Closed Microfluidic Contact Lens Network for Continuous IOP Sensing
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Solution Overview
Problem
Current intraocular pressure (IOP) monitoring technologies are either not continuous, uncomfortable, or invasive, and existing contact lens sensors suffer from discomfort, high cost, and limited durability due to electrical components that are impermeable to gases and sensitive to hydration levels, making long-term monitoring challenging.
Innovation Solution
A microfluidic strain sensor embedded in a contact lens using transparent, air-permeable materials that measures IOP fluctuations based on fluid physics, eliminating electrical components and providing continuous, comfortable monitoring through a smartphone-readable system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If electrical strain sensors are used in contact lenses for continuous IOP monitoring, then continuous measurement capability is achieved, but comfort and air permeability deteriorate due to impermeable conductive components
Solution Approach 1:
The patent extracts and removes electrical components from the contact lens sensor system, replacing them with a purely mechanical microfluidic sensing mechanism. This eliminates the gas-impermeable conductive materials while preserving continuous monitoring capability through mechanical strain detection in microfluidic channels.
Solution Approach 2:
The patent replaces the electrical sensing system with a mechanical sensing system based on microfluidic channels. The strain-induced volume changes in the microfluidic network provide a mechanical readout mechanism that eliminates the need for electrical components, thereby restoring gas permeability while maintaining continuous monitoring function.
2Measurement precision
If electrical components are embedded in contact lenses for sensor function, then sensing capability is achieved, but comfort and biocompatibility worsen due to non-transparent and non-air-permeable materials
Solution Approach 1:
The patent removes electrical components (electrodes, conductive materials, electronic circuits) from the contact lens structure, replacing them with a transparent microfluidic channel network made from contact lens material itself. This extraction eliminates the source of discomfort while preserving sensing capability through optical or mechanical readout methods.
3Device complexity
If thick silicone contact lens is used to embed electrical sensors, then sensor integration is achieved, but comfort deteriorates and adverse reactions increase
Solution Approach 1:
The patent merges the sensor structure with the contact lens material itself, creating an integrated microfluidic network that is formed from the lens material. This eliminates the need for separate sensor components and thick lens construction, achieving sensor integration while maintaining thin, comfortable lens profiles suitable for long-term wear.
4Measurement precision
If conductive components are added to contact lenses for electrical sensing, then sensing function is achieved, but gas permeability decreases by 810 orders of magnitude
Solution Approach 1:
The patent substitutes electrical signal detection with mechanical strain detection in microfluidic channels. The sensing mechanism relies on volume changes and pressure variations in the fluid network rather than electrical resistance or capacitance changes, eliminating the need for conductive materials and preserving full gas permeability of the contact lens material.
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 microfluidic sensor allows for long-term, continuous, and comfortable IOP monitoring, capable of distinguishing between internal and external factors, reducing the need for frequent doctor visits and improving glaucoma management by providing reliable data to both patients and physicians.
Implementation Method 1
a microfluidic network with channels that connect to a liquid reservoir and establish a liquid-gas equilibrium pressure interface
Implementation Method 2
The closed microfluidic network is sensitive to an axial strain... the sensing channel establishes a liquid-gas equilibrium pressure interface and equilibrium within the sensing channel, which would fluidically change as a response to radius of curvature variations on a cornea, or as a response to mechanical stretching and release of the cornea
Data Source
AI summary
A microfluidic strain sensing device for monitoring intraocular pressure. The device has a contact lens and a closed microfluidic network embedded with the contact lens. The network has a volume that is sensitive to an applied strain. The network distinguishes: (i) a gas reservoir containing a gas, (ii) a liquid reservoir containing a liquid that changes volume when the strain is applied, and (iii) a sensing channel able to hold the liquid within the sensing channel. The sensing channel connects the gas reservoir on one end and connects the liquid reservoir on another end. The sensing channel establishes a liquid-gas equilibrium pressure interface and equilibrium within the sensing channel, which would fluidically change as a response to radius of curvature variations on a cornea, or as a response to mechanical stretching and release of the cornea. The liquid-gas equilibrium pressure interface and equilibrium are used for measuring the intraocular pressure.