Imaging the anterior eye with dynamic-focus swept-source optical coherence tomography

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optical Imaging

Background:

• Accurate imaging of the anterior segment of the eye is crucial for diagnosing and monitoring various ocular conditions.
• Traditional optical coherence tomography (OCT) systems face limitations in achieving uniform high resolution and signal strength across the entire anterior segment depth.
• Dynamic focusing techniques offer a potential solution to overcome these depth-dependent imaging challenges.

Purpose of the Study:

• To develop and evaluate a custom-built dynamic-focus swept-source optical coherence tomography (SS-OCT) system for high-resolution imaging of the human anterior eye.
• To compare the performance of the developed SS-OCT system against commercial OCT systems for anterior segment visualization.
• To demonstrate the system's capability for in vivo imaging and accurate measurement of ocular parameters.

Main Methods:

• A custom 1310 nm swept-source OCT system was engineered with an electrically tunable lens for dynamic focus control over a 10 mm range.
• Consecutive B-scan images at identical positions but varying focus settings were acquired.
• Image registration, Gaussian window filtering of out-of-focus regions, and fusion of depth-focused images were performed to enhance image quality.
• In vivo imaging of the human anterior segment was conducted, and results were compared with commercial 840 nm and 1310 nm OCT systems and ultrasound biomicroscopy.

Main Results:

• The dynamic-focus SS-OCT system successfully produced high-resolution and high signal-strength images across the entire imaging depth of the anterior segment.
• Superior visualization of the human eye ciliary body was achieved compared to commercial OCT systems.
• Accurate measurement of the sulcus-to-sulcus distance was demonstrated, showing agreement with ultrasound biomicroscopy findings.

Conclusions:

• The developed dynamic-focus SS-OCT system provides enhanced imaging capabilities for the anterior eye, surpassing current commercial systems in specific applications.
• This technology holds promise for improved diagnosis and management of anterior segment pathologies.
• The system's ability to achieve uniform high-resolution imaging and accurate biometric measurements makes it a valuable tool in ophthalmology research and clinical practice.