Ophthalmic Cassette Fluid Level Detection and Alignment
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Solution Overview
Problem
Existing ophthalmic surgical cassettes with venturi pumps face issues such as inconsistent fluid level detection due to waterlogged float balls, difficulty in disconnecting tubing, lack of visual feedback during surgery, and alignment challenges during cassette insertion, which hinder efficient and safe surgical operations.
Innovation Solution
A surgical cassette with a transparent container, tapered alignment slots for easy insertion, an aspiration path directing fluid flow towards the front for visual feedback, and a fluid level indicator using a prism to enhance photo-detector accuracy, allowing the irrigation and aspiration tubing to remain connected for easier emptying and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a float ball and light detector scheme is used for fluid level detection, then the pump can be stopped when the cassette is full, but the detection precision deteriorates over time as float balls become waterlogged and vary in浮力
Solution Approach 1:
The patent replaces the mechanical float ball system with an optical detection system. A light source and photo detector are positioned to detect fluid level through direct optical measurement, eliminating the mechanical float ball that becomes waterlogged and unreliable over time. The photo detector provides consistent, maintenance-free detection without the variability inherent in floating mechanical components.
2Strength
If tubing is firmly connected to barbs on the cassette, then connections are secure during surgery, but the tubing becomes difficult and time-consuming to remove when emptying the cassette
Solution Approach 1:
The patent employs a dynamic connection system where tubing can be securely attached during surgery but easily released when needed. The barb design allows firm engagement during operation while enabling quick removal by simple pulling motion, transforming the static strong connection into a dynamically controllable connection that adapts to different operational phases.
3Productivity
If the aspiration path dumps fluid towards the rear of the cassette, then fluid collection is efficient, but the operator cannot easily see fluid flow providing visual feedback during surgery
Solution Approach 1:
The patent redirects the aspiration fluid flow path to move toward the front of the cassette, which is the dimension closest to the operator's viewing position. This spatial repositioning allows the operator to directly observe fluid entering the cassette, providing immediate visual feedback on aspiration effectiveness without compromising collection efficiency.
4Ease of operation
If the cassette is inserted without alignment guides, then the insertion process is simple, but proper alignment with the pump is difficult to achieve
Solution Approach 1:
The patent incorporates asymmetric alignment features such as tapered slots or keyed interfaces on the cassette that correspond to matching features on the pump. This asymmetric design provides mechanical guidance that naturally aligns the cassette in the correct orientation during insertion, eliminating alignment errors without complicating the insertion process.
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 solution provides consistent fluid level detection, simplifies cassette alignment and emptying, and offers direct visual feedback on aspiration flow, enhancing surgical efficiency and safety by ensuring precise fluid management and reducing operational complexity.
Implementation Method 1
the use of a prism to redirect light from a photo-detector
Implementation Method 2
venturi pumps are well known in the art
Data Source
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AI summary
A cassette 74 for use with an ophthalmic surgical pump 16 for collecting aspirant fluid and tissue from a patient's eye includes a rigid walled container 18 having an interior volume 42. At least one tapered alignment slot 20 is formed in a side wall of the container 18 and extends from a back wall 24 towards a front wall 26. An irrigation and aspiration manifold base 50 is removeably attached to the container 18. An aspiration path 46 is formed within the container 18 for receiving the aspiration fluid and the tissue from the eye and directing the flow of fluid towards a front half of the container 18 before the fluid and tissue collects within a majority of the interior volume 42 of the container 18. A fluid level indicator 34 is formed on a wall 22 of the container 18, such that an associated photo-detector 86 of the pump 16 may determine a level of fluid in the container 18.