OCT-Based Eye Alignment for Cyclorotation in Laser Vision Correction
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Solution Overview
Problem
Conventional laser vision correction (LVC) systems face challenges in precise alignment and centering of the patient's eye, leading to inaccuracies in refractive error corrections due to limitations in eye tracking, environmental conditions, and optical geometry, which can result in prismatic errors, decentering, and increased variability in refractive outcomes.
Innovation Solution
The integration of an OCT system for precise alignment and centering by comparing pre-operative measurement data with real-time OCT measurements to determine and adjust the positioning and orientation of the patient's eye relative to the LVC system, allowing for accurate alignment and compensation for individual eye characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual alignment and static cyclorotation correction are used, then the system is simple to operate, but alignment accuracy is limited and cyclorotation deviations occur
Solution Approach 1:
The patent replaces manual mechanical alignment with an OCT-based optical measurement and automated image processing system. The OCT system captures cross-sectional images of the eye, and software algorithms automatically determine the visual axis and alignment parameters, eliminating manual cyclorotation correction and significantly improving alignment accuracy.
Solution Approach 2:
The patent uses OCT imaging to create a digital copy of the eye's internal structures, including the visual axis and anatomical landmarks. This digital representation allows for precise measurement and alignment calculation without physical manipulation, enabling automated alignment while maintaining system simplicity.
2Measurement precision
If eye tracking systems are used to compensate for eye movements, then lateral correction is sufficient, but dynamic cyclorotation and rolling movements cannot be corrected
Solution Approach 1:
The patent extends eye movement compensation from two-dimensional lateral tracking to three-dimensional correction by incorporating cyclorotation (rotation around the visual axis) and rolling movements (rotation around horizontal and vertical axes). The OCT-based system captures depth information and rotational parameters, enabling comprehensive 3D eye position and orientation compensation.
Solution Approach 2:
The patent creates a universal eye movement compensation system that handles all types of eye movements—lateral displacement, cyclorotation, and rolling movements—through a single OCT-based measurement and correction framework, making the system adaptable to any eye movement scenario.
3Manufacturing precision
If conventional alignment methods are used, then the system is easier to operate, but prismatic errors and decentering occur
Solution Approach 1:
The system performs self-alignment by automatically comparing the measured visual axis with the laser system's optical axis and calculating the required correction. The automated image processing and alignment calculation eliminate manual intervention, reducing operational difficulty while ensuring high ablation precision through consistent, error-free alignment.
4Measurement precision
If large working distances are used in spot-scanning LVC systems, then the optical system design is simplified, but alignment accuracy and compensation precision are reduced
Solution Approach 1:
The patent introduces an OCT measurement system as an intermediary between the laser system and the eye. The OCT system independently measures eye position and orientation with high precision at any working distance, and this measurement data serves as a mediator to guide laser alignment and compensation, decoupling alignment precision from working distance constraints.
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 precise and reliable alignment of the LVC system independent of eye color and corneal shape, reducing prismatic errors and decentering, thereby improving the accuracy and consistency of refractive error corrections.
Implementation Method 1
an OCT system for measuring structures of the patient's eye immediately before and/or during a refractive error correction treatment and for providing OCT measurement data that characterize the measured structures of the patient's eye
Data Source
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AI summary
The present invention relates to a method for aligning a system (100) for laser-based ametropia correction relative to a patient's eye (10) to be treated. The method comprises providing predefined pre-operative measurement data (1000) which characterise at least predetermined structures (1002) of the patient's eye (10), wherein the predetermined structures (1002) comprise a part of the patient's eye (10) to be treated. In addition, the method comprises measuring at least one part of the predetermined structures (1002) of the patient's eye (10) using an OCT system (109) immediately before and/or during treatment for ametropia correction of the patient's eye (10) and providing OCT measurement data (1008), and comparing the OCT measurement data (1008) and the predefined pre-operative measurement data (1000) and preparing comparative data. The method also comprises ascertaining a position and/or orientation of the part of the patient's eye (10) to be treated relative to the system (100) and aligning the system (100) relative to the patient's eye (10) using the ascertained position and/or orientation of the part of the patient's eye (10) to be treated. The invention further relates to a system (100) for laser-based ametropia correction.