System and method for performing laser-assisted ophthalmic surgery using immersion solution

Abstract

This specification discloses a method for performing ophthalmic surgery. The surgery includes positioning a patient interface relative to the patient's eye, the patient interface defining at least partially an interface chamber together with the patient's eye. The interface chamber is filled with an immersion fluid. The fluid in the anterior chamber of the patient's eye is replaced with the immersion fluid, which matches the refractive index of the cornea. A laser system is positioned relative to the patient interface. The laser system includes a laser source configured to generate a femtosecond laser beam, and an optical delivery and scanner system communicating with the laser source to guide a three-dimensionally scanned and focused laser beam through the patient interface and into the patient's eye.

Description

[Technical Field]

[0001] The present disclosure relates to ophthalmic surgery and related systems and methods for performing laser-assisted ophthalmic surgery. [Background Art]

[0002] Ophthalmic procedures and systems for performing ophthalmic procedures contribute to improving patients' quality of life by enhancing their visual acuity. Ophthalmic systems may include a surgical laser for performing anterior segment procedures such as cataract procedures. These systems often include a patient interface for engaging and fixing a patient's eye during an ophthalmic procedure. Fixating the patient's eye during the ophthalmic procedure ensures the accuracy and success of the ophthalmic procedure. However, patient interfaces often produce corneal wrinkles that degrade the optical quality of the surgical laser beam. [Summary of the Invention] [Means for Solving the Problems]

[0003] Disclosed herein is a method of performing ophthalmic surgery. The surgery includes positioning a patient interface against a patient's eye, the patient interface at least partially defining an interface chamber with the patient's eye. The interface chamber is filled with an immersion fluid. Fluid in the anterior chamber of the patient's eye is replaced with the immersion fluid, the immersion fluid having a refractive index that matches the refractive index of the cornea of the patient's eye. A laser system is positioned relative to the patient interface. The laser system includes a laser light source configured to generate a femtosecond laser beam, and an optical delivery and scanner system in communication with the laser light source for guiding a three-dimensionally scanned and focused laser beam through the patient interface and into the patient's eye.

[0004] In one embodiment, the refractive index of the immersion fluid is between 1.37 and 1.40. The patient interface includes a suction ring for engaging with the eye and for removing any bubbles that may form in the immersion fluid. The patient interface includes a liquid interface housing extending from the suction ring and an inlet window that, together with the liquid interface housing, at least partially defines the interface chamber.

[0005] In some embodiments, the patient interface is positioned relative to the patient's eye by applying negative pressure to a suction ring on the patient interface. The immersion fluid may include Densiron-68, HWS-46-3000, or Oxane H.

[0006] In one embodiment, the ophthalmic surgery includes femtosecond laser-assisted cataract surgery (FLACS), and the replacement of the fluid in the anterior chamber of the patient's eye with an immersion fluid is performed through an opening in the cornea.

[0007] In one embodiment, the ophthalmic surgery includes femtosecond laser-adjusted intraocular lens (IOL) procedure.

[0008] In one embodiment, the ophthalmic surgery includes at least one of femtosecond retinal treatment, epiretinal membrane and internal limiting membrane surgery, dissection of retinal drusen, or cutting of vitreous traction sutures.

[0009] In one embodiment, the ophthalmic surgery includes a femtosecond laser-based airborne object removal procedure.

[0010] In one embodiment, the ophthalmic surgery includes laser-induced refractive index change (LIRIC) treatment or Perfect Lens treatment.

[0011] Representative embodiments of this disclosure are shown in the drawings as non-limiting examples and described in further detail below. However, it should be understood that novel embodiments of this disclosure are not limited to the specific forms shown in the drawings listed above. Rather, this disclosure encompasses, for example, modifications, equivalents, combinations, secondary combinations, rearrangements, groupings and alternative forms that fall within the scope of this disclosure, such as those covered in the accompanying claims. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 shows a schematic diagram of the laser system positioned relative to the patient's eye. [Figure 2] Figure 2 shows an enlarged cross-sectional view of a liquid patient interface positioned relative to the patient's eye using conventional technology. [Figure 3] Figure 3 shows a magnified cross-sectional view of the immersion solution patient interface positioned relative to the patient's eye. [Figure 4] Figure 4 shows the method for performing ophthalmic surgery. [Figure 5] Figure 5 shows another exemplary method for performing femtosecond laser-assisted cataract surgery. [Modes for carrying out the invention]

[0013] The features described above and other features of this disclosure will become clearer in more detail when the following description and the attached claims are read in conjunction with the attached drawings.

[0014] Embodiments of the present disclosure are described herein. However, it should be understood that the embodiments disclosed are merely illustrative and that other embodiments may take various alternative forms. The drawings are not necessarily to scale. Some features may be exaggerated or minimized to illustrate the details of certain components. Accordingly, certain structural and functional details disclosed herein should not be constrained, but rather should be interpreted as representative grounds to teach those skilled in the art how to employ the present disclosure in various ways.

[0015] As those skilled in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features shown in one or more other figures to create embodiments not explicitly illustrated or described. The illustrated combinations of features provide representative embodiments for typical applications. However, various combinations and modifications of features consistent with the teachings of this disclosure may be desirable for specific applications or implementations.

[0016] In the following explanation, certain terms may be used for reference purposes only and are therefore not intended to be limiting. For example, terms such as “up” and “down” refer to directions within the referenced drawings. Terms such as “front,” “rear,” “forward,” “backward,” “left,” “right,” “rear,” and “side” describe the orientation and / or position of a component or part of an element within an arbitrary reference frame, which will become clear by referring to the text and related drawings describing the component or element being discussed. Furthermore, terms such as “first,” “second,” and “third” may be used to describe separate components. Such terms may include the terms specifically mentioned above, their derivatives, and terms with similar meanings.

[0017] Figure 1 shows a schematic diagram of a laser system 100, such as a pulsed laser system positioned relative to an eye 20. The laser system 100 may be a separate surgical tool or part of a larger ophthalmic surgical system. The larger ophthalmic surgical system may include other laser systems, patient or eye positioning systems, observation systems, or any combination thereof. In particular, the laser system 100 may be part of a surgical set designed to provide substantially all of the computer-aided devices necessary to perform surgery on a given eye.

[0018] The laser system 100 includes a laser light source 102 that generates a laser beam, such as a laser beam 104. The laser beam 104 may include a laser beam from a femtosecond laser. The laser system 100 may include an optical delivery and scanner system 106 for controlling a three-dimensionally scanned and focused laser beam 108 during surgery on a patient's eye 20 (Figures 2-3). The system 106 provides lateral control axes (X and Y axes) and a longitudinal control axis (Z axis) for the three-dimensionally scanned and focused laser beam 108. "Lateral" refers to a direction perpendicular to the propagation direction of the laser beam 104. "Longer" refers to the propagation direction of the laser beam 104. The scanner 106 may be a three-dimensional scanner.

[0019] Although the laser system 100 in Figure 1 does not show various other irradiation control components, system 106 may use a longitudinal control element to longitudinally control the three-dimensional scanned and focused laser beam 108. For example, the longitudinal control element may include a lens adjustable in the longitudinal direction. Alternatively, the longitudinal control element may include a variable refractive power lens. Alternatively, the longitudinal control element may also include a deformable mirror. Furthermore, system 106 may include two or more transverse control elements, two or more longitudinal control elements, or two or more of both. In addition, the transverse and longitudinal control elements may be separate devices. Although system 106 shown in Figure 1 is shown as a single component, such a configuration is presented for illustrative purposes only. Embodiments of this disclosure may be configured to include multiple scanners (scanner systems) to enable more precise control of the three-dimensional scanned and focused laser beam 108.

[0020] The laser light source 102 and the system 106 are controlled by a computer controller 110. For example, the computer controller 110 can control which wavelength of laser beam 104 is generated from the laser light source 102. For example, the computer controller 110 can configure the laser light source 102 to generate a femtosecond laser 104. Additionally, the computer controller 110 can control the system 106 to change the three-dimensional scanning and the movement of the focused laser beam 108.

[0021] The computer controller 110 includes at least processing resources capable of executing code that generates instructions for controlling the operation of the laser 102. The computer controller 110 may communicate physically or wirelessly with the laser light source 102 and the system 106. The computer controller 110 may further include a memory, particularly a memory for storing instructions for the processing resources, a communication module for communicating with the laser light source 102 and the system 106, and other components.

[0022] In FIG. 1, not all possible components of the pulsed laser system 100 are necessarily shown for brevity. For example, the laser system 100 may include various components for guiding, focusing or otherwise manipulating a laser beam, such as scanners, mirrors, beam expanders or lenses. The laser system 100 may further include a housing and other devices for protecting and arranging the components thereof, and patient interface peripherals that may be disposable.

[0023] FIGS. 2 to 3 show the propagation of the scanned and focused laser beam through a liquid interface with or without refractive index matching immersion. For clarity, the illustration is based on a parallel laser beam 108. A person skilled in the art can understand how immersion functions in the case of a focused laser beam 108.

[0024] Figures 2 and 3 show in more detail the patient interface 200 positioned relative to the eye 20. The patient interface 200 includes, for example, a suction ring 202 that fits onto the outer surface of the eye 20 together with a suction portion. The suction portion may be coupled to a vacuum or suction supply unit 204 to apply vacuum or negative pressure to expel air from the suction chamber 206 and to secure the patient interface 200 relative to the eye 20. The fluid interface housing 208 extends outward from the suction ring 202 relative to the eye 20. In the illustrated example, the fluid interface housing 208 is sealed to the suction ring 202 and has a cylindrical outer shape. The fluid interface housing 208 may be a single, integrated part with the suction ring 202, or the fluid interface housing 208 may be attached to a housing.

[0025] The inlet window 210 is located within the interface housing 208 and is spaced apart from the suction ring 202. In one example, the inlet window 210 is removablely attached to the interface housing 208 to allow the insertion of immersion fluid 214 into the interface chamber 212. The inlet window 210 is made of a transparent material that allows a scanned and focused laser beam 108 to pass through the inlet window 210 and enter the eye 20. In the illustrated example, the interface chamber 212 is at least partially defined by a portion of the patient's eye 20, the suction ring 202, the interface housing 208, and the inlet window 210.

[0026] The anterior chamber 24 is normally filled with aqueous humor, as shown in Figure 2. However, in this disclosure, the aqueous humor in the anterior chamber 24 is replaced with an immersion fluid 214, which is also located in the interface chamber 212, as shown in Figure 3.

[0027] The refractive index of the immersion fluid 214 closely matches the refractive index of the patient's cornea 22. Such an interface, which is the subject of this disclosure, is called an Immersion Patient Interface (ILFPI). In one example where the refractive index closely matches, the refractive index of the immersion fluid 214 is between 1.36 and 1.40. In another example, the refractive index of the immersion fluid 214 is between 1.37 and 1.40. Exemplary immersion fluids 214 may include Densiron-68, HWS-46-3000, or Oxane H. However, other immersion fluids 214 that closely match the refractive index of the cornea 22 may also be used.

[0028] When the patient interface 200 is attached to the eye 20, the force applied from the suction ring 202 may cause wrinkles 22w in the cornea 22. The wrinkles 22w typically have different shapes on the anterior side 22A and the posterior side 22P of the cornea 22.

[0029] In the currently used procedure shown in Figure 2, the interface chamber 212 is filled with either equilibrium salt solution (BSS) or, more likely, water. The refractive index η of aqueous humor, water, or BSS is 1.336. The refractive index η of the cornea 22 is 1.376. Therefore, the difference in refractive index η between BSS, aqueous humor, or water and the cornea 22 is Δη = 0.04.

[0030] Assume that wrinkles 22w cause a change in corneal thickness δ = 5 μm. These changes are difficult to detect even with optical coherence tomography (OCT), if not impossible. Therefore, surgeons cannot gain knowledge of the presence of wrinkles 22W. Wrinkles 22W can cause optical aberrations with a phase error ΔΦ of the laser beam 104 when the scanned and focused beam 108 passes through the corneal 22 and enters either BSS fluid, aqueous humor, or water. Equation 1 below is used to calculate the phase error of the laser beam 104. Δφ = 2 * π * δ * Δη / λ Equation 1

[0031] Assuming the laser wavelength of the laser beam is λ = 1.035 μm, which is a typical wavelength for a femtosecond laser, the phase error (Equation 1) is Δφ = 2*p*d*Dη / l = 2*p*5 mm * 0.04 / 1.035 mm = 1.214 radians. The phase error causes an aberration, which broadens the focal region, and therefore the intensity of the scanned and focused laser beam 108 at the focal point decreases by a factor of the Strehr ratio S compared to the intensity of a beam without aberration. The Strehr ratio can be calculated as shown in Equation 2 below. S = exp - (ΔΦ) 2 formula 2

[0032] Using the two equations above, the optical aberration caused by the 5 μm wrinkle 22w with BSS, aqueous humor, or water reduces the intensity of the scanned and focused laser beam 108 at the focal point of the optical delivery system 106 from 100% to 22.9%, as shown in Equation 3 below. S = exp - DF 2 =exp-(1.214) 2 =0.229=22.9% Equation 3

[0033] During surgery or other treatments, a decrease in intensity can be compensated for by using a higher laser pulse energy of approximately 1 / s times, however, increasing the laser pulse energy may result in clinical disadvantages. Controlling the elevation d of wrinkles 22W in the cornea 22 on this scale is virtually impossible. Wrinkles 22W also vary from patient to patient and can vary even with docking in the same patient. Wrinkles 22W also occur and change during laser treatment due to minimal lateral movement of the patient's head or eye 20.

[0034] However, the Strehr ratio can be significantly improved by using the immersion solution in the anterior chamber 24 of eye 20 and the interface chamber 212 of ILFPI 208. Table 1 below shows the Strehr ratios calculated for different immersion solutions, assuming the same 1.035 mm laser wavelength and d=5 mm corneal thickness error for clinically available ophthalmic tapnades.

[0035] [Table 1]

[0036] As shown in Table 1 above, by decreasing the refractive index difference Dh, the Strehr ratio approaches the maximum possible Strehr ratio of 1. For example, by filling the anterior chamber 24 and the interface chamber 212 of ILFPI 208 with HWS 46-3000, which has a refractive index of 1.37, the Strehr ratio is 0.967. This should be compared to the Strehr ratio of S=0.229 when using BSS or aqueous humor. This shows how the focal intensity increases by 0.967 / 0.229=4.24 times by using the immersion solution HWS 46-3000.

[0037] Figure 4 shows a method 300 for performing laser-assisted ophthalmic surgery to reduce the formation of optical aberration 108A. Method 300 includes replacing the aqueous humor in the anterior chamber 24 of the eye 20 with an immersion fluid 214, such as one of the immersion fluids specified above, which closely matches the refractive index of the cornea (block 302). The replacement can be performed using a syringe or through an opening in the cornea 22. In some embodiments, the immersion fluid that matches or more closely matches the refractive index of the cornea may include an immersion fluid having a refractive index within a threshold of the refractive index of the cornea. The threshold may include refractive index differences of less than 0.04, less than 0.03, less than 0.02, less than 0.01, 0.04 to 0.00, 0.03 to 0.010, or any other range using any of the aforementioned values ​​as the endpoint.

[0038] The patient interface 200 is docked to the patient's eye 20 (block 304). The vacuum source 204 is activated so that the suction ring 202 on the patient interface 200 clamps to the cornea 22 of the patient's eye 20 (block 306). The patient interface 200 is configured to at least partially form an interface chamber 212 with the patient's eye 20 to be filled with immersion fluid 214 adjacent to the cornea 22 (block 308).

[0039] The laser system 100 is docked to the patient interface 200 (block 310) to perform laser-assisted surgical procedures (block 312). In the illustrated example, the laser system 100 includes a laser source configured to generate a femtosecond laser beam and a focusing lens that optically communicates with the laser source to direct the laser beam into the patient's eye 20 through the patient interface 200.

[0040] Exemplary surgical procedures for utilizing Method 300 include femtosecond laser-adjustable intraocular lens (IOL) procedures such as laser-induced refractive index change (LIRIC) or Perfect Lens treatment. One feature of utilizing IOLs such as phototunable lenses (LALs) is the ability to fine-tune the refractive properties of the lens after it has been surgically implanted in the eye 20. In particular, the refractive properties of an LAL can be adjusted by exposing the lens to a femtosecond laser. This makes it possible to adjust the refractive properties of the LAL after it has been implanted for a certain period of time to result in further improvement of visual acuity. One feature of the reduction of laser optical aberration 108A from Method 300 is the improved precision of the laser beam 104 when adjusting the refractive properties of the LAL. This results in further improvement of the patient's visual acuity.

[0041] Another exemplary surgical procedure utilizing Method 300 includes retinal microsurgery using femtosecond laser pulses. Retinal microsurgery may include cutting vitreous traction sutures fixed to the retina. These sutures can detach from the retina during age-related vitreous detachment.

[0042] Other exemplary surgical procedures utilizing Method 300 include epiretinal membrane and internal limiting membrane surgery or optogenetic retinal treatment to treat AMD (age-related macular degeneration), retinitis pigmentosa, and other retinal diseases.

[0043] Another exemplary surgical procedure utilizing Method 300 involves the breakdown of retinal drusen. Drusens are lipid and protein deposits that develop in the retina during the early stages of AMD.

[0044] Another exemplary ophthalmic surgical procedure utilizing Method 300 involves femtosecond laser-based vitreous floaters removal. Floaters include clumps of collagen protein that form in the vitreous humor, casting moving shadows onto the retina. In ophthalmic laser surgery, a surgeon may direct a laser beam into the vitreous humor of the eye 20 to treat floaters. Floaters are clumps of collagen protein that form in the vitreous humor. These clumps can obstruct vision by creating moving shadows and distortions. A laser beam may be used to break down the floaters to improve vision. Method 300 improves the precision of the laser beam targeting the floaters to improve fragmentation.

[0045] At the point when the surgical procedure is completed in block 312, the immersion fluid in the anterior chamber 24 is replaced with BSS (block 314).

[0046] Figure 5 shows a method 400 for performing femtosecond laser-assisted cataract surgery (FLACS) to reduce the formation of optical aberration 108A. Method 400 includes replacing the aqueous humor in the anterior chamber 24 of the eye 20 with an immersion fluid 214, such as one of the immersion fluids specified above, which precisely matches the refractive index of the cornea (block 402). The replacement can be performed using a syringe or through an opening in the cornea 22.

[0047] The patient interface 200 is docked to the patient's eye 20 (block 404). The vacuum source 204 is activated so that the suction ring 202 on the patient interface 200 clamps to the cornea 22 of the patient's eye 20 (block 406). The patient interface 200 is configured to at least partially form an interface chamber 212 with the patient's eye 20 to be filled with immersion fluid 214 adjacent to the cornea 22 (block 408).

[0048] The laser system 100 is docked to the patient interface 200 (block 410) to perform the FLACS procedure (block 412). In the illustrated example, the laser system 100 includes a laser source configured to generate a femtosecond laser beam and a focusing lens that optically communicates with the laser source to direct the laser beam into the patient's eye 20 through the patient interface 200. The FLACS procedure includes laser capsulotomy, lens fragmentation using a femtosecond laser, filling the anterior chamber 24 with a viscoelastic material (i.e., replacing the immersion fluid 214 in the anterior chamber 24 with the viscoelastic material), removing the detached capsule, phacoemulsification and aspiration of the lens, removal of lens fragments, cleaning the capsule, and implanting an IOL in place of the lens 26. Next, in block 414, the viscoelastic material in the anterior chamber 24 is replaced with BSS.

[0049] The surgical procedures identified above for methods 300 and 400 are based on four-photon laser tissue interaction. Four-photon interaction means that the process yield is proportional to the fourth exponent of the laser intensity at the focal point, i.e., the fourth exponent of the Strehr ratio. When BSS is used in the anterior chamber 24 and in the immersion chamber 214 of the patient interface 200, the Strehr ratio is 0.229. This results in a yield of 0.229 for the four-photon initial step compared to the case of an error-free optical delivery system where S=1. 4 =0.00275 times lower, and 0.967 for ILFPI using HWS 46-3000 immersion solution. 4 = 0.87. These numerical examples clearly demonstrate the importance of a well-matched immersion interface.

[0050] While the detailed description and drawings support and illustrate this disclosure, the scope of this disclosure is defined solely by the claims. Although several best modes and other embodiments for carrying out the claimed disclosure have been described in detail, various alternative designs and embodiments exist for carrying out the disclosure as defined in the appended claims.

[0051] Furthermore, the features of the embodiments shown in the drawings or the various embodiments referred to herein should not necessarily be understood as independent embodiments. Rather, each of the characteristics described in one example of an embodiment may be combined with one or more other desirable characteristics from other embodiments, resulting in other embodiments that are not described in language or not described by reference to the drawings. Thus, such other embodiments are included within the framework of the appended claims.

Claims

1. A method for performing ophthalmic surgery, Positioning a patient interface relative to the patient's eye, wherein the patient interface is positioned such that it at least partially defines the interface chamber together with the patient's eye. Filling the interface chamber with immersion fluid, Replacing the fluid in the anterior chamber of the patient's eye with the immersion fluid, wherein the immersion fluid has a refractive index that matches the refractive index of the cornea of ​​the patient's eye. Positioning the laser system relative to the patient interface, the laser system is A laser light source configured to generate a femtosecond laser beam, A light delivery and scanner system communicating with the laser light source to guide a three-dimensionally scanned and focused laser beam through the patient interface and into the patient's eye. Including positioning and A method that includes this.

2. The method according to claim 1, wherein the refractive index of the immersion fluid is 1.37 or more and 1.40 or less.

3. The method according to claim 1, wherein the patient interface engages with the patient's eye and includes a suction ring for removing any bubbles that may form in the immersion fluid.

4. The method according to claim 3, wherein the patient interface includes a liquid interface housing extending from the suction ring.

5. The method according to claim 4, wherein the patient interface includes an inlet window that, together with the liquid interface housing, at least partially defines the interface chamber.

6. The method according to claim 1, wherein positioning the patient interface relative to the patient's eye includes applying negative pressure to a suction ring on the patient interface.

7. The method according to claim 1, wherein the immersion fluid comprises Densiron-68.

8. The method according to claim 1, wherein the immersion fluid includes HWS-46-3000.

9. The method according to claim 1, wherein the immersion fluid comprises Oxane H.

10. The method according to claim 1, wherein the ophthalmic surgery includes femtosecond laser-assisted cataract surgery (FLACS).

11. The method according to claim 10, wherein the replacement of the fluid in the anterior chamber of the patient's eye with the immersion fluid is performed through an opening in the cornea.

12. The method according to claim 1, wherein the ophthalmic surgery includes femtosecond laser-adjusted intraocular lens (IOL) treatment.

13. The method according to claim 1, wherein the ophthalmic surgery comprises at least one of a femtosecond retinal treatment, epiretinal membrane and internal limiting membrane surgery, dissection of retinal drusen, or cutting of vitreous traction sutures.

14. The method according to claim 1, wherein the ophthalmic surgery includes a femtosecond laser-based airborne object removal procedure.

15. The method according to claim 1, wherein the ophthalmic surgery includes laser-induced refractive index change (LIRIC) treatment or Perfect Lens treatment.

16. A system for performing ophthalmic surgery, A patient interface for attachment to a patient's eye, comprising a patient interface that at least partially defines an interface chamber, An immersion fluid for filling the interface chamber and the anterior chamber of the eye, the immersion fluid having a refractive index of 1.36 or more and 1.40 or less, A laser system that can be positioned relative to the patient interface, A laser light source configured to generate a femtosecond laser beam, A focusing lens that is in optical communication with the laser light source in order to guide the laser beam through the patient interface and into the eye of the patient. Laser systems including A system that includes this.

17. The system according to claim 16, wherein the patient interface includes a suction ring for engaging with the patient's eye, a liquid interface housing extending from the suction ring, and an inlet window that together with the liquid interface housing at least partially defines the interface chamber.

18. The system according to claim 17, wherein the ophthalmic surgery includes femtosecond laser-assisted cataract surgery (FLACS).

19. The system according to claim 16, wherein the ophthalmic surgery includes femtosecond laser-adjusted intraocular lens (IOL) procedure.

20. The system according to claim 16, wherein positioning the patient interface relative to the patient's eye includes applying negative pressure to a suction ring on the patient interface.

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