Contact Lens Moire Pattern for Intraocular Pressure Monitoring

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Solution Overview

Problem

Current methods for monitoring intraocular pressure, such as contact applanation tonometers, are inconvenient for long-term use and require professional assistance, and are not suitable for portable monitoring due to complex calculations and weakly reflected images, which can lead to measurement errors.

Innovation Solution

A contact lens with a first pattern in the annular region and a second pattern that forms a moire pattern when overlapped, allowing for continuous intraocular pressure monitoring without affecting viewing transparency and reducing data processing, using a light transmissive material with sub-patterns arranged at intervals, which does not contact the eyeball and maintains comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a contact applanation tonometer is used for measuring intraocular pressure, then measurement can be obtained, but continual use causes burden and inconvenience to the user

Engineering Contradiction:
Improveintraocular pressure measurementVSAvoiduser convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The contact lens enables the user to monitor their own intraocular pressure without requiring assistance from a professional person. The lens continuously measures IOP through the cornea while the user wears it, eliminating the need for manual operation and making the measurement process self-service oriented

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical contact applanation tonometer with an optical measurement system. Instead of using mechanical force to flatten the cornea, the system uses optical patterns and image processing to measure cornea curvature changes, which are then converted to intraocular pressure data

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

2Measurement precision

If a stripe pattern is projected onto the cornea using a device, then cornea curvature can be measured, but the instrument is too large to carry and not suitable for portable monitoring

Engineering Contradiction:
Improvecornea curvature measurementVSAvoidportability
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The measurement system is nested within the contact lens itself. The first and second patterns are embedded in the lens structure, with the second pattern projected onto the first pattern through the lens. This nesting eliminates the need for a separate large instrument and makes the system portable since the contact lens is worn directly on the eye

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The contact lens serves multiple functions: it corrects vision (as a regular contact lens) and simultaneously measures intraocular pressure through the integrated pattern system. This multi-functionality eliminates the need for separate measurement devices, achieving portability while maintaining measurement capability

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

3Measurement precision

If a stripe pattern is projected onto the cornea, then curvature change can be obtained, but complex calculation is needed due to weakly reflected images

Engineering Contradiction:
Improvecurvature change detectionVSAvoidcalculation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses moire pattern formation between the first pattern on the contact lens and the second pattern projected onto it. The moire effect creates visible interference patterns that directly indicate cornea curvature changes, eliminating the need for complex calculations of weakly reflected images. The pattern interaction provides direct visual measurement data

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The contact lens with its first pattern serves as an intermediary between the projected second pattern and the cornea. This intermediary creates a moire pattern that amplifies the curvature change signal, making it easier to detect and measure without requiring complex image processing of weak reflections

Inventive Principle:
Principle #24Intermediary (Mediator)

4Illumination intensity

If the first pattern is formed in the annular region and forms a moire pattern with the second pattern, then viewing transparency is maintained, but the pattern must be precisely positioned

Engineering Contradiction:
Improveviewing transparencyVSAvoidpattern positioning
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The first pattern is formed only in the annular region of the contact lens, leaving the central region transparent for viewing. This local placement of the pattern ensures that the moire pattern forms only in the annular area, maintaining viewing transparency through the central pupil while still enabling measurement in the iris region

Inventive Principle:
Principle #3Local quality

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 accurate and continuous monitoring of intraocular pressure variations without the need for fluorescent agents, reducing measurement errors and improving comfort, while allowing for real-time and long-term monitoring through a portable system.

Implementation Method 1

The first pattern is configured to overlap with a second pattern to form a moire pattern

Methodology Applied
Scientific EffectMoiré effect: Moiré Effect

Data Source

PatentEP3289405B1Contact lens without moire pattern in center
Publication Date: 2021.06.30 WANG LON
  • EP3289405B1 patent drawingFigure 1~2
  • EP3289405B1 patent drawingFigure 3~4
  • EP3289405B1 patent drawingFigure 5~6

AI summary

Disclosed are a contact lens without moiré pattern in center, a method for analyzing change of moiré pattern thereof, and a system for monitoring an intraocular pressure variation related to the contact lens. The contact lens (10) includes a first material layer (110) and a first pattern (130). The first material layer has a central region (Ac) and an annular region (Aa) around the central region. When the contact lens is placed on a surface of an eyeball (20), the central region corresponds to a pupil of the eyeball and the annular region corresponds to an iris of the eyeball. The first pattern is formed in the annular region, and is formed of a plurality of first sub-patterns (13a, 13b, 13c, 13d, 13e) arranged at intervals. The first pattern is configured to overlap with a second pattern (132) to form a moiré pattern.