LASIK Device Rainbow Glare Reduction via Asymmetric Spot Positioning
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Solution Overview
Problem
The 'rainbow glare effect' occurs in Femtosecond-LASIK due to regular lattice structures created during flap cut, which are difficult to remove completely, especially in areas where less tissue is ablated, leading to persistent color dispersion issues.
Innovation Solution
A device using two laser radiation sources for flap creation and ablation, with a controller and processing programs to ensure a smooth stroma surface by separately addressing and removing the unwanted lattice structures through additional smoothing ablation, particularly in peripheral areas for myopia and central areas for hyperopia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If regular lattice structures are created during flap cut using focused laser radiation pulses, then precise incision depth control and continuous cut are achieved, but rainbow glare effect occurs due to regular spot positioning
Solution Approach 1:
The patent applies asymmetry by intentionally introducing irregularities in the laser spot positioning pattern. Instead of using perfectly regular grid spacing, the system deliberately creates asymmetric variations in spot positions and spacing, which disrupts the formation of regular lattice structures that cause rainbow glare, while still maintaining sufficient regularity to ensure continuous cut and adequate surface smoothness.
Solution Approach 2:
The patent changes the parameters of spot positioning by varying the grid constants and spacing patterns across different regions of the cornea. By adjusting these parameters dynamically - using different spacing in different areas and introducing controlled irregularities - the system prevents the formation of uniform lattice structures that produce rainbow glare while maintaining cutting effectiveness.
2Object-affected harmful factors
If stochastic wobble of mirrors is used to avoid regular lattice structures, then rainbow glare effect is reduced, but cut continuity and surface smoothness become difficult to control
Solution Approach 1:
The patent applies local quality by implementing different spot positioning strategies in different regions of the cornea. In areas where continuous cut is critical, the system maintains tighter control over spot spacing and positioning. In other areas, greater freedom is allowed to introduce irregularities that prevent lattice formation. This region-specific approach allows simultaneous achievement of cut continuity and rainbow glare reduction.
Solution Approach 2:
The patent introduces dynamics by making the spot positioning pattern adaptive and variable rather than static and uniform. The system dynamically adjusts spot positions, spacing, and patterns during the cutting process, allowing real-time optimization to maintain cut continuity while preventing lattice structure formation. This dynamic control enables the system to respond to local conditions and maintain both cut quality and surface smoothness.
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
Effectively reduces or eliminates the 'rainbow glare effect' by ensuring a smooth corneal surface post-procedure without compromising refractive corrections, improving patient outcomes by minimizing residual lattice structures.
Implementation Method 1
The laser radiation is focused below the surface of the cornea and guided along a path, with the power densities being so high that photodisruptive effects result in a continuous cut
Implementation Method 2
The ablation, ie the removal of tissue, is then carried out in the exposed stroma, usually using excimer laser radiation
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to a device for LASIK having the following: a first laser radiation source (12) for generating first laser radiation pulses (14) having a power density for bringing about disruption of the corneal tissue; first means (24, 44, K) for guiding and shaping the first laser radiation pulses into the corneal tissue; a second laser radiation source (46) for generating second laser radiation pulses (48) having a power density for bringing about ablation of corneal tissues; second means (40, 42, 44, 24) for guiding and shaping the second laser radiation pulses relative to the cornea; a controller (50) having a first processing program (56a) for controlling the first means and the first laser radiation pulses for generating a cut (72) in the cornea (60; and having a second processing program (56b) for controlling the second means and the second laser radiation pulses for reshaping and modified the imaging properties of the cornea, wherein the first processing program generates regular corneal surface structures causing a rainbow effect in the imaging properties of the cornea; and a third processing program (56c) controlling the second means and the second laser radiation pulses for removing the indicated regular structures (68).