Pre-biased Membrane Valve for Glaucoma IOP Control
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Solution Overview
Problem
Current glaucoma treatment devices lack active control over intraocular pressure (IOP) and are prone to bleb formation and fibrosis, leading to increased flow resistance and reduced effectiveness over time.
Innovation Solution
The development of pre-biased membrane valves with adjustable cracking pressures, achieved by varying the height differential between inner and outer walls within the valve housing, allowing for responsive control of aqueous humor flow without external power, using pressure differentials across the membrane to throttle fluid flow and maintain optimal IOP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive check valves are used to control IOP, then the device structure is simple, but the valve cannot provide active control and allows over-drainage leading to bleb formation
Solution Approach 1:
The membrane valve transitions from a static passive check valve to a dynamic actively responsive valve that continuously adjusts its opening degree based on real-time pressure differential between the anterior chamber and drainage site, enabling active control of aqueous humor flow
Solution Approach 2:
The cracking pressure of the membrane valve is made adjustable by changing physical parameters such as membrane material properties, membrane area, and pre-biasing forces, allowing customization of the pressure threshold for valve opening to match different clinical requirements
2Ease of manufacture
If passive drainage devices are used, then the device is simple to manufacture, but fibrosis develops over time increasing flow resistance and reducing effectiveness
Solution Approach 1:
The membrane valve is fully passive and self-regulating, using only the natural pressure differential between the anterior chamber and drainage site to control flow, requiring no external power source or complex actuation mechanisms, thereby maintaining ease of manufacture while significantly extending functional life by preventing fibrosis
Solution Approach 2:
The valve incorporates inherent feedback through the pressure differential across the membrane, which automatically adjusts the valve opening degree in response to changes in IOP or drainage site pressure, maintaining optimal flow control throughout the device's extended functional life
3Device complexity
If no mechanism to control bleb over-pressurization is provided, then the valve operation is simple, but over-drainage occurs leading to fibrosis and increased flow resistance
Solution Approach 1:
The membrane valve is pre-biased to remain closed at low pressure differentials, preventing over-drainage and bleb over-pressurization before they can occur. The valve only opens when the pressure differential exceeds the cracking pressure, providing preliminary protection against fibrosis
Solution Approach 2:
The cracking pressure parameter is carefully selected and adjustable to ensure it exceeds the pressure that would cause bleb over-pressurization and fibrosis, while still allowing adequate drainage when IOP is elevated, thereby eliminating the harmful effect of fibrosis without excessive device 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 solution provides continuous, responsive control of IOP, reducing bleb formation and fibrosis, thereby extending the functional life of the IOP control system and maintaining effective drainage of aqueous humor.
Implementation Method 1
the flexible membrane is configured to flex and selectively open and close the fluid flow channel to permit fluid to flow from the fluid inlet to the fluid outlet, and the flexible membrane is configured to control flow through the fluid flow channel from the fluid inlet to the fluid outlet by deflecting in response to pressure differentials of the reference chamber pressure and the fluid flow channel pressure
Implementation Method 2
The inner wall biases the flexible membrane from a neutral condition, and the height differential is selected to provide resistance to displacement from the inner wall until pressure acting on the membrane exceeds the target cracking pressure
Data Source
AI summary
A method of manufacturing a valve for a fluid system is described herein. The method comprises determining a target cracking pressure for the valve of the fluid system, providing an inner wall having a first height and an outer wall having a second height, the first height varying from the second height by a height differential, and attaching a flexible membrane to the outer wall at the second height, wherein a central zone of the flexible membrane is in contact with the inner wall at the first height and the inner wall biases the flexible membrane from a neutral condition. The height differential is selected to provide resistance to displacement from the inner wall until pressure acting on the membrane exceeds the target cracking pressure.