OCT-Based Working Distance Correction for Eye Topography
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Solution Overview
Problem
Current methods for acquiring accurate and repeatable images of the eye, such as corneal topography, are prone to measurement errors due to variations in the working distance between the subject eye and the imaging device, with existing approaches like reference imaging, beam triangulation, and maximum signal methods being subjective, user-dependent, and unreliable.
Innovation Solution
Integration of Optical Coherence Tomography (OCT) with ocular systems to determine and maintain a precise working distance, combining OCT information with topography data for enhanced image reproducibility and accuracy, and automating the positioning process to reduce operator subjectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the working distance between the subject eye and the imaging device is not fixed, then the imaging process is more flexible and easier to operate, but measurement accuracy and image reproducibility deteriorate
Solution Approach 1:
The system uses an OCT subsystem to continuously measure the actual working distance between the imaging device and the subject eye, providing real-time feedback. This feedback is then used to calculate and apply the appropriate magnification correction factor, ensuring measurement accuracy is maintained despite variations in working distance.
Solution Approach 2:
The system dynamically changes the magnification parameter based on the measured working distance. By adjusting the magnification factor according to the actual distance obtained from OCT measurements, the system compensates for distance variations and maintains accurate measurements.
2Measurement precision
If additional imaging devices are placed off the optical axis to determine fixed distance, then working distance can be measured, but device complexity increases and the method becomes subjective and difficult to perform
Solution Approach 1:
The system combines the OCT measurement capability with the existing topography imaging system. The OCT subsystem shares the same optical path and imaging plane as the topography camera, eliminating the need for separate additional imaging devices and reducing overall system complexity.
Solution Approach 2:
The imaging system is designed to perform multiple functions: it can capture both topography images and OCT depth information using the same optical path. This multi-functionality eliminates the need for dedicated reference imaging devices placed off the optical axis.
3Measurement precision
If multiple light beams are used for beam triangulation to set distance, then working distance can be determined, but the method is subject dependent and presents difficulties for the operator to locate the beam intersection
Solution Approach 1:
The system automatically performs working distance measurement and magnification correction without requiring operator intervention to locate beam intersections or adjust settings. The OCT subsystem autonomously measures the distance and the system automatically applies the appropriate magnification factor.
Solution Approach 2:
The system replaces the mechanical beam triangulation method with an optical measurement approach using OCT. Instead of using multiple light beams that require manual alignment, the system uses optical coherence tomography to directly measure the working distance.
4Adaptability or versatility
If the eye is moved away from the fixed distance at the focal point, then there is more flexibility in positioning, but the magnification of the virtual image changes and results in error of the topographic images
Solution Approach 1:
The system continuously monitors the working distance using OCT and provides feedback to dynamically adjust the magnification factor. This feedback mechanism ensures that even when the eye position varies, the correct magnification is applied to maintain topographic image accuracy.
Solution Approach 2:
The magnification factor is made dynamic rather than fixed. The system continuously updates the magnification value based on the current working distance measured by OCT, allowing the system to adapt to position changes while maintaining measurement accuracy.
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
The combination of OCT with ocular systems provides precise and reproducible imaging by accurately determining the working distance, minimizing measurement errors and enhancing the reliability of eye imaging, allowing for precise positioning and improved diagnostic capabilities.
Implementation Method 1
an optical coherence tomography (OCT) system
Implementation Method 2
a coupler coupled to the optical coherence tomography system and the one or more ocular systems, wherein the coupler provides a combination beam
Data Source
AI summary
An imaging method according to some embodiments of the present invention includes obtaining working distance information from an optical coherence tomography system, the working distance being the working distance to the sample; obtaining information from one or more ocular systems; combining the information from said optical coherence tomography information and said ocular system; and displaying said combined information.