WO2020125435A1 - Système et procédé de kératoplasmie thermique au térahertz - Google Patents

Système et procédé de kératoplasmie thermique au térahertz Download PDF

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WO2020125435A1
WO2020125435A1 PCT/CN2019/123438 CN2019123438W WO2020125435A1 WO 2020125435 A1 WO2020125435 A1 WO 2020125435A1 CN 2019123438 W CN2019123438 W CN 2019123438W WO 2020125435 A1 WO2020125435 A1 WO 2020125435A1
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terahertz
corneal
cornea
temperature
monitoring
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PCT/CN2019/123438
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Chinese (zh)
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刘文权
鲁远甫
李光元
佘荣斌
焦国华
吕建成
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深圳先进技术研究院
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Priority claimed from CN201811550470.XA external-priority patent/CN109481142B/zh
Priority claimed from CN201822129470.4U external-priority patent/CN209474947U/zh
Application filed by 深圳先进技术研究院 filed Critical 深圳先进技术研究院
Publication of WO2020125435A1 publication Critical patent/WO2020125435A1/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
    • A61F9/007—Methods or devices for eye surgery
    • A61F9/013—Instruments for compensation of ocular refraction ; Instruments for use in cornea removal, for reshaping or performing incisions in the cornea
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
    • A61F9/007—Methods or devices for eye surgery
    • A61F9/008—Methods or devices for eye surgery using laser
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/0008—Apparatus for testing the eyes; Instruments for examining the eyes provided with illuminating means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions

Definitions

  • This application relates to the field of biomedical engineering technology and terahertz technology, in particular to a corneal thermoforming technology using terahertz waves.
  • Corneal thermoplasty means that the collagen tissue is heated and contracted and denatured by a certain heat source at an appropriate depth of the corneal stroma layer. This leads to a change in the three-dimensional structure of the corneal stroma layer, which causes the corneal curvature to change to achieve the purpose of changing the corneal refractive power.
  • the collagen tissue of the corneal stroma layer begins to shrink or change its three-dimensional structure when it continues to 55 °C; it reaches its ideal or permanent contraction state at 65 to 70 °C; when the temperature continues to exceed 70 °C, the corneal collagen tissue begins to dissolve,
  • the hydrolysis of the collagen silk sliding cross-linked structure will lead to the destruction of the three-dimensional spiral structure, which makes the collagen fibers elongate and become relaxed; when the temperature exceeds 75-80°C, the collagen tissue will necrosis, the corneal injury reaction will occur, and the corneal cells will proliferate , New collagen production, causing scars and refractive regression.
  • the key to corneal thermoplasty is how to permanently change the three-dimensional structure of the corneal stroma. Therefore, during the implementation of corneal thermoplasty, the temperature within the cornea should be controlled as much as possible within the range of 65 °C ⁇ 70 °C.
  • corneal thermoplasty mainly focuses on probe corneal thermoplasty, conductive corneal thermoplasty, laser corneal thermoplasty, etc., mainly used for the treatment of hyperopia, presbyopia and astigmatism correction.
  • the above-mentioned existing technologies all have certain disadvantages.
  • Probe keratoplasty uses a heated probe to act on the center of the cornea. This procedure has the disadvantages of difficult to control coagulation depth, poor predictability, and obvious postoperative refractive regression.
  • Conductive keratoplasty uses radiofrequency energy as a heat source, uses the electrical properties of corneal tissue, and releases radiofrequency energy to heat collagen and cause collagen contraction; however, due to corneal contact problems, treatment is likely to cause discomfort and postoperative patients. Corneal epithelial cell ulceration; at the same time, because of the problem of hot spot location, it may also cause temporary irregular astigmatism caused by the treatment probe not perpendicular to the corneal surface; moreover, due to system design issues, it is difficult to change the surgical parameters once set .
  • Laser keratoplasty uses a laser to heat the corneal stroma, causing its collagen fibers to contract, thereby changing the corneal refractive power. It is a non-invasive treatment of the cornea.
  • the present application proposes to use the proper penetration depth of the terahertz wave and the cornea to solve the technical problem of insufficient depth of the photocoagulation point, and scan and irradiate the shaped terahertz beam
  • the optimal surgical parameters are formulated according to the real-time feedback of the corneal surface temperature, corneal thickness, corneal refractive power and corneal topography, thereby making the postoperative refractive power and corneal deformation more stable and can be effectively reduced Corneal refractive regression after operation.
  • Terahertz (THz) wave refers to electromagnetic waves with a frequency in the range of 0.1 to 10 THz.
  • the frequency is between microwave and infrared bands. It has the characteristics of microwave and light waves. It has low quantum energy, large bandwidth, and good penetration. And other characteristics, it has great scientific value and application prospects in the fields of basic physics, industrial applications, biomedicine, and national defense security.
  • Water has strong absorption of terahertz waves, so that the penetration depth of terahertz waves in biological tissues is about several hundred microns. When the terahertz wave is irradiated onto the biological tissue, it can be absorbed by the water in the biological tissue and transformed into heat, and the thermal effect of the biological tissue is generated.
  • the corneal tissue is rich in water (75%-85%), and the thickness (400-700 ⁇ m) is equivalent to the terahertz wavelength, so compared with the infrared light source used in the existing corneal thermoplasty, too
  • the wavelength of the Hertz wave is longer, and a deeper penetration depth matching the corneal tissue can be obtained in the corneal tissue, and the corresponding thermal effect is more significant.
  • the energy of the terahertz wave increases, the corneal tissue heats up under the irradiation of the terahertz wave and can completely reach the temperature of the corneal stromal layer thermal deformation. Therefore, terahertz waves can be a new heat source for corneal thermoplasty.
  • a terahertz keratoplasty system which is characterized by including a terahertz laser as a heat source and a collimated scanning module, so as to irradiate a terahertz beam onto the cornea;
  • the collimating scanning module includes a collimator, a power adjustment part and a two-dimensional scanning device.
  • the two-dimensional scanning device is a two-dimensional galvanometer scanning system with beam shaping function. Or a beam shaper and/or a corneal marker are further provided behind the two-dimensional scanning device.
  • the power adjustment part may specifically be a terahertz attenuator; the collimator includes a first terahertz reflector and a second terahertz reflector.
  • the beam after passing through the terahertz attenuator is split by a terahertz beam splitter; one beam is received by the terahertz power meter for power detection, and the other beam is used to illuminate the eyeball.
  • the system further includes a temperature monitoring control unit to obtain the spatial distribution information of the cornea temperature through a high-resolution infrared thermal imager.
  • the temperature monitoring control unit may further include a cooling module for adjusting the temperature of the cornea according to the monitoring result of the high-resolution infrared thermal imager.
  • system further includes a computer control section, through which the two-dimensional scanning device and/or the refrigeration module are controlled; wherein the control of the two-dimensional scanning device and/or the refrigeration module refers to the High-resolution infrared thermal imager monitoring results.
  • the system further includes one or more corneal physiological parameter feedback units, and the monitoring results of the corneal physiological parameter feedback unit are sent to the computer control section for adjusting the terahertz beam irradiated to the cornea.
  • the corneal physiological parameter feedback unit is one or more of an ophthalmic optical coherence tomography scanner, a corneal topograph, and an eyeball follower.
  • the system may also include an operating microscope and an ITO spectroscope for observing the surgical procedure, and the light beam passing through the two-dimensional scanning device is reflected by the ITO spectroscope and irradiated on the cornea of the eyeball; the light beam reflected by the eyeball is transmitted through The ITO spectroscope is used to obtain surgical monitoring information.
  • the present application also proposes a terahertz corneal thermoforming method, which is characterized by using a terahertz laser as a heat source, and irradiating the terahertz beam onto the cornea with a collimating scanning module.
  • the power density of the terahertz laser is 5000-8000W/m 2 , preferably 6000W/m 2 .
  • the cornea is heated for 180 to 720 seconds.
  • the method further includes using a temperature monitoring control unit to obtain corneal temperature spatial distribution information; and referring to the corneal temperature spatial distribution information to adjust the terahertz beam irradiated on the cornea, or directly referring to the corneal temperature spatial distribution information Adjust the temperature of the cornea.
  • the method further includes acquiring monitoring information during the operation, the monitoring information including one or more of corneal thickness information, corneal refractive power information, corneal topography, and the center position of the pupil of the eyeball; and adjusting the irradiation with reference to the monitoring information A terahertz beam onto the cornea, or directly adjust the temperature of the cornea with reference to the monitoring information.
  • the terahertz corneal thermoforming technology proposed in this application has the following technical effects:
  • the terahertz laser Due to the use of a high-power continuous wave terahertz laser with a frequency in the range of 0.1 to 10 THz, compared with the infrared laser used in the prior art, the terahertz laser has a longer wavelength and a deeper penetration depth in the corneal tissue And the power of the terahertz beam is adjustable, and the shaping scan of the terahertz beam is controllable, so that the corneal thermocoagulation depth and the uniformity of heating are significantly improved.
  • the system is equipped with a high-resolution infrared thermal imager. According to the spatial distribution information of the corneal surface temperature provided by the imager, the scanning situation of the terahertz beam can be estimated, and further combined with the real-time feedback of the terahertz beam scanning mirror and the eyeball follower. Greatly improve the accuracy of the control of the position of the corneal operation of the terahertz beam during the operation.
  • the temperature monitoring and control unit composed of a high-resolution infrared thermal imager and a cooling module realizes the prediction and control of the corneal temperature, which can effectively prevent the cornea from being heated too high and too fast during the operation and causing thermal damage.
  • Figure 1 shows a schematic diagram of a corneal thermal analysis model
  • Figure 2 shows the corneal temperature with time under irradiation of THz beams with different power densities (frequency 1THz, beam diameters (a) 2mm, (b) 4mm, (c) 5mm, (d) 6mm and (e) 8mm) Change graph;
  • FIG. 3 shows a prediction map of the stromal coagulation zone after a terahertz beam with a frequency of 1 THz, a beam diameter of 6 mm, and a power density of 6000 W/m 2 is irradiated to the cornea for 1200 seconds;
  • Figure 4 shows a schematic diagram of the prediction of thermal damage after a terahertz beam with a frequency of 1 THz, a beam diameter of 6 mm, and a power density of 6000 W/m 2 after irradiating the cornea for 1200 seconds; the left picture shows the spatial distribution and the right picture shows the corneal surface The thermal damage at the center changes with time;
  • FIG. 5 shows a schematic diagram of the terahertz corneal thermoforming system of the present application.
  • terahertz radiation power level generated by the laboratory is about 10mW ⁇ 100W.
  • the terahertz peak power generated by the energy recovery linear accelerator can reach 10KW (kW), and the free electron laser can even reach MW (million watt). This also cleared the technical barrier for terahertz waves to become a heat source for corneal thermoplasty.
  • the corneal tissue is rich in water (75% to 85%), and the thickness (400 to 700 ⁇ m) is equivalent to the terahertz wavelength, so it is based on the absorption of terahertz waves by water and is used in existing corneal thermoplasty Compared with the infrared light source, the terahertz wave can obtain a deeper penetration depth matching the corneal tissue in the corneal tissue, and the corresponding thermal effect is also more significant. Under the irradiation of terahertz waves with sufficient power, the thermal effect can cause the corneal tissue to heat up to the temperature of thermal coagulation deformation.
  • a thermal analysis model of the cornea is established based on a two-dimensional axisymmetric cylindrical coordinate system, as shown in FIG. 1 of the specification.
  • the model assumes that the cornea and related structures are cylinders with a diameter of 15 mm, which are mainly three-layer structures, including a tear film with a thickness of 10 ⁇ m, a cornea with a thickness of 600 ⁇ m, and an aqueous humor layer with a thickness of 2 mm.
  • T is the temperature field inside the biological tissue (°C)
  • ⁇ is the density of the biological tissue (kg/m3)
  • k is the thermal conductivity of the biological tissue (W/m/K)
  • C is the specific heat capacity of the biological tissue (J /kg/K)
  • q is the terahertz heat source.
  • terahertz beams are generally regarded as Gaussian beams. Without loss of generality, the terahertz heat source is defined as follows:
  • P d is the power density of terahertz beam
  • w 0 is the terahertz beam radius
  • ⁇ is the absorption coefficient of biological tissue
  • r and z represent radial distance and longitudinal thickness, respectively.
  • the thermal performance parameters used in corneal thermal analysis can be obtained by consulting literature reports, as shown in the following table.
  • thermal damage of corneal tissue is determined by the temperature and heating time of the tissue. According to Arrheniusequation, the thermal damage degree factor can be obtained as follows:
  • ⁇ (t) is the thermal injury degree factor of corneal tissue
  • the terahertz beam diameter is generally on the order of millimeters, and the smallest beam diameter under the focus of the commonly used terahertz lens is about 2 mm.
  • the diameter of the photocoagulation zone of laser keratoplasty is generally between 6.0 and 7.5 mm, so the selection range of the terahertz beam diameter is 2 to 8 mm.
  • the initial temperature of the cornea was set to 35 °C
  • the irradiation time was 1200 seconds
  • the finite element method was used to simulate and calculate the center position of the cornea surface in the high-power terahertz beam ( The working frequency of the simulation calculation is set to 1 THz, the beam diameter is 2 to 8 mm, and the power density is 1000 to 10000 W/m 2 )
  • the temperature increase under irradiation is shown in FIG. 2 of the specification. This results in a terahertz beam diameter of 2mm, 4mm, 5mm, 6mm and 8mm.
  • the terahertz beam can reach the power density range of safe photocoagulation temperature (55 ⁇ 75°C) and optimal operation temperature (65 ⁇ 70°C) , See Table 2 for details.
  • the analysis is made for the case where the terahertz beam diameter is 6.0 mm (the diameter of the photocoagulation area of laser corneal thermoplasty is generally between 6.0 and 7.5 mm).
  • the figure shows that, under the condition that the irradiation time and the beam diameter are fixed, the magnitude and speed of the corneal heating depends on the power density of the irradiated terahertz beam. The higher the terahertz beam power, the greater the corneal temperature increase and the faster the temperature increase.
  • the corneal temperature rise range is about 5 ⁇ 64 °C.
  • the temperature of the cornea rises sharply in the first 60 seconds, and the temperature rises gently in 60 to 180 seconds, and reaches a certain steady-state temperature value after 180 seconds (the temperature will not increase even under the long-term irradiation of the terahertz beam).
  • the optimal operation temperature of corneal thermoplasty is 65 ⁇ 70°C, and the terahertz heating of the cornea decreases from the surface to the endothelial surface, according to the heating curve, a terahertz beam with a power density of 4000 ⁇ 6000W/m 2 can Used for corneal thermoplasty, in particular, a terahertz beam of 6000 W/m 2 is preferably used for corneal thermoplasty.
  • the coagulation zone of the matrix (a region capable of degeneration) is estimated. Since the collagen tissue of the corneal stroma begins to contract and change its three-dimensional structure when continuing at 55°C, the area at a temperature of 55 to 75°C can be regarded as the stroma coagulation zone.
  • the gray area in the figure is the matrix solidification area estimated under the above simulation conditions.
  • a collagen-like degeneration zone with a cylindrical shape, a diameter of about 3000 ⁇ m, and a depth of 600 ⁇ m (up to the full cornea) is formed in the cornea along the terahertz propagation direction (corneal depth direction). Therefore, using the terahertz beam can achieve full-thickness and uniform corneal heating.
  • the thermal damage of the cornea under 1200 seconds of terahertz wave irradiation at a frequency of 1 THz, a beam diameter of 6 mm, and a power density of 6000 W/m 2 was also predicted.
  • the left picture shows the spatial distribution of the degree of corneal damage after 1200 seconds of heating.
  • thermal injury degree factor of corneal tissue there are generally the following views: when ⁇ (t) ⁇ 0.1, it can be considered as no thermal injury, which is an ideal situation; when 0.1 ⁇ (t) ⁇ 1, it is mild Thermal injury only causes undesirable reversible deformation of the corneal stroma; when ⁇ (t) ⁇ 1, it is a serious injury, which causes carbonization of the corneal stroma, resulting in irreversible necrosis and permanent destruction of the corneal tissue.
  • the center of the corneal surface is most damaged, and the thermal damage factor ⁇ reaches 0.16. The closer to the center of the corneal surface, the higher the degree of thermal damage, but it is a mild thermal injury.
  • thermal damage is also related to the amount of time accumulated, so the maximum acceptable heating time can be determined according to the time-dependent thermal damage at the center of the corneal surface (where the damage is most severe), and then Effectively avoid thermal damage to corneal tissue.
  • the time when the thermal damage factor ⁇ at the center of the corneal surface reaches 0.1 is about 720 seconds. Therefore, the longest heating time can be determined 720 seconds.
  • the cornea is optimally heated by a terahertz beam with a frequency of 1 THz, a beam diameter of 6 mm, and a power density of 6000 W/m 2 .
  • the time is 180 to 720 seconds.
  • the terahertz source is a heat source very suitable for corneal thermoplasty.
  • the terahertz heat source can be selected from currently available products such as gas lasers, quantum cascade lasers, and free electron lasers that can generate high-power terahertz radiation (0.1-10 THz).
  • this application proposes a terahertz corneal thermoforming system, as shown in FIG. 5 of the specification.
  • the system includes a high-power terahertz laser 1 and a matching collimating scanning module for generating and irradiating a terahertz beam to the human eye for surgery.
  • the laser 1 is a continuous laser with a frequency in the range of 0.1-10 THz.
  • the collimating scanning module includes a collimator composed of a first terahertz mirror 2 and a second terahertz mirror 3, a power adjustment section formed by a terahertz attenuator 4, and beam shaping and XY two-dimensional Scanned device.
  • the beam emitted by the continuous laser 1 is collimated by the first terahertz reflector 2 in the collimator to form parallel light, and the parallel light is split by a terahertz after passing through the terahertz attenuator 4
  • the mirror 5 splits the beam, one beam is received by the terahertz power meter 6 for power detection, and the other beam is reflected by the second terahertz mirror 3, and is realized by the XY two-dimensional galvanometer scanning system 7 with beam shaping function
  • the scanning of the light beam is finally irradiated onto the eyeball 9 after being reflected by the ITO beamsplitter 8 that reflects only the terahertz light beam and passes through the visible light.
  • the energy of the terahertz beam can be evenly distributed through beam shaping.
  • the scanning system 7 may be a general scanner, and a beam shaper is provided immediately after the scanning system 7.
  • a corneal marker suitable for the terahertz band can be provided after the above scanning system.
  • a metal sheet with a hole structure can be used to realize the corneal marker, and the size and shape of the aperture , Quantity, arrangement interval and other parameters are set to meet the needs in the photocoagulation area.
  • the system of the present application is also equipped with a high-resolution infrared thermal imager 10 and a cooling module on both sides of the eyeball 11.
  • the high-resolution infrared thermal imager 10 and the refrigeration module 11 together form a temperature monitoring and control unit, which helps to realize the prediction and control of the corneal temperature, and prevents the cornea from being heated too high and too fast during the surgery to cause thermal damage.
  • Infrared thermal imaging is an accurate, measurable, non-contact diagnostic technique.
  • the high-resolution infrared thermal imager 10 can use commercially available FLIR 655, FLIR T650, FLIR A6700, FLIR GF335, FLIR X8400 and other models to provide information on the spatial distribution of the corneal surface temperature. According to the previous simulation calculation, after the cornea is heated, the highest temperature is at the center of the terahertz beam on the cornea surface, and the temperature is attenuated in the direction of the beam radius. Based on the temperature profile, invisible terahertz beams can be detected and used for identification and target confirmation.
  • the cooling module 11 is, for example, a heat dissipation cooling module, which uses flowing air for cooling and cooling; or it can also use a small volume, light weight and easy to integrate plasma wind heat dissipation cooling, which uses the principle of ion discharge to generate air flow to achieve the cooling effect.
  • the distance between the cooling module 11 and the eyeball is between 5 cm and 15 cm.
  • the temperature monitoring control unit can also be combined with the monitoring results of the Ophthalmic Optical Coherence Tomography (OCT), corneal topography, and eyeball follower And feed back these monitoring result data to the computer control unit 20 to adjust the terahertz beam scanning mirror, so as to realize more precise control of the position of the terahertz beam in the corneal surgery during the operation.
  • Modules such as operating microscopes, ophthalmic optical coherence tomography (OCT), corneal topographs, and eyeball followers are equipped with light sources. After these light sources illuminate the eyeball 9, the light signal will be reflected from the eyeball 9.
  • a first beam splitter 12, a second beam splitter 13 and a third beam splitter 14 are provided in this order on the optical path of the eyeball 9 and the ITO beam splitter 8 after being reflected by the above optical signals to form a beam splitting system .
  • the first beam splitter 12 splits part of the light reflected by the eyeball to the operating microscope 15, and the operating staff can observe the entire surgical process through the operating microscope 15.
  • Ophthalmology OCT 16 is a mature instrument in the prior art. Ophthalmology OCT 16 can obtain corneal thickness information during the entire operation. In the system of the present application, the corneal thickness information obtained through the Ophthalmology OCT 16 is preferably fed back to the computer control unit 20 in real time. Specifically, Ophthalmology OCT can be used to monitor corneal thickness in real time. When the corneal thickness is less than 400 ⁇ m or greater than 700 ⁇ m, an early warning shutdown is required.
  • the size of the diameter according to the photocoagulation zone (region with a temperature greater than 55°C) can be observed in real time.
  • the contraction depth of the photocoagulation point can be obtained. Therefore, the thickness and temperature information can be corroborated with each other, and the two can be combined to evaluate the stromal coagulation area of corneal thermoforming surgery.
  • the scanning galvanometer is controlled to adjust the irradiation position of the terahertz beam, and the temperature of the cornea is controlled by using a corresponding cooling module.
  • the light beam reflected by the second beam splitter 13 and then reflected by the third beam splitter 14 will enter the corneal topograph 17 to detect the corneal topography and corneal diopter in real time.
  • a corneal topograph is used for monitoring, which can measure the corneal curvature in real time and reflect the morphological changes of the entire cornea.
  • the human eye can be roughly regarded as a complex concentric refractive system composed of multiple optical elements.
  • the light passes through the outer surface of the cornea, the corneal stroma, the inner surface of the cornea, the aqueous humor, and the anterior lens
  • the refractive effects of a series of media such as the surface lens matrix and nucleus, the posterior surface of the lens, and the vitreous body finally reach the retina for imaging.
  • the total refractive power of the eyeball is +58.64D
  • the refractive power of the cornea is +43.05D
  • the refractive power of the external corneal surface is 48.83D
  • the refractive power of the cornea accounts for 73.41% of the refractive power of the entire eyeball
  • the refractive power of the external corneal surface accounts for 83.27% of the refractive power of the entire eyeball .
  • the cornea is an important part of the refractive system of the eye, and the radius of curvature of the outer surface of the cornea plays a major role in the refractive power of the eye.
  • the effect of changing the refractive power can be evaluated based on the change in the radius of curvature of the outer surface of the cornea. For example, suppose the radius of curvature of the original outer surface of the cornea is r1. After the terahertz beam irradiates the cornea, the corneal contraction occurs according to the above-mentioned analysis of the corneal heat absorption characteristics, and the radius of curvature decreases to r2. When the radius of curvature changes from r1 to r2, its refractive power increases to ⁇ D, estimated as follows:
  • the light beam transmitted through the third beam splitter 14 and then reflected by the reflecting mirror 18 will be incident on the eyeball follower 19, which tracks and positions the pupil center of the eyeball.
  • the center of the pupil and the corneal surface temperature distribution map may be fused and registered to try to keep the pupil center mark coincident with the bright spot in the temperature distribution map.
  • the scanning system is controlled to adjust the irradiation position of the terahertz beam so that the center of the terahertz beam coincides with the center of the upper surface of the cornea.
  • the scanning system 7, high-resolution infrared thermal imager 10, cooling module 11, ophthalmology OCT 16, corneal topograph 17 and eyeball follower 19 are all connected to the computer control unit 20.
  • the detection results of high-resolution infrared thermal imager 10, ophthalmology OCT 16, corneal topograph 17 and eyeball follower 19 and other instruments are transmitted to the computer control unit, thereby monitoring the operation process in real time.
  • it can be automatically adjusted by the computer or manually by advanced users and staff to make appropriate adjustments to the terahertz heat source and temperature monitoring and control unit, so as to achieve the most optimal surgical effect and achieve the stability of the corneal thermoforming effect. It makes the postoperative refractive power and corneal deformation more stable, and effectively reduces the technical effect of postoperative corneal refractive regression.
  • the terahertz keratoplasty technology of the present application has been described above.
  • the terahertz keratoplasty system mainly includes a terahertz heat source, a temperature monitoring control unit, a corneal physiological parameter feedback, and a computer control unit.
  • the work of the system is realized by computer control.
  • the terahertz heat source unit realizes the energy adjustment, conditioning and scanning of the terahertz beam according to the feedback of the real-time monitoring parameters of the operation.
  • the temperature monitoring and control unit implements temperature monitoring and feedback control of the cornea to prevent thermal damage caused by excessive or rapid corneal temperature increase.
  • Each corneal physiological parameter feedback unit realizes the monitoring of eye state, corneal thickness, corneal refractive power, corneal topography and surgical process, which provides a basis for the optimization of surgical parameters.
  • the computer control unit adjusts the relevant parameters of the terahertz source according to the monitoring of the temperature monitoring control unit and each corneal physiological parameter feedback unit.
  • the user can also feedback the terahertz heat source, corneal temperature monitoring, and corneal physiological parameters according to the needs.
  • Each part of the unit performs corresponding operations to improve the stability of the corneal thermoforming effect as a whole and effectively reduce the incidence of corneal refractive regression after surgery.

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  • Laser Surgery Devices (AREA)

Abstract

L'invention concerne un système et un procédé de kératoplasmie thermique au térahertz. Spécifiquement, un laser térahertz (1) est utilisé comme source de chaleur, et un module de balayage à collimation correspondant est utilisé pour irradier un faisceau de lumière térahertz sur la cornée d'un globe oculaire (9). En outre, une unité de commande de surveillance de température est utilisée pour acquérir des informations de distribution d'espace de température de la cornée, et en référence aux informations de distribution d'espace de température de la cornée, le faisceau de lumière térahertz qui irradie la cornée est ajusté, ou la température de la cornée est directement ajustée. Pendant ce temps, un ou plusieurs éléments d'informations de surveillance chirurgicale, tels que des informations d'épaisseur de la cornée, des informations de dioptrie de la cornée, la topographie cornéenne et une position de centre de pupille du globe oculaire (9) sont acquises, et en référence aux informations de surveillance, le faisceau de lumière térahertz qui irradie la cornée est ajusté, ou la température de la cornée est directement ajustée. Une profondeur de réglage de chaleur et une uniformité de chauffage sont toutes deux manifestement améliorées en kératoplastie thermique, et l'apparition d'une régression de réfraction est efficacement réduite.
PCT/CN2019/123438 2018-12-18 2019-12-05 Système et procédé de kératoplasmie thermique au térahertz WO2020125435A1 (fr)

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CN201811550470.X 2018-12-18
CN201811550470.XA CN109481142B (zh) 2018-12-18 2018-12-18 一种太赫兹角膜热成形术系统和方法
CN201822129470.4U CN209474947U (zh) 2018-12-18 2018-12-18 一种太赫兹角膜热成形术系统
CN201822129470.4 2018-12-18

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