Device for laser vitreous dissolution

Abstract

This invention relates to an apparatus for laser treatment of vitreous opacities. According to the invention, the apparatus for laser vitreolysis of the eye comprises an OCDR system, a laser system with a deflection unit, optical elements for coupling the OCDR system and the laser system, a display unit, and a central control and operation unit. The OCDR system is designed to locate the floater along its optical axis, the laser system is designed to destroy the floater with laser pulses, and the central control and operation unit is designed to focus and activate the laser system on the floater, particularly when the laser focal length and the floater's position are sufficiently aligned. This invention relates to an apparatus for gentle, low-risk, and painless laser treatment of vitreous opacities, which particularly allows for partially or fully automated treatment.

Description

Technical Field

[0001] This invention relates to an apparatus for laser treatment of vitreous opacities. Background Technology

[0002] The vitreous humor is a normally transparent, gel-like substance located inside the eye between the lens and the retina. In youth, the vitreous humor is completely transparent and in contact with the retina. During life, the vitreous humor liquefies and gradually separates from the retina. This is called posterior vitreous detachment. This is a normal aging process and usually occurs after age 50. The detached portions of vitreous humor accumulate inside the eye, and the skeletal material and thickened vitreous humor are visible to the patient. Because they can also move in the field of vision, they are also called floaters. Usually, floaters are formed because a membranous structure is present on the posterior side of the vitreous humor after detachment, and sometimes even blood may remain if retinal damage has occurred during the detachment. In rare cases, when metabolism is impaired, floaters can also appear in the vitreous humor as crystalline deposits.

[0003] Even though floating objects usually have no pathological cause, they are not as harmless as commonly believed, as they can sometimes significantly impair the quality of life and work efficiency of those affected.

[0004] This cloudiness is particularly noticeable against bright backgrounds, such as when working at a computer, reading, or looking at a blue sky or snowy landscape, and it interferes with visual function. When reading, objects that slip into or out of the central field of vision due to reading motion can be especially distracting.

[0005] Because floaters are typically perceived as “flying mosquitoes,” they are described using the technical term “mouches-Volantes” (from French). However, opacities can also take other forms, such as branching, ring-shaped, or star-shaped, or appear as dot-like clouds. In the following text, the term “floaters” is used for vitreous opacities to be treated, regardless of their type or form.

[0006] Generally, floaters do not disappear without treatment because the immune system does not recognize them as abnormal and therefore does not eliminate them. Affected individuals can hardly ignore or disregard these floaters. Certain types of floaters, such as those caused by residual blood after retinal hemorrhage, can be partially reabsorbed by the body, although this usually takes weeks or months.

[0007] In a so-called vitrectomy, after opening the eye with cutting instruments, the vitreous humor is partially or completely shattered, aspirated, and removed (in a core vitrectomy). This intervention is typically performed in cases of retinal detachment or epiretinal membrane peeling, but is generally considered a disproportionate treatment for removing the vitreous opacity described. Furthermore, vitrectomy is invasive, requires a clinic stay, and carries inherent risks associated with the surgical intervention, particularly frequent induction of cataracts, less common retinal detachment, and, very rarely, endophthalmitis.

[0008] A low-risk alternative treatment is now available with the help of so-called laser vitreolysis. Laser vitreolysis is a gentle, low-risk, and painless laser treatment that atomizes or evaporates vitreous opacities without opening the eye.

[0009] In laser vitreolysis, short laser pulses are aimed at the vitreous opacities, where optical breakdown or photodestruction is achieved due to the high laser intensity in the focal region. The floaters and the surrounding vitreous absorb the laser energy, forming a cutting or expanding laser plasma that causes the floaters to evaporate and / or shatter and thus dissolve. The treatment is minimally painful and carries no risk of infection. Laser vitreolysis offers a safe and gentle method for treating disturbing vitreous opacities if important and sensitive eye structures, such as the capsule, lens, or retinal area, especially the macula, can be protected from laser damage.

[0010] Of course, the success of treatment depends on the type of floaters. Treatment is particularly successful in cases of so-called Weiss rings. Tissue chains can be severed, and tissue thickening that causes interfering shadows can be eliminated.

[0011] Over the past thirty years, (Authors Brasse, K., Schmitz-Valckenberg, S., Jünemann, A. et al. Ophthalmologe (Ophthalmology) (2019) 116: 73.) https: / / doi.org / 10.1007 / s00347-018-0782-1YAG lasers (e.g., Nd:YAG at 1064nm) have been used to treat floaters, but the prevalence of this laser treatment is significantly lower than known laser cataract treatments that use frequency-doubled YAG lasers (532nm) to remove cell growth on the back of the IOL, or retinal treatments used for localized coagulation of retinal locations, such as in diabetic retinopathy, or also for fixing and stabilizing detached retinal areas or for protective repositioning of retinal holes (micro-holes). Depending on the desired depth of penetration into the retina (green for treatments near the surface; yellow and red for deeper or pigmented retinal layers; IR for the choroid), red and yellow laser versions are also used for retinal treatment (VISULAS Trion) in addition to the green laser version. The lower prevalence of laser vitreolysis is mainly due to the uncertainty regarding potential damage to the retina, lens, or capsular bag caused by the treatment laser, and the rather time-consuming manual treatment itself. Therefore, laser vitreolysis has to date been primarily performed by ophthalmologists with extensive experience in this field.

[0012] Examples of laser systems used for laser vitreous dissolution include the MERIDIAN Microruptor II, the Laserex LQP4106 laser, and the Ellex Ultra-Q-Reflex.

[0013] Based on known existing technologies, there are already numerous solutions available for laser surgery on eye tissues, especially the vitreous body.

[0014] Therefore, DE 10 2011 103 181 A1 describes an apparatus and method for performing femtosecond laser surgery on tissues, particularly the vitreous humor of the eye. The apparatus consists of an ultrashort pulse laser having a pulse length in the range of approximately 10 fs to 1 ps, particularly approximately 300 fs, a pulse energy in the range of approximately 5 nJ to 5 µJ, particularly approximately 1 to 2 µJ, and a pulse repetition frequency in the range of approximately 10 kHz to 10 MHz, particularly 500 kHz. The laser system is coupled to a scanning system that enables spatial variation of the focal point in three dimensions. In addition to the optical system of this therapeutic laser scanner, the apparatus also comprises a navigation system coupled thereto.

[0015] US 2006 / 195076 A1 describes systems and methods for creating incisions at different depths in ocular tissues. These systems and methods enable the focusing of light energy in a pattern onto different focal points located at different depths within the ocular tissues. Multiple focal points can be created simultaneously using segmented lenses. Optimal incisions can be achieved by sequentially or simultaneously focusing light at different depths, producing a broadened column of plasma and a beam with an extended waist. Furthermore, the techniques described herein can also be used to perform novel ophthalmic methods or improve existing methods, including the anatomy of tissues in the posterior pole, such as floaters, membranes, and the retina.

[0016] US 2014 / 257257 A1 also describes a system and method for treating target tissue in the vitreous humor of the eye, the system comprising a laser unit for generating a laser beam and a detector for generating an image of the target tissue. The system also includes a computer that defines a focal spot path for emulsifying the target tissue. A comparator connected to the computer then controls the laser unit to move the focus of the laser beam. This focus movement is performed to treat the target tissue while minimizing deviation of the focus from the defined focal path.

[0017] US 2015 / 342782 A1 also relates to systems and methods for performing partial vitrectomy of the vitreous body in the eye using a computer-controlled laser system. In the surgery, an optical channel is first defined through the vitreous body. Then, glassy and suspended deposits (flocculents) in the optical channel are ablated and, in some cases, removed from the optical channel (e.g., by aspiration). In some cases, a transparent liquid can be introduced into the optical channel to replace the ablated material, thereby creating unobstructed transparency within the optical channel. Generally, the present invention relates to systems and methods for ophthalmic laser surgery. In particular, the present invention relates to systems and methods for removing so-called floaters using pulsed laser beams.

[0018] US 2018 / 028354 A1 also describes methods and systems for performing ophthalmic interventions at the eye. Undesirable features are identified based on an image of at least a portion of the eye. Vitreous opacities that impair vision, such as floaters, are considered undesirable features within the vitreous cavity. After identification and location of the floaters, they are aimed at by a physician and manually “shot” with a laser pulse. The laser energy evaporates at least a portion of the vitreous opacity. This process is repeated until the vitreous opacity is eliminated. The entire process is repeated for each opacity in the vitreous until the vitreous fluid is considered sufficiently clear.

[0019] The method described by ELLEX (Ellex Medical Pty Ltd. product brochure; "TangoReflex–Laser Floater Treatment"; PB0025B; 2018;) http: / / www.ellex.com This approach proposes using a pulsed nanosecond laser (YAG) to completely eliminate vitreous opacities by breaking them down or converting them into gas. A guide laser beam is aimed at the target area (floating matter), and then "shot" with one or more therapeutic laser pulses. Both the guide laser beam and the therapeutic laser pulses are manually triggered by the user. This manual laser treatment typically consists of two separate treatments lasting 20 to 60 minutes each.

[0020] The use of laser energy within the scope of laser vitreolysis is non-invasive and avoids the disadvantages of surgical intervention, but it is also associated with disadvantages or risks.

[0021] Therefore, aiming the laser is difficult. Because doctors are observing the vitreous humor along the beam path, it is difficult to determine the depth of the retina, the depth of the vitreous opacity, or other relevant features. As a result, there is a risk of missing vitreous opacities and / or eye injury.

[0022] In particular, treatment of most transparent floaters is difficult due to their variable and difficult-to-identify locations, and despite this, the floaters, as phase objects, can produce interfering shadows on the retina.

[0023] The application of laser energy can also cause additional movement of the vitreous opacity, making treatment more difficult. Therefore, doctors must re-align the laser after each application of energy, which takes a significant amount of time. Thus, laser-based treatments are costly and burdensome for both patients and doctors.

[0024] Another possible problem is incomplete posterior vitreous detachment, which can lead to localized vitreous traction and eventually retinal detachment. Laser treatment within the vitreous can alter the force relationships within the vitreous through the propagating shock waves, thereby causing tension, for example, at the retina.

[0025] Finally, treating such floaters located near sensitive structures of the eye proves particularly difficult. Here, laser radiation can cause damage to the retina (especially the macula), lens, or capsule. Sensitive areas can also be areas surrounding vitreous traction—regions where incompletely separated vitreous tissue exerts tension on the retina, which carries the risk of retinal tears under mechanical stress. For example, in OCT (optical coherence tomography), such areas can be identified by localized, apical anterior detachments within the retinal lamina. Summary of the Invention

[0026] The objective of this invention is to develop a laser treatment solution for vitreous opacities that overcomes the drawbacks of known technological solutions. This solution should allow for simpler, faster, and particularly safer treatment of intrusive vitreous opacities via laser vitreolysis. Furthermore, the solution should be easy to implement and cost-effective, ideally requiring only minor adaptations to current laser treatment methods.

[0027] The objective is achieved by means of the proposed device for laser vitreous dissolution, which comprises an OCDR (Optical Coherence Domain Reflectometer) system, a laser system with a deflection unit, optical elements for coupling the OCDR system and the laser system, a display unit, and a central control and operation unit. The OCDR system is designed to locate the position of the floating object along the optical axis of the OCDR system, the laser system is designed to destroy the floating object by means of laser pulses, and the central control and operation unit is designed to focus the laser system onto the position of the floating object and activate it, especially when the laser focal length and the position of the floating object are sufficiently aligned.

[0028] Here, the term OCDR (Optical Coherence Domain Reflectometer) refers to the general method of determining the location or spacing of scattering structures in the eye in an interferometric manner.

[0029] Here, the OFDR (Optical Frequency Domain Reflectometer) method is particularly preferred, and the so-called scanning source OFDR method as described in DE1020080632252, the entire contents of which are incorporated herein by reference. Implementations as SD (spectral domain) OCDR based on a spectrometer or as TD (time domain) OCDR are feasible but not preferred.

[0030] In this regard, it is particularly advantageous that the measurement beam and laser beam of the OCDR system are collinearly superimposed, have the same or nearly the same wavelength, and are focused in the same or nearly the same manner. When using other wavelengths of the OCDR system, such as approximately 780-840 nm or 1320 nm, compared to the 1064 nm YAG laser wavelength, it is necessary and permissible to align the OCDR system's measurement signal with the focal position of the YAG laser in terms of the location of the retina and posterior capsule. This calibration can be performed beforehand using artificial eye testing.

[0031] Preferably, the OCDR system operates at a wavelength of 1060 nm and can generate an A-scan in tissue at a frequency of at least 100 Hz, more preferably 1 kHz to 10 kHz, with an axial measurement resolution of at least the entire eye length (ideally up to 30 or 40 mm in tissue) and preferably 20 µm, more preferably 10 µm or 5 µm.

[0032] More preferably, the system is designed to: evaluate this A-scan at approximately the same frequency and determine the location of eye structures (cornea, lens, retina) and possible floaters with a small delay of approximately a few milliseconds (less than 100 ms, ideally less than 20 ms, less than 10 ms, or even less than 5 ms), and trigger the laser if safety criteria are met. For example, the safety criteria could be a minimum distance from sensitive eye structures. This distance can be related to the type of eye structure, for example, greater in the case of a sensitive macula than in less sensitive or critical peripheral retinal areas. The minimum distance should be specifically designed so that the plasma effects of cutting, evaporation, or atomization, acoustic shock waves, and thermal tissue coagulation do not alter the tissue, or only alter the tissue to an acceptable degree. An exemplary minimum distance of the laser focus from the macula for a 1064 nm YAG laser could be, for example, 2-3 mm, and from the capsule and peripheral retinal areas, 1.5-2 mm. This also enables: temporarily moving floaters from sensitive areas (premacula) to, for example, areas before the peripheral retina by eye movement, or atomizing them there using the rapid laser vitreolysis according to the invention.

[0033] Here, the minimum spacing can also be related to the laser energy used, the number of pulses (blast), the pigmentation state of the retina, the state of the lens (natural lens or IOL), or the changeable focal length.

[0034] In particular, it is also feasible for doctors to define prohibited or treated areas manually, for example, by using cursor lines in the OCDR view.

[0035] According to the present invention, a focusing unit is also provided, which can set the laser focus on the detected floating object or scan the floating object with the laser focus. With the solution according to the present invention, focusing can be performed quickly (e.g., in a scanning or tracking manner), that is, in several 10ms to 100ms, but it can also be performed manually and slowly while maintaining high precision in laser processing of the floating object.

[0036] According to another design, the central control and operation unit is designed to automatically trigger within a time of less than 50ms, better less than 20ms, preferably only less than 10ms, and especially preferably less than 5ms, taking into account the derived treatment exclusion criteria.

[0037] Advantageous design schemes involve a central control and operation unit that is specifically designed to determine, in addition to determining the position of the located floater, the distance between the floater and the eye structures, and to derive the exclusion criteria for treatment.

[0038] Advantageously, the central control and operation unit is able to identify changes in the eye structures closest to the located floater during treatment and derive criteria for treatment termination. Exemplary termination criteria may be the detection of initiation of retinal hemorrhage, which is represented on an A-scan as a new structure that is significantly scattering in front of the retina but also absorbs (“shadow” suddenly suppressing the OCDR signal of the posterior structures), or an increase in preretinal detachment during treatment in the presence of vitreous traction, or an increase in axial length (cornea to retina) due to increased intraocular pressure.

[0039] This invention relates to an apparatus for providing gentle, low-risk, and painless laser treatment of vitreous opacities. A partially or fully automated treatment device (system) is proposed, wherein an OCDR system for navigation and treatment control is used to position the floater during treatment and assist treatment by substantially automatically triggering at least one laser pulse upon detection of the floater by means of the OCDR, provided that the laser is sufficiently well focused on the floater. Here, focusing can be performed by focus tracking (iteratively reducing the axial distance between the focus position and the floater position, i.e., "tracking"), or by periodic focus scanning across the floater position, or also by manually focusing on the floater. Sufficiently well focused laser on the floater is understood as: in the event of such deviation, there is no perceptible worsening of floater treatment (nebulization and / or vaporization), which is typically the case when the positional deviation is less than the laser focus size in that direction, particularly when the deviation is less than 75%, 50%, 25%, or 10% of the laser focus size.

[0040] The present invention also relates to a method for manipulating a laser for vitreous lysis, wherein a floater in the vitreous humor of the eye is detected by means of an OCDR, and if the floater is detected, the laser is focused onto the floater and at least one laser pulse is emitted onto the floater.

[0041] In an alternative method of manipulating a laser used for vitreolysis, the laser focus is guided through the vitreous humor of the eye, and simultaneously detected in real time by means of an OCDR: if a floater is present at the time-related laser focus location, and if a floater is detected at that location, at least one laser pulse is triggered when the laser focus reaches the floater's location.

[0042] The proposed solution involves acquiring a (more or less) complete image of the vitreous body, locating the floater by a physician (ELLEXTango Reflex) or automatically, and then aiming the therapeutic laser at that location and triggering laser radiation. However, due to human reaction time, the time required for automatic laser alignment, and also the time required for image recording and automatic floater positioning, it cannot be guaranteed that the floater will still be at the predicted location and thus within the laser's focal point when the laser is triggered. With a typical eye movement of 1 mm / s, the floater can already move approximately 20 µm within 20 ms, thus moving out of the laser's focal point, for example, at 10 µm. Furthermore, devices known to track eye movement (eye trackers) typically fail here because the floater (as the name suggests) usually moves relative to eye structures ("landmarks" such as the iris, retinal structures such as the optic disc, macula, or blood vessels).

[0043] Preferably, the system also has an electromechanical deflection unit (current scanner), an electro-optic deflection unit (acousto-optic modulator), or a motor-driven (lens displacement) deflection unit for automated beam deflection (scanning) up to three dimensions.

[0044] When focusing a laser system, it is preferable to take into account the programmed focus movement between the target position and the positioned floating object.

[0045] In order to make good use of the acoustic pressure waves generated by the laser beam, the forward position of the floating object is preferred and is set in the user settings of the central control and operation unit.

[0046] The central control and operation unit uses the determined distance between the positioned floater and the eye structure to derive the exclusion criteria for laser treatment. More precisely, if the distance between the positioned floater and the retina, fovea, lens, or similar structures is too small, laser treatment may result in hemorrhage, retinal disease, or even retinal tear.

[0047] In addition, the processing zone and the prohibited zone can be determined from the coordinates of the located floating objects.

[0048] These zones serve two purposes: firstly, to optimize the automation of laser focus positioning; and secondly, to allow processing only when the laser focus is located outside the restricted zone or within the processing zone.

[0049] While a spacing greater than 1.5 mm is sufficient for the foreseeable optical and acoustic load in a no-go zone, a spacing greater than 2-3 mm should be used for areas sensitive to the eyes.

[0050] When the laser focus approaches a restricted area, the user can be warned (acoustically and / or optically). It can also identify, display, or acoustically notify of the approach to a sensitive structure. However, it is also feasible to abort laser processing or deactivate the laser as long as it remains within the restricted area.

[0051] Vitreous opacities exist in different forms and can be treated to varying degrees.

[0052] So-called Weiss ring floaters are relatively large, fibrous ring-shaped floaters that are typically located at a safe distance from the lens and retina of the eye. Therefore, these floaters can be safely and effectively treated using laser vitreolysis.

[0053] Flocculent floaters, often appearing in relatively young individuals, are thought to be aggregates of dots or linear tissues. Depending on their size and location, floaters can also be treated with laser vitrectomy.

[0054] In contrast, diffuse (cloud-like) floaters are a result of natural aging. While this type of floater can also be treated with laser vitreolysis, multiple treatments are usually required to achieve satisfactory results.

[0055] According to a preferred design, the central control and operation unit is also designed to determine the type of the located floater (e.g., Weiss rings or blood residue) prior to laser treatment and derive treatment criteria, such as appropriate laser energy, laser wavelength, or laser pulse number. The type of floater can be determined by OCDR signal strength (i.e., backscattering capability), absorption (e.g., by a stronger reduction in signal from structures behind the blood clot), storage (especially axial extension), location (e.g., proximity to the optic disc), mobility, or response to laser treatment.

[0056] According to a preferred design, the central control and operation unit is also designed to determine changes in the ocular structure or position of the closest locating floater during treatment and to derive criteria for treatment termination. For example, the closest structure could be a capsular bag or the vitreoretinal boundary.

[0057] According to the present invention, a decision to discontinue or continue treatment is derived during the treatment period.

[0058] Therefore, the preferred criterion is:

[0059] • Exceeding the boundary value of relative positional changes within the retinal layer (e.g., local displacement of a retinal region along the anterior direction), or

[0060] • Exceeding the threshold for intraocular pressure changes as a result of laser treatment,

[0061] • Bleeding that occurs during treatment is a criterion for cessation of treatment.

[0062] Particularly preferably, the position of the floater relative to the eye's sensitive structures is automatically detected from the OCDR results. For this purpose, the distance between the posterior capsule and the retinal structures is determined using the OCDR system, and this distance is used to determine which of the closer sensitive structures should be tracked using the OCDR.

[0063] While treatment continues, OCDR is used to monitor the treatment process: whether treatment can continue or must be stopped.

[0064] In particular, by deriving the termination criteria, it is especially important to prevent the mechanical stress relationship at the vitreoretinal boundary from unfolding unfavorably due to vitreous treatment, and the increased likelihood of subsequent retinal disease or even retinal tears.

[0065] To prevent the positioned floating object from moving out of the focal area of ​​the processing laser, according to the present invention, the processing laser is triggered for a duration of less than 10 ms after the laser focal point overlaps with the floating object.

[0066] According to the invention, the optical elements used to couple the OCDR system and the laser system are based on dichroic or polarization-sensitive optical components (e.g., wavelength-sensitive beam splitters, polarization beam splitting cubes, and wavelength-independent beam splitters, which, for example, deflect 30% of the OCDR measurement light to the eye and 70% of the processing laser), or use geometric combinations (pupil division). In the latter case, a small angle between the OCDR and the processing laser beam can also be accepted when, for example, very small floats should not be processed and sufficient superposition is achieved between the two beams, at least within the processing area.

[0067] Preferably, the beam cross-sections of the OCDR and laser before overlap are selected such that the numerical aperture of the OCDR beam in the eye is smaller than the numerical aperture of the processing laser. The advantage of this setting is that the signal intensity in the OCDR signal varies less at the axial focal position compared to other numerical aperture configurations.

[0068] A less preferred but feasible approach is to introduce a reflector very briefly into the beam path to enable very rapid switching between processing laser and OCDR beams, for example, by means of a rapidly rotating reflector with a transmission window.

[0069] The coupling of the dichroic optical components is preferably achieved by means of a notch filter, which, for example, transmits a narrow-band Nd:YAG laser and reflects a wider OCDR beam.

[0070] As a display unit, an eyepiece (screen) with a matching display, head-mounted display, and / or a separate display is used.

[0071] According to another preferred design, the OCDR system, the laser system with deflection unit, the optical elements for coupling the OCDR system and the laser system, the display unit, and the central control and operation unit are integrated into the slit lamp.

[0072] The advantage of this is that users can use a slit lamp to observe the posterior part of the eye and can locate vitreous opacities and other possible pathologies in advance, which can represent the exclusion criteria for treatment (such as peripheral retinal detachment). Attached Figure Description

[0073] The invention will now be described in more detail with reference to embodiments. For this purpose, the following is shown:

[0074] Figure 1 A symbolic view of an apparatus for OCDR-assisted laser vitreous dissolution, integrated into a slit lamp according to the present invention, is shown.

[0075] Figure 2 A schematic diagram illustrating a preferred embodiment of the invention is shown.

[0076] Figure 3 This shows a view of an A-scan with a restricted area and a processing area.

[0077] Figure 4 A schematic diagram of an eye with a fitted contact lens is shown. Detailed Implementation

[0078] to this end, Figure 1 A symbolic view of a slit lamp is shown, in which an apparatus for OCDR-assisted laser vitreous dissolution according to the present invention is integrated.

[0079] The OCDR system 2, laser system 3, beam combiner 4 (constructed here as a dichroic optical element) for coupling the OCDR system and laser system, display 5, central control and operation unit 6, and focusing unit 14 with deflection unit are also integrated into the slit lamp 1 (shown only in a frame).

[0080] It is known that the slit lamp 1 is mounted on the base unit 7 and can be positioned relative to the eye 9 on 2 or 3 axes via the operating lever 8.

[0081] In addition to the lens 10, a localized float 11 and a laser focus 12 are also imaged in the eye 9. Since the retina is the structure of the eye 9 closest to the localized float 11 in the current case, this area is examined more carefully during treatment using an OCDR (Optical Center of Respirator) at least (indicated by location number 13).

[0082] In addition to the positioning float 11, the operator can see on the display 5, for example, irradiation patterns specific to the application, exclusion criteria or termination criteria for treatment, or defined treatment areas and prohibited areas.

[0083] Figure 2 A preferred embodiment of the invention is described in more detail. Here, the figures focus on the interaction of the laser 3 and the OCDR system 2 according to the invention. Part 2a of the figure shows the case at time t1 when no float 11 is in the laser focus 12, where F(t) represents the time-dependent laser focus position. The measuring beam 15 of the OCDR system 2 is combined with the (inactive) laser beam 16 of the laser 3 by means of a beam combiner 4 and directed towards the eye 9. Before beam combining, the beam cross-section is selected such that the numerical aperture of the OCDR signal in the eye is smaller than the numerical aperture of the laser. The OCDR system 2 is capable of measuring a complete A-scan of the eye 9 at 100 Hz, preferably 1 kHz or faster. This A-scan 17 is shown here by way of example. The A-scan includes reflections from the cornea, anterior lens, posterior lens 18, and retina 19 in a manner known per se. The A-scan also includes reflections 20 from the float 11, thus detecting the position of the float in the eye. The laser focus 12 is not located in the area of ​​the float 11 and therefore does not trigger the laser. Using focusing system 14, laser focus 12 is moved to the area of ​​floating object 11 (part 2b of the figure, time point t2). When the positions of laser focus 12 and floating object 11 are aligned (reflection 20 and laser focus 12 are substantially aligned), a laser pulse is triggered (schematically represented by control pulse 21), preferably within a time period of less than 5 ms. Since the position of floating object 11 is updated every A scan in less than 10 ms, it is ensured that the floating object will not move out of laser focus 12 within such a short time period.

[0084] In addition to lenses that can be mechanically displaced on a linear slider with a position measurement system, electrically adjustable lenses (such as EL-10-30-C or -Ci) are particularly suitable for rapidly focusing the laser focus 12 by means of the focusing unit 14, wherein the electrically adjustable lens can set the target focus in less than 10 to 15 milliseconds (Optotune Switzerland AG | Bernstrasse 388, CH-8953 Dietikon). Alternatively, conventional lenses can also be periodically axially reciprocated towards the eye by means of a magnetically driven resonator to change the focus position with a fixed focal length. The lens position can also be detected here by means of a travel sensor and easily calibrated relative to an OCDR. It is feasible, but not preferred, for the entire slit lamp to be moved manually or by a motor towards the eye to change the focus.

[0085] The focus position can be calibrated relative to the OCDR in different ways. One variation involves scanning the common focus of the OCDR and the laser focus and detecting the increase in signal related to the focus position at structures such as the cornea, lens, capsular bag, vitreous scattering, or retina, since the OCDR signal has its maximum value when focused on these structures. Alternatively, the focus position can be calibrated relative to the OCDR by determining the axial position of the beam waist, for example by means of a hood or beam profiler, with the focus setting fixed, and then determining the position of the hood or beam profiler via the OCDR, which may also be performed in a test eye filled with liquid if necessary.

[0086] This device enables a method for handling floating objects, characterized by the following steps:

[0087] - Measure A-scan,

[0088] - Detect reflections from floating objects (if present) in the A-scan.

[0089] - Optionally, the posterior aspect of the lens / capsule and the retina can be detected in an A scan.

[0090] - Optionally, the reliability of the laser treatment can be checked at the location of the floating object.

[0091] - Optionally, the reliability of the laser treatment can be checked based on the floating object identification (floating object type).

[0092] - Shift the laser focus onto the floating object.

[0093] - Optional check: Is the floating object still in that location?

[0094] - Trigger a laser pulse aimed at the floating object.

[0095] The method is particularly preferred if the laser focus can be adjusted in the range of milliseconds or fractions of a second, for example by means of an electrically adjustable lens with the corresponding characteristics. However, in principle, the method works even when focusing slowly, if necessary, or even manually, although the possibility of the float escaping during focusing increases in this case. That is to say, the method maintains the aforementioned advantages through the forbidden zone and the treatment zone, but the treatment efficiency decreases.

[0096] In addition, the laser focus can be moved laterally by means of a deflection unit (such as an electric current scanner), that is, floating objects can be scanned at a constant depth in the eye.

[0097] In one alternative approach, the laser focus moves along the A-scan, and the detection of a floating object in the laser focus region (by means of evaluation of the A-scan) triggers a laser pulse within milliseconds. For this purpose, a slower focusing unit (e.g., a few hertz to tens of hertz) is suitable.

[0098] Here, the A-scan can be moved relative to the axial length of the eye for the treatment of other floaters, either manually (using lever 8) or by motor drive. In the manual variation, the physician can target one or more floaters and begin treatment. A laser pulse is triggered only when the OCDR system detects a floater in the A-scan and the laser focus is on the floater (no further interaction required). Therefore, treatment success no longer depends on the physician's skill and reaction speed.

[0099] A variant of motor control proposes that, using known methods, an overview image of the vitreous body is first created using an OCT system, and the position of the floating object is roughly detected. Then, the position coordinates are sequentially moved, where the actual position of the floating object is checked using an OCDR system, and only one (or more) laser pulses are emitted onto the actually detected floating object.

[0100] The reliability of laser treatment can be checked in different ways. First, it is necessary to rule out laser treatment that is too close to sensitive structures of the eye, such as the posterior aspect of the lens / capsule or the retina / macula. By performing an A-scan evaluation, a reliable range can be defined (greater than 1.5 mm from the posterior aspect of the capsule, and less than 2 to 3 mm from the retina). Figure 3 A corresponding example of an A-scan is shown, which has a boundary between a forbidden zone and a processing zone. The anterior forbidden zone is located anterior to the anterior boundary 22 of the processing zone, and the posterior forbidden zone is located posterior to the posterior boundary 23 of the processing zone. In particular, the posterior aspect 18 of the lens is sufficiently deep within the anterior forbidden zone, and the retina 19 is sufficiently deep within the posterior forbidden zone, such that the desired minimum distance from the structure to laser processing is achieved.

[0101] Laser processing is permitted only in the processing area surrounded by boundaries 22 and 23.

[0102] In addition, other parameters can be checked during treatment, with intraocular pressure being the preferred monitoring method. This monitoring can be performed in different ways:

[0103] 1. By examining changes in eye length along the A-scan. For this purpose, if an extension can be obtained here as a stop criterion (e.g., increasing eye length by 4.5 µm to limit the pressure increase to 2 mmHg, see Leydolt et al., “Effects of change in intraocular pressure on axial eye length and lens position”, Eye (2008) 22, 657-661), then corresponding data exist by evaluating the A-scan.

[0104] 2. Changes in intraocular pressure were measured using a contact lens with appropriate accessories (see below). Figure 4 (More detailed explanation).

[0105] 3. Based on ultrasound, as described in more detail in EP3173013A2, the contents of which are incorporated herein by reference.

[0106] Treatment should be discontinued if the intraocular pressure gradient exceeds, for example, 2, 5, or 10 mmHg, to avoid eye damage. The choice of discontinuation criteria for pressure may depend on the patient's possible condition; for example, greater caution must be exercised in cases of glaucoma.

[0107] The proposed device design uses an OCDR system based on a spectral domain method or a preferred sweep frequency source method. Alternatively, a time-domain system with a repetition rate of several hundred hertz can be used within a limited scan depth range of 2-3 millimeters.

[0108] Here, according to the present invention, with an axial resolution of less than 100 μm, preferably an FWHM of 5 μm in tissue, and a centroid wavelength of 840 nm, and at an A-scan rate of 10 to 100 kHz, an axial scan depth of greater than 1 mm, preferably 4 mm, is set in the tissue for the spectral domain system. Preferably, the system has z-tracking of the retina or capsule associated with which eye structure is closer to the localized floater. Due to the low scan depth, multiple parallel reference arms can be used, allowing for the joint detection of relevant eye structures and the posterior vitreous region beyond a single scan depth. This approach can also be considered for a time-domain system. Of course, the latter is deficient in terms of sensitivity (typically 85 dB). In contrast, the spectral domain system can always maintain a sensitivity of 90 dB at repetition rates of tens of kHz, thus also reliable for detecting normal, non-interfering vitreous structures. Correspondingly, sweep source systems with sensitivities exceeding 100 or even 110 dB in the kHz range still have a sensitivity reserve, which can even be measured through the cataract.

[0109] For the swept-frequency source system, a centroid wavelength range of 1000-1070 nm, particularly 1050 nm or 1060 nm, a scan rate of 1 kHz to 100 MHz (e.g., by means of a Fourier domain mode-locked (FDML) laser or a VCSEL laser), and a sensitivity of at least 90 dB in the processing region are preferred. According to the invention, the system is combined with an Nd:YAG laser or an fs laser, a notch filter system, and here its OCDR scan depth covers the entire eye. The axial resolution of the SS-OCDR is preferably selected such that it corresponds to the Rayleigh length of the processing laser, or is two to three times greater than the Rayleigh length. While higher axial resolution is feasible, it allows for significantly less effective handling of floating objects. If changes in axial length are detected to determine pressure changes, an axial resolution of less than 30 μm, preferably less than 10 μm, or even 5 μm is advantageous.

[0110] According to the invention, a time-domain system with a reference arm for scanning can also be applied. Besides the A-scan rate, the preferred parameters correspond to those in the OCT of the SD. In this case, the A-scan rate is approximately in the range of a few kHz, particularly 2 to 4 kHz.

[0111] For all OCDR variants, the air and the corresponding path components in the study must be considered, and appropriate location determination corrections and, if necessary, group velocity dispersion corrections will be required.

[0112] To effectively detect floaters, the system according to the invention has a sensitivity of at least 85 dB, preferably at least 90 dB, in at least a portion of the A-scan. In another preferred variant, the A-scan has a sensitivity of at least 90 dB over the entire scan depth, and more preferably greater than 100 dB. From about 90 dB onwards, normal scattering at the vitreous and lens locations can also be detected in areas without floaters, thus allowing differentiation of the lens and vitreous structures from fluid-filled bags or eye areas.

[0113] Regardless of the variants mentioned earlier, an OCDR system can be part of an OCT system, which is constructed as a two-dimensional or three-dimensional scanning system; importantly, the positioning of the floating object relative to the variable focus and the triggering of the laser pulse are based on the evaluation of the A-scan (and thus without image information).

[0114] The position of floaters in the eye (in the patient's eye coordinate system) can be determined using one-dimensional OCDR scanning (A-scan), and the distance between the floater and the retina or other boundary surfaces can be calculated, which can be done very quickly and cost-effectively. Therefore, it can be used for navigational assistance and improved safety in cases of manual floater treatment. Due to the potentially very high sensitivity of OCDR compared to all non-interferometric imaging methods, floater detection and visualization can be achieved significantly more reliably. By applying interferometric methods, particularly those in the NIR spectral range, the light load can be significantly reduced compared to VIS-based methods, including the risk of blindness or pupillary constriction if the dilation is not sufficiently strong in response to a drug.

[0115] Additionally, by implementing a processing zone, the user can be allowed to view the spacing only during processing. If the therapeutic laser is activated within a restricted zone, the user will be warned and / or the output of therapeutic radiation will be blocked.

[0116] According to the present invention, the OCDR system has a sensitivity of at least 90 dB in a portion of the A-scan.

[0117] The proposed device design utilizes laser systems based on μs to ns YAG lasers, ps- or fs- lasers.

[0118] Although a pulse duration of 1-5 ns is preferred for YAG lasers according to the present invention, the pulse duration is 1 to 1000 ps in the case of ps lasers and 50 to 1000 fs in the case of fs lasers.

[0119] Instead of YAG lasers, such as Nd:YAG lasers with wavelengths of 1064nm, 946nm, and 1320nm, similar lasers could be considered, such as Nd:YLF lasers with wavelengths of 1047 to 1053nm and parameters similar to those in the case of YAG lasers. Frequency-doubled lasers can be used in principle, but care must be taken to avoid enhanced absorption through blood, especially in blood vessels.

[0120] According to another advantageous design, in addition to the treatment beam, the laser system also has at least one aiming beam used to check the consistency between the treatment beam focus and the target area. The laser diode in the VIS is suitable for this, for example, in the red spectral range of 635 nm.

[0121] In particular, the aiming beam can be continuous or quasi-continuous. For situations where visual inspection by the user is required, it is appropriate to use a beam description within the visible spectrum.

[0122] In addition, a descriptive beam in the visible or infrared spectral range can be used so that the scattered radiation it forms at the floating object can be detected and displayed by the detection system.

[0123] According to another advantageous design, the wavelength difference between the OCDR system and the laser system is less than 50 nm, preferably less than 5 nm, which allows the use of common beam guiding and focusing elements in the treatment device, but the refraction of light from the two systems into the eye through the cornea and lens is not significantly different from each other.

[0124] Furthermore, according to the invention, the device has an additional fixation mark for the patient in order to achieve advantageous or intentional positioning of the patient's eye.

[0125] Furthermore, variable fixation markers for the patient provide the feasibility of treatment during eye movement stimulated by this method. For example, fixation markers may also be needed to bring the floater into an area available for treatment. Targeted markers for movement can also initiate eye movement by the patient to move the floater into or out of the area. For example, the degree of subjective interference by the floater can be examined by moving it into the central visual area (e.g., in front of the macula), but then moving it into an area less important to laser treatment, such as in front of the peripheral retina, and performing laser treatment there.

[0126] According to another advantageous design, an additional vacuum contact lens is used to further secure the eye. Here, an optional vacuum supply and coupling with the treatment laser are provided during treatment. This is particularly advantageous for high-precision laser treatment of floaters using femtosecond lasers with focal diameters less than 20µm, 10µm, or even 5µm. For even higher lateral resolution, pupil dilation and optional beamforming are advantageous using adaptive optics, such as deformable mirrors or liquid crystal SLMs.

[0127] Here, the contact lens can be equipped with a device for determining intraocular pressure or its changes during laser treatment. Figure 4The contact lens 24 is shown in the figure. Here, the change in intraocular pressure may be due to bubbles generated by the laser pulse. If the intraocular pressure rises above a certain level, the eye will be damaged. The measured intraocular pressure is transmitted to a control unit 6 (not shown) via control line 25, which interrupts further laser processing, for example, if the intraocular pressure difference exceeds, for example, 2, 5, or 10 mmHg. For example, the basis for determining intraocular pressure with contact lenses is described in the authors Leonardi et al.'s First Steps toward Noninvasive Intraocular Pressure Monitoring with a Sensing Contact Lens (Invest. Ophthalmol. Vis. Sci. 2004;45(9):3113-3117.doi: 10.1167 / iovs.04-0015).

[0128] The present invention provides an apparatus for OCDR-assisted laser treatment of vitreous opacities, which eliminates the disadvantages of known technical solutions.

[0129] This device allows for simpler, faster, and particularly safer treatment of disruptive vitreous opacities via laser vitreolysis. Furthermore, the solution is easy to implement and cost-effective.

[0130] This invention relates to an apparatus for gentle, low-risk, and painless laser treatment of vitreous opacities. A partially or fully automated treatment (system) is proposed, wherein an OCDR system for navigation is used to locate floaters during treatment and thereby assist in the treatment.

[0131] The proposed device also enables the safe treatment of positional and difficult-to-identify, mostly transparent floating objects, where the cost of positioning the treatment laser beam can be reduced and the requirement for a visible target laser beam is no longer necessary.

[0132] The risk of retinal damage due to incorrect focal placement or the laser focus being too close to the eye's sensitive structures can be eliminated by establishing exclusion criteria for treatment.

[0133] Furthermore, the risk of retinal damage in cases of incomplete vitreous detachment due to increased local stress on the retina can be reduced by providing appropriate treatment or by discontinuing treatment according to derived discontinuation criteria.

Claims

1. A device for laser vitreoresolization of the eye, the device comprising an OCDR system, a laser system with a deflection unit, optical elements for coupling the OCDR system and the laser system, a display unit, and a central control and operation unit, wherein, The OCDR system is designed to locate floating objects, the laser system is designed to destroy the floating objects using laser pulses, and the central control and operation unit is designed to activate the laser system based on the focal position of one or more of the floating objects relative to the laser system and their positioning relative to the eye structure. The central control and operation unit is further designed to determine changes in the structure of the eye closest to the located floating object during treatment and to derive criteria for terminating the treatment.

2. The apparatus according to claim 1, characterized in that, The central control and operation unit is designed to automatically trigger the laser system within less than 10 ms after detecting a floating object, taking into account derived exclusion criteria for treatment and generated or candidate application-specific irradiation patterns.

3. The apparatus according to claim 1 or 2, characterized in that, The OCDR system, the laser system with a deflection unit, the optical element for coupling the OCT system and the laser system, the display unit, and the central control and operation unit are integrated into a slit lamp or surgical microscope.

4. The apparatus according to claim 1, characterized in that, The OCDR system is based on the spectral domain method or the frequency sweep source method.

5. The apparatus according to claim 1, characterized in that, The laser system is based on microsecond lasers, nanosecond lasers, picosecond lasers, or femtosecond lasers, or a combination of the above lasers.

6. The apparatus according to claim 1, characterized in that, The wavelength difference between the OCDR system and the laser system is less than 50 nm.

7. The apparatus according to claim 1, characterized in that, The OCDR system has axial resolution that is superior to the minimum Rayleigh length that the laser system used can be set in the eye.

8. The apparatus according to claim 1, characterized in that, The operator can determine or change the processing area in terms of the distance between the processing area and the eye structure, and can activate laser processing in the processing area.

9. The apparatus according to claim 1, characterized in that, Laser parameters are varied based on the focal position and / or distance from the eye structure, which are altered via a common focusing unit.

10. The apparatus according to claim 9, characterized in that, The laser energy, laser focus drift relative to the OCDR, laser wavelength, or number of laser pulses are varied by changing the focal position and / or distance from the eye structure via a common focusing unit.

11. The apparatus according to claim 1, characterized in that, Compared to lasers, OCDRs have a smaller numerical aperture.

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