Interference Pattern Projection for Intraocular Pressure Sensor Alignment
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Solution Overview
Problem
Existing methods for measuring intraocular pressure (IOP) are invasive, inconvenient, and often require precise alignment of a handheld device with an implantable sensor, making frequent and accurate measurements challenging, especially for individuals with tremors or other dexterity issues.
Innovation Solution
A system and process using interference pattern projection to measure intraocular parameters, such as IOP, from a miniature implant without the need for precise spatial alignment. This involves emitting an optical beam that travels through free space and is reflected by a flexible membrane within the eye, with the reflection changing based on IOP. The interference pattern is then projected onto an image sensor, allowing for digital processing to estimate IOP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wireless implantable pressure sensing element with digital readout is used, then continuous IOP monitoring capability is improved, but precise spatial alignment between the external reader and the pressure sensing element becomes critical and difficult to achieve
Solution Approach 1:
The patent replaces the mechanical alignment system with an optical interferometric system. Instead of relying on precise physical positioning of the reader relative to the implant, the system uses optical interference patterns (Fabry-Perot interferometry) to detect pressure changes. The optical beam passes through the cornea and interacts with the implant's reflective surfaces, creating interference fringes that encode pressure information, eliminating the need for precise mechanical alignment.
Solution Approach 2:
The patent changes the measurement parameter from direct spatial positioning to optical interference pattern analysis. By measuring the interference fringe patterns created by light reflecting between different surfaces of the implant, the system translates pressure changes into optical parameter changes (fringe spacing, curvature, number of fringes) that can be detected without precise alignment.
2Measurement precision
If contact tonometry is used for accurate IOP measurement, then measurement precision is improved, but patient comfort and convenience deteriorate due to numbing and clinical setting requirements
Solution Approach 1:
The patent replaces contact mechanical tonometry with non-contact optical measurement. Instead of applying physical pressure to the cornea with a tonometer probe, the system uses optical beams to measure corneal deflection and implant position, eliminating the need for numbing drops and direct contact while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces an intermediary implantable sensor between the cornea and the external measurement device. This passive optical sensor implant serves as a mediator that translates internal pressure changes into external optical signals that can be detected without direct contact with the eye, combining the accuracy of contact methods with the comfort of non-contact measurement.
3Device complexity
If infrequent IOP measurements are performed in a doctor's office, then device complexity is reduced, but the ability to account for IOP variation over time deteriorates
Solution Approach 1:
The patent implements a self-monitoring system where the patient independently performs measurements at home using a portable reader device. The system is designed to be user-friendly with large eyebox tolerance, allowing patients with various dexterity levels to perform measurements without clinical assistance. This enables frequent self-service monitoring that captures IOP variations throughout the day and across different conditions.
Solution Approach 2:
The patent transforms the static, infrequent clinical measurement system into a dynamic, frequent home monitoring system. The portable reader and passive implant enable multiple measurements per day under different conditions (awake, asleep, with/without medication), capturing the dynamic nature of IOP variations that static annual measurements cannot detect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The technique significantly enlarges the eyebox volume by a factor of 10-100, making alignment easier and reducing misalignment sensitivity, thus enabling more convenient and accurate IOP measurements.
Implementation Method 1
a receiver to produce an interference pattern in response to receiving a plurality of reflections of the incident optical beam from the sensor
Implementation Method 2
an optical beam is emitted by a transmitter inside the reader. The reader is not physically attached to the sensor and may be outside of the eye. The beam may travel through free space (the ambient environment outside of the eye) and then enters the cornea where it impinges upon the sensor and is reflected by the sensor
Data Source
AI summary
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.