Branch retinal vein occlusion: the importance of the topographical distribution of retinal vessels among risk factors.

PurposeTo investigate the role of the topographical distribution of temporal retinal vessels in anatomical predisposition to branch retinal vein occlusion (BRVO).Patients and methodsSixty patients with BRVO and 60 control subjects were included in this retrospective-observational study. The fundus images of the individuals were classified into four topographical vessel positions: P1, the superior and inferior temporal retinal veins were closer to the foveal center; P2, the superior and inferior temporal retinal arteries were closer to the foveal center; and P3 and P4, the superior temporal retinal vein and inferior temporal retinal artery were closer to the foveal center or vice versa. The groups were compared in terms of demographics and topographical vessel positions.ResultsThere were no significant differences between the groups in terms of age and gender (P>0.05). The topographical distribution of temporal retinal vessels among the BRVO and control eyes were significant (P<0.001). P1 was less common in BRVO eyes (5%) when compared with control eyes (33.3%); however, P2 was more common in BRVO eyes (46.7 vs 20%). There were no significant differences in terms of the distribution of P3 and P4 vessel positions in the BRVO and control groups (P>0.05). A logistic regression test revealed that the risk of BRVO increases 15-fold in P2, 6-fold in P3, and 8-fold in P4 when compared with eyes having P1.ConclusionP1 eyes are less likely to be affected by BRVO. Therefore, the topographical distribution of retinal vessels can be assessed as a risk factor for BRVO.