Ophthalmic Lens Astigmatism Correction via Linear Combination

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Solution Overview

Problem

Conventional ophthalmic lenses fail to adequately address astigmatism correction for different viewing distances, leading to visual fatigue and discomfort, and often provide progressive designs unsuitable for non-presbyopic wearers or introduce distortions in presbyopic wearers, resulting in low acceptance.

Innovation Solution

A method for manufacturing ophthalmic lenses by calculating customized astigmatism features at multiple viewing distances using linear combinations of astigmatism modulus and axis values, applied to both far and near vision zones, avoiding complex free-form surfaces and ensuring consistent astigmatism correction across the lens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional prescription methods are used to manufacture ophthalmic lenses, then the manufacturing process is simple, but visual comfort deteriorates due to inadequate astigmatism correction for different viewing distances

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidvisual comfort

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by measuring and correcting astigmatism at multiple viewing distances (far vision and near vision) rather than a single distance. The method determines customized astigmatism features (modulus and axis) for each distance and combines them using linear combinations with parameters a, b, c, d to create optimized correction values that improve visual comfort while maintaining manufacturing feasibility through conventional surfacing processes.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If progressive lenses are designed to take into account astigmatism change between different viewing distances using free-form surfaces, then visual comfort improves, but device complexity increases

Engineering Contradiction:

Improvevisual comfortVSAvoidlens design complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent avoids complex free-form surfaces by changing the approach to parameter determination. Instead of using complex surface geometries, the method determines customized astigmatism features at multiple distances and combines them through linear combinations. This allows achieving improved visual comfort with simpler lens designs that can be manufactured using conventional surfacing processes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the essential astigmatism correction parameters (modulus and axis) at different viewing distances and separates the correction into measurable components. By measuring and combining these extracted parameters through linear combinations rather than relying on complex free-form surface geometries, the method simplifies the lens design while maintaining effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If progressive design is provided to non-presbyopic wearers, then near vision correction is improved, but acceptance decreases due to unfamiliarity with progressive design

Engineering Contradiction:

Improvenear vision correctionVSAvoidwearer acceptance

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by providing customized astigmatism correction tailored to each wearer's specific needs at different viewing distances. Rather than imposing a universal progressive design on all wearers, the method determines individualized correction parameters through measurement and linear combination, allowing non-presbyopic wearers to receive appropriate correction without unnecessary progressive design complexity, thereby improving acceptance.

Inventive Principle:

Principle #3Local quality

4Reliability

If progressive design is provided to presbyopic wearers, then near vision correction is improved, but additional distortions occur during progression of cylinder axis or modulus

Engineering Contradiction:

Improvenear vision correctionVSAvoidoptical distortions

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent reduces optical distortions by determining customized astigmatism features at multiple distances and combining them through controlled linear combinations. This parameter-based approach allows for smoother transitions and more predictable correction changes compared to traditional progressive designs, minimizing the harmful distortions that occur during the progression of cylinder axis or modulus while still providing effective near vision correction for presbyopic wearers.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3443408B1Method for providing an ophthalmic lens to a wearer

Publication Date: 2024.12.25 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

AI summary

A method for providing an ophthalmic lens to a wearer comprising the steps of:. Providing the wearer's astigmatism features measured at a first proximity Prox1;. Providing the wearer's astigmatism features measured at a second proximity Prox2, wherein the second proximity Prox2 is greater than the first proximity Prox1;. Determining customized wearer's astigmatism features thanks to the combination resulting of linear combinations of the wearer's astigmatism features measured at the first proximity Prox1 and of the wearer's astigmatism features measured at the second proximity Prox2;. Applying said customized astigmatism features to the ophthalmic lens.