Eye Surgery Laser Tissue Protection Control

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Solution Overview

Problem

Femtosecond laser systems used in eye treatment risk damaging eye structures outside the treatment area, such as the iris and retina, due to incomplete absorption of energy and high pigment content, leading to potential phototoxicity and photocoagulation.

Innovation Solution

A device that acquires processing data to define a treatment area and generates control data to limit the laser beam's exposure time and intensity, taking into account light propagation and eye structures' dimensions, to reduce tissue damage in areas outside the treatment area, by adjusting the laser parameters and eye dimensions, and using empirical data to determine stress limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher power laser systems are used to shorten operation times, then productivity is improved, but the risk of unwanted tissue damage increases

Engineering Contradiction:
Improveoperation timeVSAvoidtissue damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The device calculates and determines safe laser parameter ranges before treatment begins, using pre-stored optical properties of eye structures and damage threshold data. This preliminary calculation establishes protective constraints on pulse energy, repetition rate, and focal position that prevent tissue damage while enabling efficient treatment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors treatment parameters and compares them against the calculated safe ranges. The control unit adjusts laser parameters in real-time based on feedback from the treatment progress and patient response, ensuring operation remains within safe limits while maintaining productivity.

Inventive Principle:
Principle #23Feedback

2Productivity

If laser energy is increased to improve treatment efficiency, then productivity is improved, but phototoxicity and photocoagulation damage to eye structures increases

Engineering Contradiction:
Improvetreatment efficiencyVSAvoidphototoxicity and photocoagulation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The device dynamically adjusts laser parameters including pulse energy, pulse duration, repetition rate, and wavelength based on the specific treatment requirements and real-time conditions. By optimizing these parameters within safe ranges, the system achieves efficient treatment while preventing phototoxicity and photocoagulation damage to the iris and retina.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses pulsed laser delivery with controlled repetition rates instead of continuous irradiation. The periodic pulsed action allows thermal dissipation between pulses and reduces cumulative energy deposition in sensitive structures, thereby preventing photocoagulation while maintaining treatment efficiency through high peak powers.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If incomplete absorption of laser energy occurs in transparent materials, then treatment precision is improved, but energy transmission to underlying tissue layers increases causing damage

Engineering Contradiction:
Improvetreatment precisionVSAvoidenergy transmission damage
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The device pre-calculates the expected energy absorption and transmission profile based on the treatment depth, laser wavelength, and optical properties of the eye structures. This preliminary analysis identifies safe energy levels that achieve precise treatment at the target while limiting transmitted energy to levels below damage thresholds for underlying structures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system replaces mechanical depth control with optical wavelength selection and computational energy distribution modeling. By using specific infrared wavelengths with known absorption characteristics and calculating energy propagation through eye tissues, the system achieves precise energy deposition at the treatment site while preventing damage to deeper structures.

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

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

Effectively reduces tissue damage in eye structures outside the treatment area by minimizing average radiation intensity and maximum temperatures, thereby preventing overheating, phototoxicity, and photocoagulation, ensuring safer eye treatments.

Implementation Method 1

The non-linear absorption is generally not complete, which means that part of the incident energy is always transmitted when processing transparent materials.

Methodology Applied
Scientific EffectNon-linear absorption: Absorption (EM radiation)

Implementation Method 2

Damage to the eye, for example, is known to be caused by phototoxicity in the short-wavelength visible wavelength range and photocoagulation (photothermal effect over the entire wavelength range).

Methodology Applied
Scientific EffectPhototoxicity: Photo-oxidation

Implementation Method 3

Damage to the eye, for example, is known to be caused by phototoxicity in the short-wavelength visible wavelength range and photocoagulation (photothermal effect over the entire wavelength range).

Methodology Applied
Scientific EffectPhotocoagulation: Coagulation

Implementation Method 4

The control data are determined in particular in such a way that an average radiation intensity is reduced in the tissue and maximum temperatures in the tissue of eye structures lying outside the processing area, in particular in the iris and the retina, are reduced.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP1810647B1Apparatus for protecting tissue during eye surgery
Publication Date: 2009.11.11 ZIEMER HLDG
  • EP1810647B1 patent drawingFigure 1
  • EP1810647B1 patent drawingFigure 2a~2c
  • EP1810647B1 patent drawingFigure 3a~3c

AI summary

The device has a processing data module for determining processing data, which define a processing area that is processed through a focus (F) of a laser beam (21) produced by a laser system (2) during the treatment of eye. A processing module (14) provides control data for the laser system based on input data. The processing module determines the control data in consideration of light propagation in eyes, such that the control data temporarily limits the treatment through the focus of the laser beam at positions within the area. An independent claim is also included for a computer program product comprising computer program code units that are stored in a computer readable medium for controlling a processor of a tissue protection device.