Refractive Laser Surgery Alignment Using Patient-Specific Corneal Reference Points

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Solution Overview

Problem

Current refractive laser surgery techniques, such as LASIK, face inaccuracies due to the use of the pupil center as a reference point, which does not account for the depth of the anterior chamber and cornea thickness, leading to systematic errors during eye movements.

Innovation Solution

A device and control program that measure the anterior chamber depth and cornea thickness for each patient, using coherence-optical interferometric methods like Optical Low Coherence Reflectometry (OLCR), to determine a patient-specific corneal point for aligning the laser treatment, thereby improving surgical precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the pupil center is used as a reference point for laser alignment, then the alignment process is simplified, but systematic errors occur due to not accounting for anterior chamber depth and cornea thickness variations

Engineering Contradiction:
Improvealignment processVSAvoidlaser treatment accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent changes the reference parameter from pupil center coordinates to corneal surface point coordinates. By measuring and using the actual distance from the corneal surface to the pupil center for each patient, the system adjusts the reference frame to eliminate systematic alignment errors caused by variations in anterior chamber depth and corneal thickness, while maintaining practical operability through automated measurement and calculation.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If individual measurements of anterior chamber depth and cornea thickness are performed for each patient, then laser treatment accuracy is improved, but the complexity of the surgical procedure increases

Engineering Contradiction:
Improvelaser treatment accuracyVSAvoidsurgical procedure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into a single coordinated system: the same optical access path is used for both capturing corneal surface images and measuring the distance to the pupil center. The computer system performs automated image processing, coordinate transformation, and calculation of the adjusted reference point, eliminating the need for separate manual measurement procedures and reducing overall surgical complexity while improving accuracy.

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

3Manufacturing precision

If the reference point is moved from the pupil center to a point on the cornea, then alignment accuracy is improved by accounting for individual anatomical variations, but the difficulty of detecting and measuring the correct reference point increases

Engineering Contradiction:
Improvereference point alignmentVSAvoidreference point identification
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent creates a digital copy of the corneal surface geometry through image capture and processing. By generating coordinate information representing the corneal surface topography and the pupil center position, the system calculates the appropriate reference point on the cornea without requiring direct physical measurement or manual identification during surgery. This digital modeling approach simplifies the measurement process while maintaining high alignment accuracy.

Inventive Principle:
Principle #26Copying

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 allows for more accurate alignment of the laser treatment by accounting for individual variations in anterior chamber depth and cornea thickness, reducing errors and improving surgical outcomes by using a point on the cornea as a reference point instead of the pupil center.

Implementation Method 1

A device and control program that measure the anterior chamber depth and cornea thickness for each patient, using coherence-optical interferometric methods like Optical Low Coherence Reflectometry (OLCR)

Methodology Applied
Scientific EffectOptical interference: Interference

Data Source

PatentEP2337534B1Device, method and control program for ophthalmologic, particularly refractive, laser surgery
Publication Date: 2016.04.06 WAVELIGHT AG
  • EP2337534B1 patent drawingFigure 1
  • EP2337534B1 patent drawingFigure 2~3

AI summary

The invention discloses a device for ophthalmologic, particularly refractive, laser surgery, which aligns a desired ablation profile with a predetermined corneal point, which it calculates from the image data of an eye tracker, while taking the depth of the anterior chamber of the eye, including the thickness of the cornea, individually measured for the respective patient into consideration.