Optical Interferometry for Tear Film Thickness Measurement
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Solution Overview
Problem
Current methods for diagnosing and evaluating dry eye syndrome are imperfect and lack precision, particularly in measuring tear film thickness and lipid layer thickness after ophthalmic formula application, which is crucial for ocular surface health and drug delivery optimization.
Innovation Solution
A method and device using wavelength-dependent optical interferometry to measure tear film thickness, allowing for the accurate diagnosis of dry eye causes and the evaluation of ophthalmic formula effects on tear film layers, including aqueous and lipid layers, before and after application, enabling the selection of appropriate therapeutic products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current diagnostic methods (symptom assessment, fluorescein staining, TBUT) are used, then diagnosis can be performed, but measurement precision and accuracy are insufficient
Solution Approach 1:
The patent replaces mechanical and chemical diagnostic methods (fluorescein staining, Schirmer test) with optical interferometry. The optical system uses wavelength-dependent interferometry to measure tear film thickness non-invasively, eliminating the need for chemical dyes and manual assessment procedures while achieving superior measurement precision.
Solution Approach 2:
The patent changes the measurement parameter from qualitative/semi-quantitative assessments (staining intensity, break-up time) to precise quantitative optical interference patterns. By measuring the wavelength-dependent reflectance spectrum, the system derives exact tear film thickness values, transforming subjective diagnostic parameters into objective numerical data.
2Reliability
If fluorescein staining is used to assess tear film, then diagnosis can be performed, but the presence of fluorescein changes tear film properties making measurements non-physiological
Solution Approach 1:
The patent substitutes chemical staining methods with purely optical measurement. The optical interferometry system measures tear film thickness without introducing any foreign substances, ensuring that the tear film remains in its natural physiological state throughout the measurement process.
Solution Approach 2:
The patent uses optical interference patterns as an intermediary to measure tear film properties. Instead of directly interacting with the tear film through chemical dyes, the system uses light waves that reflect off the tear film interfaces, creating interference patterns that encode thickness information without altering the tear film composition.
3Measurement precision
If TBUT measurement with fluorescein instillation is used, then tear film stability can be assessed, but reflex tearing is stimulated preventing accurate measurement
Solution Approach 1:
The patent replaces the chemical stimulation method (fluorescein instillation) with a non-invasive optical measurement approach. The interferometric system measures tear film thickness and stability without stimulating the ocular surface, thereby preventing reflex tearing and maintaining natural tear film physiology throughout the measurement.
4Loss of information
If multiple diagnostic tests are performed to evaluate tear film adequately, then comprehensive diagnosis is achieved, but time and resources are consumed
Solution Approach 1:
The patent creates a universal diagnostic platform that performs multiple tear film assessments simultaneously. The optical interferometry system measures aqueous layer thickness, lipid layer thickness, and tear film stability in a single integrated procedure, replacing the need for multiple separate tests (fluorescein staining, Schirmer test, TBUT measurement) and providing comprehensive tear film evaluation in one measurement session.
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
This approach provides precise and accurate measurements of tear film layers, allowing for effective diagnosis and treatment of dry eye conditions, improving ocular surface health and optimizing ophthalmic dosage forms.
Implementation Method 1
employing an optical interferometer to measure tear film layer thickness
Data Source
AI summary
Methods and devices measure eye blinks and tear film lipid and aqueous layer thickness before and following ophthalmic formula application onto the ocular surface, especially wherein the ophthalmic formula is an artificial tear. The methods and devices are suitable for dry eye diagnosis. The methods and devices are suitable for use to evaluate ophthalmic formula effects on the tear film and to use such information to diagnose ophthalmic formula treatment of ocular disease conditions such as dry eye in the absence of contact lens wear or post-surgical eye drop treatment and diagnosis. The methods and devices are also suitable for use in the optimization of ophthalmic drug dosage forms and sustained drug release.