Significant correlation between electroretinogram parameters and ocular vascular endothelial growth factor concentration in central retinal vein occlusion eyes.

PURPOSE Central retinal vein occlusion (CRVO) leads to retinal ischemia, which then induces an upregulation of vascular endothelial growth factor (VEGF). The aim of this study was to determine whether a significant correlation exists between the ocular VEGF levels and the amplitudes and implicit times of different components of the electroretinogram (ERG) in eyes with a CRVO. METHODS The medical records of the 20 consecutive patients who had macular edema secondary to CRVO and were examined at the Nagoya University Hospital from November 2008 to February 2010 were reviewed. Because all the patients were scheduled to receive an intravitreal injection of bevacizumab (IVB), it was possible to collect samples of the aqueous humor before the IVB. The correlation between the different components of the ERGs and the VEGF concentration in the aqueous was determined. RESULTS The mean VEGF concentration of the aqueous humor was 416 pg/mL with a range of 100-1260 pg/mL. The b/a ratio of the single flash ERGs (P = 0.049; ρ = -0.45), implicit times of the cone a-wave (P = 0.028; ρ = 0.50), cone b-wave (P = 0.0059; ρ = 0.63), and 30 Hz flicker ERGs (P = 0.0058; ρ = 0.63) were significantly correlated with the VEGF concentration in the aqueous. CONCLUSIONS The significant correlations between the different components of the ERGs and the aqueous VEGF concentration indicate that full-field ERGs can be used to detect the CRVO patients at a high risk of developing neovascularization of the iris.