Optical Intraocular Pressure Sensor for Artificial Corneas
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Solution Overview
Problem
Patients with implanted artificial corneas face unreliable and subjective measurements of intraocular pressure, which is a significant risk factor for glaucoma progression leading to blindness, as standard tonometers cannot measure IOP effectively in these cases.
Innovation Solution
An optical pressure sensor with a sealed cavity and flexible membrane is integrated into the stem of an artificial cornea, using a fiber optic system to detect changes in resonance frequency caused by intraocular pressure, allowing for non-invasive and accurate measurement of IOP without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard tonometers are used to measure intraocular pressure, then the measurement process is simple and non-invasive, but the measurement reliability is poor for patients with artificial corneas
Solution Approach 1:
The measurement system is divided into separate components: an implantable sensor portion with optical cavity and membrane that remains in the eye, and an external interrogation system that performs measurements. This segmentation allows the simple external device to achieve reliable measurements through the sophisticated but miniaturized implantable sensor.
Solution Approach 2:
The patent replaces mechanical contact-based tonometry with an optical measurement system. The implantable sensor uses optical resonance frequency detection instead of mechanical pressure application, eliminating the limitations of standard tonometers for artificial cornea patients while maintaining non-invasive external measurement.
2Measurement precision
If an implantable optical sensor is used to measure intraocular pressure, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent uses a flexible membrane to seal the distal end of the optical cavity. This thin film deflects in response to intraocular pressure changes, modulating the optical resonance frequency. The flexible membrane provides precise pressure sensing while maintaining a compact, implantable form factor that minimizes overall device complexity.
Solution Approach 2:
The sensor operates by detecting changes in optical resonance frequency as the primary measurement parameter. This frequency-based measurement approach provides high precision while using simple optical interrogation from outside the eye, avoiding the need for complex electronic processing or power requirements within the implant.
3Measurement precision
If a flexible membrane is used to detect pressure changes, then the measurement sensitivity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The flexible membrane is designed as a thin film structure that provides adequate mechanical compliance for pressure sensing while maintaining optical transparency for the resonance measurement. The membrane's flexibility allows it to respond to small pressure changes with measurable deflection, achieving high sensitivity without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The flexible membrane acts as an intermediary between the intraocular pressure environment and the optical resonance detection system. It translates pressure changes into optical frequency shifts that can be detected externally, providing sensitive measurement while isolating the optical components from direct pressure exposure and reducing manufacturing complexity.
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
This method provides reliable and accurate intraocular pressure measurements, reducing the risk of undetected high pressure and improving long-term visual outcomes for patients with artificial corneas by enabling precise monitoring and potential glaucoma management.
Implementation Method 1
The sensor includes a sealed cavity that acts as an optical resonator... causing a change in the length of the sealed cavity and hence a change in the resonance frequency of light in the cavity
Implementation Method 2
The flexible membrane deflects responsive to the intraocular pressure in the eye of the patient, thus causing a change in the length of the sealed cavity
Data Source
AI summary
A system for measuring intraocular pressure in an eye of a patient includes a sensor configured to be positioned in the eye of the patient. The sensor includes a sealed cavity, and a flexible membrane sealing a distal end of the sealed cavity, the flexible membrane configured to deflect responsive to the intraocular pressure in the eye of the patient. The system includes a detection device configured to be positioned external to the eye of the patient and optically coupled to the sensor, the detection device configured to detect an indication of change in length of the sealed cavity resulting from deflection of the flexible membrane.