Patent Application
20120004528
Aqueous humor fills the space between the lens and the cornea of the human eye and is similar to the compositions of blood plasma except aqueous humor has less protein. Intraocular pressure is the fluid pressure of the aqueous humor. Changes in intraocular pressure are a sign of glaucoma. If left undiagnosed and untreated, glaucoma can lead to blindness. Thus, measuring intraocular pressure is an important part of diagnosing and treating eye diseases.
Various techniques may be used to remotely monitor and measure intraocular pressure. For example, a wired sensor may be embedded into a contact lens. However, this technique requires that the lens be molded as an exact copy of the eye surface, and the accuracy of the measurements using this technique are affected by tissue wall thickness, rigidity, eye size, and other physiological parameters such as eye movement and lid pressure. Another technique to measure intraocular pressure is to use wireless sensors built into an intraocular lens, but this technique requires replacing the patient's native lens. A third technique is to implant a pressure transducer subcutaneously on the back of the patient's neck and to measure intraocular pressure via a fluid-filled catheter and needle probe that conducts pressure from the anterior chamber to the transducer. The needle is glued into the anterior chamber. This technique, however, can cause irritation, cornea scarring, inflammation, and limitations of eye movement.
Accordingly, an implantable sensor for monitoring intraocular pressure and other physiological parameters that is easy to manufacture and implant in the patient's eye is needed.
An exemplary implantable sensor includes a housing that generally conforms to a curvature of an anterior chamber of a patient's eye. A sensing device disposed in the housing is configured to detect physiological parameters and transmit a signal representing the physiological parameters. The shape of the sensor helps anchor the sensor inside the anterior chamber of the patient's eye. As described herein, the sensor may be used to detect intraocular pressure and other physiological parameters. Moreover, the sensor is designed for ease of manufacture and implantation in a patient's eye.
The sensor 100 includes a housing 105, one or more fixation elements 110, a sensing device 115, and an antenna 120. In general, the housing 105 supports the sensing device 115 and antenna 120 inside a patient's eye, and the fixation elements 110 limit movement of the sensor 100 within the patient's eye. The housing 105 has a configuration that generally conforms to a curvature of an anterior chamber of the patient's eye. For example, the housing 105 may have a generally C-shaped configuration that may be formed by extending two ends 122 of the housing 105 toward one another and leaving an opening between the two ends 122. With this shape, the housing 105 allows light to reach the patient's retina (or eye fundus) and does not expose the patient to a significant risk of damage to the iris and the corneal endothelium. The housing 105 may have other configurations such as a substantially G-shaped or O-shaped configuration. Moreover, although illustrated as having a substantially curved periphery 112 in
The housing 105 may be formed to any size that fits within the anterior chamber of the patient's eye. For one exemplary patient, the depth of the anterior chamber may be between approximately 2.9-3.3 mm and the width of the anterior chamber may about 12.53±0.47 mm. However, the size of the anterior chamber may change for each patient. Accordingly, the housing 105 may have an overall length that is approximately two-thirds of the anterior chamber circumference length or a diameter in the range of 11.0-14.0 mm. An opening between the two ends 122 of the housing 105 is approximately 2-6 mm wide. Of course these sizes are merely exemplary. The size of the housing 105 may be customized to fit within a specific patient's eye, or alternatively, the housing 105 may be sized based on one or more demographics. For example, the housing 105 of a sensor 100 designed for an adult patient may be larger than the housing 105 of a sensor 100 designed for a child patient.
The fixation elements 110 are configured to extend from an outer periphery 112 of the housing 105 and anchor the housing 105 inside the patient's eye in a way that allows the sensor 100 to measure one or more physiological parameters. Instead of extending from the outer periphery 112, the fixation elements 110 may additionally or alternatively extend from a top or bottom surface 114 of the housing 105, or both. Moreover, the fixation elements 110 may be flush with the top and/or bottom surfaces 114. In one exemplary approach, the fixation elements 110 may be the only points of contact between the sensor 100 and, for instance, the patient's corneal endothelium.
The fixation element 110 may be integrally formed with the housing 105 or attached to the housing 105. For example, the fixation elements 110 may be semi-circular protrusions integrally formed with the housing 105. As illustrated in
The sensing device 115 is configured to detect physiological parameters and transmit a signal representing the physiological parameters. For example, the sensing device 115 may be any device configured to measure one or more of the following parameters: intraocular pressure, flow velocity of aqueous humor, blood sugar, and blood biochemicals. Of course, the sensing device 115 may be configured to measure other parameters in addition to or instead of those listed.
In one exemplary approach, the sensing device 115 may be implemented using a micro-electro-mechanical systems (MEMS) device or a nano-electro-mechanical systems (NEMS) device. The sensing device 115 may be disposed in the housing 105 and/or in the fixation element 110. This way, the sensing device 115 may be protected from exposure to, for instance, aqueous humor within the anterior chamber of the patient's eye. Indeed, the characteristics of the housing 105 may be used to increase the accuracy of the sensing device 115. In one exemplary implementation, the housing 105 may be coated with a pressure sensitive coating that helps the sensing device 115 measure, for instance, intraocular pressure. The sensor 100 may include any number of sensing devices 115 at various locations in the housing 105, which aid in balancing the weight of the housing 105.
The antenna 120 receives the signals generated by the sensing device 115 and transmits those signals to a receiver located outside the patient's body. The antenna 120 may be disposed on or embedded into the housing 105. For instance, as illustrated in
Referring now to
Computing devices, such as the processor 150, generally include computer-executable instructions, where the instructions may be executable by one or more computing devices such as those listed above. Computer-executable instructions may be compiled or interpreted from computer programs created using a variety of well known programming languages and/or technologies, including, without limitation, and either alone or in combination, Java™, C, C++, Visual Basic, Java Script, Perl, etc. In general, a processor (e.g., a microprocessor) receives instructions, e.g., from a memory, a computer-readable medium, etc., and executes these instructions, thereby performing one or more processes, including one or more of the processes described herein. Such instructions and other data may be stored and transmitted using a variety of known computer-readable media.
A computer-readable medium (also referred to as a processor-readable medium) includes any non-transitory (e.g., tangible) medium that participates in providing data (e.g., instructions) that may be read by a computer (e.g., by a processor of a computer). Such a medium may take many forms, including, but not limited to, non-volatile media and volatile media. Non-volatile media may include, for example, optical or magnetic disks and other persistent memory. Volatile media may include, for example, dynamic random access memory (DRAM), which typically constitutes a main memory. Such instructions may be transmitted by one or more transmission media, including coaxial cables, copper wire and fiber optics, including the wires that comprise a system bus coupled to a processor of a computer. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH-EEPROM, any other memory chip or cartridge, or any other medium from which a computer can read.
In some examples, system elements may be implemented as computer-readable instructions (e.g., software) on one or more computing devices (e.g., servers, personal computers, etc.), stored on computer readable media associated therewith (e.g., disks, memories, etc.). A computer program product may comprise such instructions stored on computer readable media for carrying out the functions described herein.
In operation, the sensor 100 is surgically implanted inside the patient's eye 130. While in the anterior chamber 120, the sensor 100 may measure the pressure of the aqueous humor to determine intraocular pressure using the sensing device 115. Of course, the sensor 100 may be used to measure other physiological parameters as previously discussed. The sensor 100 may transmit the measured intraocular pressure to the receiver 145 using the antenna 120, which transmits the signal representing intraocular pressure to the processor 150. The processor 150 may convert the measured intraocular pressure signal to a signal that graphically represents the intraocular pressure to the display device 155.
With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claimed invention.
Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope of the invention should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the invention is capable of modification and variation.
All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.
