Optical coherence tomography with a 2.8-mm beam diameter and sensorless defocus and astigmatism correction

Area of Science:

• Ophthalmology
• Biomedical Optics
• Medical Imaging

Background:

• Optical coherence tomography (OCT) is crucial for non-invasive retinal imaging.
• Image quality in OCT is often limited by optical aberrations.
• Efficient aberration correction methods are needed to improve diagnostic capabilities.

Purpose of the Study:

• To develop and evaluate an OCT system with enhanced aberration correction capabilities.
• To improve the contrast and dynamic range of OCT images.
• To miniaturize and integrate aberration correction components into OCT systems.

Main Methods:

• Utilized a 2.8-mm beam diameter OCT system.
• Implemented sensorless defocus correction using a Badal optometer.
• Employed a liquid crystal device for astigmatism correction.
• Applied an image-based optimization algorithm using OCT B-scans for aberration correction.

Main Results:

• Achieved defocus correction from -4.3 D to +4.3 D and astigmatism correction from -2.5 D to +2.5 D.
• Demonstrated a contrast gain of 6.9 times after aberration correction.
• Showcased a 3.7-dB gain in dynamic range compared to a 1.3-mm beam diameter OCT system.
• Reduced speckle size by 2.5 times compared to a standard OCT system.

Conclusions:

• The developed OCT system effectively corrects optical aberrations, significantly improving image quality.
• The compact and low-voltage liquid crystal device offers a practical solution for astigmatism correction in OCT.
• This technology has the potential to enhance the diagnostic accuracy and clinical utility of OCT imaging.