Abstract
Purpose :
To enable rapid and quantitative AMD screening by automatically identifying scattering disruptions in the deeper retina from alternating-offset multiply scattered light images.
Methods :
Non-mydriatic retinal images of macula- and optic nerve-centered fields were acquired in 20 subjects aged 53.1+/-13.7 yrs. Confocal and multiply scattered light images were taken using the Digital Light Ophthalmoscope (DLO) (Aeon Imaging, LLC), plus SLO and SD-OCT images (Spectralis, Heidelberg Engineering Inc).
The DLO is a line-scan, confocal retinal camera that operates at 860 nm with a 37 deg field of view. Illumination lines are projected onto the retina with a 58 um width, and are synchronized to the readout of a CMOS rolling shutter camera operating at 20 Hz with a 51 um aperture width. Multiply scattered light imaging was performed by applying alternating leading and lagging offsets (+/-25.5 um and +/-51 um) between the centers of the illumination lines and detection aperture. At each field position 200 DLO images were acquired. SD-OCT scans were dense (11 um spacing) with vertical B-scans across either a 10x20 or 15x15 deg field of view.
The OCT images were reviewed to identify areas with drusen. Corresponding DLO image frames were automatically registered, manually reviewed, and averaged. Frames with blinks and image shear were removed. Scattering disruptions seen on the DLO were automatically identified by searching for a positive-negative transition in percent difference along 30-pixel row segments of overlaid image pairs.
Results :
Acquiring SD-OCT dense scans required 15 to 30 minutes per subject. Incomplete scans occurred on 2 subjects with poor fixation. On review of the B-scans, drusen were observed in 17 subjects. Automated DLO analysis was performed on 12 subjects, 6 with subtle or no observable drusen, and 6 with significant drusen.
The identified drusen were clearly observed and automatically detected in the corresponding DLO multiply scattered light raw and averaged images with both +/-25.5 and +/-51 um offsets. The +/-51 um offset images removed more superficial scatter from the images, enabling better visualization of small drusen.
Conclusions :
Multiply scattered light imaging with alternating offsets can be automatically processed to reveal drusen at 20 Hz across a 37 deg field of view.
This is a 2020 ARVO Annual Meeting abstract.