Asymmetric Lens Angle Measurement for Precise Toric Fitting

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Solution Overview

Problem

Fitting asymmetric lenses, such as toric lenses, is challenging due to their tendency to rotate to varying angles on different eyes, leading to inefficiency or discomfort, and existing methods like slit lamps are expensive and require specialized training.

Innovation Solution

A system using a mobile device with a camera, processor, and orientation sensor to determine the angle of repose of a lens on an eye, allowing for easy and accurate measurement and modification of lens specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a slit lamp is used to determine the angle of repose, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveangle of repose measurementVSAvoidequipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a camera to capture an image of the lens on the eye, creating a visual copy that can be analyzed digitally. This replaces the need for complex optical instrumentation while preserving the ability to measure lens orientation through image processing and coordinate system transformation

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/optical slit lamp system with a digital imaging system using a camera and software-based image processing. The measurement is achieved through computational methods (coordinate transformations) rather than direct optical-mechanical measurement

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a slit lamp is used to determine the angle of repose, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveangle of repose measurementVSAvoidoperation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system automatically processes the captured image to determine lens orientation. The software performs coordinate system transformations and calculates the angle of repose without requiring manual intervention or specialized operator skills, making the measurement process self-executing and easy to operate

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Manual estimation of lens orientation by trained professionals is replaced with automated digital image processing algorithms that objectively calculate the angle of repose, eliminating the need for specialized training while maintaining measurement precision

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If asymmetric lenses are fitted without accurate angle determination, then ease of operation is improved, but reliability deteriorates

Engineering Contradiction:
Improvelens fitting processVSAvoidlens effectiveness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system determines the angle of repose before final lens specification is confirmed. By measuring the actual lens orientation on the eye and using coordinate transformation to calculate the repose angle, the system allows for preliminary adjustment of lens parameters to ensure proper alignment and effectiveness

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system provides feedback on the actual lens orientation by calculating the angle of repose from captured images. This feedback loop allows clinicians to adjust lens specifications based on measured data, ensuring the lens is properly oriented for effective vision correction

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3262459B1Systems and methods for determining an angle of repose of an asymmetric lens
Publication Date: 2025.11.26 COOPERVISION INT LTD
  • EP3262459B1 patent drawingFigure 1
  • EP3262459B1 patent drawingFigure 2A
  • EP3262459B1 patent drawingFigure 2B

AI summary

Technology to determine the angle of repose of a lens, such as the angle of repose of a contact lens on an eye, includes storing an image including the lens captured using a camera and executing graphical user interface logic. The graphical user interface logic includes a frame or frames including the captured image, and graphical constructs prompting input identifying a set of locations on the captured image that are usable to define a location of the lens in the image, and a location usable to define an angle of repose of the lens in the image. The input data accepted via the graphical user interface is processed to determine angle of repose of the lens. The angle of repose of the lens is used to produce a specification for a lens.