Multi-MHz retinal OCT.

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optical Imaging

Background:

• Optical Coherence Tomography (OCT) is crucial for retinal imaging.
• Previous OCT systems faced limitations in speed and data acquisition for in-vivo human retinal studies.
• Advancements in laser technology and scanning strategies are needed to overcome these limitations.

Purpose of the Study:

• To analyze the benefits and challenges of in vivo OCT imaging of the human retina at axial scan rates exceeding 1 MHz.
• To investigate novel scanning strategies enabled by MHz OCT line rates.
• To present a data processing approach for multi-volume OCT data.

Main Methods:

• Utilized a 1050 nm Fourier-domain mode-locked (FDML) laser with a chirped fiber Bragg grating for long coherence lengths and wide tuning range.
• Implemented advanced data acquisition and transfer for handling very large datasets.
• Investigated three imaging modes: multi-dataset averaging at 1.68 MHz, ultra-dense transverse sampling at 3.35 MHz, and dual-beam imaging at 6.7 MHz.

Main Results:

• Achieved high-quality, non-mydriatic retinal imaging over an ultra-wide field.
• Demonstrated successful in-vivo OCT of the human ocular fundus at axial scan rates up to 6.7 MHz.
• Enabled high-quality averaging of numerous frames and aligned datasets through efficient data handling.

Conclusions:

• High-speed OCT, particularly using MHz axial scan rates, offers significant advantages for human retinal imaging.
• The developed scanning strategies and data processing approach facilitate high-quality, ultra-wide field retinal imaging.
• This technology holds promise for improved diagnosis and monitoring of retinal diseases.