Tear Meniscus Image Analysis for Noninvasive Fluid Evaluation

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Solution Overview

Problem

Conventional methods for evaluating tear fluid and tear fluid amount, such as Schirmer's test and BUT test, are invasive and cause discomfort, while existing tools require contact or complex lattice projections, increasing cost and labor.

Innovation Solution

A method involving binarization and extraction of high luminance regions from tear meniscus images to noninvasively evaluate tear fluid state and amount, using a computer program and device that captures and processes images without physical contact or special components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods like Schirmer's test or BUT test are used to evaluate tear fluid, then tear fluid state can be determined, but the method becomes invasive causing pain or discomfort to the subject

Engineering Contradiction:

Improvetear fluid state determinationVSAvoidpain or discomfort to subject

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical/invasive measurement methods (filter paper insertion, fluorescent dye instillation) with an optical imaging system that captures photographs of the tear meniscus. The imaging device uses light reflection properties to detect tear fluid state without physical intrusion into the eye, thereby eliminating pain and discomfort while maintaining diagnostic capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an optical copy (photograph) of the tear meniscus instead of directly measuring the tear fluid itself. By analyzing the reflected light pattern and intensity in the captured image, the system determines tear fluid state indirectly through its optical properties, avoiding direct contact with the eye while preserving measurement accuracy.

Inventive Principle:

Principle #26Copying

2Measurement precision

If examination tools with water absorbing members are used to measure tear fluid amount, then quantitative measurement is achieved, but the tool requires contact with the tear meniscus making the method invasive

Engineering Contradiction:

Improvetear fluid amount measurementVSAvoidinvasive procedure requiring contact

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical water-absorbing contact method with an optical detection system. The imaging device captures light reflected from the tear meniscus surface, and image processing algorithms quantify the tear fluid amount based on the optical characteristics (brightness, area, shape) of the tear meniscus in the photograph, eliminating the need for physical contact.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light as an intermediary medium between the measurement system and the tear fluid. Instead of direct contact between the tool and tear meniscus, light serves as the mediator that carries information about the tear fluid amount from the eye to the imaging sensor, enabling non-contact quantitative measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If lattice projection methods are used to measure tear fluid, then physical quantity can be determined, but the device complexity and cost increase due to special components

Engineering Contradiction:

Improvetear fluid physical quantity measurementVSAvoidcomplex lattice projection setup

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes only the essential optical property (light reflection) of the tear meniscus for measurement, removing the need for complex lattice projection components. By focusing on the inherent optical characteristics of the tear fluid interface, the system achieves accurate measurement with a simpler imaging device that lacks the complicated lattice structure and projection mechanisms.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the measurement approach from projecting physical lattice patterns onto the tear fluid to analyzing optical parameters (brightness, intensity, area) of the tear meniscus in captured images. This parameter transformation from mechanical projection to optical analysis simplifies the device while maintaining measurement precision.

Inventive Principle:

Principle #35Parameter changes

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 noninvasive evaluation of tear fluid state and amount, reducing discomfort and cost, with a simple configuration that accurately assesses tear fluid levels without invasive procedures or complex setups.

Implementation Method 1

capturing at least a part of a tear meniscus of a subject to create an image

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS11514570B2Tear fluid state evaluation method, computer program, and device

Publication Date: 2022.11.29 KOWA CO LTD

AI summary

Provided are a method, a computer program and a device for noninvasively evaluating a state of a tear fluid and a tear fluid amount of a tear meniscus.Included are a binarization step of binarizing a tear meniscus image, obtained by capturing at least a part of a tear meniscus of a subject, using a predetermined threshold value; an extraction step of extracting a high luminance region indicating a tear meniscus part from the binarized image; and an evaluation step of evaluating a tear fluid state on the basis of the high luminance region.