Myopia-Control Contact Lens with Annular Add Power Meridians
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Solution Overview
Problem
Conventional contact lenses for myopia correction can cause unwanted visual side effects such as halos around images and inappropriate eye accommodation in young wearers, as they often induce myopic defocus that is not effectively controlled, leading to continued progression of myopia.
Innovation Solution
A contact lens design featuring an optic zone with a central region providing base power and an annular region with varying add power meridians, including maximum and intermediate add power meridians, which focuses light in a way that prevents a single image from forming in front of the retina, reducing halos and promoting natural accommodation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contact lenses provide full correction of distance vision, then distance vision is improved, but myopia progression continues unchecked
Solution Approach 1:
The contact lens is divided into multiple functional zones: a central distance vision correction zone and peripheral add-power zones that provide myopic defocus. This segmentation allows simultaneous distance vision correction and myopia control by directing different light paths to different retinal regions.
Solution Approach 2:
Different regions of the contact lens have different optical powers tailored to specific functions. The central region provides full distance correction while peripheral annular regions provide controlled myopic defocus, creating local optical quality variations that address both distance vision and myopia progression simultaneously.
2Reliability
If annular add-power regions are used to provide myopic defocus, then myopia progression is slowed, but halos and visual side effects occur
Solution Approach 1:
The add-power region is designed with non-uniform optical properties, creating zones of maximum add power at specific locations and intermediate add power in other areas. This local variation distributes the myopic defocus effect across multiple retinal locations rather than concentrating it at a single focal point, reducing halo formation.
Solution Approach 2:
The patent introduces variation in the add-power region across different spatial dimensions (meridians), creating intermediate add power zones at different angular positions. This dimensional complexity transforms the simple annular defocus pattern into a distributed multi-focal pattern that reduces visual side effects.
3Reliability
If add-power regions focus light in front of the retina, then myopic defocus is achieved, but inappropriate accommodation is induced in young wearers
Solution Approach 1:
The contact lens separates the myopic defocus function into specific peripheral zones rather than providing it uniformly across the entire lens. This segmentation allows the central region to maintain normal accommodation while peripheral zones provide controlled defocus for myopia management.
Solution Approach 2:
The patent varies the add-power parameter across different regions and meridians of the lens, creating intermediate add power zones that provide gradual defocus transitions. This parameter variation reduces abrupt focal shifts that would otherwise trigger inappropriate accommodation responses in young wearers.
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 effectively slows the progression of myopia while enhancing visual contrast and image quality by distributing defocus across the retina, reducing the occurrence of halos and allowing natural accommodation, thus providing improved vision and myopia control.
Implementation Method 1
The optic zone comprises a central region, the central region having a first optical axis and a curvature providing a base power... The annular region comprises at least one maximum add power meridian having a curvature providing the maximum add power... and at least one intermediate add power meridian having a curvature providing an intermediate add power
Data Source
AI summary
A contact lens for use in preventing or slowing the development or progression of myopia, and methods relating thereto, are described. The lens includes an optic zone comprising a central region having a first optical axis, and a curvature providing a base power, and centred on a centre of curvature that is on the first optical axis. The optic zone comprises an annular region, wherein the annular region surrounds the central region. The annular region comprises at least one maximum add power meridian having a curvature providing a maximum add power, and centred on a centre of curvature that is a first distance from the first optical axis. The annular region comprises at least one intermediate add power meridian, having a curvature providing an intermediate add power of between zero dioptres of add power and the maximum add power, and centred on a centre of curvature that is a different distance from the optical axis than the first distance.