Non-rotationally Symmetric Corneal Cut Surfaces for Refractive Error Correction
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Solution Overview
Problem
Conventional refractive surgery methods, such as LASIK, face limitations in correcting complex refractive errors like astigmatism and higher-order aberrations due to the use of spherical cut surfaces and transition zones, which restrict correction options and increase computational complexity and surgical time.
Innovation Solution
The method involves defining non-circular, oval posterior cut surfaces and connecting them with non-rotationally symmetric side cuts, such as cylinders or conical frustums, to enclose a volume in the cornea, eliminating the need for transition zones and allowing for more precise and efficient refractive error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If spherical cut surfaces and transition zones are used in conventional refractive surgery, then the surgical procedure can be performed with standard methods, but the correction options for complex refractive errors are restricted and computational complexity increases
Solution Approach 1:
The patent applies asymmetry by replacing spherical cut surfaces with non-rotationally symmetric cut surfaces that have oval edges. This asymmetric geometry enables precise correction of complex refractive errors like astigmatism and higher-order aberrations, while the direct connection between surfaces eliminates transition zones, thereby reducing computational complexity
2Manufacturing precision
If spherical cut surfaces with transition zones are used, then the volume removed from the cornea is larger, but the accuracy of refractive power change is reduced
Solution Approach 1:
The patent extracts and eliminates the unnecessary transition zones from the surgical procedure. By directly connecting the first and second non-rotationally symmetric cut surfaces, the method removes excess corneal tissue more precisely, thereby increasing the accuracy of refractive power change while reducing the total volume removed from the cornea
3Productivity
If conventional LASIK methods with laser ablation are used, then the refractive error can be corrected, but the surgical time and computational complexity increase
Solution Approach 1:
The patent segments the corneal volume to be removed into two distinct non-rotationally symmetric cut surfaces with oval edges. This segmentation allows for precise definition of the removal volume without requiring transition zones, thereby reducing both computational complexity and surgical time while maintaining correction effectiveness
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 simplifies the production of control data for laser processing, reduces the volume removed from the cornea, and enhances the accuracy of refractive power change, enabling correction of complex errors like astigmatism and higher-order aberrations with reduced computational and surgical complexity.
Implementation Method 1
the application of an excimer laser is provided in the LASIK operation, said laser removing the corneal tissue exposed in this way by ablation
Data Source
AI summary
A device and a method for producing control data, which are designed to control a laser machining device to surgically correct ametropia of an eye in which, in order to define a space in the cornea, defines a front cutting surface, a rear cutting surface and an edge section, which are to be produced as cutting surfaces in the cornea. The rear cutting surface has a non-circular, oval edge lying in a plane, the edge section connecting the edge to the front cutting surface and the edge section being designed as a non-rotationally symmetrical cylinder or truncated cone, the base of which is the edge.