Corneal Cut Depth Variation for Plasma Bubble Management
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Solution Overview
Problem
The existing methods for creating cut surfaces in the cornea during refractive eye surgery, such as LASIK and SMILE, face challenges with plasma bubbles forming during optical penetration, which reduce incision quality and may require higher laser power, leading to complications like the Opaque Bubble Layer.
Innovation Solution
A planning apparatus generates control data for the treatment device to create cut surfaces that are deeper around the edges than in the optically effective areas, ensuring the intended cut is made above the plasma bubble layer, thereby improving cut quality and reducing tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual optical pulses are applied to create optical penetration in the cornea, then refractive correction can be achieved, but plasma bubbles form that reduce incision quality and may require higher laser power
Solution Approach 1:
The planning apparatus calculates and determines the precise depth of the cut surface before the actual laser treatment. By pre-determining the optimal cut depth that positions the incision above the plasma bubble layer, the system prepares the treatment plan in advance to avoid plasma bubble interference, thereby maintaining incision quality without requiring higher laser power.
Solution Approach 2:
The invention changes the depth parameter of the cut surface created by the laser. Instead of creating a uniform depth cut, the system determines a specific depth that positions the incision surface above where plasma bubbles form during optical penetration. This parameter adjustment allows the laser to operate at standard power levels while avoiding plasma bubble interference with the incision quality.
2Manufacturing precision
If higher laser power is used to maintain incision quality despite plasma bubbles, then cut precision can be maintained, but tissue damage increases and complications arise
Solution Approach 1:
The planning apparatus performs preliminary calculation to determine the optimal cut depth that positions the incision above the plasma bubble layer. By establishing this depth parameter before treatment, the system enables precise cutting at standard laser power levels, eliminating the need to increase power and thereby preventing additional tissue damage.
3Ease of operation
If the cap cut diameter is made larger than the lenticule cut diameter for clinical reasons, then surgical accessibility is improved, but the complexity of determining precise cut surfaces increases
Solution Approach 1:
The planning apparatus applies different depth characteristics to different regions of the cut surface. The system determines that the cut surface should have varying depth characteristics - deeper in certain areas and shallower in others - to account for the relationship between the larger cap cut diameter and the smaller lenticule cut diameter. This localized depth variation simplifies the overall determination process while maintaining surgical accessibility.
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 the quality of corneal cuts, leading to better healing outcomes and reduced complications by preventing plasma bubbles from interfering with the laser beam, thus ensuring more precise and effective refractive corrections.
Implementation Method 1
When creating a cut surface in the cornea using a laser beam, the optical beam effect is usually used to create optical penetration by application of individual optical pulses with a duration of between approximately 100 fs and 100 ns
Implementation Method 2
bubbles of plasma arising during the optical penetration also tend to spread in the cornea tissue and therefore reduce the effectiveness of the laser beam in neighboring areas
Data Source
AI summary
A planning apparatus for generating control data for an eye surgery treatment device which creates at least one cut surface in the cornea using a laser device. The planning apparatus includes a calculation tool for determining the at least one cut surface in the cornea. The calculation tool determines the at least one cut surface in the cornea based on data from a refractive correction and generates a set of control data that control the laser device for the at least one cut surface in the cornea. The at least one cut surface in the cornea includes an edge and optically effective areas. The calculation tool determines the at least one cut surface in the cornea such the at least one cut surface in the cornea is deeper at the edge than in the optically effective areas.