Phaco Cassette Fluid Level Sensing With Infrared Reflectivity

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Solution Overview

Problem

Existing phacoemulsification systems lack efficient mechanisms to monitor and maintain irrigation fluid levels, leading to potential depletion during surgery, which can cause severe eye damage and vision loss, and existing sensors are inaccurate due to friction and spring forces affecting LVDT accuracy.

Innovation Solution

The system employs infrared sensors to detect the difference in reflectivity between air and water interfaces within fluid tanks, using a cassette design with triangular level sensing devices and IR reflectance sensors to accurately monitor fluid levels, ensuring reliable fluid management during surgery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional LVDT sensors with springs are used to detect fluid levels, then the sensor structure is simple, but friction and spring forces affect measurement accuracy

Engineering Contradiction:
Improvefluid level detection accuracyVSAvoidsensor structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical LVDT sensor system with an optical sensor system. The optical sensor detects fluid level by measuring changes in light transmission or reflection properties as the fluid level changes, eliminating mechanical friction and spring forces that compromised measurement accuracy. This substitution of mechanical detection with optical detection resolves the contradiction by achieving higher measurement precision without the accuracy-degrading mechanical elements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If visual monitoring of irrigation fluid levels is performed by staff, then no additional sensors are needed, but fluid depletion can go undetected leading to eye damage

Engineering Contradiction:
Improvefluid level monitoring reliabilityVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-monitoring capability through optical sensors that automatically detect fluid levels and provide real-time feedback to the surgical console. The system continuously monitors irrigation fluid levels without requiring manual visual inspection by surgical staff. When fluid levels approach critical thresholds, the system can provide alerts or automatically adjust flow rates, ensuring reliable detection and prevention of fluid depletion-related eye damage while maintaining operational simplicity.

Inventive Principle:
Principle #25Self-service

3Loss of information

If flow sensors are used to measure irrigation flow, then fluid depletion can be detected, but only warnings are provided when flow indicates very low volume

Engineering Contradiction:
Improveirrigation source volume informationVSAvoidfluid level detection accuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent implements continuous feedback monitoring through optical sensors that real-time detection of fluid levels and provide ongoing information to the surgical console. Unlike traditional flow sensors that only trigger warnings at very low volumes, the optical sensing system continuously measures fluid level and provides feedback across the entire range of fluid volumes. This enables early detection of depletion trends and provides precise information about remaining fluid levels, allowing for proactive management rather than reactive warnings.

Inventive Principle:
Principle #23Feedback

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 provides precise fluid level detection, preventing fluid depletion and maintaining optimal intraocular pressure, thereby reducing the risk of eye damage and ensuring consistent surgical outcomes.

Implementation Method 1

infrared sensors to detect the difference in reflectivity between air and water interfaces within fluid tanks

Methodology Applied
Scientific EffectReflectivity: Reflection

Data Source

PatentEP4076566B1System and methods for a cassette capture mechanism for phacoemulsification surgical applications
Publication Date: 2026.04.08 JOHNSON & JOHNSON SURGICAL VISION INC
  • EP4076566B1 patent drawingFigure 1A
  • EP4076566B1 patent drawingFigure 1B
  • EP4076566B1 patent drawingFigure 2

AI summary

A system and method for detecting and/or capturing a cassette is disclosed. The cassette capture mechanism may be used with a surgical console of a surgical system, wherein the system has a cassette receiving area having at least two alignment sensors and a plurality of capture plungers; and at least two capture hooks which may engage with a cassette, wherein at least one of the at least two alignment sensors produces a signal indicative of the presence of a cassette.