SYSTEM FOR OPTICAL INTERROGATION OF AN INTRAOCULAR IMPLANT THROUGH INTERFERENCE PATTERN PROJECTION
An intraocular pressure (IOP) measurement system comprising: an optical pressure sensor implantable in an eye, wherein the sensor has a substrate coupled to a membrane that changes shape as a function of an intraocular pressure of the eye, and the substrate and the membrane define a sealed cavity; an optical transmitter to emit an incident optical beam to the sensor; a receiver to produce an interference pattern in response to receiving a plurality of reflections of the incident optical beam from the sensor; an image sensor operable to receive a projection of the interference pattern; and a processor configured to estimate the intraocular pressure of the eye based on processing the projection of the interference pattern.
1 . An intraocular pressure (IOP) measurement system comprising:
an optical pressure sensor implantable in an eye, wherein the sensor has a substrate coupled to a membrane that changes shape as a function of an intraocular pressure of the eye, and the substrate and the membrane define a sealed cavity;
an optical transmitter to emit an incident optical beam to the sensor;
a receiver to produce an interference pattern in response to receiving a plurality of reflections of the incident optical beam from the sensor;
an image sensor operable to receive a projection of the interference pattern; and
a processor configured to estimate the intraocular pressure of the eye based on processing the projection of the interference pattern.
2 . The system of claim 1 wherein the plurality of reflections are frequency dependent reflections of the incident optical beam that change as a function of the intraocular pressure to produce the interference pattern.
3 . The system of claim 1 wherein the plurality of reflections comprises a first reflection from an interface between the membrane and the cavity, and a second reflection from the interface between the substrate and the cavity.
4 . The system of claim 1 wherein the interference pattern comprises a number of concentric rings and the number of concentric rings is a function of a shape of the membrane.
5 . The system of claim 1 wherein the interference pattern comprises a number of concentric rings and each ring of the number of concentric rings comprises a position that is a function of the shape of the membrane.
6 . The system of claim 1 wherein the processor determines, by processing the projection of the interference pattern, whether the projection of the interference pattern matches a theoretical interference profile to estimate the intraocular pressure.
7 . The system of claim 6 wherein the theoretical interference profile corresponds to a known membrane pressure.
8 . The system of claim 1 wherein the transmitter and the receiver are integrated within a reader and the reader is operable to read the optical pressure sensor when the reader and the sensor are positioned within a volume between 10 to 100 times greater than a volume of 2 mm×2 mm×0.2 mm.
9 . The system of claim 1 wherein the transmitter, the receiver and the image sensor are integrated within a single housing of a handheld device.
10 . They system of claim 1 wherein the sensor is implanted in a cornea of the eye.
11 . A method for measuring intraocular pressure of an eye, the method comprising:
emitting an optical beam toward the eye;
detecting, as an output signal, an interference pattern corresponding to a plurality of reflections of the optical beam from a pressure sensor that is implanted in the eye;
projecting the interference pattern to an image sensor; and
processing the projected interference pattern to compute an estimate of the intraocular pressure of the eye.
12 . The method of claim 11 wherein processing the output signal comprises performing an interferometric image processing algorithm.
13 . The method of claim 12 wherein the interferometric image processing algorithm analyzes the projected interference pattern and matches the projected interference pattern to a theoretical interference pattern that corresponds to a known pressure to determine the intraocular pressure of the eye.
14 . The method of claim 11 wherein the sensor comprises a rigid substrate and a flexible membrane attached to the substrate that define a sealed cavity.
15 . The method of claim 14 wherein the plurality of reflections are frequency dependent reflections of an incident optical beam that change as a function of the intraocular pressure to produce the interference pattern.
16 . The method of claim 14 wherein the plurality of reflections comprises a first reflection from an interface between the flexible membrane and the cavity, and a second reflection from the interface between the substrate and the cavity.
17 . The method of claim 11 wherein the emitting and the detecting are performed by a transmitter and a receiver, and the transmitter, the receiver and the pressure sensor are positioned within a volume of between 10 to 100 times greater than a volume of 2 mm×2 mm×0.2 mm during measuring.
18 . The method of claim 17 wherein the transmitter, the receiver and the image sensor are integrated within a single housing of a handheld device.
19 . The method of claim 18 further comprising a projector integrated within the single housing of the handheld device to project the interference pattern to the image sensor.
20 . The method of claim 11 wherein the sensor is implanted in a cornea of the eye.