Customized Progressive Lens Meridian Shift for Convergence Mismatch
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Solution Overview
Problem
Current progressive ophthalmic lenses do not account for individual variations in convergence ability, leading to visual fatigue and discomfort due to shifts between the convergence and accommodation planes.
Innovation Solution
A method to produce customized progressive lenses by measuring binocular convergence data and modifying the meridian line's position based on this data, ensuring alignment with the wearer's actual convergence ability, thereby improving visual field congruence and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standard progressive lens design is used, then manufacturing and design simplicity is maintained, but visual comfort deteriorates due to mismatch between convergence plane and accommodation plane
Solution Approach 1:
The patent applies local quality by customizing the meridian line position specifically in the near vision zone of the progressive lens. The horizontal position of the meridian line is adjusted laterally based on individual convergence characteristics, while other zones of the lens maintain standard design parameters. This localized modification allows the lens to adapt to individual convergence delays without requiring complete redesign of the entire lens surface.
Solution Approach 2:
The patent implements parameter changes by modifying the horizontal position parameter of the meridian line based on measured convergence data. The convergence delay value obtained from dynamic measurement is used to calculate a lateral shift amount, which is then applied to adjust the meridian line's horizontal coordinate in the near vision zone. This parameter adjustment optimizes the alignment between convergence and accommodation planes for each individual wearer.
2Object-affected harmful factors
If individual convergence measurement and customization is implemented, then visual comfort is improved, but device complexity and measurement requirements increase
Solution Approach 1:
The patent applies preliminary action by performing dynamic convergence measurement and calculating the individual convergence delay value before the lens manufacturing process. The measured convergence characteristics are used to pre-determine the appropriate lateral shift amount for the meridian line. This preliminary customization step ensures that the lens is optimally adapted to the wearer's convergence ability before production, preventing visual discomfort from the outset.
Solution Approach 2:
The patent uses copying by creating a customized lens design that replicates the standard progressive lens parameters but with a modified meridian line position. The lateral shift amount is calculated based on the individual's convergence delay, and this adjusted parameter set is used to generate the customized lens surface. This approach allows efficient reproduction of the optimized design without requiring completely new manufacturing processes.
3Manufacturing precision
If the meridian line is laterally shifted to match convergence data, then convergence plane alignment is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements feedback by using dynamic convergence measurement to obtain real data about the wearer's convergence characteristics and delay values. This measured feedback information is then used to calculate the precise lateral shift amount needed for the meridian line. The process creates a closed-loop system where measurement results directly inform design modifications, ensuring that the final lens configuration accurately matches the wearer's physiological convergence behavior.
Data Source
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AI summary
A method for producing a customized progressive ophthalmic lens intended for a wearer having a prescription for a wearer's eye corresponding to said lens, the method comprising the following steps: a) providing an initial progressive ophthalmic lens design having a meridian line; b) providing binocular convergence data for the wearer; and c) modifying the initial design so that the meridian line is laterally shifted in position with respect to said initial design, for matching the convergence data provided at step b), for said prescription, and the modified design as resulting from step c) is used for the customized lens, wherein step b) comprises the following substeps: b1 ) providing a visual stimulus in a sagittal plane of the wearer; and b2) moving the visual stimulus within the sagittal plane between a predetermined maximum distance and a predetermined minimum distance.