Phaco Probe Pressure Sensing for Stable Intraocular Pressure
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Solution Overview
Problem
Existing phacoemulsification systems face challenges in maintaining constant intraocular pressure (IOP) and preventing post-occlusion surges during cataract surgery, as they are prone to traumatic aspiration surges due to uncontrolled vacuum levels and pressure drops.
Innovation Solution
The system incorporates a phacoemulsification probe with an integrated sensing assembly that includes a pressure sensing device (PSD) and a rotatable valve, which senses fluid pressure and temperature to control the flow of irrigation and aspiration channels, using solenoids to toggle between positions and maintain constant IOP, and a connector assembly that disables the probe if disconnected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pump creates vacuum pressure to aspirate fluid from the eye, then fluid removal is achieved, but uncontrolled vacuum levels cause traumatic aspiration surges
Solution Approach 1:
The system continuously monitors IOP through a sensor and feeds this information back to a controller that adjusts pump speed in real-time. The controller increases pump speed when IOP drops and decreases pump speed when IOP rises, preventing aspiration surges while maintaining efficient fluid removal.
Solution Approach 2:
The pump speed is made dynamically adjustable rather than operating at a fixed speed. The system transitions from static vacuum pressure to dynamic pressure control, allowing real-time adaptation to changing surgical conditions to prevent harmful surges.
2Productivity
If the pump operates at high speed to maintain fluid flow, then productivity is improved, but pressure fluctuations cause harmful effects
Solution Approach 1:
The IOP sensor provides continuous feedback to the controller, which adjusts pump speed to maintain stable pressure. This closed-loop control ensures high fluid flow rates are achieved only when pressure conditions are appropriate, preventing harmful pressure fluctuations.
Solution Approach 2:
The system changes the operating parameters of the pump dynamically based on real-time IOP measurements. The controller modifies pump speed, flow rate, and vacuum pressure levels to balance productivity with pressure stability, preventing harmful effects during high-flow periods.
3Reliability
If irrigation fluid is infused to maintain IOP, then pressure stability is improved, but uncontrolled infusion causes pressure drops and surges
Solution Approach 1:
The IOP sensor continuously monitors pressure and feeds this information to the controller, which automatically adjusts irrigation fluid infusion rates. This feedback mechanism maintains pressure stability without requiring complex manual control systems.
Solution Approach 2:
The system uses its own IOP sensor and controller to automatically regulate fluid infusion, making the system self-regulating. The controller adjusts irrigation flow based on real-time pressure conditions, eliminating the need for external complex control mechanisms.
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 system effectively maintains constant IOP and reduces post-occlusion surges by rapidly responding to pressure and temperature changes, ensuring controlled fluid flow and preventing traumatic consequences to the eye.
Implementation Method 1
The phacoemulsification probe includes a piezoelectric crystal, which converts electrical energy to mechanical vibrations for oscillating the needle
Implementation Method 2
The sensing assembly includes a pressure sensing device (PSD) configured to sense a pressure of the fluid
Implementation Method 3
The rotatable valve includes solenoids wrapped around a tube including a shaft having electric dipole
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A phacoemulsification system includes a phacoemulsification probe and a sensing assembly. The phacoemulsification probe includes: (i) a needle, which is configured to be inserted into a lens capsule of an eye and to be vibrated to emulsify a lens of the eye, (ii) an irrigation channel, configured for flowing irrigation fluid into the lens capsule, and (iii) an aspiration channel, configured for removing at least eye fluid from the lens capsule. The sensing assembly is coupled with a proximal end of the phacoemulsification probe and is configured to sense a pressure of at least one of the irrigation fluid and the eye fluid.