Background/aims Branch retinal vein occlusion (BRVO) leads to retinal ischaemia, which then induces upregulation of various inflammatory factors, including vascular endothelial growth factor (VEGF). The aim of this study was to determine whether there was a correlation between inflammatory factors and components of the electroretinogram (ERG) in patients with BRVO.

Methods In 19 BRVO patients with macular oedema, vitreous fluid samples were obtained during vitreoretinal surgery to measure the levels of four inflammatory factors (VEGF, soluble intercellular adhesion molecule-1 (sICAM-1), interleukin (IL)-6 and monocyte chemotactic protein (MCP)-1). The amplitude and implicit time of the a-wave cone, b-wave cone and 30 Hz flicker were calculated automatically from the ERG. Correlations between the different components of the ERG and the four inflammatory factors were investigated.

Results Vitreous fluid levels of two factors (IL-6 and MCP-1) were significantly correlated with the implicit time of the cone b-wave (p=0.035 and p=0.016, respectively). Vitreous fluid levels of all four factors (VEGF, sICAM-1, IL-6, and MCP-1) were significantly correlated with the implicit time of 30 Hz flicker (p=0.047, p=0.031, p=0.002 and p=0.009, respectively). Vitreous fluid levels of VEGF, sICAM-1, IL-6, and MCP-1 were significantly higher in patients with an implicit time ≥36 ms than with an implicit time <36 ms (p=0.042, p=0.048, p=0.003 and p=0.024, respectively).

Conclusions These findings suggest that the implicit times of the cone b-wave and 30 Hz flicker can be used to detect BRVO patients with macular oedema who have a high risk of ischaemia.