Laser Pulse Modulation for Corneal Thermal Control

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Solution Overview

Problem

Conventional laser corneal treatments face challenges in controlling thermal energy to prevent excessive heating, which can lead to cell damage and prolonged recovery times due to fixed pulse frequencies and powers, failing to effectively manage localized temperature increases during procedures with high refractive errors.

Innovation Solution

A method and system for laser pulse modulation that dynamically controls the optical energy of laser pulses by adjusting frequency, amplitude, and duty cycle based on predetermined thresholds and real-time temperature measurements to limit thermal energy imparted to the cornea, using a thermal sensor and controller to regulate the energy delivery according to a surgical plan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fixed pulse frequencies and powers are used in laser corneal treatments, then the treatment procedure is simple and fast, but thermal energy cannot be controlled and temperature exceeds safe thresholds causing cell damage

Engineering Contradiction:
Improvecornea temperatureVSAvoidlaser pulse control system
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The laser system dynamically adjusts pulse frequency and power delivery based on real-time temperature feedback from the cornea. The controller modulates laser parameters during treatment to maintain temperature within safe thresholds, transitioning from fixed to dynamic control to prevent thermal damage while treating high refractive errors.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A temperature sensing mechanism provides real-time feedback about corneal temperature to the controller. The controller uses this feedback to continuously adjust laser pulse frequency and power, creating a closed-loop control system that prevents temperature from exceeding safe thresholds during high-energy treatments.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If high number of laser pulses are directed at the cornea to treat high refractive errors, then the treatment effectiveness is improved, but thermal energy imparted to the cornea increases causing temperature rise and potential cell damage

Engineering Contradiction:
Improverefractive correction precisionVSAvoidthermal damage to cornea
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The system uses periodic laser pulses with dynamically adjusted frequency to deliver the required number of pulses for high refractive error correction. By modulating the pulse frequency and incorporating cooling intervals when temperature thresholds are approached, the system maintains treatment effectiveness while preventing thermal accumulation that would cause cell damage.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The controller changes laser parameters (frequency, power) based on real-time temperature measurements and treatment progress. When treating areas requiring high pulse numbers, the system adjusts parameters to maintain effective ablation while keeping temperature within safe limits, preventing thermal damage through dynamic parameter optimization.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If laser pulse frequency and power are increased to reduce treatment time, then productivity is improved, but thermal energy control is lost and temperature exceeds safe thresholds

Engineering Contradiction:
Improvetreatment speedVSAvoidcornea temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The system dynamically balances treatment speed and temperature control by adjusting pulse frequency and power in real-time. During early treatment stages or in areas requiring less energy, higher frequencies are used to maintain productivity. When temperature approaches thresholds, the system automatically reduces frequency or power, ensuring safety without significantly compromising overall treatment efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The controller predicts temperature rise based on cumulative pulse energy delivery and proactively adjusts laser parameters before temperature exceeds safe thresholds. This preemptive adjustment maintains treatment productivity by minimizing interruptions while preventing thermal damage through anticipatory parameter modification.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

This approach effectively prevents temperature from exceeding harmful thresholds, reducing the risk of cell damage and optimizing treatment time by precisely managing thermal energy distribution during laser corneal treatments, ensuring safer and more efficient procedures.

Implementation Method 1

a thermal energy imparted to a first position location on the cornea by the laser pulses is controlled by modulating an optical energy of the laser pulses

Methodology Applied
Scientific EffectOptical energy to thermal energy conversion: Absorption (EM radiation)

Data Source

PatentEP3694454B1Laser pulse modulation for laser corneal treatments
Publication Date: 2023.08.16 ALCON INC
  • EP3694454B1 patent drawingFigure 1
  • EP3694454B1 patent drawingFigure 2~3
  • EP3694454B1 patent drawingFigure 4

AI summary

Laser pulse modulation for laser corneal treatments is used to control the thermal energy imparted to the cornea. The optical energy of the laser pulses may be modulated to reduce or increase the thermal energy, depending upon an expected thermal load or a measured temperature at each position location of the cornea subject to laser treatment. The laser pulse modulation may involve pulse frequency modulation, pulse amplitude modulation, and pulse duration modulation.