Faceted Contact Lens Layout for Uniform Myopic Defocus
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Solution Overview
Problem
Existing myopia control lenses, such as multifocal and orthokeratology lenses, often fail to provide uniform myopic defocus across all meridians, leading to a diminished stop signal for eye growth, thus limiting their effectiveness in slowing the progression of nearsightedness.
Innovation Solution
A myopia control contact lens design featuring a central region for correcting vision and a peripheral region with a plurality of distinct facet surfaces, each having varying powers in both radial and perpendicular directions, ensuring consistent myopic defocus to enhance the stop signal for eye growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multifocal or orthokeratology lenses are used for myopia control, then vision correction is provided, but uniform myopic defocus across all meridians is not achieved, resulting in a diminished stop signal for eye growth
Solution Approach 1:
The peripheral region of the contact lens is divided into multiple discrete facet surfaces (e.g., 6-12 facets) arranged in a circular pattern. Each facet is a separate optical element with specific curvature, allowing independent optimization of myopic defocus in different meridional directions. This segmentation enables uniform defocus across all meridians while maintaining manufacturing feasibility through modular fabrication processes.
Solution Approach 2:
Different regions of the contact lens are assigned different optical properties: the central region provides standard vision correction while the peripheral region contains multiple facets with varying curvatures specifically designed to generate myopic defocus. Each facet has locally optimized curvature to ensure uniform defocus in its corresponding meridian, creating overall uniform myopic defocus across all directions from the center.
2Reliability
If multifocal contact lenses are used to slow myopia progression, then myopia progression is reduced by about 50%, but the design complexity and fitting requirements increase
Solution Approach 1:
The lens is segmented into a central optical zone and a peripheral region with multiple discrete facets. This segmentation allows the use of simpler, more manufacturable individual facet elements rather than complex continuous aspheric surfaces, reducing manufacturing complexity while maintaining the myopia control function.
Solution Approach 2:
The invention optimizes specific parameters of the facet surfaces including the number of facets (6-12), facet curvature radii, facet spacing, and radial position. By adjusting these parameters, the lens achieves effective myopia control with standardized manufacturing processes, reducing both design complexity and fitting requirements compared to custom orthokeratology lenses.
3Reliability
If orthokeratology lenses are fitted to provide myopia control, then myopia progression is controlled, but the fitting process becomes time-consuming and requires extensive expertise
Solution Approach 1:
The contact lens uses discrete, pre-configured facet surfaces that can be manufactured using standardized processes. These segmented facets provide built-in myopic defocus in specific meridians, eliminating the need for complex custom fitting procedures required for traditional orthokeratology lenses, thereby reducing fitting time and expertise requirements.
Solution Approach 2:
The invention employs standardized parameter sets for the facet surfaces (number of facets, curvature radii, spacing) that can be applied across different lens designs. This standardization allows for quicker fitting and reduces the expertise required, as the optical principles are simplified and reproducible compared to custom ortho-k lens fitting.
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 faceted lens design provides a stronger and more uniform myopic defocus across all meridians, effectively slowing the progression of nearsightedness by maintaining a robust stop signal for eye growth, outperforming conventional designs in clinical trials with an average reduction of 45% in myopia progression.
Implementation Method 1
a peripheral region that surrounds the central region and comprises a plurality of distinct facet surfaces configured to under correct (or overcorrect) the vision at a second correction power
Data Source
AI summary
An exemplary method and apparatus are disclosed to perform myopia control using an ophthalmic device (contact lens) comprising a center region configured to correct vision at a first correction power (spherical or sphero-cylindrical) and a peripheral region that surrounds the central region, wherein the peripheral region comprises a plurality of distinct facet surfaces configured to under correct (or overcorrect) the vision at a second correction power, each of the plurality of distinct facet surfaces having a varying power in both (i) a first direction radially extending from a central location of the center region to a perimeter of the ophthalmic device and (ii) a second direction perpendicular to the first direction.