Custom Progressive Lens Blur Threshold
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Solution Overview
Problem
Progressive spectacle lenses often cause visual blur outside of designated vision zones due to variations in optical power and astigmatism, which can be uncomfortable for wearers, and existing lenses do not adequately account for individual differences in blur perception, making it difficult to find a suitable compromise between optical correction and comfort.
Innovation Solution
A method for manufacturing customized progressive spectacle lenses that takes into account the wearer's specific blur perception threshold, determined by their ophthalmic prescription and sensitivity to blur, by selecting a lens with a blur value discrepancy of less than 0.50 diopters for the reference direction of gaze, using a criterion that varies based on the addition value, ensuring compatibility with the prescribed optical power and astigmatism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If progressive spectacle lenses are designed to provide wide vision zones, then the visual field coverage is improved, but the blur outside designated zones increases
Solution Approach 1:
The patent applies local quality by customizing the blur perception threshold for specific directions of gaze (meridian line and reference directions) rather than uniformly across the entire lens. The method determines specific blur values for different zones and compares them against wearer-specific thresholds, allowing optimal visual comfort in critical areas while managing blur in peripheral zones.
Solution Approach 2:
The patent changes parameters by adjusting the blur perception threshold based on the wearer's addition value and sensitivity characteristics. The method modifies the acceptable blur level parameter according to the wearer's specific needs, transforming a one-size-fits-all approach into a customized parameter set that resolves the contradiction between wide coverage and minimal blur.
2Measurement precision
If the addition value of progressive lenses is increased, then the near vision correction is improved, but the blur outside vision zones increases
Solution Approach 1:
The patent directly addresses this contradiction by changing the blur perception threshold parameter as a function of the addition value. For higher addition values, the method adjusts the acceptable blur threshold to account for the increased near vision correction, allowing the lens to provide precise near vision while managing the inevitable increase in peripheral blur through customized tolerance levels.
3Manufacturing precision
If identical progressive lenses are used for wearers with identical prescriptions, then manufacturing consistency is improved, but individual blur perception differences cannot be accommodated
Solution Approach 1:
The patent segments the lens evaluation process into multiple specific directions of gaze (meridian line, reference directions at different elevations and azimuths). Instead of treating the lens as a single uniform object, the method divides the assessment into discrete zones with specific blur values, allowing customization for individual wearers while maintaining manufacturing consistency through standardized measurement protocols.
Solution Approach 2:
The patent applies preliminary action by determining the wearer's blur perception threshold before lens selection or manufacturing. The method performs preliminary measurements and assessments to establish the wearer's sensitivity characteristics, then uses this information to guide the lens design or selection process, ensuring individual customization is built into the foundation of the solution.
4Object-affected harmful factors
If the blur tolerance is reduced for wearers with high sensitivity, then visual comfort is improved, but compatibility with prescribed addition values becomes difficult
Solution Approach 1:
The patent resolves this contradiction by dynamically changing the blur perception threshold parameter based on the wearer's addition value and sensitivity measurements. For wearers with high sensitivity and high addition values, the method adjusts the threshold to find an optimal balance point that maintains visual comfort while ensuring the lens remains compatible with the prescribed optical correction, rather than applying a fixed low tolerance that would make compatibility difficult.
Data Source
AI summary
The invention relates to the making of a progressive spectacle lens for customizing the lens based on the blur perception by a future lens wearer. Accordingly, a blur threshold value is determined for the wearer according to a blur perception criterion that varies based on an optical-power addition value prescribed for the wearer. The blur threshold value is associated with a reference sight direction for the lens provided to the wearer.