Segmented Add Power Contact Lens for Myopia Control
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Solution Overview
Problem
Conventional contact lenses for myopia correction can cause unwanted visual side effects such as halos around images due to annular add power regions, which may lead to improper accommodation and ineffective myopia control in young subjects.
Innovation Solution
A contact lens design featuring an optic zone with a central region for base power and an annular region with an add power region that focuses light to form a focused arc, rather than a single on-axis image, minimizing halo effects and allowing natural accommodation for near vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If annular add power regions are used to provide myopic defocus, then myopia progression is slowed, but halo effects appear around focused images
Solution Approach 1:
The add power region is segmented into multiple discrete zones (first add power zone, second add power zone, etc.) arranged in an annular pattern. Each zone provides myopic defocus to specific peripheral retinal regions, achieving myopia control while reducing the continuous annular structure that causes halos.
Solution Approach 2:
Different regions of the lens are assigned different optical powers tailored to specific functions: the central optic zone provides distance correction, while discrete annular add power zones provide myopic defocus to peripheral retinal regions. This localized optimization reduces unwanted visual effects while maintaining therapeutic effectiveness.
2Reliability
If add power regions focus light in front of the retina, then myopic defocus is achieved, but natural accommodation is inhibited
Solution Approach 1:
The lens divides the visual field into central (foveal) and peripheral (extra-foveal) regions, with different optical treatments for each. The central optic zone allows clear foveal vision and natural accommodation, while peripheral add power zones provide myopic defocus without interfering with the eye's natural focusing mechanism.
Solution Approach 2:
The lens applies different optical properties to different parts of the visual field: the central region maintains full correction for natural accommodation, while peripheral regions receive controlled myopic defocus. This spatial differentiation preserves natural viewing behavior while achieving therapeutic effects.
3Reliability
If the add power region area is increased to enhance myopia control, then treatment coverage is improved, but visual side effects increase
Solution Approach 1:
The add power treatment is divided into multiple discrete annular zones rather than a continuous large-area region. This segmentation provides distributed myopic defocus coverage across peripheral retinal regions while maintaining sufficient treatment area for effectiveness without creating excessive visual interference.
Solution Approach 2:
The lens design adjusts the area, width, and dioptric power of individual add power zones to optimize the balance between treatment coverage and visual quality. By controlling these parameters, the lens achieves effective myopia control while minimizing halo effects and other visual side effects.
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 prevents or slows myopia progression while maintaining clear vision by targeting specific retinal regions with controlled add power, reducing the occurrence of halos and promoting natural accommodation for near objects.
Implementation Method 1
The add power region thereby focuses light from distant point objects to form a focused arc at the proximal focal surface
Implementation Method 2
The central region thereby focuses light from distant point objects to a distal focal surface, said light forming a blur circle or ellipse as it passes through a proximal focal surface
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3(a)~3(b)
AI summary
A contact lens (101) for use in preventing or slowing the development or progression of myopia, and methods of manufacturing and using such a lens (101). The lens (101) includes an optic zone (102) and a peripheral zone (104) that has a variation in thickness configured to control rotation of the lens (101). The optic zone (102) comprises a central region (105) having a base power that focuses light from distant point objects to a distal focal surface, said light forming a blur circle as it passes through a proximal focal surface. An annular region (103) surrounding the central region (105), includes an add power region (107) spanning less than 75% of the annular region (103), and having an add power of 0.5 D or more. Points defining centres of curvature of the add power region form a segment of an annulus. The add power region (107) focuses light from distant point objects to form a focused arc at a proximal focal surface.