Anomalies of the retinal veins and their incidence

Nonaneurysmal anomalies of the retinal veins were studied in 1,400 consecutive locally and systemically healthy individuals whose ages ranged from eight to 66 years. The anomalies included veno-venous crossing, triconfluence, congenital dilatation, prepapillary loop, anomalous macular veins, and retinociliary vein. Excluding the last three, these anomalies are not at all rare. Hypotheses to explain the development of veno-venous crossings and the bifurcation of retinal veins are also presented.