Corneal Ablation Profile Correction via Spatial Frequency Spectrum
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Solution Overview
Problem
Current methods for correcting optical defects in the eye using laser-based photorefractive corneal surgery, such as LASIK, face inaccuracies due to disruptive factors like peripheral reflection losses and biomechanical changes, leading to insufficient compensation for irregular eye structures.
Innovation Solution
A method that transforms the ablation profile into a spatial frequency spectrum, applies amplitude and phase corrections based on empirically determined relationships, and transforms it back into geometric space to achieve a more accurate target ablation profile, allowing for patient-specific corrections without relying on predefined transmission models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wavefront measurements are used to determine the ablation profile, then the theoretical accuracy of ametropia correction is improved, but the actual accuracy deteriorates due to disruptive factors like peripheral reflection losses and biomechanical changes
Solution Approach 1:
The patent applies feedback by measuring the actual postoperative ablation profile and comparing it with the desired profile. This feedback loop enables the system to identify deviations caused by disruptive factors and adjust subsequent ablation profiles to compensate for these effects, thereby improving actual accuracy despite theoretical limitations.
Solution Approach 2:
The patent modifies the ablation profile by adjusting parameters such as ablation depth and spatial distribution based on empirically determined correction factors. These parameter changes account for peripheral reflection losses and biomechanical changes, transforming the theoretical profile into a corrected profile that achieves better actual accuracy.
2Reliability
If empirically determined correction factors are applied to the ablation profile, then compensation for disruptive factors is improved, but the complexity of the correction process increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing correction factors based on empirical data from previous treatments. These pre-determined correction factors are then applied to new ablation profiles without requiring complex real-time calculations, thereby reducing the complexity of the correction process while maintaining high compensation accuracy.
3Ease of manufacture
If a uniform correction matrix is used for all patients, then the simplicity of the correction process is maintained, but the adaptability to individual eye structures deteriorates
Solution Approach 1:
The patent applies local quality by determining patient-specific correction factors tailored to each individual's eye structure and aberration profile. Instead of using a uniform correction matrix, the system adapts the correction parameters to match the specific characteristics of each patient, thereby improving adaptability while maintaining reasonable process simplicity through automated calculation.
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 provides a precise and efficient method for correcting optical defects, accounting for individual variations and frequency couplings, resulting in improved accuracy and reduced computational complexity compared to existing methods.
Implementation Method 1
corneal tissue is processed by means of laser radiation with the aim of eliminating or at least substantially reducing visual defects
Implementation Method 2
Material removal using laser radiation is also referred to as ablation
Data Source
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AI summary
The invention relates to a method for determining control information for controlling laser beams which are radiated to the cornea of an eye which is to be treated photorefractively. According to the invention, the cornea ablation profile, which is obtained by measuring the optical properties of the eye, is corrected using correction information and the control information is based on the corrected ablation profile thus produced. The ablation profile is corrected in the spatial frequency range. As a result, said ablation profile is transformed in a spatial frequency spectrum.Then, corrected amplitudes and/or phase values are determined for various discrete spectral components of the ablation profile based on stored amplitude or/and phase correction information. Subsequently, the spatial frequency spectrum is retransformed in the geometric spatial region using the amplitude or/and phase-corrected spectral components. The corrected ablation profile is then obtained. The amplitude and phase correction information represents a previously determined interrelationship between amplitude and/or phase values at the related spatial frequency and corrected amplitude and/or phase values for said spatial frequency, for several spatial frequencies which are different at least by the frequency value.