Eye Reference Structure Tracking for Spectacle Lens Prescription

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for determining the position of the center of rotation of the eye, especially in spectacle lens prescription, face inaccuracies due to the use of separate devices and subjective measurements, leading to potential discrepancies in axis alignment and lens correction.

Innovation Solution

A method that records a reference structure of the eye in multiple situations, allowing for the correction of prescription lenses based on changes in this structure, enabling better alignment and accuracy across different measurement devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate measuring devices are used for refraction and centration, then each parameter can be measured with specialized equipment, but discrepancies in axis alignment and lens correction occur due to lack of reference point between measurements

Engineering Contradiction:
Improveparameter measurement accuracyVSAvoidaxis alignment consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines multiple measurement functions (refraction, centration, and reference structure imaging) into a single integrated measurement system. The imaging device captures both the reference structure of the eye and the position of measurement markers, allowing all parameters to be measured in a coordinated manner from a common reference frame, eliminating alignment discrepancies between separate devices

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a reference structure (such as the iris pattern or other eye features) as an intermediary element that is imaged by the measuring device. This reference structure serves as a common reference frame that links refraction measurements and centration measurements, enabling accurate transformation and alignment of parameters from different measurement processes

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If video centration systems are used to measure individual parameters, then customized lens prescription is enabled, but the eye's center of rotation cannot be determined with sufficient accuracy

Engineering Contradiction:
Improvecustomized lens capabilityVSAvoidcenter of rotation accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical measurement methods with optical imaging technology. Instead of using mechanical devices to directly measure the center of rotation, the system uses an imaging device to capture images of the eye's reference structure and calculates the center of rotation position through image processing and coordinate transformation, achieving higher precision and non-contact measurement

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

3Ease of manufacture

If the eye's center of rotation is derived from eye length via the central sphere, then a calculation method is provided, but many assumptions are made that do not sufficiently correspond to actual conditions

Engineering Contradiction:
Improvecalculation simplicityVSAvoidcenter of rotation accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent enables the measurement system to automatically determine the eye's center of rotation and other parameters through direct imaging and computational methods, without relying on simplified assumptions or manual calculations based on eye length. The system uses the imaged reference structure to self-calibrate and calculate positions, providing both simplicity and accuracy

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3243428B1Method and device for prescribing a spectacle lens
Publication Date: 2020.08.26 CARL ZEISS VISION GMBH
  • EP3243428B1 patent drawingFigure 1~2
  • EP3243428B1 patent drawingFigure 3~4

AI summary

The invention relates to a method for prescribing a spectacle lens, in which at least two parameters of a system comprising an eye (10)/spectacles having a reference structure are determined, in which, for the determination of the respective parameter, the eye (10) is photographed using a separate recording device, wherein the reference structure of the eye (10) is simultaneously recorded in the photographic images and the values ​​of the parameters are related to the reference structure, comprising the steps: a) measuring the reference structure of the eye (10) in a first measurement situation; b) measuring the reference structure of the eye (10) in a second measurement situation; c) determining the change in position of the reference structure between the two measurement situations; d) prescribing a spectacle lens taking into account the determined change in position of the reference structure.