Postural Prism Alignment for Myopia Control Lenses
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Solution Overview
Problem
The inefficiency of myopia control lenses in children due to improper use, as non-presbyopic wearers tend to use the wrong part of the lens for near vision tasks, reducing the beneficial effect of progressive multifocal ophthalmic lenses in slowing down myopia progression.
Innovation Solution
A method to optimize the postural prism added to ophthalmic multifocal lenses, ensuring the wearer gazes through the correct vision zone by determining the smallest postural prism that aligns the gazing direction with the first vision zone, minimizing aberrations and maximizing lens efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If progressive multifocal ophthalmic lenses are used to correct myopia and provide near vision, then the lens can slow down myopia progression, but non-presbyopic wearers tend to use the wrong part of the lens for near vision tasks, reducing the beneficial effect
Solution Approach 1:
The patent modifies the optical parameters of the lens by adding a postural prism component to the progressive multifocal lens. This changes the overall prism characteristics of the lens, creating a prismatic effect that guides the wearer's gaze through the appropriate near vision zone. The postural prism value is calculated based on the wearer's specific gaze behavior and lens design parameters, optimizing the directional guidance effect.
Solution Approach 2:
The patent implements a feedback mechanism where the wearer's actual gaze direction is measured and used to adjust the postural prism value. By monitoring whether the wearer is using the correct portion of the lens and adjusting the prism accordingly, the system learns from the wearer's behavior patterns and optimizes the lens performance over time to ensure proper usage.
2Reliability
If a postural prism is added to guide the wearer's gaze through the correct vision zone, then the efficiency of the lens is improved, but chromatic aberrations and other optical aberrations increase
Solution Approach 1:
The patent carefully controls the postural prism parameter to balance two competing requirements: it must be large enough to effectively guide the wearer's gaze through the correct vision zone, but small enough to minimize chromatic and other optical aberrations. The optimization process determines the maximum postural prism value that achieves adequate gaze guidance while keeping aberrations within acceptable limits.
Solution Approach 2:
Instead of applying a large prism that would definitely guide gaze but cause significant aberrations, the patent applies a partial or optimized amount of prism that achieves sufficient gaze guidance with minimal aberrations. The postural prism value is set to the minimum necessary to correct the wearer's gaze tendency, avoiding excessive correction that would introduce harmful optical effects.
3Reliability
If the postural prism value is increased to ensure proper gaze direction, then the wearer uses the correct vision zone, but the complexity of lens design and manufacturing increases
Solution Approach 1:
The patent combines the postural prism function with the existing progressive multifocal lens design in a unified optical element. Rather than adding a separate prism device or complex mechanical adjustment mechanism, the prism effect is integrated directly into the lens prescription and manufacturing process, simplifying the overall system while achieving gaze direction control.
Solution Approach 2:
The patent determines the postural prism value through optimization based on measurable parameters such as the wearer's gaze angle, lens addition power, and frame geometry. By using these quantifiable parameters to calculate the optimal prism value, the design process becomes more systematic and less complex, allowing for standardized manufacturing approaches.
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 optimized postural prism ensures the wearer uses the lenses efficiently, aligning the gazing direction with the correct vision zone, thereby enhancing the effectiveness of myopia control lenses in slowing down myopia progression while minimizing chromatic aberrations.
Implementation Method 1
a postural prism adding step S2, during which a same postural prism is added to each ophthalmic multifocal lens
Data Source
AI summary
Methods for optimizing postural prism to be added to a pair of ophthalmic multifocal lenses (lenses) adapted to a wearer and to slow down myopia progression are described. The method includes an initial pair of lenses in a providing step S1. In a postural prism adding step S2, a same postural prism is added to each lens. In a gazing step S3, the wearer gazes at a first distance target through the lenses with the added postural prism. A gazing direction determining step S4 determines the wearer's gazing direction during S3. Steps S2 to S4 may be repeated while changing the added postural prism, wherein the added postural prism is smaller than or equal to a maximum prism value. Steps S2 to S4 may be repeated to determine the smallest added postural prism for which the wearer's gazing direction in step S4 passes through the first vision zone.