WO2003073959A2

WO2003073959A2 - Implantable passive intraocular pressure sensor

Info

Publication number: WO2003073959A2
Application number: PCT/IL2003/000163
Authority: WO
Inventors: Shay Kaplan
Original assignee: Microsense Cardiovascular Systems 1996
Priority date: 2002-03-05
Filing date: 2003-03-03
Publication date: 2003-09-12
Also published as: AU2003214592A8; WO2003073959A3; AU2003214592A1

Abstract

An implantable passive intraocular pressure sensor (10) is disclosed. The sensor (10) Includes a sealed housing having a passage (20) therein. The passage (20) allows light (36A, 36B) to pass and reach the retina (38). The sensor's (10) housing has walls forming a sealed chamber. At least one wall of the housing is a movable wall configured for moving or deforming in response to changes in the pressure outside the sensor (10). The sensor (10) includes a passive electromagnetic resonant circuit (14). At least one portion of the circuit (14) is mechanically coupled to one or more of the movable or deformable walls of the housing, such that the resonance frequency of the resonant circuit (14) varies as a function of the pressure outside the sensor. The passage (20) within the housing may be open or, alternatively, one or more optical elements such as an intraocular lens or filters, or other optical elements may be disposed in the passage (20) to modify light (36A, 36B) passing through the passage (20). A system (28) for use with the implantable intraocular sensors (10) and methods for implanting the sensors (10) are disclosed.

Description

INTRAOCULAR SENSOR

FIELD OF THE INVENTION

The present invention relates to wireless pressure sensors and systems in general and to sensors and systems for intraocular pressure measurement in particular.

BACKGROUND OF THE INVENTION

Intraocular pressure measurement in the eye may provide important medical data for diagnostic purposes or for follow-up of therapeutic and/or surgical eye treatment. Currently, such measurements need to be performed by a specialist which may be expensive and is inconvenient to the patient. Passive sensors (for implanting into the human body or for mounting at some inaccessible location within a machine) are known in the art. These sensors are typically electromagnetic, providing an electromagnetic signal when activated.

The prior art sensor systems typically comprise a sensor, disposed in the region in which the measurement is to be performed, and an activating and detecting system. The sensor is typically an oscillating circuit whose oscillation frequency changes in response to the physical variable to be measured. The oscillating circuit typically includes a capacitor and an inductor, one or more of which is built to vary in accordance with the physical variable being measured. As a result, the oscillation frequency of the sensor circuit is a function of the physical variable. When the sensor is irradiated with electromagnetic energy from the activating system, some of the energy is absorbed by the oscillating circuit, depending on how close the incident frequency or frequencies are to the resonant frequency of the circuit (which, in turn, depends on the physical variable being measured). The change in the electromagnetic field due to the absorption of energy by the oscillating circuit is detected by the detecting system.

Electromagnetic sensors and systems are described in the U.S. Patent 4,127,110 and in an article: Carter C. Collins, "Miniature Passive Pressure Transensor for Implanting in the Eye", IEEE Transactions on Bio-Medical Engineering, Vol. BME-14, No. 2, April 1967, both incorporated herein by reference in their entirety for all purposes. Unfortunately, within living tissue, the passive sensor is detectable within a range of approximately 10 times the diameter of its antenna (part of the oscillating circuit). For the application of intraocular pressure measurement, the use of implantable wireless intraocular sensors may pose problems. Typically, the limited ocular space puts a limit on the size and volume of the sensor that may be practically implanted within an eye without impairment of a patient's vision. On the other hand, one may not use sensors which are bellow a certain size or diameter because the above range limit (10 times the diameter of the antenna) may practically prevent detection of the desired signal.

An article by Andrew DeHennis and Kensall D. Wise, entitled "A Double Sided Single Chip Wireless Pressure Sensor" published, pp. 252-255, MEMS 2002, the 15^th IEEE International Conference on micro electro mechanical systems 2002, (January 20- 24, 2002), incorporated herein by reference in it's entirety, for all purposes, discloses a single chip wireless pressure sensor implementing battery-free passive telemetry for transcutaneous pressure monitoring. In the transcutaneous pressure monitoring system disclosed by DeHennis and Wise, the diameter of the on-chip inductor is set at 6.0 millimeters, in order to achieve a practical coupling distance from the external antenna of approximately 3.0 centimeters. While, theoretically, such a coupling distance may be sufficient for intraocular operation of a sensor, the on-chip sensor disclosed is not suitable for intraocular implantation due to it's relatively large size, and is intended primarily for intracranial pressure measurement applications.

As far as the present inventor is aware, at the time of filing of the present application, there is no commercially available system for intraocular pressure measurement in human patients using an implantable wireless pressure sensor.

SUMMARY OF THE INVENTION

There is therefore provided in accordance with an embodiment of the present invention, an implantable passive intraocular pressure sensor. The sensor includes a sealed housing having a passage therein for allowing light to pass through the passage. The housing has walls forming a sealed chamber therebetween. At least one wall of the walls is a movable wall configured for moving in response to changes in the pressure outside the sensor. The sensor also includes a passive electromagnetic resonant circuit. At least one portion of the resonant circuit is mechanically coupled to the at least one movable wall such that the resonance frequency of the resonant circuit varies as a function of the pressure outside the sensor.

Furthermore, in accordance with an embodiment of the present invention, the dimensions of the passage are configured to allow light to pass through the passage to reach the retina of an eye when the sensor is implanted within the eye.

Furthermore, in accordance with an embodiment of the present invention, the housing is selected from the group consisting of: a flat annular housing, a flat regular polygonal annular housing, an annular housing having a flat ellipsoidal cross-section and a non-symmetrical housing having an irregular shape.

Furthermore, in accordance with an embodiment of the present invention, the passage is selected from the group consisting of: a passage having a circular cross- section, a passage having a polygonal cross-section, a passage having an ellipsoidal cross-section, a passage having a regular polygonal cross-section and an irregularly shaped passage.

Furthermore, in accordance with an embodiment of the present invention, the sealed chamber surrounds the passage.

Furthermore, in accordance with an embodiment of the present invention, the resonant circuit includes an electrically conducting member having at least two electrically coupled electrically conducting portions, and the distance between the at least two portions varies as a function of the pressure outside the sensor.

Furthermore, in accordance with an embodiment of the present invention, at least one electrically conducting portion of the at least two electrically conducting portions is attached to the at least one movable wall. Furthermore, in accordance with an embodiment of the present invention, the chamber includes a gas sealed therein.

Furthermore, in accordance with an embodiment of the present invention, the at least one movable wall is a flexible deformable wall. At least a portion of the deformable wall is configured to change its shape in response to changes in the pressure outside the sensor. Furthermore, in accordance with an embodiment of the present invention, the passage is an open passage.

Furthermore, in accordance with an embodiment of the present invention, the sensor also includes at least one optical element attached to the housing and disposed within the passage.

Furthermore, in accordance with an embodiment of the present invention, the sensor is a foldable sensor configured to be folded to facilitate insertion thereof into an eye.

Furthermore, in accordance with an embodiment of the present invention, the at least one optical element is selected from a lens, an optical filter, a light polarizing element, and combinations thereof.

Furthermore, in accordance with an embodiment of the present invention, the sensor further includes at least one handling member attached to the housing or formed as a part thereof to facilitate handling or grasping the sensor. Furthermore, in accordance with an embodiment of the present invention, the lens further includes an additional electrically conducting member attached to the lens and electrically coupled to the passive electromagnetic resonant circuit to form an extended resonant circuit.

Furthermore, in accordance with an embodiment of the present invention, the additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting material attached to a surface of the lens.

Furthermore, in accordance with an embodiment of the present invention, the additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting optically transparent material attached to a surface of the lens. Furthermore, in accordance with an embodiment of the present invention, the electrically conducting optically transparent material comprises indium tin oxide.

Furthermore, in accordance with an embodiment of the present invention, the lens is an implantable contact lens configured to be placed adjacent to the natural lens of an eye, and the sensor is configured to be implanted within the anterior chamber of the eye to enable determining the pressure therein. Furthermore, in accordance with an embodiment of the present invention, the lens is configured to replace the natural lens of an eye, and the sensor is configured to be implanted within the posterior chamber of the eye to enable determining the pressure therein. Furthermore, in accordance with an embodiment of the present invention, the lens is configured to replace the natural lens of an eye in cataract surgery performed on a patient.

Furthermore, in accordance with an embodiment of the present invention, the housing of the sensor includes two opposing non-planar annular membranes. Each membrane of the two membranes has an inner circumference and an outer circumference. The two membranes are sealingly attached to each other along their inner circumference and outer circumference to form the sealed chamber between them. At least one of the membranes is a flexible or deformable membrane.

Furthermore, in accordance with an embodiment of the present invention, the resonant circuit includes at least a first electrically conducting portion and a second electrically conducting portion. The first portion is electrically coupled to the second portion. The first electrically conducting portion is attached to a first membrane of the two membranes and the second electrically conducting portion is attached to the second membrane of the two membranes. The distance between at least a part of the first portion and at least a part of the second portion varies as a function of the pressure outside the sensor.

Furthermore, in accordance with an embodiment of the present invention, at least one of the first portion and the second portion of the resonant circuit includes a spirallike layer of electrically conducting material attached to a surface of a membrane of the two membranes.

Furthermore, in accordance with an embodiment of the present invention, at least one of the first portion and the second portion of the resonant circuit includes a layer of electrically conducting material attached to a surface of a membrane of the two membranes. The layer is shaped as an annular layer having a gap therein. Furthermore, in accordance with an embodiment of the present invention, the first portion and the second portion of the resonant circuit are electrically coupled by an electrically conducting member. The electrically conducting member is configured such that it does not substantially hinder the changing of the distance between the at least part of the first portion and at least a part of the second portion of the resonant circuit when the pressure outside the sensor changes. Furthermore, in accordance with an embodiment of the present invention, the electrically conducting member is selected from an electrically conducting wire, an electrically conducting ribbon, an electrically insulated electrically conducting wire and an electrically insulated electrically conducting ribbon.

Furthermore, in accordance with an embodiment of the present invention, the first portion of the resonant circuit includes a first spiral-like layer of electrically conducting material attached to a surface of the first membrane, and the second portion of the resonance circuit includes a second spiral-like layer of electrically conducting material attached to a surface of the second membrane.

Furthermore, in accordance with an embodiment of the present invention, the first spiral-like layer and the second spiral like layer are configured such that the windings of the first spiral-like layer oppose the windings of the second spiral-like layer.

Furthermore, in accordance with an embodiment of the present invention, the first spiral-like layer and the second spiral like layer are configured such that the windings of the first spiral-like layer are laterally offset with respect the windings of the second spiral-like layer.

Furthermore, in accordance with an embodiment of the present invention, the first spiral-like layer and the second spiral like layer are configured such that the windings of the first spiral-like layer are interdigitated with the windings of the second spiral-like layer. Furthermore, in accordance with an embodiment of the present invention, the first portion of the resonant circuit includes a first spiral-like layer of electrically conducting material attached to a surface of the first membrane, and the second portion of the resonant circuit includes a second layer of electrically conducting material. The second layer is shaped as a single loop. The second layer is attached to a surface of the second membrane. Furthermore, in accordance with an embodiment of the present invention, the second layer is shaped as an electrically conducting single loop selected from a closed single loop and an open single loop having a gap therein.

Furthermore, in accordance with an embodiment of the present invention, the sensor further includes at least one handling member attached to the housing or formed as a part thereof to facilitate handling or grasping of the sensor.

Furthermore, in accordance with an embodiment of the present invention, at least part of the housing includes at least one biocompatible material.

Furthermore, in accordance with an embodiment of the present invention, the passage has a circular cross-section having a diameter equal to or larger than two millimeters.

Furthermore, in accordance with an embodiment of the present invention, the passage has a circular cross-section having a diameter equal to or larger than three millimeters. Furthermore, in accordance with an embodiment of the present invention, the biocompatible material is selected from the group consisting of polytetrafluoroethylene, polyethylene, polypropylene, Parylene® C, and combinations thereof.

Furthermore, in accordance with an embodiment of the present invention, at least part of the sensor includes at least one transparent material. Furthermore, in accordance with an embodiment of the present invention, the transparent material is transparent to at least part of the portion of the electromagnetic spectrum visible to humans.

There is also provided, in accordance with an embodiment of the present invention a method for implanting a sensor in an eye. The method includes the step of Inserting into an eye a sensor including a sealed housing having a passage therein for allowing light to pass through the passage. The housing has walls forming a sealed chamber therebetween. At least one wall of the walls is a movable wall configured for moving in response to changes in the pressure outside the sensor. The sensor also includes a passive electromagnetic resonant circuit. At least one portion of the circuit is mechanically coupled to the at least one movable wall such that the resonance frequency of the resonant circuit varies as a function of the pressure outside the sensor. The method also includes the step of positioning the sensor within the eye to allow part of the light entering the eye to reach the retina of the eye by passing through the passage.

Furthermore, in accordance with an embodiment of the present invention, the sensor also includes at least one optical element attached to the housing and disposed within the passage, and the step of positioning includes positioning the sensor within the eye to allow part of the light entering the eye to reach the retina of the eye by passing through the at least one optical element.

Furthermore, in accordance with an embodiment of the present invention, the at least one optical element is an intraocular contact lens configured for implantation adjacent to the natural lens of an eye, and the step of inserting includes inserting the sensor into the anterior chamber of the eye to dispose the intraocular contact lens adj acent the natural lens of the eye .

Furthermore, in accordance with an embodiment of the present invention, the at least one optical element is a lens configured for replacing the natural lens of an eye, and the step of inserting includes inserting the sensor into the posterior chamber of the eye for replacing the natural lens of the eye following the surgical removal of the natural lens.

Furthermore, in accordance with an embodiment of the method of present invention, the optical element is selected from a lens, a multi-element lens, an optical filter, a light polarizing optical element and combinations thereof.

There is also provided, in accordance with an embodiment of the present invention a composite implantable intraocular lens. The lens includes an optically transparent lens body and a pressure sensor including a sealed housing having a passage therein. The housing is attached to the lens body. The lens body is disposed within the passage. The housmg has walls forming a sealed chamber therebetween. At least one wall of the walls is a movable wall configured for moving in response to changes in the pressure outside the sensor. The sensor also includes a passive electromagnetic resonant circuit. At least one portion of the circuit is mechanically coupled to at least one movable wall such that the resonance frequency of the resonant circuit varies as a function of the pressure outside the sensor.

Furthermore, in accordance with an embodiment of the present invention, the lens body and the sensor are foldable. Furthermore, in accordance with an embodiment of the present invention, the passage has a circular cross-section having a diameter equal to or larger than three millimeters.

Furthermore, in accordance with an embodiment of the present invention, the lens body is attached to the housing of the sensor by a spacer member. Furthermore, in accordance with an embodiment of the present invention, the spacer member is an annular spacer member.

Furthermore, in accordance with an embodiment of the present invention, the composite lens further includes one or more handling members for facilitating the handling or grasping of the composite lens. Furthermore, in accordance with an embodiment of the present invention, the one or more handling members are attached to the housing or are formed as part of the housing.

Furthermore, in accordance with an embodiment of the present invention, the lens body is an implantable contact lens configured to be placed adjacent to the natural lens of an eye, and the sensor is configured to be implanted within the anterior chamber of the eye to enable determining the pressure therein.

Furthermore, in accordance with an embodiment of the present invention, the lens body is configured to replace the natural lens of an eye, and the sensor is configured to be implanted within the posterior chamber of the eye to enable determining the pressure therein.

Furthermore, in accordance with an embodiment of the present invention, the lens body is configured to replace the natural lens of an eye in cataract surgery performed on a patient.

Furthermore, in accordance with an embodiment of the present invention, the lens further includes an additional electrically conducting member attached to the lens body and electrically coupled to the passive electromagnetic resonant circuit to form an extended resonant circuit.

Furthermore, in accordance with an embodiment of the present invention, the additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting material attached to a surface of the lens body.

Furthermore, in accordance with an embodiment of the present invention, the additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting optically transparent material attached to a surface of the lens body. Furthermore, in accordance with an embodiment of the present invention, the electrically conducting optically transparent material comprises indium tin oxide.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings, in which like components are designated by like reference numerals, wherein:

Fig. 1A is a schematic cross-sectional view, illustrating a wireless intraocular implantable pressure sensor constructed in accordance with an embodiment of the present invention; Fig. IB is a schematic front view of the sensor of Fig. 1A as viewed from a direction indicated by the arrow 7 of Fig. 1 A;

Fig. 2 is a schematic diagram illustrating an electrical circuit equivalent of the resonant circuit 14 of Figs. 1A and IB;

Fig. 3 is a schematic, part cross-sectional view of an eye, illustrating a system for wireless intraocular pressure measurement including the wireless intraocular pressure sensor of Figs. 1A and IB implanted within the eye, an external antenna, and excitation and detection circuitry disposed outside the eye, in accordance with an embodiment of the present invention;

Figs. 4A and 4B are schematic cross-sectional views illustrating various different types of intraocular implantable pressure sensors having different configurations, in accordance with additional embodiments of the present invention; Fig. 4C is a schematic top view, illustrating in detail one of the membranes of the sensor of Fig. 4B;

Fig. 5 is a schematic cross-sectional views illustrating another type of intraocular implantable pressure sensor having a resonant -circuit including interdigitated electrical conducting members, in accordance with additional embodiments of the present invention; and

Fig. 6 is a schematic cross sectional view illustrating an implantable intraocular lens including a wireless intraocular pressure sensor, in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Notation Used Throughout The following notation is used throughout this document.

Term Definition

CVD Chemical Vapor Deposition

ICL Implantable contact lens

IOL Implantable Ocular Lens

ITO Indium-Tin oxide

PE Polyethylene

PP Polypropylene

PTFE Polytetrafluoroethylene

The present invention discloses implantable passive wireless electromagnetic pressure sensors and systems for determining intraocular pressure.

Reference is now made to Figs. 1A and IB. Fig. 1A is a schematic cross- sectional view, illustrating a wireless implantable pressure sensor constructed in accordance with an embodiment of the present invention. Fig. IB is a front view of the sensor of Fig. 1A as viewed from a direction indicated by the arrow 7 of Fig. 1 A.

The implantable sensor 10 of Figs. 1A-1B may include a flat hollow annular housing 12 and a resonant circuit 14. The annular housing 12 may include a first annular membrane 12A and a second annular membrane 12B. The annular membranes 12A and 12B may be sealingly attached or glued or welded to each other at their outer circumference 12C and at their inner circumference 12D. The sealed space 16 is a sealed chamber enclosed between the membranes 12A and 12B may includes a gas (not shown) or a gas mixture (not shown) therein. The membranes 12A and 12B may be made from a suitable flexible biocompatible material, such as a suitable plastic material, or the like. For example, the membranes 12A and 12B may be made from Polytetrafluoroethylene (PTFE), or Polyethylene (PE), or Polypropylene (PP), Parylene® C, or the like. Preferably, but not obligatorily, the membranes 12A and 12B may be made from an optically transparent (for light in the human visual range) biocompatible plastic material, but other non-transparent materials may also be used.

The annular housing 12 has an opening (a hole) 20 therein. The opening 20 may be a circular opening disposed at the center of the housing 12 as illustrated in Figs. 1A and IB. The opening 20 may, however, be differently shaped depending on the sensor's structure and shape. For example, the housing 12 may be shaped as a flat polygonal annular housing (not shown) with a polygonal opening (not shown) therein. Furthermore, the housing 12 may be radially symmetrical with respect to the axis 22 (as illustrated in Fig. 1A), but may also be non symmetrically shaped (not shown).

The resonant circuit 14 includes a first electrically conducting spiral member 14A and a second electrically conducting spiral member 14B. The first electrically conducting spiral member 14A may be attached to the first membrane 12 A, and the second electrically conducting spiral member 14B may be attached to the second membrane 12B.

The spiral electrically conducting members 14A and 14B are made from an electrically conducting material, such as, but not limited to, a metal, or any other suitable electrically conducting material. In accordance with one exemplary embodiment of the invention, the spiral members 14A and 14B may be formed by forming a layer of a conducting material or metal (such as, but not limited to, gold, silver, copper, or the like) on the internal surfaces 12E and 12F of the membranes 12A and 12B, respectively, followed by standard lithography methods, using various known techniques such as, photo-resist masking, etching, and the like, as is known in the art. Optically transparent, electrically conducting materials, such as, but not limited to, indium-tin oxide (ITO) or the like, may also be used for forming the members 14A and 14B of the resonant circuit 14, or of any other resonant circuits of the present invention disclosed in detail hereinafter.

Other, different methods for forming the spiral members 14A and 14B may also be used, such as, but not limited to, electroplating, chemical plating, sputtering, chemical vapor deposition, or the like, or any other suitable method known in the art for forming a layer of conducting material on a substrate.

It is noted that the schematic front view of the sensor 10 illustrated in Fig. IB is drawn to show both of the spiral electrically conducting members 14A and 14B as may be seen through a transparent membrane 12A is made from a material. Thus, the spiral electrically conducting members 14A and 14B of the resonant circuit 14 are typically not co-planar as may be seen in the cross-sectional view of Fig. 1 A.

The spiral electrically conducting member 14A is electrically connected to the spiral electrically conducting member 14B by a suitable electrical conductor 14C. The electrical conductor 14C may be any suitable electrically conducting member, such as, but not limited to, an electrically conducting wire, or flat ribbon, or the like. The electrical conductor 14C may be suitably electrically connected to the spiral electrically conducting members 14A and 14B by any suitable method known in the art, such as, but not limited to, welding methods, gluing with an electrically conducting glue (not shown), wire bonding methods, or the like. The electrical conductor 14C may be an electrically insulated conductor, but may also be a non-insulated conductor.

The electrical conductor 14C is configured such that it does not substantially hinder, prevent, or restrict the movement of the membranes 12A and 12B when the pressure outside the sensor 14 changes. Different configurations of the electrical conductor 14C may be used. In accordance, with the embodiment illustrated in Fig. IB, the electrical conductor is suitably disposed within the space 16 of the housing 12 and may have some slack (by having a sufficient length) in order not to substantially hinder, prevent, or restrict the movement of the membranes 12A and 12B when the pressure outside the sensor 44 changes.

In accordance with another embodiment of the invention, the electrical conductor 14C or at least parts thereof may be attached to, or disposed on, or deposited upon the external surfaces 12G and 12H of the membranes 12A and 12B, respectively (this embodiment is not shown in Fig. 1A). The parts of the electrical conductor 14C which may be attached to the external surfaces 12G and 12H, may be properly electrically insulated by a suitable layer (not shown) or coating of a suitable biocompatible electrically insulating material, such as, but not limited to, Parylene® C, or the like. Care must be taken that the design, thickness and flexibility of the electrical conductor 14C (and of the insulation thereof, if used) are adapted to minimized or reduce substantial hindrance or restriction of the membranes 12A and 12B when the pressure outside the sensor 44 changes.

The electrically conducting spiral members 14A and 14B (and ,optionally, the conductor 14C) may be electrically insulated by coating them or the surfaces 12E and 12F with a suitable thin layer of an electrically insulating material. However, the electrically conducting spiral members 14A and 14B (and ,optionally, the conductor 14C) may also be non insulated.

Reference is now made to Fig. 2 which is a schematic diagram illustrating an electrical circuit equivalent of the resonant circuit 14 of Figs. 1A and IB.

The circuit 31 includes a variable inductance LI, a variable capacitor C and a resistor R connected in series, hi the particular embodiment of the resonant circuit 14 of Figs. 1A and IB, the inductance LI schematically represents the variable lumped inductance of the resonant circuit 14 (which includes the spiral electrically conducting member 14A and the spiral electrically conducting member 14B), the capacitor C schematically represents the variable lumped capacitance of the entire resonant circuit 14, and the resistor R schematically represents the lumped resistance of the entire resonant circuit 14. The resonance frequency of the circuit 31 depends on the values of LI, C and R. In operation, when an external pressure acts on the membranes 12A and 12B of the housing 12, the membranes 12A and 12B may deform, or may change their shape and/or their position relative to each other as is known in the art. If the pressure acting on the membranes 12A and 12B is greater than the pressure of the gas (or gases) within the sealed space 16, the membranes 12A and 12B may move closer to each other, and the distance between the spiral electrically conducting members 14A and 14B diminishes. If the pressure acting on the membranes 12A and 12B is smaller than the pressure of the gas (or gases) within the sealed space 16, the membranes 12A and 12B may move away from each other, and the distance between the spiral electrically conducting members 14A and 14B increases.

It is noted that since the membranes 12A and 12B may be concave membranes, when the membranes 12A and 12B deform or change their shape or move as a result of a pressure change, some parts of the membranes may move or change their shape differently than other parts of the same membranes. Thus, the change of the distance between some of the windings of the electrically conducting members 14A and 14B may be different from the change of the distance between some other of the windings of the electrically conducting members 14A and 14B. In other words, the changes in the distance between different parts of the members 14A and 14B in response to a change in the pressure acting on the sensor 10 may not be uniform.

It is further noted that while the sensor 10 is shown in a configuration in which both of the membranes 12A and 12B are flexible or deformable membranes, and both of the membranes may deform or change their shape or move with respect to each other, other embodiments of the present invention may include configurations in which only one of the membranes 12A and 12B is a flexible or deformable or movable membrane, while the remaining membrane is a substantially non-flexible membrane or a substantially non-deformable membrane which is sufficiently rigid and does not change its shape or deform in response to changes of the pressure outside the sensor. The rigid membrane may be made rigid by fabricating it from a material or materials (or composite) having sufficient mechanical strength and greater rigidity than the material or materials (or composite) included in the more flexible or more deformable membrane of the sensor. In accordance with another embodiment of the present invention, one membrane

(not shown) of the sensor may be made substantially rigid by increasing its thickness relative to the thickness of the second flexible or deformable membrane. It may further be possible to change both the thickness and the material composition of one of the membranes to increase its rigidity. Furthermore, while the membranes 12A and 12B of the sensor 10 are implemented as concave or convex membranes having a curvature, one or more of the membranes may be a planar or nearly planer membrane. Such nearly planar membranes are shown, for example, in Fig. 5 hereinbelow, but many other configurations may also be used including but not limited to generally annular sensors having a passage therethrough and having any combination of flat and/or concave/convex membranes with at least one membrane being a movable or deformable or flexible membrane.

Further yet, while a simple form of mechanically coupling the spiral electrically conducting members 14A and 14B to the membranes 12A and 12B is the direct attachment of the electrically conducting members 14A and 14B to the membranes 12A and 12B as shown in Figs. 1A and IB, one or more parts of the resonant circuit of the sensor of the present invention may be mechanically coupled to one or more of the movable or deformable walls of the sensor by any mechanical coupling means known in the art. For example, one or more of the spiral electrically conducting members 14A and 14B of the resonant circuit 14 of Figs. 1A and IB may be mechanically coupled to one the membranes 12 by a suitable coupling member (not shown) or coupling layer (not shown) as is known in the art.

Generally, many of the different configurations and variations known in the art for forming wireless pressure sensors with passive electromagnetic jesonant circuits may be used to implement the intraocular pressure sensor having a passage or opening of the present invention. Thus, in accordance with another exemplary embodiment of the present invention, the membrane 12A of the sensor 10 may be a substantially rigid membrane while the membrane 12B may be a flexible or deformable or movable membrane. Similarly, in accordance with another embodiment of the present invention both of the membranes 12A and 12B may be configured as flat rigid annular membranes (not shown) each membrane having an opening therein (similar to the opening 20 of Figs. 1A and IB), and the rigid flat membranes may be sealingly attached to each other by a suitably flexible connecting collar (such as by two accordion-like cylinders or crimped cylinders (not shown) suitably sealingly attached to the outer and inner circumference or rims of the rigid membranes. While the value of R may typically be negligibly affected by changes in the distance between the spiral electrically conducting members 14A and 14B, the values of C (the variable lumped circuit capacitance of the resonant circuit 14 in the example illustrated in Figs. 1A and IB) and of LI (the variable lumped inductance of the resonant circuit 14,) may be substantially affected by changes in the distance between the spiral electrically conducting members 14A and 14B of the resonant circuit 14. Changes in the pressure acting on the sensor 10 may thus lead to changes in the resonance frequency of the resonant circuit 14 of the sensor 10. These changes may be detected and the pressure acting on the sensor 10 may thus be determined, as is known in the art. The methods for determining the pressure acting on sensors having resonant circuits (such as, for example, the resonant circuit 14 of the sensor 10) from the resonance frequency of the resonant circuit, are well known in the art, are not the subject matter of the present invention, and are therefore not described in detail hereinafter.

Briefly, any of the methods for radio frequency (RF) excitation of a sensor's resonant circuit and for detection of the circuit's resonant frequency and determining the pressure therefrom disclosed in detail in U.S. Patent 4,127,110, in the article by Carter C. Collins, and in the article by Andrew DeHennis and Kensall D. Wise, or similar methods using RF excitation and detection an external antenna, may be used, as is known in the art. Such methods may include, but are not limited to, passive load modulation methods (these methods may require suitable on-sensor circuitry for a wireless system to actively modulate a reflected load on a coupled primary inductor, as disclosed in detail by K. Stangel et al., in an article entitled " A Programmable Intraocular CMOS Pressure Sensor System Implant", published in IEEE Journal of Solid State Circuits, Nol. 36, July 2001, pp. 323-324), incorporated herein by reference in its entirety for all purposes, and other resonant peak monitoring methods, as is known in the art.

Reference is now made to Fig. 3 which is a schematic part cross-sectional view of an eye, illustrating a system for wireless intraocular pressure measurement including the wireless intraocular pressure sensor of Figs. 1A and IB implanted within the eye, an external antenna, and excitation and detection circuitry disposed outside the eye, in accordance with an embodiment of the present invention.

The system 28 includes a sensor 10 which may be placed within the vitreous body 32 of an eye 30, and may be disposed behind the lens 34 of the eye 30. The sensor 10 may be positioned such that light rays (such as, for example, the light rays 36 A and 36B) entering the eye and focused by the lens 34 may pass through the opening 20 of the sensor 10 and reach the retina 38 without being obstructed. The axis 27 passes through the center point 37 of the annular sensor 10 and intersects the center of the fovea 39.

Preferably, the diameter of the opening 20, and the distance between the sensor 10 and the lens 34 may be adapted such that no obstruction or rriinimal possible obstruction by the sensor 10 of light rays entering the eye and exiting from the lens 34 occurs, to ensure undisturbed or minimally disturbed visual function, respectively.

The system 28 further includes an external antenna 26 which may be disposed outside the eye 30. The antenna 26 may include a coil 26A made from an electrically conducting material such as an insulated metal wire, made from copper, silver, or any other suitable electrically conducting material. The external antenna 26 and the intraocularly disposed resonance circuit 14 of the sensor 10 may together form a loosely coupled transformer, as is known in the art.

The coil 26A may include one or more windings or loops of electrically conducting materials. The coil 26 may or may not be an axi-symmetric coil and may also be a coil having an irregular shape. Preferably (but not obligatorily), the coil 26A is a substantially circular coil having an approximate center point 23. Other coil forms may however also be used, including but not limited to,_coils having a regular polygonal structure, elliptically shaped coils, axially extended coils, irregularly shaped coils, or any other coil shapes and structures which are known in the art and suitable for use in loosely coupled transformer circuits.

The terminals 26B and 26C of the coil 26A may be suitably attached to excitation and detection circuitry 35, as is known in the art, for performing resonant peak passive telemetry, as is known in the art and disclosed in detail hereinabove, and to determine the intraocular pressure from the measured resonant peak, as is known in the art.

The advantage of the intraocular sensor 10 and of other intraocular implantable pressure sensors disclosed hereinafter over other implantable pressure sensors known in the art is that the opening in the disclosed sensors (such as, for example, the circular opening 20 of the sensor 10) and the sensor's positioning within the eye 30 allows the external antenna 26 to be disposed at a sufficiently large distance from the eye 30 to make practical and adequately accurate intraocular pressure measurements possible. Typically, for a sensor 10 configured for having an approximate inner diameter (which is equivalent to the diameter of the opening 20) of 3 millimeters or larger, the approximate allowable separation between the antenna 26 and the sensor 10 is about 3 centimeters orTarger. Thus, for a sensor having the above indicated approximate dimensions, the distance between the center point 23 of the circular coil 26A and the center point 38 of the circular opening 20 may practically be 3 centimeters or even larger. Such a distance may allow the practical attachment of the antenna 26 on or within a suitable frame or member (not shown in Fig. 3) which may be worn by a patient. Such a frame may be shaped similar to a pair of spectacles. Alternatively, the antenna 26 may be suitably attached to a real pair of spectacles which are normally (or, optionally, post operatively) worn by the patient for vision correction, or for other purposes.

If such a spectacle-like frame is used, the antenna 26 may be suitably coupled to the excitation and detection circuitry 35 as is schematically illustrated in Fig. 3. Practically, the excitation and detection circuitry 35 may include a miniaturized integrated circuit (IC) and a suitable power source (not shown), and may be suitably installed within, or suitably attached to, or suitably embedded within the frame or spectacles. For example, one or more such excitation and detection circuitry 35 or parts thereof may be installed within, or suitably attached to, or suitably embedded within the handles of the spectacles or spectacles-like frame, or the part or parts of the spectacles or spectacles-like frame which are used to fix or attach the frame to the ears of the patient. Other suitable methods for attaching or affixing the antennas 26 and/or the excitation and detection circuitry 35 to frames worn by the patient may ,however, be used, as is known in the art.

Alternatively, the excitation and detection circuitry 35 may be included within a separate unit (not shown) which may include a suitable power source (not shown). Such a separate unit may be worn by the patient (such as, for example, by being attached to a belt worn by the patient, or carried in the patient's pocket, or the like). In cases in which such a separate unit is used, the antenna 26 may be suitably coupled to the unit (not shown) by suitable insulated electrically conducting wires (not shown), or by other suitable electrical conductors. It is noted that to improve the signal to noise ratio in the measurement and to properly determine the resonance frequency of the sensor 10 (of Fig. 3), the antenna 26 and the sensor 10 may need to be suitably oriented and aligned relative to each other as is known in the art for loosely coupled transformers and passive resonant circuits. The particular arrangement and alignment of the intraocular sensor (such as, for example, the sensor 10 of Fig. 3) and the external antenna (such as, for example, the antenna 26 of Fig. 3) relative to each other may depend, inter alia, on the structure, shape, and dimensions of the resonant circuit included in the sensor, and on the structure, shape, and dimensions of the external antenna, as is known in the art. Deviations from a substantially parallel arrangement of the electrical conductors

14A and 14B comprising the resonant circuit 14, and the windings of the coil 26 A (as shown in the non-limiting example of Fig. 3) may result in reducing the signal to noise ratio of the measured signal, which may affect the measurement quality.

Thus, in accordance with an embodiment of the present invention, if the coil 26A of the antenna 26 is attached to a spectacle-like frame or device, the spectacle-like frame or device may include an adjustable attaching mechanism (not shown) to adjust the alignment of the coil 26A relative to the resonant circuit 14 of the sensor 10. For example, the attaching mechanism may include adjustment screws (not shown) which may be turned to move the coil 26 relative to the spectacle-like frame or device (not shown). Other, different, adjustment mechanisms or devices may be used for adjusting the position and/or orientation of the coil 26 relative to the spectacle-like frame or device, as is known in the art. The advantage of such adjustment mechanisms is that they may allow the fine tuning and individual adjustment of the position and/or orientation of the coil 26 to each individual patient in accordance with the individual patient's sensor positioning within the eye, in order to compensate for individual differences in implantation position of the patient's sensor within the eye. Another advantage is the ability of adjusting the position and/or orientation of the coil 26 to allow for individual differences in the facial and cranial anatomy of different patients, such as, but not limited to, the patient's inter-ocular distance, which may be necessary for optimization of the signal to noise ratio in an individual patient. It is noted that more than one sensor and more than one antenna may be used, for intraocular pressure measurement in more than one eye. For example, if necessary, two implantable intraocular pressure sensors (such as, but not limited to the sensor 10 of Fig. 3) may be implanted in the patient, one sensor may be implanted in each eye of the patient. In such a case, two antennas (such as, for example, the antenna 26) may be used, such that one antenna may be used for each implanted sensor. The antennas may be integrated within or attached to spectacles or other types of frames which may be worn by the patient, as disclosed in detail hereinabove.

It will be appreciated by those skilled in the art that the structure and configuration of the sensor 10 illustrated in Figs. 1A, IB, and 3 is given by way of example only, and that many variations in the structure and configuration of the sensor may be made, including, but not limited to, modifications in the size, shape, configuration and composition of the annular housing of the intraocular sensor (such as, for example, the exemplary annular housing 12 of Figs. 1A and IB), and/or of any of the membranes included in the sensor's housing. Similarly, many variations in the structure and configuration of the sensor's resonant circuit may be made, including, but not limited to, modifications in the size, shape, configuration, and composition of the resonant circuit, and modifications in the distance between and the geometrical relationship between the components of the resonant circuit of the intraocular sensor (such as, for example, the exemplary spiral electrically conducting members 14A and 14B of the resonant circuit 14 of Figs. 1A and IB). Such design modifications in the sensor or it's components are considered within the scope and spirit of the present invention.

Reference is now made to Figs. 4A, 4B and 4C which are schematic cross- sectional views illustrating various exemplary different types of intraocular implantable pressure sensors having different configurations, in accordance with additional embodiments of the present invention.

In Fig. 4 A, the sensor 40 may include an annular housing 12 similar to the annular housing 12 of the sensor 10 (of Fig. 1A). The sensor 40 further includes a resonant circuit 44 attached to, or deposited on, or plated on the inner surface membranes 12A and 12B, as disclosed in detail hereinabove for the resonant circuit 14 of the sensor 10. The resonant circuit 44 includes a first electrically conducting spiral member 44 A and a second electrically conducting spiral member 44B. The first electrically conducting spiral member 44A may be attached to the first membrane 12 A, and the second electrically conducting spiral member 44B may be attached to the second membrane 12B.

The spiral electrically conducting members 44A and 44B may be made from an electrically conducting material, such as, but not limited to, a metal, (such as, but not limited to, gold, silver, copper, or the like), or any other suitable electrically conducting material, as disclosed in detail hereinabove for the spiral members 14A and 14B of the sensor 10. Optically transparent, electrically conducting materials, such as, but not limited to, indium-tin oxide (ITO) or the like, may also be used for forming the members 44A and 44B of the resonant circuit 44, or of any other resonant circuits of the present invention disclosed in detail hereinafter. h accordance with one exemplary embodiment of the invention, the spiral members 44A and 44B may be formed by forming a layer of a conducting material or metal on the internal surfaces 12E and 12F of the membranes 12A and 12B, respectively, followed by standard lithography methods, using various known techniques such as, photo-resist masking, etching, and the like, as is known in the art. Other different methods for forming the spiral members 44A and 44B may also be used, such as, but not limited to, electroplating, chemical plating, sputtering, or the like, or any other suitable method known in the art.

The spiral members 44 A and 44B are different than the spiral members 14A and 14B, in that while the spiral members 14A and 14B are not opposed to each other, but are rather interleaved, the spiral members 44A and 44B of the sensor 40 are opposed to each other (in a direction parallel to the axis 47 of the sensor 40) as illustrated in Fig. 4A.

The spiral electrically conducting member 44A may be electrically connected to the spiral electrically conducting member 44B by a suitable electrical conductor 44C.

The electrical conductor 44C may be any suitable electrically conducting member, such as, but not limited to, an electrically conducting wire, or flat ribbon, or the like. The electrical conductor 44C may be suitably electrically connected to the spiral electrically conducting members 44A and 44B by any suitable method known in the art, such as, but not limited to, welding, gluing with an electrically conducting glue (not shown), wire bonding methods, or the like. The electrical conductor 44C may be an electrically insulated conductor. However, the electrical conductor 44C may also be a non-insulated conductor. Similar to in the electrical conductor 14C, the electrical conductor 44C is configured such that it does not substantially hinder, prevent, or restrict the movement of the membranes 12A and 12B when the pressure outside the sensor 44 changes. The electrical conductor 44C may be implemented in accordance with any of the layouts and implementations disclosed in detail hereinabove for the electrical conductor 14C (including, but not limited to, being attached to, or deposited on the internal or external surfaces, 12G and 12H of the membranes 12A and 12B, respectively, and being insulated or non-insulated).

The electrically conducting spiral members 44A and 44B (and optionally, the conductor 14C) may be electrically insulated by coating them or the surfaces 12E and 12F with a suitable thin layer of an electrically insulating material (the insulating material is not shown for the sake of clarity of illustration). However, the electrically conducting spiral members 44A and 44B may also be non-insulated conducting members.

The design of the resonant circuit 44 may be advantageous in that it may have a higher lumped capacitance value, due to the opposed relationship of the electrically conducting spiral members 44 A and 44B. As the membranes 12A and 12B move towards or away from each other, the lumped capacitance of the resonant circuit 44 may change, contributing to a change in the detectable resonance frequency of the resonant circuit 44. In Fig. 4B, the sensor 50 may include an annular housing 12 similar to the annular housing 12 of the sensor 10 (of Fig. 1A).

The sensor 50 may further include handling members 55A and 55B which may be attached, or glued, or otherwise suitably affixed to the housing 12. The handling members 55 A and 55B may be used for handling and grasping the sensor 50 using any specially designed or standard surgical tool (not shown) during the surgical insertion procedures of inserting the sensor into an eye, as is known in the art. The handling members 55A and 55B may be of any shape, dimensions, and material composition known in the art which is suitable for handling, grasping and/or folding of the sensor 50 (if the sensor 50 is implemented as a foldable sensor by suitable choice of materials and structural design). The sensor 50 may further include a resonant circuit 54 attached to, or deposited on, or plated on the inner surfaces of the membranes 12A and 12B, as disclosed in detail hereinabove for the resonant circuit 14 of the sensor 10. The resonant circuit 54 includes an electrically conducting spiral member 54A and a relatively broad electrically conducting loop member 54B formed as an annular layer having a gap therein forming an open loop. The electrically conducting spiral member 54A may be attached to the first membrane 12 A, and the electrically conducting loop member 54B may be attached to the second membrane 12B.

The electrically conducting members 54A and 54B may be made from an electrically conducting material, such as, but not limited to, a metal, (such as, but not limited to, gold, silver, copper, or the like), or any other suitable electrically conducting material, as disclosed in detail hereinabove for the spiral members 14A and 14B of the sensor 10. Optically transparent, electrically conducting materials, such as, but not limited to, indium-tin oxide (ITO) or the like, may also be used for forming the members 54A and 54B of the resonant circuit 54, or of any other resonant circuits of the present invention disclosed in detail hereinafter. In accordance with one exemplary embodiment of the invention, the members 54A and 54B may be formed by forming a layer of a conducting material or metal on the internal surfaces 12E and 12F of the membranes 12A and 12B, respectively, followed by standard lithography methods, using various known techniques such as, photo-resist masking, etching, and the like, as is lαiown in the art. Other different methods for forming the members 54A and 54B may also be used, such as, but not limited to, electroplating, chemical plating, sputtering, or the like, or any other suitable method known in the art.

The members 54A and 54B are different than the spiral members 14A and 14B, in that the broad loop member 54B is a broad flat electrically conducting member opposed to the spiral windings of the spiral member 54 A (in a direction parallel to the axis 57 of the sensor 50) as illustrated in Fig. 4A. Reference is now briefly made to Fig. 4C which is a schematic top view of the membrane 12B of the sensor 50 of Fig. 4B. The broad loop member 54B is attached to, or deposited on, or otherwise affixed to the inner surface 12F of the membrane 12B as illustrated. The membrane 12B has a circular opening 51 therein. The broad loop member 54B is shaped as an open loop having a gap 55 therein. It is, however noted that, in accordance with another embodiment of the present invention, the broad loop member 54B may also be configured as a closed loop (not shown in Fig. 4C) having no gap therein.

The handling member 55 A (Fig. 4C) may be attached to or may form an integral part of the membrane 12B. The handling member 55B (Fig. 4B) is not shown in Fig. 4C, and may be attached to or may form an integral part of the membrane 12 A as shown in Fig. 4B. Alternatively, in accordance with another embodiment of the invention, the handling members 55 A and 55B may both be attached to, or integral parts of the membrane 12B (this embodiment is not shown in Figs 4B and 4C). Furthermore, in accordance with yet another embodiment of the invention, the handling members 55 A and 55B may both be attached to, or integral parts of the membrane 12A (this embodiment is not shown in Figs 4B and 4C).

Returning to Fig. 4B, the spiral electrically conducting member 54 A may be electrically connected to the loop member 54B by a suitable electrical conductor 54C. The electrical conductor 54C may be any suitable electrically conducting member, such as, but not limited to, an electrically conducting wire, or flat ribbon, or the like. The electrical conductor 54C may be suitably electrically connected to the spiral electrically conducting member 54A and to the loop member 54B by any suitable method known in the art, such as, but not limited to, welding, gluing with an electrically conducting glue (not shown), wire bonding methods, or the like. The electrical conductor 54C may be an electrically insulated conductor or may be a non-insulated conductor.

Similar to the electrical conductors 14C and 44C, the electrical conductor 54C is configured such that it does not substantially hinder, prevent, or restrict the movement of the membranes 12A and 12B when the pressure outside the sensor 54 changes. The electrical conductor 54C may be implemented in accordance with any of the layouts and implementations disclosed in detail hereinabove for the electrical conductors 14C and 44C (including, but not limited to, being attached to, or deposited on the internal or external surfaces, 12G and 12H of the membranes 12A and 12B, respectively, and being insulated or non-insulated).

^"The electrically conducting spiral member 54A and the loop member 54B (and ,optionally, the conductor 54C) may be electrically insulated by coating them, or the surfaces 12E and 12F, with a suitable thin layer of an electrically insulating material (the insulating material is not shown for the sake of clarity of illustration). The electrically conducting spiral member 54A and the loop member 54B (and optionally, the conductor 54C) may, however, also be electrically non-insulated members. The design of the resonant circuit 54 may be advantageous in that it may have a lumped capacitance value which may even be higher than the lumped capacitance value of the sensor 44 of Fig. 4A, due to the opposed relationship of the electrically conducting spiral member 54A of broad loop member 54B, and due to the larger surface area of the broad loop member 54B. As the membranes 12A and 12B move towards or away from each other, the lumped capacitance of the resonant circuit 54 may substantially change while the changes in the lumped inductance of the resonant circuit 54 may be small or even negligible, thus, the main contributor to the change in the detectable resonance frequency of the resonant circuit 54 may be the change in the lumped capacitance of the resonant circuit 54. Reference is now made to Fig. 5 which is a schematic cross-sectional view illustrating another type of intraocular implantable pressure sensor having a resonant circuit including interdigitated electrical conducting members, in accordance with an additional embodiment of the present invention.

In Fig. 5, the sensor 60 may include an annular housing 62. The housing 62 includes two membranes 62A and 62B which are sealingly attached to each other, by a suitable glue (not shown) or by thermal press welding, or by any other suitable method known in the art. The annular housing 62 has a sealed space 66 therein. The space 66 may be filled with a gas or a gas mixture as disclosed hereinabove for the space 16 of the sensor 10. As illustrated in Fig. 5, substantial parts of the inner surfaces 64E and 64F of the membranes 64 A and 64B, respectively, may be (optionally, but not obligatorily) substantially parallel to each other. It is noted that, while the membranes 62A and 62B of the sensor 60 may be different than the membranes 12A and 12B of the sensor 10 in shape and configuration, the membranes 62A and 62B may be made from flexible materials, such as, but not limited to, plastic materials, including, inter alia, PTFE, PP, PE and Parylene® C, or the like, as described in detail for the membranes 12A and 12B hereinabove.

The sensor 60 further includes a resonant circuit 64 attached to, or deposited on, or plated on the inner surfaces 64E and 64F of the membranes 62 A and 62B, respectively. The resonant circuit 64 may include a first electrically conducting spiral member 64A and a second electrically conducting spiral member 64B. The first electrically conducting spiral member 64A may be attached to the first membrane 62A, and the second electrically conducting spiral member 64B may be attached to the second membrane 62B.

The spiral electrically conducting members 64A and 64B may be made from an electrically conducting material, such as, but not limited to, a metal, (such as, but not limited to, gold, silver, copper, or the like), or any other suitable electrically conducting material, as disclosed in detail hereinabove for the spiral members 14A and 14B of the sensor 10. Optically transparent, electrically conducting materials, such as, but not limited to, indium-tin oxide (ITO) or the like, may also be used for forming the members 64A and 64B of the resonant circuit 64, or of any other resonant circuits of the present invention disclosed in detail hereinafter.

In accordance with one exemplary embodiment of the invention, the spiral members 64A and 64B may be formed by forming a layer of a conducting material or metal on the internal surfaces 62E and 62F of the membranes 62 A and 62B, respectively, followed by standard lithography methods, using various known techniques such as, photo-resist masking, etching, and the like, as is known in the art. Other different methods for forming the spiral members 64A and 64B may also be used, such as, but not limited to, electroplating, chemical plating, sputtering, chemical vapor deposition (CND) methods or the like, or any other suitable method known in the art for forming a layer of conducting material on a substrate. The spiral members 64A and 64B are different than the spiral members 14A and 14B. The thickness HI of the spiral member 64 A and the thickness H2 of the spiral member 64B may be substantially greater than the thickness of the spiral members 14A and 14B. The thickness HI of the spiral member 64A may be equal to the thickness H2 of the spiral member 64B. Alternatively, in accordance with another embodiment of the invention, the thickness HI of the spiral member 64A may be larger or smaller than the thickness H2 of the spiral member 64B.

The spiral members 64 A and 64B are also different than the spiral members 14A and 14B in that th'e spiral members 44 A and 44B are interdigitated, or interleaved such that the windings of the spiral member 64A may partially overlap some (or portions) of the windings of the spiral 64B along a direction parallel to the axis 67 of the sensor 60, as illustrated in Fig. 5.

The electrically conducting spiral member 64A may be electrically connected to the spiral electrically conducting member 64B by a suitable electrical conductor 64C. The electrical conductor 64C may be any suitable electrically conducting member, such as, but not limited to, an electrically conducting wire, or flat ribbon, or the like. The electrical conductor 64C may be suitably electrically connected to the spiral electrically conducting members 64A and 64B by any suitable method known in the art, such as, but not limited to, welding, gluing with an electrically conducting glue (not shown), wire bonding methods, or the like. The electrical conductor 64C may be an electrically insulated conductor to prevent accidental short circuiting. The insulation of the electrical conductor 64C may be implemented by using an electrical insulator layer 69 disposed over the electrical conductor 64C, or by using any other electrical insulation method known in the art. Preferably, since the insulator layer may be in contact with patient tissues, the insulator layer 69 is a biocompatible insulator layer.

Alternatively, the electrical conductor for electrically connecting the spiral member 64A with the spiral member 64B may also be a non-insulated conductor (not shown) which may pass within the space 66 of the housing 62. Such a design (not shown in Fig. 5) for the electrical conductor may be similar to the design illustrated for the electrical conductor 44C of the sensor 40 (of Fig. 4A). Similar to the electrical conductors 14C, 44C, and 54C, the electrical conductor 64C may be sufficiently flexible, and may be configured such that it does not substantially binder, prevent, or restrict the movement of the membranes 62A and 62B when the pressure outside the sensor 64 changes. The electrical conductor 64C may be implemented in accordance with any suitable configuration of the layouts and configurations disclosed in detail hereinabove for the electrical conductors 14C, 44C, and 54C (including, but not limited to, being attached to, or deposited on the internal or external surfaces, 62G and 62H of the membranes 62 A and 62B, respectively, and being insulated or non-insulated). The electrical insulator layer 69 may be advantageous in preventing undesirable short circuiting, and in increasing the lumped capacitance of the resonant circuit 64 due to the high dielectric constant of the layer of electrically insulating material.

The design of the resonant circuit 64 of the sensor 60 may be advantageous in that it may have a higher lumped capacitance value, due to the partial overlap between the interdigitated electrically conducting spiral members 64A and 64B. As the membranes 62A and 62B move towards or away from each other, both the lumped capacitance of the resonant circuit 64, and the lumped inductance of the resonant circuit 64 may change substantially, and may thus contribute to a change in the detectable resonance frequency of the resonant circuit 44. Reference is now made to Fig. 6 which is a schematic cross sectional view illustrating a composite implantable intraocular lens including a wireless intraocular pressure sensor, in accordance with another embodiment of the present invention.

The implantable composite lens 70 may include an optical lens body 72 and a wireless sensor 80 suitably attached to the lens body 72. The sensor 80 may be similar in construction and operation to any of the sensors 10, 40, 50, and 60, disclosed hereinabove. The sensor 80 may include a resonant circuit 84, which may be similar to the resonant circuit 14 of the sensor 10 in structure and operation. The resonant circuit 84 may include a first spiral electrically conducting member 84A, a second spiral electrically conducting member 84B, and an electrical conductor 84C for electrically connecting the members 84A and 84C. The first spiral electrically conducting member 84A, the second spiral electrically conducting member 84B, and the electrical conductor 84C may or may not be insulated, as disclosed in detail hereinabove for the first spiral electrically conducting member 14A, the second spiral electrically conducting member 14B and the conductor 14C of the sensor 10.

The lens body 72 may be any type of suitable implantable intraocular lens known in the art. The details of the construction, design, and implantation of intraocular implantable lenses are well known in the art, are not the subject matter of the present invention and are therefore not disclosed in detail hereinafter.

In accordance with one embodiment of the invention, the lens 72 may be attached to the sensor 80 by suitable attachment means. For example, the lens 72 may be attached to the sensor 80 by a suitable spacer member 74 (Fig. 6). Alternatively, the lens 72 may be directly attached to the sensor 80 by a suitable biocompatible glue (not shown) or the like.

In accordance with another different embodiment of the invention, the lens 72, and the sensor 80 may be formed or manufactured as a single integrated unit. The handling members 75 A and 75B may be suitably attached to the sensor 80.

The handling members 75A and 75B may be similar in design to the handling tabs or members used in intraocular implantable lenses, as is known in the art. The handling members 75A and 75B may also be formed as an integral part of the sensor 80. The handling members 75A and 75B may be used to handle the composite lens 70 during the lens implantation surgical procedure, as is lαiown in the art.

It is noted that the handling members 75A and 75B may have any suitable shape and configuration known in the art, and are not limited to the exemplary shape illustrated in Fig. 6.

The shape of the lens 72 illustrated in the exemplary embodiment of Fig. 6, is suitable for use for replacing the natural lens of a patient in cases were surgical procedures for extracting a cataract are performed, and in which the cataract is removed and the composite lens 70 may be inserted in its place. The shape and dimensions of the lens 72 may be similar (but not necessarily identical to) to the shape and dimensions of implantable ocular lens (IOL) designs known in the art and usable for replacing the patient's natural lens (due to cataract formation or other reasons). It is, however, noted that in accordance with other embodiments of the composite lens of the present invention the lens 72 may be differently shaped to adapt the composite lens for other procedures. For example, the lens 72 may have other shapes and configurations which may be similar to implantable contact lens (ICL) designs, known in the art and suitable for implantation in front of (and not as a replacement of) the patient's natural lens in procedures which are lαiown in the art for correction of vision impairment of highly myopic patients. In such myopic patients, the ICL is surgically placed in front of the patient's natural lens without removing the natural lens. In cases in which the implantable composite lens (not shown) is placed adjacent to the lens 34 within the anterior chamber of the eye 30 similar to the placement of an ICL, the sensor included in the composite lens may enable the measurement of the pressure in the anterior chamber of the eye. hi accordance with an embodiment of the invention, the components of the composite lens 70, including, inter alia, the sensor 80, may be flexible and foldable components, and may be made from suitably pliable and foldable materials in order to enable the folding of the composite lens 70 during it's insertion into the eye.

In accordance with another embodiment of the present invention, additional electrically conducting members (not shown in Fig. 6) may be included in the composite lens of the invention. A thin spiral comprising an electrically conducting layer may be formed on or deposited upon or otherwise attached to the surface of the lens 72. For example, an optically transparent, electrically conducting spiral made from a thin layer of indium-tin oxide (ITO) may be attached on the surface 72A or on the surface 72B of the lens 72. Typically, this spiral member may be disposed on the surface 72A or on the surface 72B near the peripheral part of the lens 72 close to the spacer member 74. This electrically conducting spiral (not shown) may be suitably electrically connected to one of the members 84A and 84B of the sensor 80 (which member may be in an open loop configuration) by a suitable electrically conducting connecting member (not shown). The thin ITO layer of this electrically conducting spiral may be covered by a layer of transparent biocompatible material (layer is not shown), such as, but not limited to, Parylene® C, or the like, to prevent contact of the ITO with the vitreous body 32. The use of such an optically transparent, electrically conducting spiral disposed on the peripheral part of the lens 72 may be advantageous since it increases the number of windings in the resonant circuit (as compared to the number of windings of the members 84A and 84B of the sensor 80 taken alone) which may improve the tuning and performance of the resulting extended resonant circuit (not shown). The use of an optically transparent material such as ITO in this additional spiral member may allow light to pass through the additional spiral member without undue impairment of visual function while significantly improving the performance and tunability of the resulting extended resonant circuit. The various different embodiments of the composite lens of the present invention may be used for determining the intraocular pressure in combination with one or more external antenna and appropriate excitation/and detection circuitry (such as, but not limited to, the exemplary antenna 26 and the excitation and detection circuitry 35 of Fig. 3), or any other similar antenna and circuitry components usable for wireless intraocular pressure measurement known in the art.

Moreover, while the sensors, the sensor systems, and the composite lenses including sensors of the present invention has been described and illustrated with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made which are within the scope and spirit of the invention.

For example, many of the parameters of the sensors and sensor components of the present invention may be modified or changed depending, inter alia, on the particular design and application of the sensor. The parameters which may be modified by the person skilled in the art, may include, but are not limited to, the shape, configuration, dimension and material composition of the sensor's housing (such as, but not limited to, the housing of the sensors 10, 40, 50, 60, and 80), the shape, dimensions, cross-sectional area, equivalent circuit electrical properties, and material composition of the resonant circuit included in the sensor (such as, but not limited to, the resonant circuits 14, 44, 54, 64, and 84), the shape, dimensions, cross-sectional area, material composition, and spatial interrelationship of the different components of the resonant circuit included in the sensor (such as, but not limited to, the electrically conducting members 14 A, 14B and the conductor 14C, the electrically conducting members 44A, and 44B, and the conductor 44C, the electrically conducting members 54A, 54B, and the conductor 54C, the electrically conducting members 64A, 64B, and the conductor 64C, and the electrically conducting members 84A, 84B, and the conductor 84C), the shape, dimensions, cross-sectional area, and material composition of the lens 72, the shape, dimensions, cross-sectional area, and material composition of the handling members (such as, but not limited to, the handling members 55A and 55B, and 75A and 75B). A3. Furthermore, the housing of the sensors of the present invention may be modified into any suitable desired form of housing, including but not limited to, a flat annular housing, a flat regular polygonal annular housing, an annular housing having a flat ellipsoidal cross-section and a non-symmetrical housing having an irregular shape.

Similarly, the passage or opening in the housing of the sensors of the present invention may be any suitable passage or opening suitable for passing light therethrough such as, but not limited to, a passage having a circular cross-section, a passage having a polygonal cross-section, a passage having an ellipsoidal cross-section, a passage having a regular polygonal cross-section, and any suitable type of irregularly shaped passage.

It is also noted that the sensors of the present invention, such as, but not limited to the sensors 10, 40, 50, and 60, may be implanted at various different positions within the vitreous body 32 of the eye 30. The dimensions of the sensors (such as but not limited to the sensors 10, 40, 50, and 60), and the dimensions of the openings of the sensors (such as but not limited to the openings 20, 51, 61) may be adapted to, or designed in accordance with, inter alia, the desired distance between the lens of the eye and the implanted sensor (such as, for example, the desired distance between the lens 34 and the sensor 10 of Fig. 3). Additionally, the permissible distance between the lens (such as, for example, the lens 34 of Fig. 3) and the implanted sensor (such as, for example the sensor 10 of Fig. 3) may be determined, inter alia, by the dimensions of the sensor's opening (such as, for example the opening 20 of the sensor 10), the dimensions, configuration, and electrical properties of the sensor's resonant circuit (such as, for example, the resonant circuit 14), and the dimensions, distance from the eye, configuration, and electrical properties of the excitation and detection circuitry coupled to the resonant circuit of the implanted sensor (such as, for example, the excitation and detection circuitry 35 of Fig. 3).

It is noted that, while some of the embodiments of the sensors of the present invention (such as, for example, the embodiment illustrated in Fig. 6) a lens is disposed in the passage or opening of the implantable pressure sensor, generally, any other suitable desired optical element may be disposed within the passage or attached to the housing of the sensor. For example, the lens 72 of Fig. 6 may be substituted with another optical element, such as, but not limited to, an optical filter, a light polarizer, a multi-element lens, or the like. Moreover, in accordance with other embodiments of the sensor of the present invention, more than one optical element may be attached to the sensor or disposed in the passage or opening of the sensor.

For example, a multi-element lens may be attached or disposed or formed within the passage, or a combination of a lens (not shown) and an optical filter (not shown) may be attached or disposed or formed within the passage in any desired order, or alternatively, a single suitably dyed or colored lens may be disposed in the passage of the sensor 80 instead of the lens 72, and may serve as a lens and a filter. Such pressure sensors including one or more optical elements may be implanted in the anterior chamber or in the posterior chamber of the eye as disclosed in detail hereinabove.

Finally, it is noted that while in some of the embodiments of the sensors disclosed hereinabove the conducting members included in the resonant circuits may be attached or disposed or glued or deposited on the internal surfaces of the membranes comprising the housing of the sensor or on the external surfaces of the membranes comprising the housing of the sensor (using suitable electrically insulating materials for any externally disposed conducting member), another possibility for configuring the sensor may also be used in some embodiments of the sensor. For example, the sensors 10, 40, and 50 may be modified by embedding the electrically conducting members of their respective resonant circuits within the membranes included in the housing of the sensors. For example, the conducting members 14A and 14B of the sensor 10 may be embedded within the membranes 12A and 12B , respectively, the conducting members 44A and 44B of the sensor 40 may be embedded within the membranes 12A and 12B of the sensor 40, respectively, and the conducting members 54A and 54B of the sensor 50 may be embedded within the membranes 12A and 12B, respectively of the sensor 50.

Practically, the embedding of a conducting member of the resonant circuits within a membrane of the sensor may be performed by any suitable embedding method known in the art. For example, each membrane (such as the membranes 12A and 12B) may be formed by preparing a first membrane (not shown) attaching or gluing or depositing a suitably shaped electrically conducting layer (not shown) on a surface of the first membrane and attaching or gluing or welding or depositing or otherwise forming a second membrane on top of the conducting layer, such that the electrically conducting layer is sandwiched between the first membrane and the second membrane, two such membranes each having an embedded conducting layer therein may then be joined or welded or glued or otherwise sealingly attached to each other to form the housing of a sensor in a way similar to that disclosed and illustrated for the membranes 12A and 12B of the sensors 10, 40 and 50 above. When such embedded or sandwiched electrically conducting members or layers are used, the conducting members embedded within each of the two opposed joined membranes may be electrically coupled to form the resonant circuit by any method lαiown in the art, such as, for example, by removal of some insulating membrane material after the membranes are formed and electrically connecting the conducting member as disclosed hereinabove (using a conducting wire or ribbon or the like as disclosed in detail hereinabove), or by leaving suitably exposed portion of each of the electrically conducting members outside the membranes during the sandwiched membrane forming stage and electrically coupling the two electrically conducting members by suitable methods such as, but not limited to, welding, laser welding, soldering, connecting by electrically conducting glue, or by any other method known in the art for electrically connecting conducting materials or members.

It is further yet noted that it may be possible to configure the pressure sensors and the composite lenses disclosed hereinabove as foldable sensors or foldable composite lenses by suitable choice of materials and structural design.

Claims

1. An implantable passive intraocular pressure sensor comprising:

a sealed housing having a passage therein for allowing light to pass through said passage, said housing has walls forming a sealed chamber therebetween, at least one wall of said walls is a movable wall configured for moving in response to changes in the pressure outside said sensor; and

a passive electromagnetic resonant circuit, at least one portion of said circuit is mechanically coupled to said least one movable wall such that the resonance frequency of said resonant circuit varies as a function of the pressure outside said sensor.

2. The sensor according to claim 1 wherein the dimensions of said passage are configured to allow light to pass tiierethrough to reach the retina of an eye when said sensor is implanted within said eye.

3. The sensor according to claim 1 wherein said housing is selected from the group consisting of a flat annular housing, a flat regular polygonal annular housing, an annular housing having a flat ellipsoidal cross-section and a non-symmetrical housing having an irregular shape.

4. The sensor according to claim 1 wherein said passage is selected from the group consisting of a passage having a circular cross-section, a passage having a polygonal cross-section, a passage having an ellipsoidal cross-section, a passage having a regular polygonal cross-section and an irregularly shaped passage.

5. The sensor according to claim 1 wherein said sealed chamber surrounds said passage.

6. The sensor according to claim 1 wherein said resonant circuit comprises an electrically conducting member having at least two electrically coupled electrically conducting portions, and wherein the distance between said at least two portions varies as a function of the pressure outside said sensor.

7. The sensor according to claim 6 wherein at least one electrically conducting portion of said at least two electrically conducting portions is attached to said least one movable wall.

8. The sensor according to claim 1 wherein said chamber comprises a gas sealed therein.

9. The sensor according to claim 1 wherein said at least one movable wall is a flexible deformable wall, at least a portion of said deformable wall is configured to change its shape in response to changes hi the pressure outside said sensor.

10. The sensor according to claim 1 wherein said passage is an open passage.

11. The sensor according to claim 1 wherein said sensor further includes at least one handling member attached to said housing or formed as a part thereof to facilitate handling or grasping said sensor.

12. The sensor according to claim 1 wherein said sensor is a foldable sensor configured to be folded to facilitate insertion thereof into an eye.

13. The sensor according to claim 1 wherein said sensor also comprises at least one optical element attached to said housing and disposed within said passage.

14. The sensor according to claim 13 wherein said sensor further includes at least one handling member attached to said housing or formed as a part thereof to facilitate handling or grasping said sensor.

15. The sensor according to claim 13 wherein said at least one optical element is a lens, said lens further comprises an additional electrically conducting member attached to said lens and electrically coupled to said passive electromagnetic resonant circuit to form an extended resonant circuit.

16. The sensor according to claim 15 wherein said additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting material attached to a surface of said lens.

17. The sensor according to claim 15 wherein said additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting optically transparent material attached to a surface of said lens.

18. The sensor according to claim 17 wherein said electrically conducting optically transparent material comprises indium tin oxide.

19. The sensor according to clahn 13 wherein said at least one optical element is selected from a lens, an optical filter, a light polarizing element, a multi-element lens and combinations thereof.

20. The sensor according to claim 19 wherein said lens is an implantable contact lens configured to be placed adjacent to the natural lens of an eye, and said sensor is configured to be implanted within the anterior chamber of the eye to enable determining the pressure therein.

21. The sensor according to claim 19 wherein said lens is configured to replace the natural lens of an eye, and said sensor is configured to be implanted within the posterior chamber of the eye to enable determining the pressure therein.

22. The composite lens according to claim 19 wherein said lens is configured to replace the natural lens of an eye in cataract surgery performed on a patient.

23. The sensor according to claim 19 wherein said housing comprises two opposing non-planar annular membranes, each membrane of said two membranes has an inner circumference and an outer circumference, said two membranes are sealingly attached to each other along their inner circumference and outer circumference to form said sealed chamber therebetween, at least one of said membranes is a flexible or deformable membrane.

24. The sensor according to claim 23 wherein said resonant circuit comprises at least a first electrically conducting portion and a second electrically conducting portion, said first portion is electrically coupled to said second portion, said first electrically conducting portion is attached to a first membrane of said two membranes and said second electrically conducting portion is attached to the second membrane of said two membranes, and wherein the distance between at least a part of said first portion and at least a part of said second portion varies as a function of the pressure outside said sensor.

25. The sensor according to claim 24 wherein at least one of said first portion and said second portion comprises a spiral-like layer of electrically conducting material attached to a surface of a membrane of said two membranes.

26. The sensor according to claim 24 wherein at least one of said first portion and said second portion comprises a layer of electrically conducting material attached to a surface of a membrane of said two membranes, said layer is shaped as an annular layer having a gap therein.

27. The sensor according to claim 24 wherein said first portion and said second portion are electrically coupled by an electrically conducting member, said electrically conducting member is configured such that it does not substantially hinder the changing of the distance between said at least a part of said first portion and at least a part of said second portion when the pressure outside said sensor changes.

28. The sensor according to claim 27 wherein said electrically conducting member is selected from an electrically conducting wire, an electrically conducting ribbon, an electrically insulated electrically conducting wire and an electrically insulated electrically conducting ribbon.

29. The sensor according to claim 24 wherein said first portion comprises a first spiral-like layer of electrically conducting material attached to a surface of said first membrane, and said second portion comprises a second spiral-like layer of electrically conducting material attached to a surface of said second membrane.

30. The sensor according to claim 29 wherein said first spiral-like layer and said second spiral like layer are configured such that the windings of said first spiral-like layer oppose the windings of said second spiral-like layer.

31. The sensor according to claim 29 wherein said first spiral-like layer and said second spiral like layer are configured such that the windings of said first spiral-like layer are laterally offset with respect the windings of said second spiral-like layer.

32. The sensor according to claim 29 wherein said first spiral-like layer and said second spiral like layer are configured such that the windings of said first spiral-like layer are interdigitated with the windings of said second spiral-like layer.

33. The sensor according to claim 24 wherein said first portion comprises a first spiral-like layer of electrically conducting material attached to a surface of said first membrane, and said second portion comprises a second layer of electrically conducting material, said second layer is shaped as a single loop, said second layer is attached to a surface of said second membrane.

34. The sensor according to claim 33 wherein said second layer is shaped as an electrically conductmg single loop selected from a closed single loop and an open single loop having a gap therein.

35. The sensor according to claim 1 wherein said sensor further includes at least one handling member attached to said housing or formed as a part thereof to facilitate handling or grasping said sensor.

36. The sensor according to claim 1 wherein at least part of said housing comprises at least one biocompatible material.

37. The sensor according to claim 36 wherein said at least one biocompatible material is selected from the group consisting of polytetrafluoroethylene, polyethylene, polypropylene, Parylene® C, and combinations thereof.

38. The sensor according to claim 1 wherein said passage has a circular cross-section having a diameter equal to or larger than two millimeters.

39. The sensor according to claim 1 wherein said passage has a circular cross-section having a diameter equal to or larger than three millimeters.

40. The sensor according to claim 1 wherein at least part of said sensor comprises at least one transparent material.

41. The sensor according to claim 40 wherein said transparent material is transparent to at least part of the portion of the electromagnetic spectrum visible to humans.

42. The sensor according to claim 1 wherein said sensor is a foldable sensor configured to be folded to facilitate insertion thereof into an eye.

43. A method for implanting a sensor in an eye the method comprises the steps of:

Inserting into an eye a sensor comprising a sealed housing having a passage therein for allowing light to pass through said passage, said housing has walls forming a sealed chamber therebetween, at least one wall of said walls is a movable wall configured for moving in response to changes in the pressure outside said sensor, and a passive electromagnetic resonant circuit, at least one portion of said circuit is mechanically coupled to said at least one movable wall such that the resonance frequency of said resonant circuit varies as a function of the pressure outside said sensor; and

positioning said sensor within said eye to allow part of the light entering said eye to reach the retina of said eye by passing through said passage.

44. The method according to claim 43 wherein said sensor also includes at least one optical element attached to said housing and disposed within said passage, and wherein said step of positioning comprises positioning said sensor within said eye to allow part of the light entering said eye to reach the retina of said eye by passing through said at least one optical element.

45. The method according to claim 44 wherein said at least one optical element is an intraocular contact lens configured for implantation adjacent to the natural lens of an eye and wherein said step of inserting comprises inserting said sensor into the anterior chamber of said eye to dispose said intraocular contact lens adjacent said natural lens.

46. The method according to claim 44 wherein said at least one optical element is a lens configured for replacing the natural lens of an eye and wherein said step of inserting comprises inserting said sensor into the posterior chamber of said eye for replacing said natural lens following the surgical removal of said natural lens.

47. The method according to claim 44 wherein said at least one optical element is selected from a lens, a multi-element lens, an optical filter, a light polarizing optical element and combinations thereof.

48. A composite implantable intraocular lens comprising:

An optically transparent lens body; and

a pressure sensor comprising a sealed housing having a passage therein, said housing is attached to said lens body, said lens body is disposed within said passage, said housing has walls forming a sealed chamber therebetween, at least one wall of said walls is a movable wall configured for moving in response to changes in the pressure outside said sensor, and a passive electromagnetic resonant circuit, at least one portion of said circuit is mechanically coupled to said at least one movable wall such that the resonance frequency of said resonant circuit varies as a function of the pressure outside said sensor.

49. The composite lens according to claim 48 wherein said lens body and said sensor are foldable.

50. The composite lens according to claim 48 wherein said passage has a circular cross-section having a diameter equal to or larger than three millimeters.

51. The composite lens according to claim 48 wherein said lens body is attached to said housing by a spacer member.

52. The composite lens according to claim 51 wherein said spacer member is an annular spacer member.

53. The composite lens according to claim 48 wherein said composite lens further includes one or more handling members for facilitating the handling or grasping of said composite lens.

54. The composite lens according to claim 53 wherein said one or more handling members are attached to said housing or are formed as part of said housing.

55. The composite lens according to claim 48 wherein said lens body is an implantable contact lens configured to be placed adjacent to the natural lens of an eye, and said sensor is configured to be implanted within the anterior chamber of the eye to enable determining the pressure therein.

56. The composite lens according to claim 48 wherein said lens body is configured to replace the natural lens of an eye, and said sensor is configured to be implanted within the posterior chamber of the eye to enable determining the pressure therein.

57. The composite lens according to claim 48 wherein said lens body is configured to replace the natural lens of an eye in cataract surgery performed on a patient.

58. The composite lens according to claim 48 wherein said lens further comprises an additional electrically conducting member attached to said lens body and electrically coupled to said passive electromagnetic resonant circuit to form an extended resonant circuit.

59. The composite lens according to claim 58 wherein said additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting material attached to a surface of said lens body.

60. The composite lens according to claim 58 wherein said additional electrically conducting member is shaped as a spirally shaped layer of electrically conducting optically transparent material attached to a surface of said lens body.

61. The composite lens according to claim 60 wherein said electrically conducting optically transparent material comprises indium tin oxide.