Retinal Oximetry via Auto-fluorescence Signal Isolation
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Solution Overview
Problem
Current retinal oximetry techniques face challenges in accurately measuring retinal blood vessel oxygen saturation due to contamination from multiple light sources and reflections, leading to unreliable oxygen saturation calculations.
Innovation Solution
The method employs retinal auto-fluorescence (AF) to determine oxygen saturation by using one or more excitation sources, such as lasers, to provide light to the retina, and detectors to capture AF signals, which are then analyzed by a processor to calculate oxygen saturation based on the intensity of AF, avoiding the issues of reflected light and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional retinal oximetry techniques are used to measure oxygen saturation, then measurement can be performed, but the measurements are inaccurate due to contamination from multiple light sources and reflections
Solution Approach 1:
The patent extracts and isolates the auto-fluorescence signal from the retina by using specific excitation wavelengths (450-520 nm) that selectively excite lipofuscin in the RPE. The system separates the useful AF signal from harmful reflected light and other contaminations through wavelength-specific detection, effectively extracting only the relevant fluorescence information while rejecting other light sources.
Solution Approach 2:
The patent introduces auto-fluorescence as an intermediary signal mechanism. Instead of directly measuring oxygen saturation through transmitted or reflected light, the system uses AF as an intermediate indicator that is modulated by blood flow and oxygen saturation levels. The AF signal serves as a mediator that indirectly but more accurately reflects vascular oxygen saturation without being contaminated by direct light reflections.
2Measurement precision
If multiple excitation sources are used to improve measurement accuracy, then measurement precision can be improved, but device complexity increases
Solution Approach 1:
The patent makes the excitation sources and detectors multi-functional. The excitation sources (450-520 nm range) serve both to excite lipofuscin fluorescence and to provide a basis for calculating oxygen saturation through spectral analysis. The detectors are designed to detect multiple wavelengths simultaneously, allowing a single detection system to perform both fluorescence measurement and oxygen saturation calculation functions.
Solution Approach 2:
The patent utilizes parameter changes in the excitation light (wavelength, intensity, modulation frequency) to encode multiple pieces of information. By modulating the excitation light at different frequencies and analyzing the emitted AF at corresponding frequencies, the system can distinguish between different depth layers and vascular structures, obtaining multiple measurement parameters from a relatively simple hardware configuration.
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 more accurate and reliable measurements of retinal blood vessel oxygen saturation by leveraging the spatial relationship between retinal vessels and the retinal pigment epithelium, reducing contamination and improving measurement accuracy.
Implementation Method 1
One or more excitation sources (e.g., lasers) can be used to provide light to the retina (e.g., to the retinal pigment epithelium), and retinal AF can be detected by one or more detectors.
Data Source
AI summary
Systems and methods for quantitatively imaging retinal blood vessel oxygen saturation using retinal auto-fluorescence (AF) are provided. One or more excitation sources can be used to provide light to the retina, and retinal AF can be detected by one or more detectors. The quantitative level of oxygen saturation in the blood can be determined based on the intensity of AF.