Abstract
Purpose :
Motion correction of retinal OCT imaging is required for accurate assessment of diseases. We have developed Lissajous scan OCT which enables motion correction while preserving global structure. This study aims at comparing the image quality of Lissajous scan OCT with those of the conventional raster scan.
Methods :
The Lissajous and raster scan OCT have been obtained by a custom-made 1.0-µm swept-source OCT device with a scan speed of 100,000 A-line/s. The motion-corrected raster scan OCTA has been obtained with DRI OCT Triton (Topcon Corp., Tokyo, Japan). For Lissajous scan OCT, the eye movements are estimated by co-registering small portions of the Lissajous scan. And motion-free three-dimensional volumes and en face images of OCT and OCT angiography (OCTA) images are created by using the estimated motion amounts.
Fifty-two eyes of 62 patients with retinal abnormalities were scanned over a 3×3 mm2 area. The motion-corrected superficial retinal OCTA images of Lissajous scan and raster scan have been evaluated by an expert grader and scored with six levels (0: low to 5: high). In 21 eyes of 21 subjects, cross-sectional OCT B-scan of Lissajous scan and raster scan have beam compared.
Results :
Figure 1 shows motion-corrected en face superficial OCTA images of a representative case. The mean score of motion-corrected superficial OCTA images were 3.7 for raster and 3.4 for Lissajous. Although the score of raster scan is slightly high, the difference was not statistically significant (p-value=0.067, Wilcoxon's signed-rank test). Figure 2 shows representative OCT B-scans of the raster and Lissajous scan at the almost same location. In 19 out of 21 eyes, both raster and Lissajous scans showed the same score. In 2 out of 21 eyes, Lissajous-scan-based B-scans showed a better score.
Conclusions :
Lissajous scan OCT achieves comparable image quality in en face OCTA and cross-sectional OCT imaging to those of raster scan OCT.
This is a 2021 ARVO Annual Meeting abstract.