Abstract
Purpose :
OCT allows the detection of temporal retinal nerve fiber (RNF) trajectories noninvasively. Chauhan et al. reported that the temporal raphe defined by the intersection of superior and inferior RNF trajectories has individual variability and is often not horizontal. Such RNF trajectories are not readily visible clinically without complex OCT methods. Here we used the vessel images obtained by RS-3000 Advance OCT (NIDEK, Gamagori, Japan) and also obtained with fundus photographs (FP) to detect detailed capillary vessels and investigated the correlation between the raphe defined by retinal vessels and the temporal raphe obtained by Atlantis® (SS-OCT).
Methods :
Subjects were 22 eyes of 22 normal volunteers (spherical equivalent, -3.3 ±2.7D, average age, 35.5 ± 9.4 years). Three-dimensional images were taken using SS-OCT, with en-face images that had clear RNF trajectories analyzed by EnView®. We superimposed these images on FP by matching the vessels and measured the fovea-raphe angle (defined as the angle between horizontal and the line connecting the fovea to the raphe). Using RS-3000 Advance, for 11 participants, we also took 3 mm × 3 mm images with Macular map, OCT-Angiography, and chose the en-face image with the clearest vessels. These were also superimposed on the FP using retinal vessel alignment. For all 22 subjects, we counted the points where the fovea-raphe line crossed the blood vessels on the FP. For the 11 vessel images, we applied the same method.
Results :
The fovea-raphe angle averaged 2.6° ± 3.3° (-2.46° to 9.71°). For the FPs, the number of the points where the blood vessels crossed the fovea-raphe line averaged 4 points superiorly and 7 points inferiorly. For the 11 OCT vessel images, the superior blood vessels crossed the fovea-raphe line on average at 6 points and inferiorly at 10 points. There was a significant negative correlation between the fovea-raphe angle and the number of the points where the fovea-raphe line crossed the inferior vessels (R2=0.42 by OCT image, R2=0.27 by FP, p<0.05).
Conclusions :
As the fovea-raphe angle became smaller, so the number of the points where the inferior vessels crossed the fovea-raphe line increased. In the temporal retina, the blood vessels were not correlated with RNF trajectories, and RNF trajectories cannot be surmised based on the retinal vessel trajectories.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.