Concentric Contact Lens Optics for Myopic Defocus Control
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Solution Overview
Problem
Existing contact lenses that aim to slow the progression of myopia often compromise distance vision and are ineffective in providing targeted myopic defocus to prevent eye growth, while dual-focus lenses may cause halos and vision disturbances.
Innovation Solution
A contact lens design featuring a central region with a specific diameter and concentric annular zones with defined curvatures and widths, including myopic defocus zones and distance corrective zones, to provide targeted myopic defocus without compromising distance vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If under-correction is used to provide myopic defocus, then myopia progression is slowed, but distance vision is degraded
Solution Approach 1:
The contact lens is divided into distinct functional zones: a central distance correction zone for clear distance vision and one or more peripheral myopic defocus zones for controlling myopia progression. This segmentation allows each zone to perform its specific function independently, resolving the contradiction between maintaining distance vision and providing myopic defocus.
Solution Approach 2:
Different regions of the contact lens are assigned different optical properties: the central region provides full distance correction while the peripheral regions provide under-correction to create myopic defocus. This local differentiation of optical quality enables simultaneous achievement of clear distance vision and effective myopia control.
2Ease of operation
If dual-focus lenses are used to provide distance and near correction, then vision at both distances is improved, but halos and vision disturbances occur
Solution Approach 1:
The lens is segmented into a central distance correction zone and peripheral myopic defocus zones with distinct optical powers. This segmentation prevents the formation of multiple focal points that cause halos, while still providing effective myopic defocus in the peripheral regions.
Solution Approach 2:
The peripheral zones provide partial correction (under-correction) rather than full correction, creating myopic defocus without generating the excessive multiple images that cause halos. This partial action approach eliminates harmful visual artifacts while maintaining therapeutic effect.
3Ease of operation
If conventional spectacle lenses are used for distance correction, then distance vision is improved, but they do not provide myopic defocus to control myopia progression
Solution Approach 1:
The contact lens divides the optical surface into central and peripheral zones with different refractive powers. The peripheral zones are specifically designed to create myopic defocus on the retina, which triggers biological mechanisms that slow axial eye growth and myopia progression, a function that conventional spectacle lenses cannot provide.
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 design effectively slows myopia progression by providing consistent myopic defocus towards the lens center, maintaining clear distance vision, and reducing peripheral defocus, while using hydrogel or silicone hydrogel materials for comfort and stability.
Implementation Method 1
Uncorrected myopic eyes focus incoming light from distant objects to a location in front of the retina. Consequently, the light diverges towards, and is out of focus upon arrival at, the retina. Conventional ophthalmic lenses (e.g., spectacle lenses and contact lenses) for correcting myopia move the focus onto the retina.
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3B
AI summary
A contact lens (101) including an optic zone (102). The optic zone (102) comprises a central region (105) having a curvature that is centred on an optical axis (19). The central region (105) has a distance corrective power and a chord diameter of 2.7mm. The optic zone (102) comprises a first annular zone (103a) having an add power, an on-axis centre of curvature, and a width of 0.7mm. The optic zone (102) comprises a second annular zone (103b) that is a distance corrective zone, has an on-axis centre of curvature, and has a width of 0.6 mm. The optic zone (102) comprises a third annular zone (103c) having an add power, an on-axis centre of curvature, and a width of 0.8mm. The optic zone (102) comprises a fourth annular zone (103d) that is a distance corrective zone, an on-axis centre of curvature, and a width of 0.925mm.