DE102004056757A1 - Device for measuring the intra-ocular pressure of an eye comprises a measuring unit arranged in a flat sleeve which is placed with a flat abutment on the outer surface of the eye sclera in a pressure contact - Google Patents

Abstract

Device for measuring the intra-ocular pressure of an eye comprises a measuring unit (1) arranged in a flat sleeve which is placed with a flat abutment (14) on the outer surface of the eye sclera in a pressure contact. Preferred Features: A pressure sensor and a telemetry unit are integrated in a chip. An inductive coil is arranged on or close to the outer side of the chip body. The inductive coil is arranged on the surface side of the chip body, on which the pressure sensor is arranged, or on the surface side of the chip body lying opposite.

Description

The The invention relates to a device for intraocular pressure measurement with an implantable measuring device, the at least one Pressure sensor and a telemetry device with connected inductive Coil in a pressure transferring and biocompatible serving and with an extracorporeal telemetry interrogator.

Such a device is off DE 199 45 879 A1 known. In the known device, the measured values can be transmitted telemetrically to a receiving device arranged outside the eye.

Out DE 101 06 881 A1 a device for telemetric intraocular pressure measurement is known in which the pressure sensor is arranged on the inner surface of the eye sclera in the region of the pars plana.

Further is from Flick, B.B .; Organ Master, R .; "A portable microsystembases telemetric pressure and temperature measurement unit, IN: IEEE Transaction on Biomedical Engineering, Vol. 47/1, Jan. 2000, pages 12-16 an intracorporeal pressure sensor known which in the intracranial pressure measurement Use finds.

task The invention is an apparatus for intraocular pressure measurement of the type mentioned above, in which the measuring device in an easily accessible Place in the eye is implantable.

These The object is achieved by the characterizing features of claim 1 solved.

The under claims contain advantageous developments of the invention.

In the invention, the intracorporeal measuring device is arranged in a flat envelope, wherein the envelope can be placed with a flat and attachable to the ocular sclera abutment, in particular a plate on the outer surface of the ocular sclera with pressure contact. The material of the abutment is preferably not deformable. The intracorporeal measuring device is located on the underside of the abutment, which is fixed to the ocular sclera by sewing, for example. The surgical procedure is low invasive and can be made reversible if necessary. The procedure is similar to the fixation of a glaucoma shunt. The abutment may be like the plate used in a glaucoma shunt (e.g. US 5,598,629 ), wherein the intracorporeal measuring device is arranged on the underside of this plate.

The Intracorporeal measuring device includes at least one pressure sensor and the electronic telemetry device, which is in a chip can be integrated. Preferably, the electronic components of the telemetry device With the inductive coil by bonding directly electrically contacted. The at least one pressure sensor is located on one side and the inductive coil on the other side of the flat chip body. It can however, the pressure sensor and the inductive coil are also at the same surface side of the chip body be provided. When implanting in the sclera is at least a pressure sensor preferably directed towards the inside of the eye Side of the chip body and the coil on the outside directed side of the chip body.

Of the Intraocular pressure, which is called the pressure difference between the absolute Defines pressure inside the eye and the air pressure surrounding the eye is, and in particular, an elevated one Intraocular pressure leads to a mechanical deformation of the sclera and to changes the mechanical stress distribution within the sclera, which is called pressure change can be detected by the pressure sensor. In an advantageous way this pressure over relatively large volume and pressure transmitting medium, which is a liquid, be a gel or oil can transmit to the at least one pressure sensor. The pressure transferring Medium can do this in a z. B. by gluing, vulcanizing or weld together closed and deformable film, which together with the pressure transferring Medium the serving forms, be arranged. The serving can also be an enveloping body biocompatible material, e.g. As silicone.

The chip is characterized by a low volume and can be sized in height, in particular smaller than 0.5 mm. The chip area can be a few mm ² . The coil can also be formed with a small height, for example about 20 microns as a planar coil or also with a smaller height dimension as a preferably deformable wound coil. The coil can be produced by microsystem technology, for example by microgalvanization, in particular photolithographically. The total height of the measuring unit, including the sheath, may be sized 0.7 mm or smaller and with a corresponding incision in the sclera, e.g. B. Sclera pocket can be arranged.

With an implant, which has the chip and the inductive coil arranged thereon, For example, the measured value acquisition, the energy transmission and the telemetric data transmission, in particular in digital form, can be carried out. The chip preferably accommodates the pressure transducer, optionally a temperature measuring device, the analog / digital converter and the telemetry / transponder electronics. The pressure measurement is preferably carried out capacitively. For this purpose, the pressure-sensitive surface of one or more membranes can be formed, which each forms a capacitor assignment in the capacitive pressure measurement. It is also possible to provide a plurality of pressure-sensitive surfaces, in particular membranes. With such a measuring device, it is possible to achieve a high transponder range of several cm. At a transponder frequency between 10 and 15 MHz, for example 13.56 MHz, a range of about 5 cm is achieved.

With biocompatible serving is a flexible adaptation of the measuring device to the outer surface of Sclera, especially in the tenon space, reached at the implantation site. The coil can be outside dimensions between about 5.0 mm and 8.0 mm. The coil can be circular, square, rectangular or elliptical. The coil is together with the Transferring chip in the pressure Medium of serving embedded. In the invention, an implantable measuring device is provided, which in geometry the anatomical conditions at the implantation site is adjusted. In the implantable measuring device, a single chip with small dimensions and thus small pressure receiving surface can be used. Due to the pressure transferring Medium in which the chip is embedded, at the measuring location or Implantationsort an enlarged pressure receiving surface of the Measuring device reached. Preference as are more on the chip for the pressure measurement For example, four pressure receiving surfaces, in particular membranes for the provided capacitive pressure measurement.

The Augensklera is extremely tear-resistant and extremely flexible. The outer surface of the intracorporeal measuring device (implant), which the chip and the Coil is preferably on the side (bottom), which directed towards the inside of the eye, flexible. hereby is achieved that the bottom of the implant flexible at the pressure changes slightly changing sclerogenesis in the eye clings and through these changes is moved. Especially in the field of pressure sensors, which provided at the bottom of the chip is in the form of a pressure transferring Medium, for example, a gel, a relining provided over which the pressure changes be transmitted in the eye to the pressure sensors. The pressure transferring Medium is from a flexible membrane, such as a silicone membrane tightly closed. Through the abutment, the so-designed, Pressure transmitting Bottom of the implant with a low initial pressure (contact pressure) pressed on the sclera. This achieves optimal transfer of the pressure changes inside the eye to the pressure sensor, in particular on the pressure sensing Membrane of the respective pressure sensor on the chip.

At the Chip can Furthermore, in particular passivated pressure measuring points should be provided, which applied with a fixed predetermined (standardized) pressure are. For the detection of intraocular pressure will be the difference between the pressure transmitting Medium mediated pressure and standardized pressure used. This achieves a compensation of drifts and others influences on the pressure transducer. Since no electrical connection lines between the coil and the chip are provided, but the chip directly is connected to the coil, for example by flip-chip bonding, can low external dimensions adapted to the measuring or implantation site the implantable measuring device can be achieved. Due to the One-chip solution is the susceptibility the measuring device compared to systems with several modules low.

The Measuring device can transmit after its wrapping with the pressure Medium be pre-calibrated. The final calibration is done for example, using a conventional tonometer after Implantation. By change of intraocular pressure, the mechanical stress states become within the sclera changed. This changes also on the pressure sensors, in particular their measuring membranes applied pressure. The determination of the transfer function of Intraocular pressure for pressure on the diaphragm may be patient specific by sensor measurement of at least two different intraocular pressure values by means of conventional Tonnometers can be determined in the classical way. From the calibration function the not yet implanted measuring device (pre-calibration) and the at least two tonometrically determined on the patient measured values determines the patient-specific characteristic. The thereby determined Characteristic can be integrated in the integrated telemetry electronics or stored in the extracorporeal retrieval and evaluation device.

Each chip can receive a specific identifier which is queried in each telemetric measurement and assigned by the evaluation device processing the measurement data. In this way, several implantable measuring devices, for example, up to several hundred measuring devices processed with an evaluation who the.

The Detection is performed with a telemetric interrogator. at The calibration of the measuring device becomes a certain characteristic determined. This characteristic is preferably in the query or Evaluation device associated with the specific identifier of the chip saved. As a result, recognizes the query or evaluation in the telemetric measurement the respective measuring device and considered in the evaluation, the associated characteristic curve.

When Abutment, which for the placement of the measuring device on the outer surface of An ocular sclera may serve as a plate, such as an acrylic plate. However, it is also possible a glaucoma valve, which disassembles with a drainage cannula too high intraocular pressure, such as from U.S. Pat. 5,454,796 known on the outer surface of the Ocular sclera is implanted. The arranged in the envelope Measuring device is placed at the bottom of the glaucoma venitl and with pressure contact on the outer surface of the Held eye sclera.

A another embodiment is that the intraocular pressure over one through the ocular sclera cannula placed in the anterior chamber of the eye direct the intraocular pressure to eat. The cannula may be like that of U.S. Pat. 5,454,796 known drainage cannula of the glaucoma valve be laid. Here, the aqueous humor in the lumen of the cannula acts directly on the pressure-transmitting wrapping the measuring device. In the embodiment in which the measuring device with the glaucoma valve can be used dependent on be controlled by the measured internal pressure, the valve actuation.

The Query and the evaluation and an associated recording device can in a structural unit, which is preferably designed as a hand-held device is to be accommodated. The interrogator also contains the extracorporeal induction coil attached to the extracorporeal Telemetry device is connected. The polling device can over a cable to be connected to the evaluation. However, it is also possible through radio transmission the measurement data from the interrogator to the evaluation transferred to. It is also possible, the interrogator or at least the associated extracorporeal Coil near eye or tail with help a fixing device, for example on a spectacle frame or with the help of a patch on the patient's scalp fix. The extracorporeal coil can be via a cable or another suitable electrical connection with the interrogation and evaluation be connected.

at The invention is a permanent one Measurement of intraocular pressure possible. It can especially in glaucoma patients all pressure fluctuations that occur throughout the day can, be recorded. This achieves a more accurate detection of the Disease process.

Based the figures is based on an embodiment the invention even closer explained.

It shows

1 a perspective view of an eye detail with an implanted on the outer surface of the sclera of the eye embodiment of the measuring device;

2 a schematic side view of an embodiment of the measuring device, which on the outer surface of the eye sclera, as in 1 shown implanted, and an extracorporeal interrogator;

3 a schematic side view of another embodiment of the measuring device, which on the outer surface of the eye sclera, as in 1 shown is implanted;

4 in perspective view an eye cutout with another implanted on the outer surface of the sclera of the eye embodiment of the measuring device;

5 a perspective view of a first embodiment of an intracorporeal measuring device;

6 a schematic side view of a second embodiment of the intracorporeal measuring device;

7 a schematic side view of a third embodiment of the intracorporeal measuring device;

8th a schematic side view of a fourth embodiment of the intracorporeal measuring device (implant); and

9 a plan view of the embodiment of 8th ,

The in the 5 to 9 illustrated implantable measuring devices 1 include a single hybrid chip 7 and an inductive coil 4 which in the embodiments of the 5 to 7 on the outside of the chip 7 is arranged. Unless the transmission properties sufficient, the coil can also be integrated in the chip body. In the embodiment of 8th and 9 the coil is on an annular support 12 which is formed as a thin plate or as a film. The chip 7 is the coil 4 arranged overlapping. The chip 7 includes a pressure sensor 2 with one or more pressure receiving surfaces, which may be formed as membranes. The membranes are part of, in particular capacitor assignments of a capacitive pressure sensor. The pressure-receiving surfaces measure the pressure, which results from the respective stress state of the sclera and depends on the absolute pressure inside the eye. From this, the intraocular pressure, which is the pressure difference between the absolute pressure in the eye and the air pressure surrounding the eye, z. B. by means of the previously detected characteristic (calibration curve) can be determined. Furthermore, in the chip 7 an analog / digital converter and a telemetry device with a telemetry / transponder electronics provided. The electronics are connected via an electrical contact 3 , z. B. flip-chip bonding directly to the inductive coil 4 contacted. In the embodiment of 8th and 9 is the telemetry device with 18 designated. The electrical connection of the chip-containing electronics with the inductive coil 4 done by electrical contact points 17 which by the carrier 12 contact and are formed, for example, as a flip-chip bonding.

The inductive coil 4 is in the embodiments of 5 to 7 on one of the two surfaces of the chip 7 arranged. In the embodiment of 5 the inductive coil is on the same surface side of the chip 7 like the pressure sensor 2 , In the embodiment of 6 is the pressure sensor 2 on the one surface side (underside) of the chip 7 and the inductive coil 4 is located on the other surface side (top side) of the chip 7 , In the embodiments of the 5 and 6 is the inductive coil 7 designed as a planar coil. In the embodiment of 7 is the inductive coil 4 on the periphery of the chip 7 arranged. For this purpose, the coil may be formed all thin wire coil. However, it is also possible in the embodiment of 7 a planar coil, for example, to use a multilayer planar coil. Also in the embodiments of the 5 and 6 Multi-layer planar coils or thin wire coils can be used. In the same way, the inductive coil 4 of the embodiment of 8th and 9 on the preferably annular support 12 be educated.

In the implanted state is preferably the surface with the pressure sensor 2 into the inside of the eye and the surface with the inductive coil 4 directed to the outside. This can be with the in the 6 and 8th . 9 realize embodiments shown. Like from the 5 to 8th can be seen are the chip 7 and the coil 4 from a serving 5 which is a flexible closed shell 6 may be surrounded. Inside the case 6 there is a pressure transmitting medium 11 , in particular a gel or a biocompatible liquid, for example silicone-based oil. The chip 2 and the adjacent coil region become pressure-tight by the pressure-transmitting medium 11 envelops or are in pressure-transmitting medium 11 embedded. The case 6 , which may be formed as a film, can be closed by welding, gluing or vulcanization. The serving 5 can also us from a biocompatible envelope, z. As silicone, which is also the pressure-transmitting medium 11 forms exist. For the shell 6 For example, a polyurethane film or silicone film is suitable.

The case 6 surrounds the pressure transmitting medium 11 preferably stress-free, so that an undisturbed transfer of the intraocular pressure to be measured on the pressure-sensitive sensor surfaces of the chip 7 integrated pressure sensor 2 is reached. Since the sclera is very flexible, the sclera geometry is changed by pressure changes in the eye. Due to the flexible design of the underside of the implant with the pressure-transmitting medium 11 and the flexible shell 6 a co-movement of the shell takes place 6 with the changing sclera geometry and optimal pressure transfer to the pressure sensors 2 , The pre-calibration of the measuring device 1 done after the serving 5 is closed, ie after completion of the implantable measuring device 1 , The final calibration, as already explained, is done after implantation.

The turns of the coil 4 are preferably prepared by microsystem technology, in particular photolithographic methods. The coil turns can be provided as planar coil turns next to one another and / or one above the other on the chip body. The coil may for example have a height of 20 microns. In this way, a measuring device can be 1 with a total height or total thickness, including the wrapping, of 0.7 mm and manufacture. The length can be from 5.0 mm to 8.0 mm. The width can be from 1.0 mm to 2.0 mm.

Like from the 1 to 4 can be seen, the measuring device 1 on the outer surface of the eye sclera 13 arranged in the area of Parsplana. The arrangement is preferably between two eye muscles. In the embodiments of the 1 to 3 the fixation of the measuring device by means of a plate 14 , which also serves as an abutment in the pressure measurement. The plate 14 may preferably be formed as an acrylic plate. The plate 14 can also consist of a silicone material. The plate 14 has a slight three-dimensional curvature similar to the glaucoma shunt of U.S. Patent No. 5,598,629. This creates a free space for the measuring device 1 created at the bottom of the plate 14 is arranged and pressed with a certain initial pressure on the sclera outside. In the embodiment of 4 becomes the measuring device 1 with the help of a glaucoma valve 15 , which forms the abutment in the pressure measurement, on the outer surface of the ocular sclera 13 held in pressure contact. The plate 14 and the glaucoma valve 15 are at attachment points 10 preferably by suturing with the ocular sclera 13 attached.

That in the 3 illustrated embodiment of the measuring device 1 has a cannula 16 , which as in the embodiment of 4 led into the anterior chamber of the eye. In this way one achieves a direct pressure measurement across the lumen of the cannula 16 , which preferably consists of silicone. The aqueous humor is delivered via the lumen of the cannula 16 directly on the surface of the cladding 5 the measuring device 1 directed, so that a direct pressure measurement of intraocular pressure can be done. In the embodiments of the 1 . 2 and 4 During pressure measurement, the mechanical deformations of the sclera caused by intraocular pressure are recorded.

To carry out the measurement extrakorporal an interrogator 8th near the implanted measuring device 1 brought. For this purpose, the interrogator 8th in the eye or temporal area of the patient with the aid of a fixing device 9 which in the 2 and 3 is shown only schematically attached to a pair of glasses or by means of a patch on the head of the patient. The polling device 8th has an inductive coil for telemetric energy transfer to the inductive coil 4 the measuring device 1 and for receiving the telemetrically transmitted measurement data of the implanted measuring device 1 , At least the inductive coil of the interrogator 8th can be attached to the patient's head in transponder range. This allows measurement data to be constantly polled. The polling device 8th can be designed as a handheld device and via a cable 15 be connected to an evaluation device with display device. However, it is also possible to integrate the evaluation device and a display device in the handset. Furthermore, the interrogator 8th transmit the measurement data to an evaluation device via radio.

The calibration of the measuring arrangements shown in the figures can after implanting the measuring device 1 on the eye sclera 13 respectively. The patient-related calibration curve or characteristic curve is created using a conventional tonometer, as already explained.

1

measuring device

2

pressure sensor

3

electrical contact points

4

inductive Kitchen sink

5

wrapping

6

closed shell

7

chip

8th

interrogator

9

fixing

10

attachment points

11

Pressure transmitting medium

12

carrier

13

Augensklera

14

when Plate formed abutment

15

when Glaucoma valve trained abutment

16

cannula

17

electrical contact points

(Flip-chip bonding)

18

telemetry device

Claims (15)

Device for intraocular pressure measurement with an implantable measuring device which has at least one pressure sensor and a telemetry device with connected inductive coil in a pressure-transmitting and biocompatible sheath, and an extracorporeal telemetric interrogator, characterized in that the measuring device in a flat envelope ( 5 ) arranged with a flat and attachable to the eye sclera abutment ( 14 ; 15 ) can be placed on the outer surface of the ocular sclera with pressure contact. Apparatus according to claim 1, characterized in that the pressure sensor ( 2 ) and the telemetry device in a chip ( 7 ) and the inductive coil ( 4 ) is disposed at or near the outside of the chip body. Device according to claim 1 or 2, characterized in that the inductive coil ( 4 ) on the surface side of the chip body ( 7 ), at which the at least one pressure sensor ( 2 ), or on the opposite surface side of the chip body ( 7 ) is arranged. Device according to one of claims 1 or 2, characterized in that the inductive coil ( 4 ) at the periphery of the chip body ( 7 ) is arranged. Device according to claim 1 or 2, characterized in that the inductive coil ( 4 ) to egg preferably annular carrier ( 12 ) is arranged. Device according to one of claims 1 to 5, characterized in that the inductive coil ( 4 ) is designed as a planar coil or as a thin wire coil. Device according to one of claims 1 to 6, characterized in that the envelope ( 5 ) a closed envelope ( 12 ), in which at least the pressure sensor ( 2 ) in a pressure-transmitting medium ( 11 ) with respect to the pressure sensor ( 2 ) is arranged enlarged pressure transfer surface. Device according to one of claims 1 to 7, characterized in that the envelope ( 5 ) from a pressure-transmitting medium ( 11 ) forming enveloping body is formed. Device according to one of claims 1 to 8, characterized in that the extracorporeal interrogator ( 8th ) can be placed on a fixing device which can be placed in the vicinity of the eyes or the patient ( 9 ) are arranged or provided in a hand-held device. Device according to one of claims 1 to 9, characterized in that further comprises the telemetry device and the inductive coil ( 4 ) in the pressure-transmitting medium ( 11 ) are arranged. Device according to one of claims 1 to 10, characterized in that the flat abutment as preferably three-dimensionally curved plate ( 14 ) is trained. Device according to one of claims 1 to 11, characterized in that the measuring device ( 1 ) at the bottom of the abutment ( 14 . 15 ) is arranged. Device according to one of claims 1 to 12, characterized in that the flat abutment of a glaucoma valve ( 15 ) is formed. Device according to one of claims 1 to 13, characterized in that the measuring device ( 1 ) a cannula ( 16 ) whose lumens pressure-tight to the surface of the pressure-transmitting envelope ( 5 ) connected. Device according to one of claims 1 to 14, characterized in that the pressure-transmitting medium ( 11 ) is a gel.