Refractive Error Measurement Using Maximum Distance of Best Acuity

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Solution Overview

Problem

Current optometric examination methods for refractive error measurement require professional intervention and reliance on subjective patient responses or less accurate objective methods, lacking efficiency and accuracy in self-administered assessments.

Innovation Solution

A system utilizing a personal device with a display and sensor, allowing users to conduct self-examinations by measuring the distance to a target image, calculating refractive error based on maximum distance of best acuity, and estimating dioptric power without the need for corrective lenses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If subjective refraction method is used with professional examiner and trial lenses, then measurement accuracy is improved, but device complexity and professional intervention requirement increase

Engineering Contradiction:
Improverefractive error measurement accuracyVSAvoidexamination system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system enables patients to perform self-refraction examinations using their personal computing devices. The application guides patients through the examination process, automatically presenting targets at calculated distances and interpreting responses to determine refractive error, eliminating the need for professional examiners and complex trial lens equipment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical trial lens system with a computational approach. Instead of physically interposing lenses of various dioptric powers, the system uses software to present targets at dynamically calculated distances based on the patient's suspected refractive error, achieving the same diagnostic purpose through digital means.

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

2Ease of operation

If objective refraction methods such as auto refraction are used, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveself-administration capabilityVSAvoidrefractive error measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system incorporates iterative feedback mechanisms where the application adjusts target distance based on patient responses. The algorithm refines the estimated refractive error with each response, presenting subsequent targets at optimized distances, thereby improving measurement accuracy while maintaining ease of self-administration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The examination process is dynamic rather than static. The system continuously adapts the target distance and presentation parameters based on real-time patient responses and the evolving estimate of refractive error, optimizing the measurement process throughout the examination.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If traditional subjective refraction with cross cylinder and trial frame is used, then measurement precision is improved, but ease of operation and productivity worsen due to professional intervention requirement

Engineering Contradiction:
Improvecylindrical power and axis determination accuracyVSAvoidexamination efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system automates the entire refraction process including cylindrical power and axis determination. Patients independently complete the examination by responding to systematically presented targets, with the algorithm automatically calculating refractive parameters, eliminating the time-consuming manual process of professional examiners using cross cylinders and trial frames.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary calculations of target distance and presentation parameters before each target is shown to the patient. This pre-computation optimizes the examination flow and enables rapid processing of multiple targets, increasing productivity while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3003121B1System for measurement of refractive error of an eye based on subjective distance metering
Publication Date: 2021.05.12 6 OVER 6 VISION LTD
  • EP3003121B1 patent drawingFigure 1
  • EP3003121B1 patent drawingFigure 2
  • EP3003121B1 patent drawingFigure 3A~3B

AI summary

Method and system for measuring refractive error of an eye of a subject, The method include: (a) displaying at least one dynamic target image of at least one sign over a display area; (b) receiving subjective feedback from the subject indicating that the subject is positioned at a maximum distance of best acuity (MDBA) from the target image, wherein the MDBA is the maximum distance in which the subject recognizes the sign; (c) measuring one or more parameter associated with distance, during the time the subject has reached the MDBA distance, using at least one sensor; (d) estimating the MDBA by estimating the distance between the eye of the subject and the display area in which the target image is displayed by using the sensor data and (e) calculating the refractive error of the eye according to the estimated MDBA and characteristics of the target image.