Central Retinal Vessel Trunk Dragging in Highly Myopic Eyes.

Abstract

To assess occurrence and associations of central retinal vessel trunk (CRVT) dragging. Retrospective, population-based cohort study. Using optical coherence tomographic images of the optic disc and macula, taken in the participants of the Beijing Eye Study, we assessed the prevalence of CRVT-dragging, defined as an optic disc tissue prominence at the inferior, superior and nasal, but not the temporal, optic disc border. The study included 3336 individuals (3336 eyes) (mean age:64.2±9.6 years; axial length:23.4±1.2mm (range:20.16-30.88mm). CRVT dragging prevalence increased from 0/3046 (0%) to 9/173 (5.2%;95%CI:2,9), 9/74 (12.2%;95%CI:5,20), 6/25 (24.0%;95%CI:6,42) and to 13/18 (72.2%;95%CI:49,95) in eyes with an axial length of ≤25.0mm, 25.01mm-26.0mm, 26.01mm-27.0mm, 27.01mm-28.0mm, and >28.0mm, respectively. Higher CRVT dragging prevalence was associated (multivariable analysis) with longer optic disc-fovea distance (OR:5.82;95%CI:2.23,15.2;P<0.001) and higher prevalence of parapapillary retinoschisis (OR:8.61;95%CI:2.43,30.5;P<0.001), with adjusting for longer axial length (OR:1.95;95%CI:1.25,3.05;P=0.003) and older age (OR:1.08;95%CI:1.02,1.14;P=0.008). In eyes with an axial length of ≥25.0 mm, CRVT dragging prevalence increased 5.69-fold (95% CI:2.30,14.1) for each mm increase in fovea-disc distance. These relationships were complemented by univariate associations between CRVT dragging prevalence and temporal retinal vessel straightening, smaller angle kappa, higher myopic macular degeneration stage and prevalence, and larger parapapillary beta zone and gamma zone. CRVT-dragging as a common feature in highly myopic eyes may etiologically be explained by the myopic axial elongation-related increase in the fovea-disc distance. Influencing the three-dimensional appearance of the optic nerve head, CRVT dragging may be of importance for the morphological diagnosis of optic neuropathies in highly myopic eyes.