Retinal vessel course and retinal nerve fiber bundle trajectories in the human eye

AbstractPurpose To determine the relationship between the retinal vessel course and the retinal nerve fiber bundle (RNFB) trajectories in the human retina.Methods High‐quality fundus photographs were used, comprising 28 eyes of 28 subjects (Exp Eye Res 2012). Mean (range) refraction was ‐0.4 (‐8.75 to +6.25) D. In total 625 RNFB trajectories were traced. For all individual trajectories, the departure from the previously published RNFB trajectory model (Vision Res 2009) was calculated. Subsequently, we calculated, per subject, a 'mean departure' for the superior‐temporal and inferior‐temporal regions. To quantify the retinal vessel course, we measured the angles between a line connecting the centers of the fovea and the ONH and a line connecting the center of the ONH and the crossing of the superior or inferior temporal artery or vene with a circle around the ONH; circle radius was half the fovea‐ONH distance. This yielded four angles: AAS, AVS, AAI, and AVI. Multiple linear regression analysis was performed for the superior‐temporal and inferior‐temporal regions separately, with mean departure as dependent variable and refraction, ONH inclination, and the vessel angles as independent variables.Results In the superior‐temporal region, refraction (P=0.017), ONH inclination (P=0.021), and AAS (P<0.001) were significantly associated with mean departure. The explained variance was 0.54. In the inferior‐temporal region, AAI (P=0.037) and AVI (P=0.021) were significantly associated with mean departure. The explained variance was 0.30.Conclusion The wiring of the human retina displays a considerable variability. The angles at which the vessels leave the ONH explain an important part of this variability.