Orthokeratology Lens Base Arc Zone Segmentation for Presbyopia Correction
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Solution Overview
Problem
Current orthokeratology lenses are inadequate for correcting presbyopia as they fail to differentiate between myopia and presbyopia shaping regions due to limitations in radius of curvature change, asymmetric pressure distribution, and design issues that lead to incomplete correction and peripheral extension beyond the pupil, affecting the effectiveness of presbyopia correction.
Innovation Solution
An orthokeratology lens with a base arc zone featuring multiple regions of varying radii of curvature, allowing for the creation of multiple focal points to simultaneously correct ametropia and presbyopia, with a method to determine the optimal radii for each region based on individual refractive needs, ensuring proper alignment and pressure distribution for effective presbyopia correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single radius of curvature is used for the base arc zone, then the lens structure is simple, but the lens cannot simultaneously correct ametropia and presbyopia
Solution Approach 1:
The base arc zone is divided into multiple regions (first region, second region, third region) with different radii of curvature. The first region has a first radius of curvature for ametropia correction, the second region has a second radius of curvature for presbyopia correction, and the third region has a third radius of curvature. This segmentation allows the lens to simultaneously address both myopia and presbyopia correction needs.
Solution Approach 2:
Different regions of the base arc zone are assigned different radii of curvature tailored to their specific functions. The first region uses a specific radius for myopic defocusing, the second region uses a different radius for presbyopic correction, and the third region uses another radius for additional shaping. This local differentiation enables simultaneous correction of multiple refractive errors.
2Adaptability or versatility
If asymmetric pressure distribution is applied to the cornea, then presbyopia correction can be achieved, but the corneal shaping becomes incomplete and peripheral regions extend beyond the pupil
Solution Approach 1:
The base arc zone is segmented into multiple regions with different radii of curvature, each contributing to specific aspects of corneal shaping. This segmentation allows for precise control over the pressure distribution pattern, ensuring that the corneal deformation is complete and confined within the pupil boundary while achieving presbyopia correction.
Solution Approach 2:
The radii of curvature of the base arc zone regions are specifically designed and optimized parameters. By carefully selecting and adjusting these radius values, the lens achieves the optimal pressure distribution pattern that produces complete corneal shaping within the pupil aperture, preventing peripheral extension while maintaining presbyopia 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
The lens provides a convenient, effective, and reversible solution for presbyopia correction without the drawbacks of external wear, maintaining clear vision and avoiding complications associated with surgical interventions, while ensuring the cornea returns to its original state when not in use.
Implementation Method 1
applies pressing force through eyelid-orthokeratology lens-cornea to promote migration/deformation of cornea epithelial cells and change radius of curvature of the cornea
Implementation Method 2
This is a reversible, non-operative refractive correction product
Data Source
AI summary
The present disclosure relates to an orthokeratology lens which may comprise an inner surface facing a cornea of a human eye when the orthokeratology lens is worn and an outer surface opposite the inner surface, the inner surface comprising a centrally located base are zone, wherein the base arc zone is configured for pressing and shaping an anterior surface of the cornea to have a shape that conforms to the base are zone, wherein the base arc zone comprises two or more regions, at least two of the two or more regions having different radii of curvature. The present disclosure also relates to a method for making orthokeratology lenses.