Ultrafast laser device for selective ablation of retinal blood vessels}

The present invention relates to a surgical device for the selective removal of retinal vessels using ultrafast laser, and more particularly to retinal and safe retinal vessel removal using ultrafast laser according to the type or structural characteristics of intraocular retinal vessels. It is to provide a surgical device for the selective removal of upper vessels.

Rapid advances in laser technology have led to the emergence of exciting and feasible new laser surgical devices. In particular, high-tech lasers are easily used for tissue transaction, ablation and coagulation surgery by focusing lasers on small lesions. This potential characteristic of laser beams has already been reported in multicenter clinical trials to ensure feasibility in vitreoretinal surgery. Retinal resection using the first laser technique was attempted with a Nd: YAG laser, and resection of the vessel wall was not possible before introducing the 2940 nm: YAG laser wavelength [D. J. D'Amico et al., "Erbium: YAG laser photothermal retinal ablation in enucleated rabbit eyes," Am. J. Ophthalmol. 117, 783790 (1994).

Although clinical trials of these relatively long pulsed lasers have been attempted for a variety of retinal surgeries, these systems have caused significant damage to the retinal tissues and are not suitable for selective and regenerative excision of the Inner Limiting Membrane (ILM). There is a report.

In general, laser-assisted tissue resection has been described as an optical breakdown model or a thermal confinement model. The optical breakdown model considers plasma formation, staged shock wave formation, cavitations, and tissue destruction. The thermal confinement model compares the thermal effects of evaporation with water flow and the diffusion of heat that causes secondary damage. If we assume that the pulse duration is less than the thermal relaxation time due to the size of the excised tissue, then this model is also very inadequate to account for secondary damage.

The recently amplified ultrafast lasers offer less thermal damage, higher precision, and faster processing of microstructures and surfaces of materials that minimize mechanical and thermal strain with energy-depleted fast pulses. It is reported that because of the contactless nature of the form, it is very efficient for micromachining directly to the material. In laser ablation, the ablation threshold, F _th (J / cm ² ), is the minimum thermal exposure required for effective material removal, and the fluence threshold is used for tissue ablation and finer ablation. It has been reported that the low ablation threshold, which determines the proper precision of the laser and generally focuses ultrafast laser pulses on the material, is adequate to minimize light damage in the immediate vicinity of the ablation area.

In addition, the light of the powerful ultrafast laser beam causes multiphoton stimulation of the target material, so that the duration of the laser pearl is shorter than the constant vibration relaxation time of approximately several picoseconds, so that the energy absorbed by the material does not thermally diffuse into the region of the adjacent material. It is transported electronically, minimizing thermal damage around the tissues, and also making biological tissues insensitive to damage caused by photoacoustic shock waves that occur in stages, effectively fs-laser surgical process non-thermal). However, high-density free electrons form a local plasma of the target material, and this heated plasma formation causes permanent damage even in the submicron range of internal cells, so tissue excision and removal such as corneal stroma is not possible. Very low ablation critical fluence values have been reported by reducing the pulse width by the laser. For these reasons, ultra-fast lasers have been reported to be used for precise tissue treatment by minimizing thermal damage or impact pressure on biological tissues such as retina and neovascularization, particularly in ophthalmology among medical lasers.

However, existing treatment techniques mainly use methods that rely on laser-induced thermal action or photochemical mechanisms. In most cases, the method causes serious side effects of the underlying tissue or lesion tissue. Therefore, the present invention has been completed in order to enable the removal and removal of very safe blood vessels that are selective for retinal blood vessels as a safe tool for minimizing adverse side effects.

The present invention is to provide a surgical device for the selective removal of retinal vessels using ultrafast laser according to the type or structural characteristics of intraocular retinal vessels.

Another object of the present invention is to minimize damage caused by laser light in normal blood vessels of peripheral tissues or regions other than selective vascular lesions, and to remove and remove blood vessels relatively free and very safe from thermal energy or mechanical energy around the focal point. It is to provide a new surgical device.

The present invention is a surgical device for the selective removal of the retinal vessels selectively and safely by resecting and removing the vessels by focusing on the retinal vessels using ultrafast laser ultra-fine processing technology and optical method, the surgical device generates a laser beam Laser system; An optical system for focusing the laser beam from the laser light source; Positioning the tissue including retinal vessels; And a monitoring device for monitoring tissue including retinal vessels; Wherein the laser beam system comprises a primary blood vessel from the retinal center, a secondary blood vessel branched from the primary vessel, and a tertiary vessel branched from the secondary vessel Laser control unit for controlling the laser beam fluence for each vessel type to remove the retinal vessels having a blood vessel type consisting of a tertiary blood vessel and a quaternary blood vessel branched from the tertiary vessel It provides a surgical device for the selective removal of retinal vessels comprising a.

The surgical device for the selective removal of retinal vessels using an ultrafast laser according to the present invention comprises a laser system for generating a laser beam; An optical system for focusing the laser beam from the laser light source; Positioning the tissue including retinal vessels; And a monitoring device for monitoring tissue including retinal vessels; It includes.

The optical system is adopted to process the beam generated from the ultra-fast laser light source and adjust the path to focus, and may include all of the conventional laser beam optical systems, and a dichroic mirror for selectively reflecting light according to the wavelength. ), The optical filter including the objective lens and the notch filter can be used to control and focus the path of the pure short wavelength laser beam, and the intensity of the laser beam can be controlled using the neutral density filter. In addition, only a single pulse can be extracted from the pulse train of the laser beam using a fast optical shutter.

The stage for positioning the focused object including the retinal vessels is employed to control the irradiation position setting of the laser beam for accurate laser beam irradiation to the site where the retinal vessels are located. It is driven using galvanoscopy or angiography of the upper vessels. In order to control the irradiation position setting of the laser beam, it is preferable to include a device that can observe the object to be focused in real time image.

The real-time imaging device may be used as a monitoring device for monitoring tissue including retinal vessels, and a CCD (charge coupled device) camera may be provided to detect a photoluminescence signal split by a beam splitter. .

At this time, the galvano scan (galvano-scanner mirror), the photodetector, the optical shutter, and the CCD camera are preferably controlled in conjunction with a control program driven by the digital processor.

The retinal vessels should be retinal vessels that satisfy all of Equations 1 to 4 below.

[Equation 1]

9.6 <H1 <10.4 (H1 is the thickness of the primary vessel)

[Equation 2]

7.7 <H2 <8.0 (H2 is the thickness of the secondary vessel)

[Equation 3]

5.8 <H3 <7.5 (H3 is the thickness of the tertiary vessel)

[Equation 4]

4.8 <H4 <6.8 (H4 is the thickness of the fourth vessel)

The retinal vessels have a relatively complex shape. See FIG. 2. First, the blood vessels from the center of the retina are the primary blood vessels and go to the periphery of the retina. In this case, the first branch from the primary vessel is named the secondary vessel, the third vessel, and finally the fourth vessel. At this time, the blood flow supplied to the eye passes from the primary vessel to the secondary vessel, the third vessel, and the fourth vessel, and finally supplies the nutrition to the cells on the retina through the capillaries.

After cryo-sectioning the retinas of the blood vessels of Formulas 1 to 4, and using H & E staining and observing them with an optical microscope, the vascular wall and blood and the thickness of the inner boundary membrane present in the stomach were examined. The plotted results show that the diameter of the blood vessel, the thickness of the internal boundary membrane, and the thickness of the blood vessel wall are very significant according to the type of blood vessel. In other words, the diameter of blood vessels is reduced to 10.1 mm, 7.8 mm, 6.6 mm and 5.8 mm, respectively, with primary, secondary, tertiary and quaternary vessels. The primary and fourth vessels were reduced to 21.5 mm, 16.4 mm, 13.6 mm, and 12.3 mm, respectively. Structural characteristics of these retinal vessels were changing strongly by vessel type. See FIGS. 3 and 5 and Table 1.

It was found that the structural characteristics of the retinal vessels changed very strongly for each vessel type, and that the removal conditions of the vessel types had to be changed in order to remove a safe and selective vessel using an ultrafast laser.

The range of the laser beam fluence according to the present invention may vary depending on the type and part of the animal to be treated, but the range of the laser beam fluence (F) to be irradiated should be controlled by blood vessel type, and the fluence of the laser beam ( The range of F) preferably ranges from primary vessels 3.6 to 99.4 J / cm ² , secondary vessels 3.6 to 71.0 J / cm ² , tertiary vessels 3.6 to 56.8 J / cm ² and quaternary vessels 3.6 to 28.4 J / cm Must be ²

Since the laser beam is inevitably irradiated to tissues or normal blood vessels adjacent to the retinal vessels during the laser beam irradiation to the retinal vessels, the laser beam fluence for irradiating the laser beam to the retinal vessels is above a certain range. When the retinal blood vessels are removed, the normal blood vessels damaged by the laser beam irradiation due to adjacent to the retinal blood vessels do not recover to normal blood vessels that function normally after the laser beam irradiation. Or range of the application of the fluence (F) of the laser beam irradiated in the surgical device for the selective removal of retinal blood vessels according to the present invention because it damages tissue cells other than normal blood vessels causing irreparable damage of the tissues Is most important in achieving the object of the surgical device of the present invention One configuration.

In addition, the surgical device for selective retinal vessel removal according to the present invention should be able to be controlled according to the removal target for each vessel type, the scope of the laser beam fluence (F) irradiated when the removal target is an internal boundary membrane for each vessel type Is preferably primary vessel 3.0 ± 0.8 J / cm ² , secondary vessel 1.27 ± 0.47 J / cm ² , tertiary vessel 0.69 ± 0.14 J / cm ² and quaternary vessel 0.15 ± 0.04 J / cm ² . The value according to the blood vessel-specific inner boundary membrane means a minimum laser fluence required for the removal of tissue that is not affected by the thickness of the removed inner boundary membrane.

When the object to be removed is a blood vessel wall of each vessel type, the range of the laser beam fluence (F) to be irradiated is preferably the primary vessel 6.2 ± 2.0 J / cm ² , the secondary vessel 4.88 ± 1.86 J / cm ² , the third vessel 2.53 ± 1.22 J / cm ² and fourth vessel 0.98 ± 0.6 J / cm ^{2 .}

The laser fluence for each type of blood vessel is relatively large by irradiating the laser energy of a properly controlled laser pullion in the case of tissues or organs in which a blood vessel having a relatively large and thick vessel wall and a very small blood vessel divided into capillaries are mixed. The walls of blood vessels have the advantage of being able to effectively ablate only small vessel walls without damage.

The laser beam employed in the surgical device for selective removal of retinal vessels according to the present invention is a laser beam in the near infrared region, preferably a single pulse laser beam, more preferably a femtosecond single pulse laser beam, the beam width of 100 It is preferable that it is -200 fs, and a wavelength is 780-840 nm. If the tissue is repeatedly irradiated with pulses, a rise in temperature due to continued accumulation of heat will occur if a constant temperature rise is caused by the immediately irradiated pulse and does not return to thermal equilibrium prior to the arrival of the continuing pulse. There may be. The method of minimizing the accumulation of photo-thermodynamic damage and photochemical damage is to use a single pulse laser beam, more preferably to use a femtosecond single pulse laser beam.

The surgical device according to the present invention is a surgical device for the selective removal of retinal vessels, the laser light in the normal vessels of the surrounding tissues or areas other than the lesions of the selective vessels while being able to remove only the target retinal vessels in a selective and safe manner. Minimizes damage caused by heat, and can be removed and removed from the thermal or mechanical energy around the focal point and can be applied to accurate and precise tissue treatment and surgery.

It is to be understood that the specific embodiments shown and described herein are merely illustrative of the principles of the invention and that various modifications will be apparent to those skilled in the art without departing from the scope and spirit of the invention.

Example 1

Experimental apparatus for penetrating porcine retinal vessels using femtosecond laser resection is as follows. The laser system consists of a Regenerative-amplified Ti: Sapphire (810 nm) laser with a pulse width of about 150 fs at a repetition rate of 1 kHz (Quantronix, USA). The laser beam was focused on the retinal vessel surface using an objective lens (N.A. = 0.4). The diameter of the laser beam is about 1.3 micron. Retinal vascular tissue was fixed in an automatic XY translation stage, which was used to control the sample to focus new areas of tissue at each laser pulse. An optical shutter with a response speed of less than 0.6 ms was used to accurately focus a single laser pulse on the sample.

Pig eyes were harvested from the slaughterhouse and stored in HBSS (Hank's Balanced Salt Solution, Welgene Inc. Korea) at 4 ° C. In cold HBSS, the eyes immediately behind the ora-serrata, cornea, iris and lens were carefully dissected and the viscous vitreous humour removed. . Enzmann et al., "Alterations of sensory retinal explantsexposed to choroidal melanoma cells ex vivo", Graefe's. Arch. Clin. Exp. Ophthalmol. 238, 985-992 (2000). After removing the retina from the pigment epithelial cells, a retinal piece of about 3 × 5 mm ² size was prepared by placing it on a filter paper (Whatman, UK). During the experiment, all retinal fragments were covered with 100 microl of vitreous fluid to prevent the retina from drying out and bring it closer to in vivo. All experiments were completed within 3 hours after slaughter. To obtain a scanning electron microscopy (SEM) image, a retinal tissue of about 10 x 10 mm ² was placed on the cover glass and the laser-resected retinal tissue was generally 0.1% fixed solution (p-formaldehyde) at 4 ° C. solution was fixed for 1 hour, 30 minutes in 0.5% fixative, 30 minutes in 1.0% fixative, 30 minutes in 1.5% fixative and 1 hour at 2.0%. The fixed tissue was completely dried within 4 to 6 hours at room temperature and then thinly coated with platinum.

Experimental Example 1 Analysis of Histologic Structure by Type of Retinal Veins

As shown in FIG. 2, the blood vessels of the eye retina have a relatively complicated shape. First, the blood vessels from the center of the retina are the primary blood vessels and go to the periphery of the retina. In this case, the first branch from the primary vessel is named the secondary vessel, the third vessel, and finally the fourth vessel. At this time, the blood flow supplied to the eye passes from the primary vessel to the secondary vessel, the third vessel, and the fourth vessel, and finally supplies the nutrition to the cells on the retina through the capillaries.

Meanwhile, in order to obtain information about the shape of these blood vessels, the retina was cryo-sectioned and subjected to H & E staining, and the results of observation using an optical microscope are shown in FIG. 3. 150 images from three different eyeballs were acquired and irradiated, respectively, to plot the observed vascular wall and blood and the thickness of the inner boundary membrane present in the stomach with respect to the state of each blood vessel. Indicated.

Both the diameter of the blood vessel, the thickness of the internal boundary membrane, and the thickness of the blood vessel wall show very significant changes according to the types of blood vessels. In other words, the blood vessel diameters are decreased to 10.1 mm, 7.8 mm, 6.6 mm and 5.8 mm in primary, secondary, tertiary and quaternary vessels, respectively. The thickness of the vessel wall was also decreased to 21.5 mm, 16.4 mm, 13.6 mm and 12.3 mm, respectively, with primary, secondary, tertiary and quaternary vessels. It shows strong dependence toward secondary, secondary, tertiary and quaternary vessels and decreases to 11.5 mm, 8.5 mm, 6.9 mm and 7.1 mm. It was confirmed that the structural characteristics of these retinal vessels are very strongly changed by vessel type.

Experimental Example 2 Laser Ablation of Retinal Vessels

In order to determine the percentage of damage to the retinal vessel wall, 74 samples were run five times to continuously damage the vessel in the laser fluence range of 1.4 J / cm ² to 99.4 J / cm ² . In the high laser fluence of about several tens of J / cm ² or more at the surface of the retinal vessels, it was confirmed in FIG. 4 that the blood vessel wall was clearly destroyed and continuous blood leakage for 2 to 3 seconds. The red color of the vessels disappeared after about 5 minutes, and after 10 minutes the bleeding almost stopped. On the other hand, bleeding caused by low laser fluence stopped bleeding within 1 minute after a small amount of blood leaked.

Experimental Example 3 Ultrafast Laser Ablation of Primary Retinal Veins

In order to clarify the characteristics of the resection and removal of the primary retinal vascular wall of pigs using ultrafast laser light, the tissues were continuously sliced to a thickness of 20 μm while the first retinal vascular wall was included. At low laser fluence, the probability of damaging the surface of the blood vessels using laser beams was low, but at high laser fluences, most of the inner boundary membranes, which form the glial cell layer, were clearly destroyed. Significant partial resection of the internal limiting membrane using laser fluence of 28.4 J / cm ² was observed in the 1st and 5th sections. No obvious damage and bleeding of the vascular epidermal layer was observed by laser light.

In addition, a single pulsed laser beam with a high laser fluence of 56.8 J / cm ² was able to ensure complete ablation of the vessel wall, while a single pulsed laser beam with a higher 71.0 J / cm ² laser fluence often resulted in marked damage to the vessel wall. It can be seen that this is observed continuously. The diameter of this damage is greater than 20 µm at high laser fluences. In addition, based on the experimental results, it was not possible to observe changes below the retinal cell layer in the laser fluence of 85.2 J / cm ² or more except for destruction at the retinal vessel wall and internal boundary membrane. However, a slight break down of tissue was observed at a high laser fluence of 99.4 J / cm ² .

Frozen sections of retinal slices using a single pulsed laser beam by ultrafast laser were divided into three groups: one without any change, one with internal boundary membrane, and one with vessel wall. In the range of 3.6 J / cm ² to 99.4 J / cm ² fluence, the probability of resection of the vascular wall was increased, while the probability of internal boundary membrane resection was mostly in the fluence range of 28.4 J / cm ² or more. Laser fluence for damage of the inner membrane layer was between 1.4 J / cm ² and 3.6 J / cm ² , and excision of the vascular wall was high fluence of high fluence between 3.6 J / cm ² and 7.1 J / cm ^2. It was markedly caused by the laser beam. If the least squares approximation for low fluence was attempted, the laser fluence thresholds for ablation of the internal boundary membrane and ablation of the vessel wall were determined to be 3.0 ± 0.8 J / cm ² and 6.2 ± 2.0 J / cm ² , respectively.

Experimental Example 4 Ultrafast Laser Ablation of Secondary Retinal Veins

The wall thickness of the secondary vessel on the retina is about 16.3 microns, including 8.5 microns of the inner boundary membrane thickness. In order to elucidate the characteristics of the resection and removal of the retinal secondary vascular wall of pigs using ultrafast laser beam, laser-treated retinal tissues were first fixed, and continuous sections were made to a thickness of 20 μm. At low laser fluence, as in the case of primary vessels, the probability of damaging the surface of the vessel using a laser beam is low. However, this low laser fluence shows that most of the inner boundary membranes that form the glial cell layer are clearly destroyed. On the other hand, even when there is a partial removal of the internal boundary membrane, it was confirmed that there is no optical change in other tissues.

A single pulsed laser beam of higher laser fluence shows a greater probability that the inner layer layer can be removed and a higher 42.6 J / cm ² laser fluence of single pulsed laser beam produces a clear It can be seen that cutting damage is observed continuously.

Frozen sections of retinal slices using a single pulsed laser beam by ultrafast laser were divided into three groups: one without any change, one with internal boundary membrane, and one with vessel wall. The graph of Figure 8 shows the statistical interrelationship of the three groups of damage. The probability of ablation of the vessel wall was increased in the range of 3.6 J / cm ² to 71.0 J / cm ² fluence, and the laser fluence for damage of the inner membrane layer was between 1.5 J / cm ² and 2.0 J / cm ^2. . However, ablation of the vessel wall is markedly caused by high fluence ultrafast laser beams between 3.0 J / cm ² and 6.7 J / cm ² . If you plot using a least-squares approximation at low fluences, the critical fluences at which the internal membrane and excision of the vessel wall occur are 1.27 ± 0.47 J / cm ² and 4.88 ± 1.86 J / cm ² . I can guess.

Experimental Example 5 Ultrafast Laser Ablation of Tertiary Vein

The wall thickness of the retinal tertiary vessel is about 13.6 microns, including 6.9 microns, the thickness of the internal border membrane. In order to test the retinal tertiary vessel wall of pigs using ultrafast laser light in the same manner as the secondary vessel, the retinal tissues were continuously sliced to a thickness of 20 μm after laser irradiation. 9 shows a histological picture of this tissue section. At low laser fluence, as in the case of primary and secondary vessels, the probability of damaging the surface of the vessel using the laser beam was low, but the ultrafast laser pulse of energy corresponding to the laser fluence below 3.6 J / cm ² was applied to the retina. In the case of irradiation, it was confirmed that there was a marked destruction of the inner membrane. However, even in this case, there was no evidence of damage to the basement tissue or other tissues. Frozen sections of retinal slices treated with a single pulsed laser beam by ultrafast laser were divided into three groups: one without any change, one with internal border membrane and one with vessel wall. The graph of FIG. 10 shows the statistical interrelationship of the damages of the three groups. In the range of 3.6 J / cm ² to 56.8 J / cm ² fluence, the excision probability of the vessel wall was increased. Plotting using a least-squares approximation at low fluence, the critical fluences at which the internal boundary membrane and the vessel wall are excised can be determined as 0.69 ± 0.14 J / cm ² and 2.53 ± 1.22 J / cm ² . have.

Experimental Example 6 Ultrafast Laser Ablation of Retinal Fourth Vessel

The wall thickness of the retinal fourth vessels is about 12.3 microns, including 7.1 microns of the internal limiting membrane, which is very similar to the tertiary vessels. In the same way as the other types of blood vessels, in order to test the retinal fourth vessel wall of pigs using ultrafast laser light in the same manner, after the laser irradiation, the retinal tissue was made a continuous section of 20 ㎛ thickness. 11 shows a histological picture of this tissue section. As with other types of blood vessels, the probability of damaging the surface of the blood vessels by using laser beams was low at low laser fluences, but the apparent destruction of the internal boundary membranes with 0.36 J / cm ² laser fluences in the retina was not significant. The tissues could be observed without any signs of damage. Frozen sections of retinal slices using a single pulsed laser beam by ultrafast laser were divided into three groups: one without any change, one with internal boundary membrane, and one with vessel wall. The graph of Figure 12 shows the statistical interrelationship of the three groups of damage. In the range of 3.6 J / cm ² to 28.4 J / cm ² fluence, the excision probability of the vessel wall was increased. Using the least squares approximation method at low fluence, the critical fluence values for the ablation of the internal boundary membrane and the ablation of the vessel wall can be estimated as 0.15 ± 0.04 J / cm ² and 0.98 ± 0.6 J / cm ² .

1 is a schematic diagram of a surgical device for selective removal of retinal vessels using a femtosecond laser according to the present invention,

2 is an image of an ocular retinal vessel observed using an ophthalmoscope,

3 is an image observed using an optical microscope after cryocleaving the blood vessels of the eye retina and H & E staining,

(A: 4th vessel, B: 3rd vessel, C: 2nd vessel, D: 1st vessel)

4 is an image showing changes in blood flow after irradiating a single pulsed laser beam of 810 nm wavelength to the ocular retinal vessels,

Scale bar: 100 μm

5 is a result of examining the thickness of the blood vessel wall and the internal boundary membrane of the retinal blood vessels from the eyeballs of 150 extracted pigs for the state of blood vessels,

FIG. 6 shows histological images of 20 μm thick continuous sections of the vascular wall after resection and removal of the hematopoietic wall of porcine retinal vessels using femtosecond laser,

FIG. 7 shows histological images of 20 μm thick continuous sections of the secondary vessel wall after resection and removal of porcine secondary vessels using femtosecond laser;

FIG. 8 is a graph showing the statistical correlation of damage to the internal boundary membrane and blood vessel wall in the excised section of secondary vessels using femtosecond laser,

(■: excision of the internal limiting membrane, ●: excision of the blood vessel wall, ▲: excision without change)

9 shows histological images of 20 μm thick continuous sections of the secondary vessel wall after resection and removal of the porcine tertiary vessel using femtosecond laser.

FIG. 10 is a graph showing the statistical correlation between damage of the internal boundary membrane and blood vessel wall in the resected section of the tertiary vessel using femtosecond laser,

(■: excision of the internal limiting membrane, ●: excision of the blood vessel wall, ▲: excision without change)

FIG. 11 shows a histological image of a 20 μm thick continuous section of the secondary vessel wall after resection and removal of the pig vessel fourth vessel using femtosecond laser.

FIG. 12 is a graph showing the statistical correlation between damage of the internal boundary membrane and the vessel wall in the excised section of the fourth vessel using femtosecond laser,

(■: excision of the internal limiting membrane, ●: excision of the blood vessel wall, ▲: excision without change)

FIG. 13 is a graph showing critical fluence values of femtosecond lasers for type of retinal vascular removal and resection of blood vessels according to retinal vessel types of porcine ocular.

(■: excision of the internal limiting membrane, ●: excision of the vessel wall)

Claims (10)

A laser system for generating a laser beam; An optical system for focusing the laser beam from the laser light source; Positioning the tissue including retinal vessels; And A monitoring device for monitoring tissue including retinal vessels; It is configured to include, The laser beam system comprises a primary blood vessel from the center of the retina, a secondary blood vessel branched from the primary vessel, a tertiary blood vessel branched from the secondary vessel and And a laser controller for controlling the laser beam fluence for each of the vessel types by removing a retinal vessel having a vessel type composed of a quaternary blood vessel branched from the tertiary vessel. Surgical device for selective removal of retinal vessels.  The method of claim 1, The blood vessel is a surgical device for selective removal of retinal vessels, characterized in that the retinal vessels satisfying all of the following formula 1 to 4. [Equation 1] 9.6 <H ₁ <10.4 (H ₁ is the thickness of the primary vessel) [Equation 2] 7.7 <H ₂ <8.0 (H ₂ is the thickness of the secondary vessel) [Equation 3] 5.8 <H ₃ <7.5 (H ₃ is the thickness of the tertiary vessel) [Equation 4] 4.8 <H ₄ <6.8 (H ₄ is the thickness of the fourth vessel) 3. The method of claim 2, The fluence (F) of the laser beam, which is controlled for each vessel type, is 3.6 to 99.4 J / cm ^{2 for the} primary vessel, Surgical device for selective removal of retinal vessels, characterized in that the secondary vessel 3.6 to 71.0 J / cm ² , the third vessel 3.6 to 56.8 J / cm ² and the fourth vessel 3.6 to 28.4 J / cm ² . The method of claim 1, The removal object is a surgical device for selective removal of retinal vessels, characterized in that the inner membrane of the blood vessels. The method of claim 4, wherein The fluence (F) of the laser beam, controlled by vessel type, is: primary vessel 3.0 ± 0.8 J / cm ² , secondary vessel 1.27 ± 0.47 J / cm ² , tertiary vessel 0.69 ± 0.14 J / cm ^2, and quadratic Surgical device for selective removal of retinal vessels, characterized in that the blood vessels 0.15 ± 0.04 J / cm ² . The method of claim 1, The removal object is a surgical device for selective removal of retinal vessels, characterized in that the blood vessel wall of the blood vessels. The method of claim 6, The fluence (F) of the laser beam, controlled by vessel type, is: primary vessel 6.2 ± 2.0 J / cm ² , secondary vessel 4.88 ± 1.86 J / cm ² , tertiary vessel 2.53 ± 1.22 J / cm ^2, and quadratic Surgical device for selective removal of retinal vessels, characterized in that the blood vessel 0.98 ± 0.6 J / cm ² . The method of claim 1, The laser beam is a surgical device for selective removal of retinal vessels, characterized in that the laser beam in the near infrared region. The method of claim 8, The laser beam is a femtosecond single-pulse laser beam surgical device for selective removal of retinal vessels, characterized in that. The method of claim 9, The laser beam has a pulse width of 100 to 200 fs, the wavelength of 780 to 840nm surgical device for selective removal of retinal vessels, characterized in that.

Images