Variable Pulse Rate Laser Control for Eye Surgery

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Solution Overview

Problem

Traditional laser systems for eye tissue ablation have a fixed pulse repetition rate, limiting the physician's ability to adjust based on patient-specific needs or treatment type, which can lead to concerns about local heating and tissue damage, discouraging the use of higher pulse repetition rate systems.

Innovation Solution

A laser apparatus with a processor-based control unit that allows selection of variable pulse repetition rates through a user interface, enabling physicians to customize pulse emission sequences for different phases of treatment, such as epithelial and stromal tissue ablation, and store patient-specific settings for future reference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed pulse repetition rate is used in traditional laser systems, then the system structure is simple and reliable, but the physician cannot adjust the pulse repetition rate based on patient-specific needs or treatment type, leading to thermal risks and longer treatment times

Engineering Contradiction:
Improveadjustability of pulse repetition rateVSAvoidcomplexity of control system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic pulse repetition rate control system where the laser apparatus can switch between multiple predefined pulse repetition rates (e.g., 500 Hz, 1000 Hz, 1500 Hz) based on user input. The control unit dynamically adjusts the pulse emission sequence during different phases of treatment (epithelial ablation vs. stromal ablation), allowing the system to adapt to varying clinical requirements while maintaining operational simplicity through predefined rate options.

Inventive Principle:
Principle #15Dynamics

2Productivity

If a high pulse repetition rate is used, then treatment time is reduced, but local heating of eye tissue increases causing thermal damage risks

Engineering Contradiction:
Improvetreatment speedVSAvoidlocal heating and thermal damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent employs periodic action by utilizing multiple predefined pulse repetition rates that can be selected based on treatment phase and clinical requirements. The control unit delivers laser pulses in structured sequences with different repetition rates for different ablation phases, allowing optimization between treatment speed and thermal management. This periodic variation in pulse delivery patterns enables the system to achieve fast treatment when appropriate while preventing excessive thermal accumulation.

Inventive Principle:
Principle #19Periodic action

3Ease of operation

If a single pulse repetition rate is used for all treatment phases, then the control system is simple, but the treatment cannot be optimized for different tissue types (epithelial vs. stromal ablation)

Engineering Contradiction:
Improvesimplicity of controlVSAvoidprecision of tissue ablation
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent segments the treatment process into distinct phases (epithelial ablation and stromal ablation) with different optimal pulse repetition rates. The control unit is configured to deliver different pulse sequences for each phase, allowing optimization for specific tissue types. This segmentation enables precise control over the ablation process for different tissue layers while maintaining ease of operation through automated phase-based rate selection.

Inventive Principle:
Principle #1Segmentation

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

Enables flexible and tailored laser treatment protocols, reducing thermal risks and allowing for shorter treatment times, accommodating both modern and older systems, while ensuring patient comfort and safety.

Implementation Method 1

an apparatus for laser eye surgery for performing a transepithelial photorefractive keratectomy

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

laser ablation is performed on the stromal tissue of the cornea thereby exposed

Methodology Applied
Scientific EffectPhotothermal effect: Heating

Data Source

PatentEP3313337B1Apparatus for eye laser surgery for performing a transepithelial photorefractive keratectomy
Publication Date: 2024.02.21 ALCON INC
  • EP3313337B1 patent drawingFigure 1
  • EP3313337B1 patent drawingFigure 2

AI summary

An apparatus for laser eye surgery comprises a laser module (12), which is equipped to emit pulsed, focused laser radiation of a variable pulse repetition rate, and a processor-based control unit (18), which is equipped to receive at least one user input pertaining to a selection of one of several predefined pulse repetition rates over a user input and to control the laser module in accordance with the at least one selected pulse repetition rate. In certain specific embodiments, the user interface enables input of two user entries, each of which relates to a selection of one of several predefined pulse repetition rates. The control unit controls the laser module for a first phase of a laser treatment in accordance with one of the two user inputs, and for a second phase of the laser treatment, it controls the laser module in accordance with the other one of the two user inputs. For example, such specific embodiments permit an epithelial tissue ablation to be performed at a different pulse repetition rate than a stromal tissue ablation as part of a transepithelial keratectomy on a human eye.