Abstract
Purpose :
To compare the reliability of visualizing scattering defects as seen on the Digital Light Ophthalmoscope (DLO) vs on OCT images.
Methods :
Twenty subjects (53.1 +/- 13.7 yrs, range 27-73 yrs) were imaged using both the DLO (Aeon Imaging, Bloomington, IN, USA) and OCT (Spectralis, Heidelberg, Germany). The DLO uses 860 nm light in a line scan to collect retinal images over a 37 deg field of view at 20 Hz. Multiply scattered light imaging suppresses superficial light scatter and reveals scattering disruptions in the deeper retina. Thus, we used a mode that offsets the scanning beam from the camera aperture by 51µm, leading and lagging, for collecting multiply-scattered light in equal but opposite directions. These pairs of images were automatically aligned and then processed to obtain images of differences to emphasize scattering defects. Three graders independently marked the center of each region with scattering defects. The DLO has a digital resolution of 10.8 µm/pixel.
One reviewer marked the center of the defects found in vertical OCT B-scans, which were taken with 870nm light. OCT scans were spaced 11 µm apart, and only the center of drusen or other sufficiently large scattering defects in the outer retina was marked. The en face scan provided by the Spectralis was aligned to the DLO image. The OCT scan boundary rectangle provided on the en face scan was used to compare the defect coordinates between the OCT scans and DLO images.
Results :
Ten subjects were fully analyzed with both OCT and DLO, and 26 light-scattering defects were found on both instruments, with agreement in locations of at least two of the DLO image graders. Regions where OCTs were taken comprised of a smaller area than the total area imaged with the DLO, thus, a larger number of defects were found on the DLO, because of the larger field of view.
Conclusions :
There was good agreement between the marked defects on the DLO and OCT B-scan images. The DLO images covered a larger region of the retina than the dense OCT scans, and numerous small defects were immediately and simultaneously observable from a single composite image, making it a promising device for detecting early signs of AMD.
This is a 2021 ARVO Annual Meeting abstract.