Contact probe laser delivery system to treat conjunctivochalasis

Abstract

Embodiments disclosed herein include a laser system to safely treat conjunctivochalasis, a condition characterized by the looseness of the conjunctiva of the eye. The laser system includes a handpiece that uses a near-infrared laser to heat and shrink the conjunctiva. The laser wavelength is chosen so that absorption by water in the conjunctiva produces heating to a depth well-matched to the conjunctival thickness. To ensure accurate and consistent treatment, the handpiece employs a light guide placed in direct contact with the conjunctiva and delivers light with uniform fluence. The treatment is quick, controllable, and with shorter recovery times.

Description

CONTACT PROBE LASER DELIVERY SYSTEM TO TREAT CONJUNCTIVOCHALASISClaim of Priority

[0001] This application claims priority of U.S. provisional patent application no. 63 / 615,614, filed December 28, 2023, entitled “Contact Probe Laser Delivery System To Treat Conjunctivochalasis,” and incorporated herein by reference.Statement of Government Interest

[0002] This invention was made with government support under TR000128 awarded by The National Institutes of Health. The government has certain rights in the invention.Technical Field

[0003] Embodiments herein relate to the treatment of conjunctivochalasis.Background

[0004] Conjunctivochalasis is an underdiagnosed and common condition characterized by loose, redundant, and non-edematous conjunctival folds typically located in the inferior bulbar conjunctiva. Conjunctivochalasis can cause symptoms, ranging from mild discomfort and tearing to visual loss in severe stages. However, current methods for treating conjunctivochalasis can cause significant inflammation, pain, and scarring in the postoperative period.Brief Description of the Drawings

[0005] Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings and the appended claims. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

[0006] FIG. 1 depicts components of a laser delivery system 100, in accordance with various embodiments.

[0007] FIG. 2A depicts an exploded view of an example handpiece 200 or probe, in accordance with various embodiments.

[0008] FIG. 2B depicts a half cross-sectional view of an example handpiece 250, in accordance with various embodiments.

[0009] FIG. 2C depicts a view of the female connector 252 and a light pipe guide or slot 260 of the handpiece of FIG. 2B.

[0010] FIG. 2D depicts an exploded view of another example handpiece 270 or probe, in accordance with various embodiments.

[0011] FIG. 2E depicts a half cross-sectional view of the handpiece 270 of FIG. 2D, in accordance with various embodiments.

[0012] FIG. 2F depicts a view of an optical fiber cable 280 with the handpiece 270 of FIG. 2D, in accordance with various embodiments.

[0013] FIG. 3A depicts an example plot of relative standard deviation of emitted light at the light pipe facet as a function of the light pipe length, in accordance with various embodiments.

[0014] FIG. 3B depicts an example plot of relative standard deviation of emitted light at the light pipe facet as a function of the optical fiber numerical aperture (NA), in accordance with various embodiments.

[0015] FIG. 4A depicts the distal end of a rectangular light pipe 320 that conforms to the surface of the conjunctiva 310 of the eye 300, in accordance with various embodiments.

[0016] FIG. 4B depicts the distal end of a light pipe 420 with curved crosssection shaped to conform to the surface of the conjunctiva, in accordance with various embodiments.

[0017] FIG. 5A depicts a close-up view of an example implementation of the distal end of the handpiece 200 of FIG. 2A, in accordance with various embodiments.

[0018] FIG. 5B depicts a close-up view of another example implementation of the distal end of a handpiece 200A, where the light pipe protrudes out from the distal end of the probe, in accordance with various embodiments.

[0019] FIG. 5C depicts a close-up view of an example implementation of the distal end of a handpiece 200B, where pins are provided to hold the conjunctiva in place relative to the light pipe, in accordance with various embodiments.

[0020] FIG. 5D depicts a close-up view of another example implementation of the distal end of a handpiece 200C, where the distal end is curved such as in FIGs. 3 or 4, in accordance with various embodiments.

[0021] FIG. 6 depicts the laser delivery handpiece contacting the conjunctiva, where the conjunctiva is marked with lines of ink prior to treatment to monitor conjunctival shrinkage following treatment with the device and to identify areas to apply the laser lines, in accordance with various embodiments.

[0022] FIG. 7 depicts the laser delivery handpiece applied to the eye in sagittal section, in accordance with various embodiments.

[0023] FIGs. 8A and 8B depict laser treatment patterns on the conjunctiva: FIG. 8A depicts a pattern for treatment with a 7 mm x 1 mm contact probe where 3 columns of parallel lines are used to cover the inferior bulbar conjunctiva, in accordance with various embodiments; and FIG. 8B depicts a pattern for treatment with a 10 mm x 1 mm contact probe where only 2 columns of parallel lines are used to cover the inferior bulbar conjunctiva, in accordance with various embodiments.Detailed Description of Disclosed Embodiments

[0024] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.

[0025] Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding embodiments; however, the order of description should not be construed to imply that these operations are order dependent.

[0026] The description may use perspective-based descriptions such as up / down, back / front, and top / bottom. Such descriptions are merely used to facilitate the discussion and are not intended to restrict the application of disclosed embodiments.

[0027] The terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” may be used to indicate that two or more elements are in direct physical contact with each other. “Coupled” may mean that two or more elements are in direct physical contact. However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other.

[0028] For the purposes of the description, a phrase in the form “A / B” or in the form “A and / or B” means (A), (B), or (A and B). For the purposes of the description, a phrase in the form “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C). For the purposes of the description, a phrase in the form “(A)B” means (B) or (AB) that is, A is an optional element.

[0029] The description may use the terms “embodiment” or “embodiments,” which may each refer to one or more of the same or different embodiments.Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments, are synonymous, and are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.).

[0030] With respect to the use of any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. The various singular / plural permutations may be expressly set forth herein for sake of clarity.

[0031] As mentioned at the outset, various challenges are presented in treating conjunctivochalasis.

[0032] Conjunctivochalasis is a condition where the conjunctiva, the thin transparent membrane that covers the white part of the eye, becomes lax and folds onto itself. The condition is commonly seen in older individuals. Tear film does not distribute evenly on conjunctival folds and therefore patients often complain of eye dryness and irritation. The condition is often exacerbated by coexisting dry eye syndrome. The prevalence of clinically significant conjunctivochalasis in patientsover sixty had been found to be 18% in a population-based study. This represents a very common clinical problem.

[0033] Current methods for treating conjunctivochalasis include thermocautery, electrocautery, and surgical excision. However, these techniques can cause significant inflammation, pain, and scarring in the postoperative period.

[0034] One possible treatment involves argon laser (532 nm wavelength) conjunctivoplasty. The laser heating causes denaturation collagen in the conjunctival stroma, effectively shrinking and tightening the lax conjunctiva. However, the green wavelength is primarily absorbed by blood and causes rupture of blood vessels and conjunctival hemorrhage, an undesirable side effect.

[0035] Another possible treatment involves laser thermal keratoplasty at a near-infrared wavelength of 1460 nm. This wavelength is predominantly absorbed by water in the conjunctiva and therefore the heating is more uniform and can be more precisely controlled. The initial proposed delivery system comprises forceps to grasp a conjunctival fold and a cylindrical lens to focus a laser line on the fold. The method was shown to be effective in shrinking the conjunctiva. However, a limitation of this approach is that the geometry of the fold, as well as the amount of conjunctiva tissue grasped and exposed to the laser, depends on the grasping motion of the surgeon and is variable, which makes the result less predictable. Another limitation is that the cylindrical lens does not produce even fluence along the laser line. Yet another limitation is that the beam path in air could be partially blocked by eye lid or eye lash, interfering with predictable delivery.

[0036] Another possible treatment involves a laser delivery system employing a contact probe, where the probe is designed to deliver laser energy deep into the eye. As such the laser light exits an optical fiber of only 0.6 mm diameter. The laser wavelength of 810 nm is poorly absorbed by water, permitting the light to penetrate to the ciliary body where it is absorbed by melanin. The above-mentioned treatments have different implementations based on the different tissue targets and therapeutic goals.

[0037] There is a need for an improved handpiece to make the laser delivery to the conjunctiva more predictable.

[0038] The solutions provided herein address the above and other issues. In one aspect, the solutions provide an improved laser delivery system to treatconjunctivochalasis, where the system includes a near-infrared laser, an optical fiber, and a handpiece. The laser handpiece can use a contact probe to eliminate any beam path in air that could be blocked. The laser fluence at the face of the contact probe is uniform and the contact probe surface flattens the conjunctiva, making conjunctival heating highly predictable. The system uses a laser wavelength that has an absorption depth that is well matched to the thickness of the conjunctiva. By using short laser pulses, minimal thermal diffusion occurs during the laser pulse and therefore the peak temperature rise is confined to the conjunctiva with minimal heating of deeper eye structures.

[0039] Furthermore, the face of the contact probe conducts heat away from the epithelial surface of the conjunctiva, thus minimizing epithelial damage while providing effective heating of the conjunctival stroma to produce the desired shrinkage. In further detail, it is expected that heat conduction occurs through contact to the light pipe facet. The light pipe can comprise glass, which is a better heat conductor than air or plastic. A noncontact probe would have less ability to conduct heat since air is a worse heat conductor than glass. For even better heat conduction, the light pipe could be made out of a material having a higher heat conductivity than glass, such as quartz or sapphire, but this would be more costly and contrary to the goal of making the light pipe part of a disposable unit.

[0040] The laser operating parameters (e.g., wavelength, pulse duration, pulse energy) are selected to efficiently heat the conjunctiva while sparing surrounding tissues from excessive thermal damage. A near infrared laser wavelength (e.g. 1460nm) ensures that the bulk of the laser light is absorbed by water within the conjunctiva. The pulse duration of the laser can be sufficiently short so that significant thermal conduction does not take place during the laser pulse. The optimal pulse duration is around 0.2 second in some embodiments. Shorter pulse durations could be used but require a more powerful laser which would be more expensive. The longest pulse length is about 0.5 second in some embodiments beyond which we empirically observe less predictable shrinkage. The laser pulse duration may therefore be 0.5 second or less in some embodiments.

[0041] Finally, the pulse energy can be selected so that the conjunctiva is heated sufficiently to cause shrinkage following a single pulse of laser light in an example embodiment. One pulse is optimal in some embodiments because this isfastest and best confines the heating to the contact area. More pulses can be used, but since time between pulses (e.g., 0.5 sec. or more) is needed for tissue cooling, this would significantly increase the procedure time and only minimally increase the conjunctival shrinkage effect. Furthermore, stabilizing the eye becomes an issue if the treatment lasts more than a few seconds. An example of a potential upper limit of pulses is about five pulses.

[0042] A comparative device used four pulses, as the laser did not output sufficient energy with a single pulse, which increased the length of time of the procedure. The increased procedure time required the use of forceps to confine the heating and to stabilize the eye. A more powerful laser, in accordance with several embodiments disclosed herein, can output sufficient energy in one pulse to heat the conjunctiva to cause the desired amount of shrinkage, without the need for forceps to grasp the conjunctiva tissue, stabilize the eye, and / or confine the heating.

[0043] The laser light can be delivered to the handpiece using an optical fiber suitable for near infrared transmission (e.g. glass optical fiber with a low hydroxyl ion (OH) concentration). The ends of the optical fiber can be connectorized so that they can be easily attached to the laser and to the handpiece. Finally, the optical fiber can be surrounded by a protective sheath so that it is not inadvertently damaged.

[0044] The handpiece can include an optical fiber connector, a rectangular light pipe, and a housing for both. The housing or enclosure ensures that the face of the optical fiber is centered on and parallel to the proximal face of the rectangular light pipe. Light from the optical fiber is launched into the optical light pipe. The light pipe is designed to bounce light multiple times within the light pipe so that light exiting from the distal face is nearly uniformly distributed. There is no maximum number of bounces, and the minimum number of bounces depends on the numerical aperture of the fiber. An average of five bounces is appropriate in some embodiments.

[0045] The light pipe may have a minimum axial length that produces uniform optical power at the output facet. Optically, uniform output for even the most eccentric geometries can be achieved by increasing the length of the light pipe and or the numerical aperture of the fiber. The length can be chosen to ensure uniform output over the face of the light pipe. The uniformity of the output can be expressed as a ratio of the minimum light intensity at a darkest point on the output facet to theaverage light intensity across the output facet. A higher number, close to 1 .0, indicates greater uniformity. The uniformity may be at least 0.8, 0.9 or 0.95, for example.

[0046] In example embodiments, the optimal width of the light pipe is approximately 1 mm, e.g., in a range of about 0.5 to about 2 mm, and the optimal transverse length is approximately 7 mm to 10 mm, or more generally, about 2 to about 20 mm can be used.

[0047] The ophthalmologist or other operator places the distal end (face) of the light pipe in contact with the bulbar conjunctiva and delivers one or more laser pulses. The laser heats the conjunctiva, causes denaturation of stromal collagen, and shrinkage of the area of the conjunctiva. The face of the light pipe is elongated to deliver the laser light in a line field. The laser line is applied parallel to the lower lid margin so that the conjunctival shrinkage reduces the redundant conjunctival folds, which are also formed parallel to the lid margin. The ophthalmologist applies the laser thermal conjunctivoplasty treatment as a sequence of laser heating lines in the lower bulbar conjunctiva. The conjunctiva can be marked with lines of visible ink to monitor conjunctival shrinkage following treatment with the device and / or prior to treatment to identify areas to apply the laser lines.

[0048] The solutions provided herein improve the uniformity of the light energy applied to the conjunctiva. Contact between the light pipe facet to the conjunctival epithelium also helps conduct heat away from the epithelium to reduce the temperature rise and thereby decrease the area of epithelial damage. This reduces the time it takes for the epithelial defect to heal postoperatively, discomfort and risk of infection.

[0049] Additionally, compared to applying light directly from an optical fiber, the light pipe can spread out the laser light to a wide rectangular or curved line. The light pipe thereby has a much broader surface area at the output facet than an optical fiber.

[0050] The above and other features can be understood further in view of the following discussion.

[0051] I. General Overview

[0052] The solutions provided herein include a laser system to safely and effectively treat conjunctivochalasis, a condition characterized by loose conjunctivalfolds on the surface of the eye. The system includes a handpiece that delivers laser light that heats and shrinks the conjunctiva. To ensure accurate and consistent treatment, the handpiece is placed in direct contact with the conjunctiva and delivers light uniformly. This new technology provides a non-invasive alternative treatment for conjunctivochalasis that is quick, controllable, and with shorter recovery time.

[0053] II. Contact Probe Apparatus

[0054] The system includes three components: (1 ) a near-infrared laser, (2) an optical fiber, and (3) a handpiece (see FIG. 1 ).

[0055] Laser wavelength

[0056] The emission wavelength of the laser is chosen so that light is primarily absorbed by water within the conjunctiva. The thickness of the conjunctiva varies but is in the range of 0.1 -1 .0 mm. Since the conjunctiva is primarily water, the wavelengths that are more strongly absorbed by water than in other tissue components would produce more even heating. Wavelengths from 1400-1500 nm and from 1900-2500 nm have sufficiently short water absorption lengths for most incident light to be absorbed within the thickness of the conjunctiva. The water absorption length can be between the same as the thickness of the conjunctiva, e.g., between 0.1 mm and 1.0 mm, in an example embodiment.

[0057] In some embodiments, a desired absorption length in tissue is between the full thickness of the conjunctiva (~250 microns or 0.25 mm) to the combined thickness (~400 microns or 0.4 mm) of the conjunctiva and underlying Tenon’s capsule. The absorption length in tissue is slightly longer than the absorption length in water because tissue is mostly water but not entirely water.

[0058] Absorption length is defined as the length over which light is attenuated by a factor equal to one divided by Euler's number (e-1). In one embodiment, a laser at the wavelength of 1460 nm is used. This is suitable at the current time as compact, efficient, and economic diode lasers now produce sufficient power for this application. In alternate embodiments, a thulium fiber laser operating, for example, at 1940 nm or a holmium laser operating, for example, at 2100 nm may be used. It should be understood that other laser sources in the suitable wavelength range could be used.

[0059] Laser pulse duration

[0060] The pulse duration of the laser is chosen to ensure that minimal thermal conduction takes place during the laser pulse. Thermal conduction depends on the thermal diffusivity K of the medium. Soft tissue has a thermal diffusivity of K=0.1 3 mm2 / s. The thermal diffusion time for a one-dimensional heat diffusion problem is d2 / 4 K, where d is the diffusion length. Using the average conjunctival thickness of 0.25 mm as the diffusion length, the diffusion time is 0.12 seconds. Including the Tenon’s capsule (a layer of loose connective tissue between the conjunctiva and the sclera), the combined conjunctiva-Tenon thickness is about 0.4 mm and the diffusion time would be approximately 0.31 seconds. Experiments found pulse durations of 0.3 seconds or shorter to be acceptable in terms of minimizing damage to the conjunctival epithelium and sclera. Thus, in an embodiment, a pulse duration of less than 0.5 second is used. In other embodiments, a pulse duration of 0.4 seconds, 0.3 seconds, 0.2 seconds, or 0.1 second is used.

[0061] Laser fluence

[0062] Collagen, being the predominant protein within the conjunctiva, undergoes shrinkage upon exposure to temperatures exceeding 55°C. This shrinkage is attributed to the denaturation and subsequent uncoiling of its triple helix structure. Typically, the collagen shrinkage at a temperature of 55°C necessitates a duration of several minutes at that temperature. However, at elevated temperatures ranging between 90-95°C, the shrinkage process can be achieved in less than a second.

[0063] Fluence is a measure unit of energy delivered per unit area, such as the measure of energy density at an illuminated area. The applied laser fluence to the conjunctiva should be calibrated to elevate the conjunctival temperature to a level that induces shrinkage (exceeding 55°C) but remains below the boiling point of water (100°C) and the potential generation of steam. It is feasible to heat the conjunctiva to a temperature within the range of 55-99°C, or more specifically, within the range of 70-95°C. In a particular embodiment, the laser's power and the duration of its pulse are configured to deliver a fluence in a singular pulse that is adequate to achieve the desired shrinkage of the conjunctiva. Experiments in room temperature ex vivo eyes found significant shrinkage to occur in the fluence range of 60 to 110 mJ / mm2. In one approach, the laser pulse fluence is between 50 to 150 mJ / mm2atthe conjunctival surface. In an alternative embodiment, multiple pulses are used to increase the amount of conjunctival shrinkage, with sufficient time (e.g. 0.5 to 2 seconds) between pulses for substantial tissue cooling to occur. Generally, at least 0.5 sec. is needed to provide cooling between pulses. More than about two seconds may unnecessarily prolong procedure time and increase the need to manage eye movement.

[0064] The time between pulses refers to, e.g., the pulse spacing or the inverse of the pulse repetition rate and in various embodiments the pulse spacing may be 0.5 seconds, 0.6 seconds, 0.7 seconds, 0.8 seconds, 0.9 seconds, 1 .0 second, 1 .1 seconds, 1 .2 seconds, 1 .3 seconds, 1 .4 seconds, 1 .5 seconds, 1 .6 seconds, 1 .7 seconds, 1 .8 seconds, 1 .9 seconds, or 2 seconds.

[0065] Laser control

[0066] FIG. 1 depicts components of a laser delivery system 100, in accordance with various embodiments. The laser 130 is connected to the handpiece 140 with an optical fiber 135. The power control unit 110 is connected to the laser electrically. The footswitch 120 allows the ophthalmologist to deliver one or more pulses to the handpiece.

[0067] The laser has a power control unit that contains the electrical circuit delivering the electrical current that drives laser output. In one embodiment, the laser driving current is activated by a footswitch actuator. Each press of the foot pedal causes the delivery of a single laser pulse or the preset number of pulses needed to shrink a conjunctival treatment site. In another embodiment, instead of a foot pedal, the laser is actuated by pressing a button on the handpiece. Other mechanisms can be used as well to allow the operator to deliver one or more laser pulses to the patient.

[0068] Laser optical fiber connection

[0069] In an embodiment, the output from a high-powered diode laser is coupled to a multimode optical fiber. Multimode fibers are larger than single-mode fibers and couple to high-powered diode lasers more efficiently and can withstand higher power. In an embodiment, the optical fiber is a glass fiber made of a material (e.g., low-OH glass) that transmits near-infrared light with minimal loss. The optical fiber may have a protective sheath around it. In embodiments, both the core diameter and the numerical aperture of the fiber match the laser input for efficientcoupling. As is well known in the art, laser manufacturers generally can provide laser systems with power electronics to drive the laser and connectorized fiber optic coupling of laser output.

[0070] Optical fiber end coatings

[0071] The proximal and distal ends of optical fibers should be anti-reflection coated for the laser wavelength. This minimizes light loss at the laser-fiber, fiberfiber, and fiber-handpiece connections.

[0072] Optical fiber connection

[0073] In an embodiment, the optical fiber is provided with a precise and robust mechanical connection. This may be provided by an optical fiber that is connectorized on both ends with a standard male subminiature assembly (SMA) connector. Other standardized optical fiber connectors can also be used. Such connectorized fibers are commonly and conveniently provided with a protective sheath to protect the optical fiber. The ferrule of the male SMA optical fiber connector is inserted into the female SMA connector on the laser system. The optical fiber can include a core, a cladding and an outer jacket.

[0074] Handpiece components

[0075] FIG. 2A depicts an exploded view of an example handpiece 200, also referred to as probe or contact probe, in accordance with various embodiments. In an embodiment, the handpiece comprises an optical fiber connector 210, a light pipe 220, and a housing portions 230A, 230B (enclosure) for both. Both the light pipe and the connector are fixed to the housing, in this example. A proximal end of the housing portions 230A, 230B may be attached to a base 233 by screws 234, for example. The light pipe is one example of an optical element that guides the laser beam from the optical fiber to a distal end 231 of the handpiece. The light pipe may be made of a rigid, transparent material such as glass or a transparent plastic such as polycarbonate or polymethyl methacrylate (PMMA). The light pipe may have a rectangular cross-section. The light pipe may be a rectangular prism. The light pipe has an axial length in a z-direction, a width or thickness in the x direction and a transverse length in the y direction.

[0076] The housing holds the end 211 of the optical fiber and the proximal face 221 of light pipe in a fixed relation. Typically, the center of the optical fiber connector is centered on the proximal face of the light pipe. A female SMAconnector can ensure precise and repeatable connections to the male SMA connector on the optical fiber. In one possible approach, the end 211 of the optical fiber is abutted to (touching) the proximal face 221 of light pipe. In another possible approach, the end 211 of the optical fiber is spaced apart from the proximal face 221 of light pipe by about 0.2 mm or less. In another possible approach, one or more lenses are positioned between the end 211 of the optical fiber and the proximal face 221 of light pipe to focus light from the optical fiber into the light pipe. Care should be taken to avoid scratching the end 211 of the optical fiber or the proximal face 221 of light pipe.

[0077] The distal output facet 222 of the light pipe 220 serves as the tip of the contact probe that is applied to the conjunctival surface during the treatment. The distal output facet is an example of an elongated contact surface with the conjunctiva.

[0078] FIG. 2B depicts a half cross-sectional view of an example handpiece 250, in accordance with various embodiments. The cross-section is along the length of the handpiece. In this example, the light pipe 220 is 1 mm thick (x direction), 8mm wide (4mm of which is shown) (y direction). The length is only 6mm because the optical fiber 135 in the center has a numerical aperture of 0.5. The cross-section shows the male SMA connector 251 screwed onto a female SMA connector 252 at the bottom part of the handpiece. The optical fiber is at the center of the male SMA connector and couples light into the waveguide / light pipe at an interface 265.

[0079] In an example embodiment, the handpiece includes the light pipe and the male and / or female connectors. An additional enclosure or housing around the light pipe is optional.

[0080] FIG. 2C depicts a view of the female connector 252 and a light pipe guide or slot 260 of the handpiece of FIG. 2B, in accordance with various embodiments. The light pipe can be secured in the slot of the handpiece with glue, such as a UV-curing optical adhesive, or set screws, for example.

[0081] FIG. 2D depicts an exploded view of another example handpiece 270 or probe, in accordance with various embodiments. The handpiece includes opposing housing portions 271 A, 271 B attached at proximal ends 271 C, 271 D, respectively, to a base 273. The base in turn is attached to a female SMA connector274. An optical pipe 272 extends between the opposing housing portions 271 A, 271 B and protrudes beyond the distal end 276 of the handpiece.

[0082] FIG. 2E depicts a half cross-sectional view of the handpiece 270 of FIG. 2D, in accordance with various embodiments. This figure depicts an optical fiber 275 positioned close to the proximal end 278 of the light pipe. A small gap of less than about 0.5 mm may be provided between the face 279 of the optical fiber and the proximal end 278 of the light pipe. The optical fiber is surrounded by a fiber ferrule 282, the female SMA connector 274, and a male SMA connector 277.

[0083] FIG. 2F depicts a view of an optical fiber cable 280 with the handpiece 270 of FIG. 2D, in accordance with various embodiments. The optical fiber cable includes the optical fiber 275, the male SMA connector 277, and a strain relief section 281 . The optical fiber cable can screw onto the handpiece for easy assembly. The male SMA connector 277 may have an interior threaded surface (not shown) to mate with the exterior threaded surface of the female SMA connector 274,

[0084] Handpiece shape

[0085] The handpiece may have a cylindrical tapered shape that allows the ophthalmologist to comfortably hold it and gently place the distal end of the light pipe (output facet) on the conjunctiva. In an embodiment, the handpiece is tapered so the distal end is roughly the size of the light pipe. Due to the tapering, the view of the tip of the contact probe is not obstructed by the housing of the handpiece.

[0086] In one embodiment the distal end of the light pipe is flush with the distal end of the housing of the handpiece. In another embodiment, the light pipe may extend past the distal end of the housing of the handpiece (for example by about 0.25 mm, 0.5mm, 0.75 mm, 1 .0 mm, 1 .25 mm, 1 .5 mm, 1 .75 mm, 2.0 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3.0 mm, 3.25 mm, 3.5 mm, 3.75 mm, 4.0 mm, 4.25 mm, 4.5 mm, 4.75 mm, 5.0 mm or more) to improve the ability of the ophthalmologist to see the area of the conjunctiva that will be treated. See FIG. 5B. In one embodiment, the cylindrical tapered shape of the housing of the handpiece, in combination with the light pipe extending past the distal end of the housing of the handpiece, improves the ability of the ophthalmologist to view the distal end of the light pipe and the treatment area, and apply the treatment in a precise, repetitive way to the conjunctiva, thereby improving the outcome for the patient.

[0087] Handpiece-optical fiber connection

[0088] In embodiments, the optical fiber connection may be robust and reproducible. This can be accomplished by incorporating a female SMA connector into the handpiece housing.

[0089] Handpiece light pipe

[0090] In one embodiment, the light pipe has a constant rectangular crosssection of 8 mm x 1 mm over a length of 50 mm. The light pipe is comprised of a material transparent to the laser wavelength such as glass or sapphire. The dimensions of all sides of the light pipe are flat and polished. Since the index of refraction of the light pipe is higher than any of the materials surrounding it, any light launched into the light pipe at its input end from the optical fiber will be confined to the pipe due to total internal reflection, and propagate without loss to the distal / output end. As an alternative to relying on total internal reflection for light confinement, the sides of the light pipe could be coated with metallic or dielectric materials. Ideally, the proximal end of the light pipe will be coated with an antireflection layer to minimize coupling loss due to surface reflection between the optical fiber and the light pipe.

[0091] FIG. 3A depicts an example plot of relative standard deviation (o) of emitted light at the light pipe facet as a function of the light pipe length, in accordance with various embodiments. In this approach, the uniformity is expressed by a relative standard deviation of emitted light, e.g., as a percent, where a lower value denotes higher uniformity. The plot indicates the relative standard deviation decreases as the length increases. Additionally, the rate of decrease is relatively high at lower lengths and relatively low at greater lengths. In an example implementation, the light pipe has an 8x1 mm cross-section, the optical fiber has a 400pm diameter fiber core and NA=0.50, and the relative standard deviation decreases from 5% at 10nm to 2% at 20nm to 1 % at 40nm.

[0092] FIG. 3B depicts an example plot of relative standard deviation (o) of emitted light at the light pipe facet as a function of the optical fiber numerical aperture (NA), in accordance with various embodiments. The vertical axis has the same scale as in FIG. 3A. The plot indicates the relative standard deviation decreases as the NA increases. Additionally, the rate of decrease is relatively high at lower NAs and relatively low at greater NAs. In an example implementation, the light pipe has an 8x1 mm cross-section, the optical fiber has a 400pm diameter fibercore, and the relative standard deviation decreases from 18% at NA=0.10 to 2.5% at NA=0.20 to 1% at NA=0.50.

[0093] A design goal is to make the light pipe long enough that the beam becomes homogeneous at its output. Its design is strongly influenced by the numerical aperture and weakly by the diameter of the optical fiber that couples light into the light pipe. The appropriate length of the light pipe is further affected by its dimensional parameters, notably its cross-sectional aspect ratio of its width to its height. The length of the light pipe is chosen to ensure that light, undergoing total internal reflection within the light pipe, bounces an average of 2 to 10 times, for example. The number of bounces correlates with the uniformity of the output such that a longer light pipe will have relatively more bounces and the handpiece emission will be relatively more uniform.

[0094] In one embodiment, a 400 micron diameter optical fiber with a numerical aperture of 0.22 is coupled into an 8mmx1 mm rectangular cross-section light pipe requiring a light pipe length of 50mm in length to homogenize the output. In an example embodiment, the light pipe length is 35 mm or longer. In another example embodiment, a 400 micron diameter optical fiber has a numerical aperture is 0.4, and the light pipe has an 8x1 mm rectangular cross-section and is 38mm long.

[0095] Higher numerical aperture fibers allow shorter light pipes to achieve the homogeneous output. In one embodiment, a 400 micron diameter optical fiber with a numerical aperture of 0.5 coupled into a 10mm x 1 mm rectangular cross-section light pipe requires a minimal light pipe length of 7mm to homogenize the output. Longer light pipes can improve the uniformity of the output. For example, extending the light pipe to 10 mm, 15mm, 20mm, or 25mm in length reduces the variation of light emission across the output face of the light pipe compared to the 7mm long light pipe.

[0096] Beside the 8 mm x 1 mm and 10 mm x 1 mm rectangular cross-section light pipes, other embodiments are possible. For example, the wide dimension of the cross section could be in the range of 2 to 20 mm, for example, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm, and the narrow dimension of the cross section could be in the range of 0.5 to 2 mm, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 .0 mm, 1 .1 mm, 1 .2 mm, 1 .3 mm, 1 .4 mm, 1 .5 mm,1 .6 mm, 1 .7mm,18. mm,1 .9 mm, or 2.0 mm. In one embodiment, a 400 micron diameter optical fiber with a 0.5 numerical aperture is coupled into a 20 mm x 1 mm rectangular cross-section light pipe that is 20 mm long. In another embodiment, a 400 micron diameter optical fiber with a 0.5 numerical aperture coupled into a 20 mm x 2 mm rectangular cross-section light pipe is also 20 mm long. The cross section could have rounded corners or be elliptical.

[0097] The length of the light pipe could be longer than 50mm in some cases, for example, if the optical fiber delivering the light has a diameter of 400 microns and a numerical aperture of 0.1 then the length would need to be 70 mm for a 1 mm x 10mm rectangular cross-section light pipe.

[0098] In one embodiment, the output facet of an 8x1 mm rectangular crosssection light pipe is shaped to match the inferior bulbar conjunctival surface of the eye, such as shown in FIGs. 4A and 4B.

[0099] FIG. 4A depicts the distal end of a rectangular light pipe 320 that conforms to the surface of the conjunctiva 310 of the eye 300, in accordance with various embodiments. The light pipe 320 has a top surface 320t and a distal end surface 320e which faces the conjunctiva. The end surface 320e is concave and angled at an angle ex relative to a vertical axis z which is perpendicular to the top surface 320t. This angle may range from 0° to 40° to match the normal upwards rotation of the eye. The specific embodiment shown in the figure is angled at 20°.

[0100] The bulbar conjunctiva has a radius of curvature of approximately 11 - 12 mm. The distal end of the light pipe is shaped to match the surface of the conjunctiva. The handpiece housing the light pipe is adapted so that it conforms to the curved distal end of the light pipe and does not obstruct the ophthalmologist's line of sight.

[0101] The light pipe can also be slightly curved in cross section to follow the curvature of the lower lid margin. The distal end of the light pipe may be flat or shaped to conform to the bulbar surface of the conjunctiva, such as shown in FIG. 4B.

[0102] FIG. 4B depicts the distal end of a light pipe 420 with curved cross section shaped to conform to the surface of the conjunctiva, in accordance with various embodiments. The curved cross-section would have a radius of curvature of larger than the radius of the limbus (11 -12mm). The edges of the light pipe arecurved upwards so that the light pipe 420 has a concave top surface 420t. The distal end surface 420e of the light pipe which faces the conjunctiva is also concave and angled relative to a vertical axis z such as in FIG. 4A.

[0103] In the embodiment shown in FIG. 4B, the distal end of the light pipe may be ground and polished to match the shape of the conjunctiva. The handpiece housing is adapted so that it conforms to the curved distal end of the light pipe and does not obstruct the ophthalmologist's line of sight. This angle may range from 0° to 40° to match the normal upwards rotation of the eye. The specific embodiment shown in the figure is angled at 20°. For example, the distal end of the handpiece can be concave or otherwise curved to follow the shape of the distal end of the light pipe. See FIG. 5D, for example.

[0104] Handpiece auxiliary features

[0105] FIG. 5A depicts a close-up view of an example implementation of the distal end of the handpiece 200 of FIG. 2A, in accordance with various embodiments. The handpiece includes the housing 230 and the light pipe 220 with its distal output facet 222 flush with the distal end 231 of the handpiece 200A.

[0106] FIG. 5B depicts a close-up view of another example implementation of the distal end 231 A of a handpiece 200A, where the light pipe 220A with its distal output facet 222A protrudes out from the distal end of the probe, in accordance with various embodiments.

[0107] FIG. 5C depicts a close-up view of an example implementation of the distal end 231 B of a handpiece 200B, where one or more pins 501 are provided at the distal end of the handpiece to hold the conjunctiva in place relative to the light pipe, in accordance with various embodiments. The distal output facet 222 of the light pipe is also depicted. Ten pins are shown but other embodiments are possible with any number of pins. Other embodiments with less than or more than ten pins are possible. In some examples, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 24, 26, 28, 30 or more pins could be used. For example, four pins could be used with one on each corner of the distal end of the probe. The pins can be on the top, bottom and / or side edges of the probe. The spacing between the pins can be equidistant or varying. The pins can have a round, rectangular or other cross sectional shape. The pins can be distributed across any or all edges of the probe. Spacing of the pins should be more than one pin diameter apart.

[0108] In one embodiment, the handpiece features pins that flank the light pipe with semi-sharp ends that protrude, for example about 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or more, beyond the output facet of the light pipe. The pins can protrude by at least 0.1 -0.5 mm. The purpose of the pins is to hold the conjunctiva in place relative to the light pipe output facet and prevent sliding movement during laser application. The pins are an example of protruding gripping structures at the distal end of the probe. The pins can extend along a periphery of the distal end of the probe.

[0109] Handpiece alternative contact probe design

[0110] In an alternative embodiment, instead of the light pipe, the handpiece uses a cylindrical lens to focus the output of the optical fiber into a line field at a rectangular aperture at the exit of the housing. The housing enclosure protects the light path from potential obstruction. In one embodiment, the exit aperture is covered with a transparent footplate that has good transmittance of the laser wavelength. Suitable materials for the footplate include glass and sapphire. The cylindrical lens and the transparent footplate are examples of optical elements that guide the laser beam from the optical fiber to a distal end of the handpiece.

[0111] III. Laser Thermal Conjunctivoplastv Method

[0112] The apparatus described above is designed for use by an ophthalmologist, other eye care professionals, and their assistants. It is suitable for use in a clinic or minor procedure room.

[0113] Before the procedure, the handpiece, optical fiber, and laser are connected and the light pipe output is calibrated to ensure accurate fluence is delivered. The eye to be treated is anesthetized by numbing eye drops (e.g. proparacaine 0.5%). The ocular surface is cleansed with an antiseptic solution (e.g. povidone-iodine). These standard preparatory steps are commonly used in minor ophthalmic procedures.

[0114] The ophthalmologist may then apply marking on the inferior bulbar conjunctiva using an inked (e.g. Gentian violet) stamp to guide the placement of the laser treatment and / or to monitor shrinkage of the conjunctiva (see FIG. 6).

[0115] FIG. 5D depicts a close-up view of another example implementation of the distal end 231 C of a handpiece 200C, where the distal end is curved such as in FIGs. 3 or 4, in accordance with various embodiments. The distal output facet 222Cof the light pipe 220C is curved correspondingly. In some embodiments, the distal output facet 222C of the light pipe 220C is flush with the distal end of the handpiece. In other embodiments, the distal output facet of the light pipe protrudes from the distal end of the handpiece.

[0116] FIG. 6 depicts the laser delivery handpiece 200A contacting the conjunctiva 600, where the conjunctiva is marked with lines 610 of ink prior to treatment to guide placement of the laser treatment and / or monitor shrinkage of the conjunctiva, in accordance with various embodiments. The distal end 231 A of the handpiece and the protruding light pipe 220A are also depicted.

[0117] Using the laser handpiece, the surgeon places the output facet of the light pipe on each treatment site (FIG. 7) and presses the actuator once to deliver the laser pulse(s) necessary to shrink the bulbar conjunctiva locally.

[0118] FIG. 7 depicts the laser delivery handpiece 200 applied to the eye in sagittal section, in accordance with various embodiments. The conjunctiva 700A, 700B is shown as a dashed line. The lower lid 720 is pulled down out of the way so that the light pipe of the handpiece can be placed directly in contact with the bulbar conjunctiva. The upper lid 710 is also depicted.

[0119] The ophthalmologist sequentially applies the laser pulses to the conjunctiva, at different locations on the conjunctiva, to complete the planned overall treatment pattern (FIGs. 8A and 8B). FIGs. 8A and 8B depict laser treatment patterns on the conjunctiva.

[0120] FIG. 8A depicts a pattern for treatment with a 7 mm x 1 mm contact probe where 3 columns of parallel lines 800 are used to cover the inferior bulbar conjunctiva, in accordance with various embodiments.

[0121] FIG. 8B depicts a pattern for treatment with a 10 mm x 1 mm contact probe where only 2 columns of parallel lines 850 are used to cover the inferior bulbar conjunctiva, in accordance with various embodiments. Since the eye is round and the conjunctival surface has a spherical shape, straight line treatment appears curved when viewed from the front.

[0122] The treatment pattern comprises approximately horizontal lines parallel to the lower lid margin. The treatment starts with the inferior-most (closest to the lower lid fornix) lines and sequentially moves superiorly. The known locations of the extraocular muscles and the corneal limbal region are avoided. The tip of the contactprobe is wiped with a sponge moistened with balanced salt solution between applications to keep it clean and cool. Laser heating shrinks the conjunctiva along the narrower dimension of the line. This vertical shrinkage reduces the lax conjunctival folds characteristic of conjunctivochalasis.

[0123] Various solutions described herein may provide one or more of the following advantages.

[0124] First, since the handpiece is designed as a contact probe and the light pipe is directly in contact with the conjunctival treatment site, the ophthalmologist can directly visualize and precisely control the placement of laser treatment lines. This eliminates the need for a visible light aiming beam, or a supplemental device, such as a forceps, to grasp a conjunctival fold and / or to stabilize the eye, and enables precise application of a treatment pattern.

[0125] Second, the contact application effectively prevents obstruction of light delivery by eye lid or lashes, as there is no open-air gap in the light path.

[0126] Third, the contact application helps avoid inadvertent delivery of laser light to sensitive structures such as the cornea or limbus.

[0127] Fourth, the contact application presses the conjunctiva directly on the sclera which promotes adhesion of the conjunctiva to sclera and prevents reformation of conjunctival folds after healing.

[0128] Fifth, an elongated shape of laser heating shrinks the conjunctiva along the narrow dimension. This effectively reduces redundant conjunctival folds.

[0129] Sixth, a light pipe of sufficient length provides uniform fluence delivered to the conjunctiva under the output facet.

[0130] Seventh, the light pipe eliminates the need for a lens in the handpiece. This reduces the need for precision optomechanical alignment.

[0131] Eighth, the selected wavelength is strongly absorbed by water, which allows even absorption by conjunctival tissue and prevents focal damage such as blood vessel rupture.

[0132] Ninth, the short pulse and strong water absorption of the laser pulses prevent damage to internal eye structures.

[0133] Tenth, the cool surface of the contact probe conducts heat away from the conjunctival epithelium during laser irradiation and minimizes epithelial damage.

[0134] In an example embodiment, an apparatus for laser thermal conjunctivoplasty includes: a near-infrared laser, wherein a laser wavelength of the near-infrared laser is selected to have a water absorption length of between 0.1 mm and 1 .0 mm, the laser wavelength is in a range of 1900 to 2500 nm, and a laser pulse duration of the near-infrared laser is less than 0.5 second; an optical fiber optically coupled to the near-infrared laser; and a handpiece comprising a light pipe and a housing, wherein the light pipe is optically coupled to the optical fiber and is configured to distribute the light substantially evenly along an elongated contact surface of the conjunctiva.

[0135] In another example embodiment, a method for laser thermal conjunctivoplasty comprises: placing a laser probe in contact with the conjunctival surface; delivering one or more laser pulses at a wavelength selected to have a water absorption length of between 0.1 mm and 1 .0 mm; and forming a pattern of laser heating on the lower bulbar conjunctiva comprising a series of lines substantially parallel to the lower lid margin.

[0136] In another example embodiment, a handpiece for laser thermal conjunctivoplasty comprises: a light pipe; and an enclosure for the light pipe, wherein the light pipe comprises an input end to receive light from a laser and a distal end, opposite the input end, and the light pipe has a curved contact surface to deliver the light evenly on the conjunctiva of a patient.

[0137] Although certain embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and / or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope. Those with skill in the art will readily appreciate that embodiments may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments be limited only by the claims and the equivalents thereof.

Claims

ClaimsWhat is claimed is:1 . An apparatus for laser thermal conjunctivoplasty, comprising: a near-infrared laser, wherein a laser wavelength of the near-infrared laser is selected to have a water absorption length of between 0.1 mm and 1 .0 mm; an optical fiber; and a handpiece, wherein the optical fiber is configured to deliver light from the laser to the handpiece, and the handpiece comprises an optical element that is configured to distribute the light uniformly along an elongated contact surface of the conjunctiva.

2. An apparatus as described in claim 1 , wherein the laser wavelength is in a range of 1400 to 1500 nm.

3. An apparatus as described in claim 1 , wherein the laser wavelength is in a range of 1900 to 2500 nm.

4. An apparatus as described in claim 1 , wherein the optical element comprises a light pipe of sufficient length to homogenize a laser beam of the nearinfrared laser over the conjunctival contact surface.

5. An apparatus as described in claim 4, wherein the sufficient length is 35 mm or longer.

6. An apparatus as described in claim 1 , wherein the optical element comprises a light pipe having a rectangular cross-section.

7. An apparatus as described in claim 6, wherein a distal end of the light pipe is shaped to match the conjunctival surface.

8. An apparatus as described in claim 1 , wherein the handpiece comprises a housing for the optical element, and the optical element protrudes past a distal end of the housing.

9. An apparatus as described in claim 1 , wherein a laser pulse duration of the near-infrared laser is less than 0.5 second.

10. An apparatus as described in claim 1 , wherein the handpiece comprises pins which extend along a periphery of a distal end of the handpiece.

11. An apparatus as described in claim 1 , wherein the conjunctival contact surface has long dimension of 2 mm to 20 mm and narrow dimension of 0.5 to 2 mm.

12. A method for laser thermal conjunctivoplasty, comprising: placing a laser probe in contact with the conjunctival surface; delivering one or more laser pulses at a wavelength selected to have a water absorption length of between 0.1 mm and 1 .0 mm; and forming a pattern of laser heating on the lower bulbar conjunctiva comprising a series of lines substantially parallel to the lower lid margin.

13. The method of claim 12, wherein the laser wavelength is in a range of 1400 to 1500 nm.

14. The method of claim 12, wherein the laser wavelength is in a range of 1900 to 2500 nm.

15. The method of claim 12, wherein a duration of the one or more laser pulses is less than 0.5 second.

16. The method of claim 12, wherein a fluence of the one or more laser pulses is between 50 to 150 mJ / mm2at the conjunctival surface.

17. The method of claim 12, wherein the one or more laser pulses elevate a temperature of the conjunctiva to 55-99 C.

18. The method of claim 12, wherein the one or more laser pulses elevate a temperature of the conjunctival surface to 70-95 C.

19. The method of claim 12, wherein a time between laser pulses is 0.5 to 2 seconds.

20. A handpiece for laser thermal conjunctivoplasty, comprising: a light pipe; and an enclosure for the light pipe, wherein the light pipe comprises an input end to receive light from a laser and a distal end, opposite the input end, and the light pipe has a curved contact surface to deliver the light evenly on the conjunctiva of a patient.21 . A handpiece as described in claim 20, further comprising pins which extend along a periphery of the distal end of the enclosure.

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