Anterior Eye OCT Fixation Control for Tilt-Corrected Imaging
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Solution Overview
Problem
Anterior eye segment analysis techniques using optical coherence tomography (OCT) suffer from reduced accuracy due to image tilting and distortion, particularly in wide scan areas, affecting the determination of parameters like the corner angle in glaucoma diagnosis.
Innovation Solution
An ophthalmic apparatus with a fixation target presenting unit, OCT imager, tilt information generator, and controller that adjusts the fixation target based on generated tilt information to correct image tilt and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wide scan area is used in OCT imaging, then coverage of anterior eye segment is improved, but image tilt and distortion increase
Solution Approach 1:
The system performs preliminary tilt detection by analyzing the OCT image to identify feature points (corneal apex, iris surface, lens surface) and calculate tilt angles before the actual measurement. Based on the detected tilt, the fixation target is pre-adjusted to compensate for the tilt, ensuring that subsequent measurements are performed on properly aligned images.
Solution Approach 2:
The system implements a feedback loop where tilt information from the OCT image is continuously monitored, and the fixation target position is automatically adjusted based on the detected tilt angle. This closed-loop control ensures that the eye remains properly aligned during scanning, maintaining measurement accuracy across wide scan areas.
2Measurement precision
If fixation target is adjusted based on tilt information, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system performs self-alignment by automatically detecting tilt from the OCT image itself and adjusting the fixation target without requiring external alignment devices or manual intervention. The OCT image provides the tilt information needed for correction, making the system self-sufficient and reducing overall complexity.
Solution Approach 2:
The OCT imaging system serves multiple functions: it captures the anterior eye segment image for measurement, detects tilt by analyzing feature points in the same image, and provides guidance for fixation target adjustment. This multi-functionality eliminates the need for separate alignment devices, reducing system complexity while improving precision.
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
Enhances the accuracy of OCT anterior eye segment analysis by correcting image tilt, thereby improving the precision of measurements and diagnoses such as corner angle analysis.
Implementation Method 1
an OCT imager configured to apply optical coherence tomography (OCT) scanning to an anterior eye segment of a subject's eye to construct an image
Data Source
AI summary
An ophthalmic apparatus of according to an embodiment example includes a fixation target presenting unit, an OCT imager, a tilt information generator, and a controller. The fixation target presenting unit is configured to present a fixation target to a subject. The OCT imager is configured to apply optical coherence tomography (OCT) scanning to an anterior eye segment of a subject's eye to construct an image. The tilt information generator is configured to generate tilt information that represents a tilt state of the anterior eye segment depicted in the image. The controller is configured to control the fixation target presenting unit based on the tilt information.