Corneal Deformation Compensation for Laser Treatment Control
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Solution Overview
Problem
Existing corneal treatment methods using contact elements for fixing the eye during laser surgery result in deformation of the cornea, leading to inaccuracies in lenticule separation and refractive power correction due to shape changes and incomplete modeling of the cornea's closure, necessitating complex and time-consuming compensation calculations.
Innovation Solution
A method utilizing a corneal deformation model, based on the Euler-Bernoulli beam theory, to create a look-up table that compensates for corneal deformations by varying preset parameters, allowing for precise control data generation to account for shape changes during and after lenticule removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid contact element is used to fix the eye during treatment, then the eye stability is improved, but the cornea shape is deformed leading to treatment inaccuracy
Solution Approach 1:
The patent applies preliminary action by pre-calculating deformation compensation values and storing them in a look-up table before treatment. The system determines compensation values based on corneal parameters and contact element characteristics in advance, then retrieves the appropriate compensation during treatment rather than calculating it in real-time. This resolves the contradiction by preparing the compensation data beforehand, allowing accurate treatment despite corneal deformation during the procedure.
2Ease of manufacture
If standard methods are used to determine lenticule geometry, then the treatment process is simplified, but the correction accuracy deteriorates due to idealized cornea assumptions
Solution Approach 1:
The patent applies parameter changes by introducing compensation values that adjust the standard lenticule geometry parameters. Instead of using idealized cornea assumptions directly, the system modifies the geometric parameters (radius of curvature, lenticule thickness, etc.) by adding deformation compensation values retrieved from the look-up table. This maintains the simplicity of standard methods while improving accuracy through parameter adjustment.
3Manufacturing precision
If complex compensation calculations are performed to account for corneal deformation, then the treatment accuracy is improved, but the calculation time and complexity increase
Solution Approach 1:
The patent resolves this contradiction by performing the complex compensation calculations in advance and storing the results in a look-up table. During actual treatment, the system only needs to retrieve pre-calculated compensation values based on measured corneal parameters, avoiding time-consuming real-time calculations while maintaining high treatment accuracy.
4Device complexity
If the cornea closure after lenticule removal is not modeled, then the treatment process is simpler, but the final correction accuracy deteriorates
Solution Approach 1:
The patent addresses cornea closure effects by introducing additional compensation values that account for the change in corneal shape after lenticule removal. These closure compensation values are calculated based on the assumed closure geometry and added to the overall compensation. This approach models the closure effect without requiring complex real-time simulation, maintaining process simplicity while improving refractive power correction accuracy.
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 simplified and accurate compensation for corneal deformations, reducing the need for complex calculations and improving treatment outcomes by ensuring precise correction of optical disorders.
Implementation Method 1
A method utilizing a corneal deformation model, based on the Euler-Bernoulli beam theory, to create a look-up table that compensates for corneal deformations
Data Source
AI summary
An apparatus and method are disclosed for providing control data for a laser of a treatment apparatus for the correction of a cornea. The method includes determining a look-up table for preset corneal parameters by a corneal deformation model, wherein the cornea can be modeled in deformed and non-deformed states by the corneal deformation model. A value of at least one preset corneal parameter in the non-deformed state of the cornea is varied and an effect of this variation on values of the corneal parameters in the deformed state of the cornea is ascertained for determining the look-up table. The method further includes ascertaining a corneal value to be achieved from predetermined examination data, determining by the look-up table a deformation-corrected corneal value to be achieved for compensating for the deformation of the cornea, and providing control data, which uses the deformation-corrected corneal value for correcting the cornea.