Abstract
Purpose :
To develop a nonmydriatic, easy to use screening tool for age-related macular degeneration (AMD), we evaluated retinal images acquired with confocal and multiply scattered light (MSL) using the Digital Light Ophthalmoscope (DLO).
Methods :
Sixteen subjects had one eye tested known not to have exudative AMD. Subjects ranged in age from 26-68 yr, (mean 47 yr., st. dev. 14 yr.). Nonmydriatic confocal and MSL images were acquired with the DLO, which has 860nm illumination over a 37 deg field. MSL imaging was performed by shifting the detection aperture electronically with respect to the illumination. Pairs of leading and lagging offsets were used to observe the shadows of scattering defects cast in opposite directions. Subjects were also imaged with a scanning laser ophthalmoscope (SLO) and optical coherence tomography (OCT) system (Spectralis, Heidelberg, Germany). Dense (11μm) B-scans were acquired over 20 x 15 deg. An ophthalmologist graded the OCT B-scans for drusen and other lesions, and then reviewed the DLO images for congruency. Calibrated lesion sizes were measured using Photoshop (Adobe, San Jose, CA).
Results :
Five of the subjects had drusen and other lesions identified with OCT. Three of these subjects had 10 total lesions seen on OCT but not on the SLO, and 8 of these 10 lesions were identifiable in the DLO MSL images. The two lesions not identifiable within the MSL images were very small, having diameters of approximately 23.5 and 25 microns, and were associated with defects within the photoreceptor layers only. All drusen identified with the OCT B-scans were identifiable in the DLO MSL images, even when the lesions had a thickness of only 12 microns. A large number of lesions were visible in 2 subjects on SLO and OCT, which were identifiable on the DLO MSL images. The drusen in the DLO MSL images were conspicuous by their cast shadows, which were in opposite directions for leading and lagging aperture offsets. Regions of confluent drusen had shadows cast at the edges rather than for individual drusen.
Conclusions :
Many lesions identified from OCT dense B-scans, including all drusen, were identified in DLO MSL images. The DLO identified the lesions over a large 37 degree field and could be used as a screening device for identifying the early markers for AMD as it readily identified pathology at a comfortable light level without mydriasis.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.