Progressive Ophthalmic Lens with Intermediate Zone Astigmatism
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Solution Overview
Problem
Progressive multifocal ophthalmic lenses can exacerbate myopia in children due to overcorrection in peripheral vision, leading to increased myopia progression, as they provide lower optical quality in intermediate vision zones, causing children to use these zones more frequently, which results in higher aberrations and elongation of the eye.
Innovation Solution
A progressive multifocal ophthalmic lens design with a power addition prescription and complex surface, featuring a peripheral zone of positive power relative to the far-vision zone, an intermediate vision zone positioned between far and near vision zones, and optimized astigmatism levels to encourage use of far and near vision zones, reducing intermediate zone usage and associated myopia progression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a progressive multifocal ophthalmic lens is used to correct myopia in children, then far vision and near vision zones provide good optical quality, but the intermediate vision zone produces lower optical quality images with higher aberrations
Solution Approach 1:
The patent applies local quality by creating distinct optical zones with different characteristics: the far vision zone and near vision zone are optimized for low aberrations and high optical quality, while the intermediate vision zone intentionally has higher aberrations and lower optical quality. This spatial differentiation of optical properties ensures that children are discouraged from using the intermediate zone, thereby resolving the contradiction between providing comprehensive vision correction and maintaining high optical quality throughout.
2Adaptability or versatility
If the intermediate vision zone is used frequently by children, then they can access various viewing distances, but this results in rapidly increasing levels of aberrations and increases myopia progression
Solution Approach 1:
The patent converts the potentially harmful intermediate vision zone into a beneficial element by deliberately designing it with high aberrations and low optical quality. What could have been a harmful zone that promotes myopia progression is transformed into a deterrent that guides children to use only the optically superior far and near vision zones, thereby converting the intermediate zone's potential harm into a benefit for myopia control.
3Measurement precision
If ophthalmic lenses with optical power adapted for far vision and foveal vision are used, then central vision is corrected, but peripheral vision suffers from overcorrection and image formation behind the retina
Solution Approach 1:
The patent applies segmentation by dividing the lens into distinct functional zones: a central zone (far vision and near vision zones) optimized for low aberrations and high optical quality, and a peripheral zone (intermediate vision zone) with intentionally higher aberrations. This segmentation allows the central zone to provide precise foveal vision correction while the peripheral zone's degraded optical quality prevents its use, thereby eliminating the harmful peripheral defocusing effect.
Data Source
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AI summary
The invention relates to a progressive multifocal ophthalmic lens comprising a power addition prescription Add and a complex surface, the complex surface comprising having far and near vision zone with resulting astigmatism smaller than Add / 3 and an intermediate vision zone with resulting astigmatism greater than Add / 3.