Retinal cone mosaic imaged with transverse scanning optical coherence tomography

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Optical Imaging

Background:

• High-resolution imaging of the human retina is crucial for understanding visual function and disease.
• Existing optical coherence tomography (OCT) systems often require adaptive optics for detailed imaging of retinal structures like the cone mosaic.
• Previous transverse priority scanning OCT systems have shown promise but require further refinement for comprehensive analysis.

Purpose of the Study:

• To enhance a transverse priority scanning OCT system for simultaneous high-resolution imaging in both transverse and axial directions.
• To enable precise on-line focusing using an integrated scanning laser ophthalmoscope (SLO) channel.
• To achieve imaging of the human retinal cone mosaic off the foveal center without the need for adaptive optics.

Main Methods:

• Improved a recently reported retinal OCT system utilizing transverse priority scanning.
• Integrated an additional SLO channel for precise on-line focusing.
• Demonstrated simultaneous cone mosaic imaging in both OCT and SLO channels.

Main Results:

• Achieved high resolution in both transverse and axial directions.
• Successfully imaged the human retinal cone mosaic off the foveal center without adaptive optics.
• Presented simultaneous OCT and SLO imaging of the cone mosaic.
• Observed the cone mosaic in two adjacent layers on OCT B-scan images.
• Acquired the first C-scan OCT images of the cone mosaic.
• Found that light backscattered from below the photoreceptor layer is largely not guided back toward the pupil by the photoreceptors.

Conclusions:

• The enhanced retinal OCT system provides high-resolution, simultaneous imaging of the cone mosaic.
• This advancement allows for in-vivo visualization of the cone mosaic off the foveal center without adaptive optics.
• The findings offer new insights into light propagation within the retina and photoreceptor function.