In-Vivo Eye Moisture Measurement Device Using Electrical Impedance
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Solution Overview
Problem
Current methods for diagnosing dry eye disease, such as Schirmer's test and in-vitro tear osmolarity measurements, are not always reliable and can be invasive, raising patient safety concerns and providing inconsistent results.
Innovation Solution
A device with an alternating current source and a biocompatible electrode arrangement that contacts the inner eyelid to measure electrical impedance, which correlates with moisture levels, using a processor to compute and display a moisture parameter based on empirical correlations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Schirmer's test is used to determine eye moisture, then the test can be performed with simple paper strips, but the diagnostic reliability is poor and false normal results are produced
Solution Approach 1:
The patent replaces the mechanical absorption method of Schirmer's test with an electrical measurement system. Instead of using paper strips to absorb and measure tear volume, the device uses electrodes to measure electrical impedance through the eyelid tissue, which correlates with moisture content. This substitution of mechanical measurement with electrical measurement provides more reliable diagnostic results while maintaining ease of use.
2Measurement precision
If in-vitro tear osmolarity measurement is used, then tear composition can be analyzed, but the method is invasive and raises patient safety concerns
Solution Approach 1:
The patent uses electrical impedance as an intermediary parameter to indirectly assess tear moisture without directly contacting or removing tear fluid. Instead of measuring osmolarity through invasive tear collection, the device measures the electrical properties of the eyelid tissue through which tears are distributed, providing a non-invasive proxy that correlates with tear moisture status and eliminates patient safety concerns associated with invasive procedures.
Solution Approach 2:
The patent replaces the mechanical invasive collection method with an electrical measurement approach. Instead of physically collecting and analyzing tear fluid in a laboratory setting, the device uses electrical impedance measurement through the eyelid to non-invasively assess tear moisture, eliminating the need for invasive procedures while maintaining measurement precision.
3Measurement precision
If in-vitro tear analysis is performed, then detailed tear composition can be obtained, but the process is time-consuming and not suitable for rapid diagnosis
Solution Approach 1:
The patent replaces the time-consuming laboratory analysis process with rapid electrical measurement. Instead of requiring tear fluid collection, centrifugation, and osmolarity analysis in a laboratory setting, the device performs immediate electrical impedance measurement through the eyelid, providing results instantly without the time delay associated with in-vitro processing while maintaining diagnostic precision.
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 device provides accurate, repeatable, and patient-friendly measurements of eye moisture, correlating with established dry eye disease diagnostics, offering a safer and more reliable assessment of eye dryness.
Implementation Method 1
when the electrode arrangement is provided with the alternating current, and is disposed against the soft tissue, the soft tissue electrically bridges between the electrodes to form an electrical circuit, wherein an electrical signal is produced by the alternating current passing from the first electrode to the second electrode via the soft tissue
Implementation Method 2
the processor is adapted to receive in-vivo based electrical information originating from the electrical signal, via the circuit, and to produce an output relating to, or derived from, the moisture parameter, based on the in-vivo electrical information
Data Source
AI summary
A medical diagnostic device and method, the device including: (a) an alternating current source, adapted to produce an alternating current; (b) an electrode arrangement having at least first and second electrodes, separated by an electrically insulating region, the arrangement having an at least semi-rigid region that fixes the electrodes in a spaced-apart manner, the arrangement adapted to contact the soft tissue on the inner surface of the eyelid; and (c) a processor, associated with the electrode arrangement, said electrodes electrically connected to the alternating current source; wherein, when the electrode arrangement is provided with the alternating current, and is disposed against the soft tissue, the soft tissue electrically bridges between the electrodes to form an electrical circuit, wherein an electrical signal is produced by the alternating current electrically passing between the electrodes via the soft tissue; wherein the processor is adapted to receive in-vivo based electrical information originating from the electrical signal, via the circuit, and to produce an output relating to, or derived from, the moisture parameter, based on the in-vivo electrical information; and wherein the processor is designed and configured to compute the moisture parameter in the soft tissue, at least partially based on the in-vivo electrical information, and based on an empirical correlation between the in-vivo electrical information and the moisture parameter.