Ultrasound intraocular pressure sensor in sclera or in cornea
An intraocular pressure (IOP) measurement system. An ultrasound pressure sensor is implantable in an eye, wherein the sensor has a sealed cavity that changes shape as a function of IOP of the eye. An ultrasound transmitter emits an incident ultrasound beam. A receiver produces an output signal in response to receiving a reflected ultrasound beam. A spectrometer is configured to estimate the IOP of the eye based on processing the output signal of the receiver. Other aspects are also described and claimed.
1 . An intraocular pressure (IOP) measurement system comprising:
an ultrasound pressure sensor implantable in an eye, wherein the sensor has a sealed cavity that changes shape as a function of IOP of the eye, the sealed cavity defined by a membrane and a rigid substrate;
an ultrasound transmitter configured to emit an incident ultrasound beam, the ultrasound pressure sensor being configured to be positioned in a manner that the incident ultrasound beam reaches the rigid substrate before the membrane;
a receiver configured to produce an output signal determined based on interfering reflections of an ultrasound beam off the membrane and the rigid substrate; and
a spectrometer configured to estimate the TOP of the eye based on processing the output signal of the receiver.
2 . The system of claim 1 wherein the sensor is implantable in a cornea of the eye.
3 . The system of claim 2 wherein the sensor is implantable in the cornea in its entirety so that it is entirely embedded in the cornea.
4 . The system of claim 1 wherein the sensor is implantable in a sclera of the eye.
5 . The system of claim 4 wherein the sensor is implantable in the sclera in its entirety so that it is entirely embedded in the sclera.
6 . The system of claim 1 wherein the membrane is a flexible membrane which is attached to the rigid substrate.
7 . The system of claim 6 wherein the membrane and cavity provide a frequency dependent, acoustic impedance to the incident ultrasound beam, that changes as a function of the IOP.
8 . The system of claim 6 wherein the sealed cavity is a gaseous cavity.
9 . The system of claim 6 wherein the rigid substrate is at least partially transparent to the incident ultrasound beam while the membrane is reflective to the incident ultrasound beam thereby producing the interfering reflections.
10 . The system of claim 1 wherein the ultrasound transmitter and the receiver are integrated within a single housing of a reader.
11 . The system of claim 10 wherein the reader is a handheld device, and the spectrometer comprises a digital processor that is outside of the handheld device.
12 . A method for measuring IOP of an eye, the method comprising:
emitting an ultrasound beam toward a pressure sensor, which is implanted in a cornea or a sclera of the eye, the pressure sensor being configured to be positioned in a manner that the ultrasound beam reaches a rigid substrate of the pressure sensor before a membrane of the pressure sensor;
detecting, as an output signal, interfering reflections of the ultrasound beam from the membrane and the rigid substrate; and
processing the output signal to compute an estimate of the TOP of the eye.
13 . The method of claim 12 wherein processing the output signal comprises performing a spectroscopy algorithm.
14 . The method of claim 13 wherein the sensor is implanted in the cornea.
15 . The method of claim 14 wherein the sensor is implanted in the cornea in its entirety so that it is entirely embedded in the cornea.
16 . The method of claim 12 wherein the sensor is implanted in the sclera.
17 . The method of claim 16 wherein the sensor is implanted in the sclera in its entirety so that it is entirely embedded in the sclera.
18 . The method of claim 12 wherein processing the output signal comprises computing an estimate of frequency dependent, acoustic impedance presented to the ultrasound beam, that changes as a function of the IOP.
19 . The method of claim 12 wherein the membrane is a flexible membrane which is attached to the rigid substrate to define a sealed cavity.
20 . The method of claim 19 wherein the sealed cavity is a gaseous cavity.
21 . The method of claim 12 wherein the rigid substrate is at least partially transparent, and the membrane is reflective to the ultrasound beam.
22 . The method of claim 12 wherein emitting, detecting, and processing are performed by electronics that are integrated within a single housing of a reader.
23 . The method of claim 22 wherein the reader is a handheld device, and the method further comprises transmitting a digital version of the output signal to a digital processor that is outside of the handheld device and that performs the processing of the output signal to compute the estimate of the IOP of the eye.
24 . A non-transitory processor-readable storage medium storing a plurality of processor-executable instructions for measuring IOP of an eye, the plurality of processor-executable instructions being executed by a processor to perform operations comprising:
actuating an ultrasound transmitter to emit an ultrasound beam toward the eye;
detecting, as an output signal, interfering reflections of the ultrasound beam from a membrane and a rigid substrate of a pressure sensor that is implanted in a cornea or sclera of the eye, the pressure sensor being configured to be positioned in a manner that the ultrasound beam reaches the rigid substrate before the membrane; and
processing the output signal to compute an estimate of the TOP of the eye.