Customized Transition Zone for Corneal Ablation
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Solution Overview
Problem
Conventional corneal refractive surgeries, such as PRK and LASIK, often result in curvature discontinuities at the edge of the optical zone, leading to visual issues like spherical aberration, glare, and halos, especially in low light conditions, due to the reliance on mean population response models that do not account for individual biomechanical responses and limited ablation zones.
Innovation Solution
A customized corneal ablative pattern with a wider optical zone and transition zone of continuous curvature, where the transition zone's effects on vision correction are accounted for, using pre-operative and post-perturbation measurements to predict and design an ablation pattern that considers individual biomechanical responses and structural changes in the cornea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ablation patterns with abrupt transitions are used, then the optical zone can be clearly defined, but curvature discontinuities occur at the edge leading to visual disturbances
Solution Approach 1:
The patent applies curvature continuity principles by designing the ablation pattern to maintain continuous first and second derivatives across the transition zone. The mathematical formulation ensures that the ablation depth profile follows a smooth curve rather than abrupt steps, eliminating the curvature discontinuities that cause spherical aberration, glare, and halo effects while preserving clear optical zone definition.
Solution Approach 2:
The patent modifies the ablation depth parameter continuously across the transition zone rather than maintaining abrupt changes. By varying the ablation depth according to a continuous mathematical function that accounts for individual corneal biomechanics, the system achieves smooth curvature transitions while maintaining precise optical zone boundaries, resolving the contradiction between clear definition and curvature continuity.
2Ease of manufacture
If mean population response models are used, then standardized treatment protocols can be applied, but individual biomechanical responses are not accounted for limiting customization
Solution Approach 1:
The patent implements local quality by tailoring the ablation pattern to individual corneal characteristics. The system measures specific biomechanical properties of each patient's cornea and adjusts the ablation depth profile accordingly, rather than applying a uniform standardized protocol. This allows customization of the transition zone parameters based on individual responses while maintaining systematic measurement and treatment approaches.
Solution Approach 2:
The patent incorporates feedback mechanisms by measuring individual corneal biomechanical responses and using this information to adjust the ablation pattern. The system evaluates patient-specific parameters and modifies the treatment protocol accordingly, creating a closed-loop approach that combines standardized measurement protocols with individualized treatment customization based on observed corneal responses.
3Area of stationary object
If the ablation zone is expanded to increase the optical zone, then more corneal tissue must be removed, but this increases the biomechanical response and may compromise corneal integrity
Solution Approach 1:
The patent uses continuous curvature profiling to distribute the ablation load more evenly across the cornea. By ensuring continuous first and second derivatives in the ablation depth profile, the system reduces stress concentrations at transition zones, allowing for larger optical zones without proportionally increasing the biomechanical risk to corneal integrity.
Solution Approach 2:
The patent adjusts ablation depth parameters based on individual corneal thickness and biomechanical properties. The system dynamically modifies the ablation profile to maximize the optical zone area while maintaining corneal strength by reducing ablation depth in regions where the cornea is thinner or more vulnerable, thereby expanding the treatable area without compromising structural integrity.
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 minimizes biomechanical responses and curvature discontinuities, improving visual outcomes by expanding the ablatable zone and ensuring continuous curvature, thereby reducing spherical aberration and other visual disturbances.
Implementation Method 1
an excimer laser to produce the desired result
Implementation Method 2
the amount and/or character of ablation that can occur within the optical zone
Data Source
AI summary
The present invention discloses a corneal refractive procedure providing a customized transition zone. The customized transition zone provided according to the methods and systems of the present invention exhibits continuous curvature between an ablated optical zone and a non-ablated zone to address curvature discontinuity at the edge of the optical zone, thereby minimizing the biomechanical response and its postoperative effects on vision.