Eye Refraction Measurement Using Retinal Reflection Geometry

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Solution Overview

Problem

Existing methods for determining eye refraction require complex, expensive devices and trained personnel, limiting access to a large part of the world population.

Innovation Solution

A method using a light source and image-capture apparatus positioned in different planes, allowing self-administration with portable devices like smartphones or tablets, to determine eye refraction by analyzing reflections of the light source on the retina.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional autorefraction methods are used, then measurement precision is improved, but device complexity and cost increase significantly

Engineering Contradiction:
Improverefraction measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent positions the light source and image-capture apparatus in different spatial planes (illumination plane and image-capture plane) with an optical distance difference greater than 0.2 meter. This dimensional separation allows the system to determine refraction features using reflections from the retina without requiring complex optical alignment, thereby maintaining measurement precision while significantly simplifying device complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent enables the use of portable electronic devices with standard components (light source and camera) to perform refraction measurement, a function previously requiring specialized medical equipment. This multi-functionality allows common devices to serve both general purposes and specialized ophthalmic measurement, reducing device complexity and cost while maintaining adequate measurement precision

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If traditional autorefraction devices are used, then measurement precision is improved, but ease of operation deteriorates due to requiring qualified personnel

Engineering Contradiction:
Improverefraction measurement precisionVSAvoidease of operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent enables subjects to perform their own refraction measurement using portable devices. The subject positions the device, activates the light source, and captures the retinal reflection image independently, eliminating the need for qualified personnel to operate the equipment. This self-service capability significantly improves ease of operation while maintaining measurement precision through the geometric constraints on light source and camera positioning

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

By separating the illumination and image-capture functions into different planes with a specified optical distance difference, the system creates a measurement geometry that is inherently more robust to misalignment. This dimensional separation allows subjects without training to obtain usable images, improving ease of operation while preserving measurement precision

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If traditional autorefraction methods are used, then measurement precision is improved, but accessibility deteriorates due to limited availability of specialized devices

Engineering Contradiction:
Improverefraction measurement precisionVSAvoidaccessibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transforms portable electronic devices with standard light sources and cameras into refraction measurement instruments. Since these devices are widely available and commonly used, the measurement capability becomes accessible to a broad population rather than being limited to specialized medical facilities. This universality maintains measurement precision through geometric constraints while dramatically improving accessibility

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes inexpensive, mass-produced portable electronic devices instead of expensive specialized medical equipment. These common devices can be readily obtained and used by individuals without requiring access to expensive clinical instruments, thereby improving accessibility while maintaining adequate measurement precision through the innovative geometric approach

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables accessible and precise determination of eye refraction features using widely available devices, eliminating the need for specialized equipment and trained personnel.

Implementation Method 1

illuminating a pupil of the eye of the subject by means of said light source

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

acquiring at least one picture of said pupil of the eye of the subject comprising an image of the reflection of said light source on the retina of said eye of the subject

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3669751B1Method for determining a refraction feature of an eye of a subject
Publication Date: 2025.12.10 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP3669751B1 patent drawingFigure 1~5
  • EP3669751B1 patent drawingFigure 2
  • EP3669751B1 patent drawingFigure 3

AI summary

The invention concerns a method comprising the steps of: a) illuminating a pupil (30) of the (3) eye of a subject by means of a light source (12); b) acquiring at least one picture of said pupil comprising an image of the reflection of said light source on the retina of said eye, by means of an image-capture apparatus (10); c) determining a refraction feature of said eye from at least a geometrical feature, a positional feature, or an intensity distribution of said image of the reflection of said light source wherein optical distances (dsource, dcam) between said pupil and, respectively, said light source and said image-capture apparatus, are different. An associated device (8) is also described.