Visual Aid Addition Calculation Using Individual Depth of Field
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Solution Overview
Problem
Current methods for determining the required addition of visual aids, such as multifocal or progressive lenses, are inaccurate due to reliance on age and estimated properties, leading to unnecessarily high additions that compromise lens design and wearer satisfaction.
Innovation Solution
A method that objectively determines the individual depth of field and accommodation width of the eye, using equations to calculate the necessary addition, ensuring a more precise fit tailored to the user's specific needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If age-based estimation methods are used to determine addition, then the determination process is simple, but the accuracy of addition determination deteriorates
Solution Approach 1:
The patent changes the parameters used for addition determination from age-based estimates to individually measured physiological parameters (depth of field, accommodation width, near point distance). This allows accurate determination of addition by measuring actual eye properties rather than relying on population averages, directly resolving the contradiction between simple determination and accurate results
Solution Approach 2:
The patent replaces subjective estimation methods with objective measurement systems using optical devices to measure depth of field, accommodation width, and near point distance. This substitution of mechanical/optical measurement for human estimation eliminates the inaccuracy while maintaining practical simplicity through automated measurement and calculation
2Reliability
If higher addition values are prescribed, then the near vision capability is improved, but the lens design quality and wearer satisfaction deteriorate
Solution Approach 1:
The patent determines the precise addition value needed for each individual's specific near vision requirements based on their measured physiological parameters. This allows the lens to be optimized locally for the wearer's actual needs rather than using standardized high addition values, improving both near vision capability and lens design quality by matching the correction to the individual's specific visual demands
3Productivity
If standardized addition values are used, then the lens production process is simplified, but the individual visual needs are not met
Solution Approach 1:
The patent performs preliminary individual measurements of depth of field, accommodation width, and near point distance before lens production. These pre-measured parameters are then used to calculate the precise addition value, allowing customized lenses to be produced efficiently without complex real-time adjustments during manufacturing, thus maintaining productivity while achieving individual adaptability
Data Source
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AI summary
The invention relates to a method for determining the individually required addition (Add) of a visual aid for one eye, comprising the following steps: a) a preliminary addition (AddPreliminary) is determined, b) the depth of field (T) of the eye is individually determined, c) the addition (Add) is calculated according to the following equation: Add = AddPreliminary - ωT, where ω is a real number in the range 0 < ω ≤ 1. The invention further relates to a corresponding device for carrying out the method and a computer program.