Patent Application
20140107459
Glaucoma, a group of eye diseases characterized by an increase in intraocular pressure (TOP), is one of the leading causes of blindness worldwide. Most forms of glaucoma result when the IOP increases to pressures above normal for prolonged periods of time, thereby adversely affecting the retina and optic nerve. IOP can increase due to high resistance to the drainage of the aqueous humor relative to its production. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers resulting in a progressive, permanent loss of vision. Thus, monitoring the intraocular pressure is crucial to proper treatment and evaluation of glaucoma.
Anatomically, an anterior chamber 170 and a posterior chamber 175 include the structures that cause elevated IOP which may lead to glaucoma. The eye's ciliary body 140, which lies beneath the iris 130 and adjacent to the lens capsule 110, continuously produces aqueous humor, the clear fluid that fills the anterior segment of the eye (the space between the cornea 120 and lens capsule 110). The aqueous humor flows out of the anterior chamber 170 (the space between the cornea 120 and his 130) through the trabecular meshwork 150 and the uveoscleral pathways (not shown), both of which contribute to the aqueous drainage system located in the angle of the anterior chamber 170. The trabecular meshwork 150, which is commonly implicated in glaucoma, extends circumferentially around the anterior chamber 170 and appears to act as a filter limiting the outflow of aqueous humor and providing a back pressure that directly relates to IOP. Schlemm's canal 160 is located beyond the trabecular meshwork 150, and is fluidically coupled to collector channels (not shown) allowing aqueous humor to flow out of the anterior chamber 170. The two arrows in
In general, glaucoma therapy today consists of monitoring and regulating the IOP by either medical or surgical interventions. An important aspect of treating glaucoma includes frequent monitoring of the IOP. The IOP of normal people varies throughout the day. Abnormal pressure elevations may occur at odd hours, e.g., very early in the morning, or when it is impractical for the patient or healthcare provider to measure and record IOPs. Such diurnal curves, which measure individual IOP measurements over time, are considered to be of great value in the diagnosis and treatment of glaucoma, and to evaluate the response to glaucoma therapy. Thus, frequent monitoring is necessary to obtain an accurate assessment of a patient's average intraocular pressure.
Measurement of IOP is commonly done with an external tonometer in a physician's office. The need to have a healthcare professional available during these IOP measurements and the risks of corneal abrasion, reactions to topical anesthetics, and the transmission of infectious agents limit the accessibility and ease of monitoring intraocular pressure in glaucoma patients. Other disadvantages of these external IOP measurements include their cost, the disruption to the patient's normal activities, and possible interference with the measured IOP caused by artificial changes to natural sleep patterns and/or repeated manipulation of the corneal surface (i.e., the tonography effect). Moreover, IOP readings using external devices are a function of both the IOP value and the corneal stiffness, which reduces the accuracy of the IOP reading.
The devices, systems, and methods disclosed herein overcome one or more of the deficiencies of the prior art.
In one exemplary embodiment, the present disclosure describes an implantable sensor assembly sized for insertion within an eye of a patient, comprising a sensor and an antenna system coupled to the sensor. In one aspect, the antenna system is pliable between an expanded condition and an unexpanded condition, and the expanded condition has a predetermined shape configured to interface with tissue within the eye in a manner that stabilizes the sensor assembly.
In some embodiments, the antenna system comprises an antenna surrounded by a casing.
In some embodiments, the sensor assembly further comprises a haptic coupled to the antenna system, wherein the haptic is shaped and configured to stabilize the sensor assembly within the eye.
In another exemplary embodiment, the present disclosure describes a sensor assembly system for measuring characteristics within an eye of a patient, the sensor assembly comprising a sensor, an antenna system coupled to the sensor, and a delivery instrument configured to position the sensor assembly in the eye. In one aspect, the antenna system is configured to self-expand into a predetermined shape configuration and is sized to stabilize the sensor assembly in the eye. In one aspect, the delivery instrument comprises a lumen and a plunger longitudinally disposed within the lumen. The lumen is sized to receive the sensor assembly and the plunger is configured to translate longitudinally within the lumen to engage the sensor and displace the sensor assembly from the lumen.
In another exemplary embodiment, the present disclosure describes a method for positioning a sensor assembly relative to an eye. The method comprises inserting the sensor assembly in an unexpanded condition into a lumen of a delivery instrument sized to receive the sensor assembly, wherein the sensor assembly comprises a sensor coupled to an antenna system configured to self-expand, and wherein the delivery instrument comprises a plunger longitudinally disposed within a lumen and configured to selectively engage the sensor. The method further comprises moving the plunger along the longitudinal axis of the lumen toward a distal end of the delivery instrument to displace the sensor assembly from the lumen of the delivery instrument into the eye.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description.
The accompanying drawings illustrate embodiments of the devices and methods disclosed herein and together with the description, serve to explain the principles of the present disclosure.
For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is intended. Any alterations and further modifications to the described devices, instruments, methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately. For simplicity, in some instances the same reference numbers are used throughout the drawings to refer to the same or like parts.
The present disclosure relates generally to sensor assemblies and associated delivery systems and methods. In some embodiments, the sensor assemblies are configured for use in ophthalmic conditions requiring frequent or constant monitoring of intraocular pressure (IOP), such as, by way of non-limiting example, glaucoma. In some embodiments, the sensor assemblies are configured for use in ophthalmic conditions requiring frequent or constant monitoring or measurement of other ocular characteristics, including, by way of non-limiting example, measurement of the anterior chamber pressure, measurement of capsular tension or strain (e.g., the pressures or forces exerted by ciliary zonules), and/or measurement of the Ph levels or other chemical characteristics of the anterior chamber. In some instances, embodiments of the present disclosure may be configured to be part of an ophthalmic surgical system.
In one exemplary aspect, the present disclosure provides a sensor assembly utilizing a sensor coupled to an antenna having shape memory characteristics. The sensor assembly may assume an unexpanded condition to facilitate atraumatic insertion into and removal from an eye through a primary incision, and can assume a predetermined, expanded condition within the eye. In one embodiment, in its expanded condition, the sensor assembly comprises a substantially circular ring antenna with an attached microsensor. In some embodiments, the sensor assembly includes substantially pliable engaging portions referred to here as haptics that support the sensor assembly against internal structures of the eye, allowing the sensor assembly to be self-stabilized and self-retained in the eye (i.e., without the use of sutures, tacks, or a manually held instrument). Therefore, the sensor assembly disclosed herein allows for constant monitoring of a patient's IOP or other ocular characteristics, thereby facilitating the diagnosis, the treatment, and/or the monitoring of the progression of various eye conditions. The present disclosure also provides an inserter that may be used to insert the sensor assembly. In some embodiments, the sensor assembly may be inserted into the eye during a phacoemulsification procedure through the same incision that was used to insert an IOL.
The sensor assembly 200 comprises an antenna system 205 having an antenna 210 surrounded by a casing 215 and comprises a sensor 220. In the pictured embodiment, the sensor assembly 200 further comprises support members or haptics 225 extending from the casing 215.
In the pictured embodiment, the antenna system 210 comprises a conductive circular ring or toroid. The antenna 210 can be considered a loop or annular antenna having a central opening 230. In some embodiments, the antenna 210 comprises a radiofrequency (RF) antenna.
The antenna 210 is expandable from an unexpanded condition to an expanded condition having a predetermined shape configuration. For example, in the embodiment pictured in
The antenna 210 is constructed from a structurally deformable biocompatible material that can elastically or plastically deform without compromising its integrity. The antenna 210 may be made from or coated with a self-expanding biocompatible material. Examples of the antenna material include conductive materials such as, by way of non-limiting example, Nitinol, an elastically compressed spring temper biocompatible material, copper, silver, platinum, gold, and alloys of similar conductive materials. Examples of the antenna coating materials or composite coatings include, by way of non-limiting example, silicone, polyimide, peek, polypropylene, parylene or similar materials. Other materials having shape memory characteristics, such as particular metal alloys, may also be used. The shape memory materials allow the antenna to be restrained in a low profile configuration during delivery into the eye and to resume and maintain its expanded shape in vivo after the delivery process. The material composition of the antenna 210 resiliently biases the antenna toward the expanded condition. In particular, in this example, the antenna is formed of an elastic material allowing the antenna to elastically deform to an unexpanded state to facilitate delivery through a small incision (e.g., through a tubular delivery instrument), and spring back to an expanded state as it enters the eye. In other embodiments, the antenna may be made of a shape memory alloy having a memory shape in the expanded configuration. In other embodiments the antenna may be comprised of a conductive material, with a shape memory alloy or a material with a spring back characteristics coupled to it in a non-conductive manner.
The antenna 210 may be sized to have an external diameter D1 ranging from, for example only, approximately 3 to 6 mm in an expanded condition to provide adequate stabilization in the eye and communication capabilities while remaining small enough to limit interference with other surgical instruments and/or implants, such as, by way of non-limiting example, an IOL. The antenna may be sized to have a cross-sectional diameter or thickness T1 ranging from, for example only, approximately 0.25 mm to 2 mm. In some embodiments, the antenna includes a thickness T1 greater than its height, which may range from, for example only, approximately 50 to 100. Other diameter and thickness ranges are contemplated. In some embodiments, the diameter D1 matches the diameter of a capsular bag in an average human eye.
The casing 215 is a tubular sleeve completely encasing the antenna 210. The casing 215 may be formed of any of a variety of structurally deformable biocompatible materials that can elastically or plastically deform without compromising integrity, including, by way of non-limiting example, flexible polymers such as polytetrafluoroethylene (PTFE), silicone, silicone polyimide, polycarbonate, polymethylmethacrylate (PMMA), nylon, prolene, polyurethane, silastic, polyamide or a combination thereof, or any other biocompatible material having the requisite properties of resilience and flexibility. The casing 215 may be sized to have a cross-sectional diameter or thickness T2 ranging from, for example only, approximately 0.9 to 100 μm, although other sizes are contemplated. In combination, the antenna 210 and casing 215 is sized to have an external diameter D2 comprising D1+(2×T2)+T1. In combination, the antenna 210 and casing 215 may be sized to have an external diameter D2 ranging from, for example only, approximately 3.25 to 8.0 mm in an expanded condition to provide adequate stabilization in the eye while remaining small enough to limit interference with other surgical instruments and/or implants, such as, by way of non-limiting example, an IOL. Other diameter ranges are contemplated. In some embodiments, the diameter D2 matches the diameter of a capsular bag in an average human eye.
The sensor 220 is fixedly disposed on or coupled to the antenna system 205, and the sensor 220 extends radially from the antenna 205. In other embodiments, the sensor may be removably coupled to the antenna 205. In some embodiments, the sensor is coupled to the antenna 210. In some embodiments, the sensor 220 may consist of a microchip sensor, such as, for example, a pressure sensor microchip that changes the antenna response as a function of pressure. In some embodiments, the sensor includes microelectromechanical systems (MEMS) technology. In some embodiments, the sensor assembly 200 may include an electronic circuit such as an integrated circuit chip with a sensor component for interaction with optic, electromagnetic, sonic, or other energy forms. In some embodiments, the sensor 220 is configured to measure pressure, such as, for example, the pressure within the anterior chamber 170. Such sensors may assist in the determination of IOP when coupled to an accessory and/or external device. In some embodiments, the sensor 220 is configured to measure pH levels or other chemical characteristics of the anterior chamber 170. In some embodiments, the sensor 220 is configured to measure the temperature within the anterior chamber 170. Such temperature measurements may allow the user and/or the sensor assembly to calibrate for temperature variations in the sensor measurements. In some embodiments, the sensor 220 is configured to measure capsular tension, or forces exerted by the zonules 145 on the lens capsule 110 (shown in
In the pictured embodiment, the sensor assembly 200 includes only one sensor 220 fixedly coupled to the antenna 220. In other embodiments, the sensor assembly may include any number and arrangement of sensors that allow for adequate measurement and/or monitoring of ocular characteristics. The number and arrangement of the sensors 220 may be selected in consideration of, among other factors, the type of characteristic(s) to be measured, the patient's medical condition, and/or locations at which sensors are typically placed for particular measurements, inclusive of redundancy to prevent or avoid single point failure.
In some embodiments, the sensor 220 is integrally formed with the antenna. In other embodiments, the sensor assembly 200 comprises a multi-component device with the sensor 220 attached to the antenna 210 and/or the casing 215 by any of a variety of attachments mechanisms, including one or more of an adhesive, a threaded engagement, a snap-fit engagement, a frictional engagement, over-molding, heat-shrinking, heat welding, and/or any other mechanism for fixedly coupling the sensor 220 and the antenna 210. In some embodiments, the sensor 220 is removeably coupled to the antenna.
In the pictured embodiment, the sensor assembly 200 includes two haptics 225, which are shaped and configured to allow the sensor assembly to be self-supporting and self-stabilizing within the eye when in an expanded condition. In other embodiments, the sensor assembly may include any number and arrangement of haptics that allow for adequate self-stabilization of the sensor assembly 200 within the eye. In other embodiments, the antenna 210 and the casing 215, in combination and without haptics, are shaped and configured such that the sensor assembly is self-supporting and self-stabilizing within the eye when in an expanded condition. The haptics 225 comprise substantially pliable, curved, elongate members extending outwardly from the casing 215. In
In some embodiments, the haptics 225 include spring-like shape memory characteristics such that the haptics can assume an unexpanded condition with the application of force by being offset from the neutral or expanded position (e.g., by being compressed against the casing 215) and subsequently returned to an expanded condition when the force is removed. In particular, the haptics 225 are configured to be easily compressed or constrained and held in such a compressed or unexpanded condition to facilitate insertion into the eye. The resilient haptics 225 are configured to spontaneously return to an expanded, at rest condition, as illustrated in
The haptics 225 can be formed from any of a variety of flexible, nonbiodegradable, and biocompatible materials, such as, by way of non-limiting example, polymethylmethacrylate (PMMA), silicone, silicone polyimide, polycarbonate, nylon, prolene, polyurethane, silastic, polyamide or a combination thereof, or any other biocompatible material having the requisite properties of resilience and flexibility. In other embodiments the haptics may be made from or have a shape memory alloy core. In some embodiments, the haptics 225 are integral extensions of the casing 215, and may be formed from the same shape memory material as the casing 215. In other embodiments, the root ends 235 of the haptics 225 are fixedly attached to the casing 215.
In the pictured embodiment, the haptics 225 extend radially away from the casing 215 to form the farthest periphery of the sensor assembly 200. The haptics are sized and configured such that the haptics can, in an expanded condition, provide adequate stabilization of the sensor assembly within the interior of the eye while remaining small enough to limit interference with other surgical instruments and/or implants. In the pictured embodiment, the haptics 225 have a curved shape configured as non-tapering arcs. In other embodiments, the haptics may have any of a variety of shapes and configurations, including by way of non-limiting example, crescents or teardrops. In some embodiments, the haptic may be tapered along its length from the root end to the free end. Such tapering may provide for a more even distribution of stress across the haptic when the sensor assembly is deployed within the patient. In the pictured embodiment, the haptics 225 have substantially circular cross-sectional shapes. In other embodiments, each haptic may have any of a variety of cross-sectional shapes, including without limitation, rectangular, ovoid, square, rhomboid, and crescent. Each haptic 225 may be sized to have a length (i.e., from the root end 235 to the free end 240) that permits the sensor assembly in an expanded condition to fit within a space having a diameter of up to 12.4 mm. Other diameters are contemplated. Each haptic 225 may be sized to have an external diameter or thickness T3 ranging from, for example only, approximately 0.2 to 3.0 mm. Other length and diameter ranges are contemplated. Although the haptics 225 of the sensor assembly 200 are substantially identical in size and cross-sectional shape, other embodiments may include haptics of varying sizes and shapes.
As shown in
In some embodiments, the sensor assembly 200 is shaped and configured to be transparent enough to provide for visualization through the antenna 210, the casing 215, the haptics 225, and/or the sensor 220 to observe, by way of non-limiting example, underlying tissue, vessels, air bubbles, and/or bleeding. In alternate embodiments, the antenna 210, the casing 215, the haptics 225, and/or the sensor 220 are semi-transparent or opaque so as to be clearly visible during ophthalmic procedures. In the pictured embodiment, the external surfaces of the casing 215, the haptics 225, and the sensor 220 are substantially smooth. In other embodiments, the external surfaces of the casing 215, the haptics 225, and/or the sensor 220 may be textured. The various components of the sensor assembly 200 may be coated with any of a variety of biocompatible materials, including, by way of non-limiting example, polytetrafluoroethylene (PTFE).
With reference to
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The plunger 615 is shaped and configured to releasably hold the sensor assembly 200 as the plunger 615 pushes the sensor assembly through the delivery instrument 600. The plunger 615 includes a receiving port 620 that is shaped and configured to engage the sensor 220 as the plunger pushes the sensor assembly 200 through the lumen 610. In the pictured embodiment, the plunger 615 comprises two support arms 630 that are shaped and configured to selectively grasp the sensor 220 within the receiving port 620 while the support arms are within the lumen 610 of the delivery instrument 600. The support arms 630 and the receiving port 620 are shaped and configured to prevent damage to the sensor 220. In some embodiments, the receiving port 620 is configured to surround the sensor 220 and protect the sensor from damage as it is advanced through the delivery instrument 600. In some embodiments, the receiving port 620 is shaped to complement the shape of the sensor 220. In that regard, the support arms 630 can comprise any of a variety of shapes configured to grasp the sensor 220, including, by way of non-limiting example, straight rods, curved arcs, and curvilinear rods, each with or without linear recesses shaped to accommodate portions of the sensor 220. In some embodiments, the support arms 630 are shaped as jaws that can surround more than two surfaces of the sensor 220.
In some embodiments, interior surfaces 635 of the support arms 630 include a sensor engaging feature shaped and configured to releasably couple the plunger 615 to the sensor. In such embodiments, the sensor engaging feature and at least a portion of the sensor 220 are shaped and configured as a mating pair of selectively detachable fasteners. In some embodiments, the sensor engaging feature provides the user with a gripping surface on the support arms 630 that mates with an exterior surface 640 of the sensor 220. The sensor engaging feature and/or the exterior surface 640 may include any of a variety of selectively detachable fasteners such as, by way of non-limiting example, protrusions, indentations, grooves, hooks, and/or loops.
As indicated by
The plunger 615, and in particular the support arms 630, allows the user to manipulate (i.e., position, reposition, remove, and/or otherwise move) the sensor assembly 200 during an ophthalmic procedure while shielding the sensor 220 from damage. The support arms 630, by providing separate contact surfaces around the sensor 220, may function to protect the sensor 220 from damage while the sensor assembly 200 is contained and moved within the lumen 610 of the delivery instrument 600.
Referring to
As indicated by
In some instances, when the need for the implanted sensor assembly 200 has concluded, the reverse of the insertion procedure depicted in
The various sensor assembly embodiments described herein can utilize a sensor and a flexible antenna to detect and communicate various physiological characteristics, such as, by way of non-limiting example, ocular characteristics. For example, in some embodiments, the sensor assemblies are configured to wirelessly measure anterior chamber (and/or posterior chamber) characteristics, such as, by way of non-limiting example, chemical features within the chamber, temperature, pressures within the chamber, and/or forces exerted by the zonules 145. The implantable sensor assemblies described herein allow a user to wirelessly take different types of measurements (e.g., IOP, zonule forces, capsular tension, temperature, and pH) on a regular basis, without having to visit a healthcare professional or repeatedly manipulate the eye.
It will be clear to one of skill in the art that the sensor assembly embodiments described herein may be altered in various ways without departing from the scope of the invention, and may be used in a variety of non-ocular applications. For example, the sensor 220 may be coated with a medical-grade biocompatible coating prior to being implanted. In some instances, the sensor assembly may be shaped and configured for use in measuring intravascular pressure, pulmonary pressure, biliary-duct pressure, blood pressure, joint pressure, and/or pressure in other fluid-containing bodily tissue. The sensor assemblies may find application in blood pressure monitoring systems, vital signs monitoring systems, chemostasis monitoring systems, respiratory health monitoring systems, and drug delivery systems. In some instances, the sensor assemblies may be incorporated within surgical monitoring equipment, for example where intratubal pressure or chemical readings are required.
The sensor assemblies described herein can assume an unexpanded condition to facilitate atraumatic insertion into and removal from an eye through the same incision used for insertion of a standard IOL, and can assume a predetermined, expanded condition within the eye. Moreover, the various sensor assembly embodiments described herein can stabilize and self-retain their position on an eye and move with the eye as necessary. Although the various sensor assembly embodiments described herein may be used without the aid of a specialized delivery instrument, in some embodiments, the sensor assembly embodiments may be used in conjunction with a specialized delivery instrument utilizing support arms configured to protect the sensor and/or electronics of the sensor assembly during insertion and to provide increased maneuverability of the sensor assembly within the eye. Thus, the delivery instruments and sensor assemblies described herein allow for implanting sensor assemblies and/or MEMS-based assemblies into the eye post-IOL implantation, without damaging the delicate sensor components or requiring an additional incision.
Persons of ordinary skill in the art will appreciate that the embodiments encompassed by the present disclosure are not limited to the particular exemplary embodiments described above. In that regard, although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure. It is understood that such variations may be made to the foregoing without departing from the scope of the present disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the present disclosure.
