Adaptive Lens Stack for Myopia Control Without Peripheral Blur
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Solution Overview
Problem
Conventional prescription lenses for myopia correction cause further eye growth due to fixed negative optical power, leading to myopia development, especially in children, and existing adaptive lenses suffer from optical artifacts and reduced vision quality.
Innovation Solution
An adaptive optical apparatus with a passive lens having a central portion with a higher negative optical power than the peripheral portion, combined with an active lens that adjusts its optical power based on gaze direction to minimize eye strain and optical artifacts, using an eye tracker and processor to control the active lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed negative optical power is provided in an entirety of a lens for myopia correction, then distance vision is corrected, but peripheral vision focuses behind the retina promoting further eye growth and myopia development
Solution Approach 1:
The patent applies local quality by providing different optical powers in different regions of the lens. The central portion has a first negative optical power for distance vision correction, while the peripheral portion has a second negative optical power that is lower in magnitude. This regional differentiation ensures that peripheral vision focuses appropriately on the retina while maintaining distance vision correction in the central area.
2Measurement precision
If a fixed negative optical power is provided continuously across the lens, then distance vision is corrected, but the eye lens must generate many dioptres to overcome the negative power for close focus, expediting myopia development
Solution Approach 1:
The patent implements local quality by creating a peripheral portion with reduced negative optical power. When the user looks through the peripheral portion for close objects, the eye lens encounters less negative power to overcome, reducing the accommodation demand and making close focus easier while still maintaining distance vision correction through the central portion.
3Object-affected harmful factors
If a smaller negative optical power is provided at the peripheral portion compared to the central portion, then myopia control is achieved, but vision becomes blurred when gaze direction is off centre
Solution Approach 1:
The patent employs dynamics by using an adaptive lens that can dynamically adjust its optical properties based on the user's gaze direction. When the gaze is off-centre, the adaptive lens modifies its power distribution to maintain clear vision while preserving the myopia control effect of reduced peripheral negative power. This dynamic adaptation prevents blurring while keeping the myopia control benefit.
4Object-affected harmful factors
If lenslets or rings with spaces are used to create differential myopic defocus, then myopia control is achieved, but the field of view is limited and contrast is reduced causing blurring
Solution Approach 1:
The patent applies local quality by implementing a continuous peripheral portion with modified negative optical power rather than using discrete lenslets or rings with spaces. This continuous design provides differential myopic defocus across the entire peripheral field of view without creating gaps, thereby maintaining a wide field of view and avoiding the blurring and contrast reduction associated with segmented designs.
5Object-affected harmful factors
If adaptive lenses are implemented as negative Fresnel lenses to produce negative optical powers, then myopia control is achieved, but optical artifacts are caused
Solution Approach 1:
The patent uses parameter changes by implementing an adaptive lens that can dynamically modify its optical power parameters based on gaze direction and viewing conditions. Rather than using fixed negative Fresnel lenses that cause artifacts, the adaptive lens adjusts its power distribution to maintain myopia control while minimizing optical artifacts and preserving vision quality across different viewing scenarios.
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 apparatus effectively controls myopia progression by reducing eye strain and maintaining high-quality vision without blurring, suitable for both children and adults, by dynamically adjusting optical power based on gaze direction.
Implementation Method 1
adaptive lenses to produce a negative optical power for distance viewing. Such adaptive lenses can be switched on and off on a need basis
Implementation Method 2
a passive lens, wherein a magnitude of a negative optical power at a central portion of the passive lens is larger than a magnitude of a negative optical power at a peripheral portion of the passive lens
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
An optical apparatus (100) comprises a lens stack (102a, 102b) comprising an active lens (110) and a passive lens (112). A magnitude of a negative optical power at a central portion (114) of the passive lens is larger than a magnitude of a negative optical power at a peripheral portion (116) of the passive lens. When it is detected that a focussing distance of a user is less than a first predefined threshold distance, a magnitude of a positive optical power to be produced in the active lens is selected, based on whether the user's gaze passes through the central portion or the peripheral portion of the passive lens. A magnitude of the positive optical power is smaller than the magnitude of the negative optical power at the central portion of the passive lens. A drive signal is generated to control the active lens to produce the positive optical power in the active lens.