Corneal Deformation Compensation in Laser Eye Surgery Control
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Solution Overview
Problem
Current ophthalmic surgical methods, such as LASIK, face challenges in precision due to the assumption of spherical corneas and negligible tear film thickness, leading to inaccuracies in cut surface creation and optical correction, especially when using contact lenses with non-spherical shapes.
Innovation Solution
A method for generating control data for ophthalmic surgical treatment devices that accounts for corneal deformation caused by contact glasses, allowing for precise coordinate transformation and deformation consideration, enabling more accurate laser surgical operations by determining deformation-related and relaxation-related displacements of points on the cornea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spherical cornea assumption and negligible tear film thickness are used, then calculation simplicity is improved, but manufacturing precision of cut surface deteriorates
Solution Approach 1:
The patent changes the parameters of the corneal model from simple spherical assumption to a more complex aspherical geometry that accounts for deformation. The control data generation now includes deformation amount information that modifies the target coordinates based on actual corneal shape changes during surgery, thereby improving cut surface precision without sacrificing excessive computational complexity.
2Measurement precision
If contact glass deformation is considered, then target point coordinate accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating the deformation amount and incorporating it into the control data generation process. The system determines the deformation amount based on contact glass parameters and corneal properties before surgery, and uses this information to adjust target coordinates in advance, thereby improving accuracy without adding significant operational complexity during the actual procedure.
3Adaptability or versatility
If non-spherical contact lenses are used, then adaptability is improved, but measurement precision deteriorates due to lack of standardized transformation equations
Solution Approach 1:
The patent extends the coordinate transformation approach by incorporating deformation amount as an additional parameter. This allows the system to handle various contact lens geometries (spherical, aspherical, different curvatures) by adjusting the transformation calculations based on the specific deformation characteristics, thereby maintaining measurement precision across different lens types.
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 enhances precision in ophthalmic surgical operations by accurately accounting for corneal deformation, allowing the use of non-spherical contact lenses and reducing deviations in cut surface creation, thereby improving the accuracy of optical corrections.
Implementation Method 1
a contact glass having a contact surface deforms the cornea into the shape of the contact surface during operation of the laser device
Implementation Method 2
If the power density of the radiation is above a threshold value, an optical breakthrough occurs, which creates a plasma bubble in the cornea
Implementation Method 3
uses laser radiation to create a cut surface in the cornea
Data Source
Figure 1~2
Figure 1a
Figure 3
AI summary
The invention relates to a method for generating control data for an eye-surgical treatment device (1), which separates tissue layers in the eye cornea (5) by means of a laser device (E), wherein a contact glass (25) having a contact surface deforms the cornea (5) into the shape of the contact surface during the operation of the laser device (E), for which purpose the contact surface is first placed on a cornea apex at a contact surface apex and is then pressed against the same for deforming the cornea, the method comprising the following steps: the control data of the laser device (E) is generated such that the data specifies coordinates of target points (28) located in the cornea (5) for the laser device (E), and upon generation of the target point coordinates the deformation of the cornea (5) which is present during the operation of the laser device (E) as a result of the contact glass (25) is taken into consideration, wherein the invention provides that the several steps are carried out in consideration of the deformation in order to determine a displacement of a point P in the undeformed cornea (5) caused by the deformation.