Dual trunk central retinal vein incidence in clinical practice.

In a study carried out on 123 eyes to establish the incidence of dual trunk central retinal vein, 25 (20.5%) eyes showed such an arrangement. The presence of such anomalies has also been substantiated through the results of anatomical, histological, and microdissectional studies by various workers. The zone of the retina drained by the individual central retinal vein varied from 30% to 70%. The arrangement was not only superior or inferior, but could also be medial, lateral, diagonal, or crossed. The clinical relevance of this finding is a newly described fundus condition called hemi-central retinal vein occlusion.