Fourier-domain OCT Corneal Mapping for Keratoconus Diagnosis
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Solution Overview
Problem
Current methods for measuring corneal epithelial and stromal properties, such as thickness and refractive power, are not suitable for clinical use due to limitations in speed, accuracy, and convenience, particularly in diagnosing early-stage keratoconus, which can lead to poor surgical outcomes and visual impairment.
Innovation Solution
A non-contact method using Fourier-domain optical coherence tomography (FD-OCT) with specific scanning patterns and data analysis techniques to reliably map corneal epithelial and stromal properties, including thickness and power, enabling accurate diagnostic information for eye diseases like keratoconus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If time-domain OCT is used to measure corneal epithelial and stromal properties, then non-contact measurement is achieved, but the measurement speed is slow making it susceptible to eye movements
Solution Approach 1:
The patent transitions from time-domain OCT to Fourier-domain OCT, fundamentally changing the operational parameter of the imaging system. This parameter change enables acquisition speeds 10-100 times faster while maintaining non-contact measurement capability, directly resolving the contradiction between ease of operation and productivity
2Productivity
If Fourier-domain OCT is used to increase measurement speed, then acquisition speed increases 10-100 times, but data acquisition and analysis becomes more complex
Solution Approach 1:
The patent implements automated algorithms that enable the system to self-process the complex Fourier-domain data. The computer automatically performs spectral decomposition, generates corneal maps, and extracts measurements without requiring complex manual analysis, resolving the contradiction between high speed and analysis complexity
3Measurement precision
If peripheral epithelial thickness is measured using OCT or confocal microscopy, then thickness data is obtained, but the number of measurement points is limited and measurement is very time consuming
Solution Approach 1:
The patent uses continuous Fourier-domain OCT scanning to capture thousands of data points across the entire corneal surface in rapid succession. This continuous measurement approach eliminates the time-consuming point-by-point measurement limitation while maintaining high precision thickness measurement through automated spectral analysis
4Measurement precision
If ultrahigh frequency ultrasound imaging is used to map corneal epithelium and stromal thickness, then comprehensive mapping is achieved, but the eye must be immersed in a fluid bath causing inconvenience and discomfort
Solution Approach 1:
The patent replaces the mechanical ultrasound imaging system with an optical Fourier-domain OCT system. This substitution eliminates the need for fluid bath immersion while maintaining comprehensive corneal mapping capability, directly resolving the contradiction between measurement precision and patient convenience
Data Source
AI summary
This invention discloses methods and systems for measuring corneal epithelial thickness and power, stromal thickness, subepitheila corneal power and topography. The systems and methods disclosed herein are non-invasive, non-contact and automated imaging methods which preferably makes use of Fourier-domain optical tomography. Also disclosed herein are scanning patterns and image analysis methods for utilizing and analyzing Fourier-domain optical coherence tomography images to obtain information about conical epithelial and stromal properties as well as parameters useful for evaluating the properties. The methods and systems described herein are useful as eye disease diagnostic tools and eye surgery planning tools.