Phacoemulsification Tip Engagement Detection via Impedance Tracking

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Solution Overview

Problem

Existing phacoemulsification systems struggle to accurately detect the engagement and disengagement of the phacoemulsification tip with the eye lens during cataract surgery, as the resonance frequency drifts due to changes in mechanical loads, making it difficult for physicians to control the procedure effectively.

Innovation Solution

A system that utilizes piezoelectric vibration and measures electrical impedance changes to detect engagement and disengagement of the phacoemulsification tip with the lens by adjusting the driving signal level or frequency in response to impedance changes, providing audio, visual, or tactile notifications to the user.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If visual monitoring of tip engagement is used, then the surgeon can observe the procedure, but the method is time-consuming and increases surgical risk

Engineering Contradiction:
Improvesurgical safetyVSAvoidprocedure time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical/visual monitoring system with an electronic sensing system. A force sensor detects tip engagement with the lens by measuring force changes, and a processor automatically interprets these signals to determine engagement status, eliminating the need for time-consuming visual monitoring while maintaining or improving surgical safety

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

Solution Approach 2:

The surgical system performs self-monitoring through automated electronic detection. The force sensor and processor work together to automatically detect and interpret tip engagement without requiring continuous surgeon attention or manual visual inspection, allowing the system to monitor itself throughout the procedure

Inventive Principle:
Principle #25Self-service

2Productivity

If electronic detection systems are implemented, then procedure time is reduced, but device complexity increases

Engineering Contradiction:
Improvesurgical efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The force sensor serves multiple functions: it monitors tip engagement, tracks phacoemulsification progress, and provides real-time feedback on surgical conditions. This multi-functionality justifies the added device complexity by delivering multiple benefits from a single component integration

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The processor acts as an intermediary that automatically interprets complex sensor signals and converts them into meaningful engagement status information. This intermediary component manages the complexity by handling signal processing and interpretation, presenting simplified information to the surgeon while enabling sophisticated detection capabilities

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances the precision of phacoemulsification procedures by providing real-time feedback on tip engagement and disengagement, allowing for better control of the surgical process and reducing the risk of complications.

Implementation Method 1

a force sensor positioned to detect changes in force caused by tip engagement with the lens

Methodology Applied
Scientific EffectForce detection:

Data Source

PatentEP4380520B1Electronically detecting phacoemulsification tip engagement with a lens
Publication Date: 2026.05.06 JOHNSON & JOHNSON SURGICAL VISION INC
  • EP4380520B1 patent drawingFigure 1
  • EP4380520B1 patent drawingFigure 2
  • EP4380520B1 patent drawingFigure 3~4

AI summary

A system and method include vibrating a needle of a phacoemulsification handpiece by driving one or more piezoelectric crystals in the handpiece with one or more electrical signals having different respective frequencies using one or more respective drive modules. The needle is inserted into an eye of a patient. The frequencies of the electrical signals are tuned to respective one or more target frequencies, and respective electrical impedances seen by the drive modules are registered. In response to an electrical impedance seen by at least one of the drive modules undergoing a change exceeding a preset impedance change, an indication is provided that material in the eye surrounding the needle has changed, a level of vibration of the needle is changed, and/or the frequency of at least one of the drive modules is adjusted to an electrical resonant frequency thereof.