Abstract
Purpose:
A hemi-central retinal vein occlusion (hCRVO) is a disease related to a CRVO but not to a branch retinal vein occlusion (BRVO). A CRVO leads to retinal ischemia which induces an up-regulation of vascular endothelial growth factor (VEGF). The up-regulation of VEGF can lead to iris neovascularization. Similar changes occur in eyes with hCRVO but not in eyes with BRVO. We have reported that there is correlation between aqueous VEGF level and the implicit time of 30 Hz flicker ERG in eyes with a CRVO. The purpose of this study was to determine whether there are differences in the level of VEGF in the aqueous and in the amplitudes and implicit times of different components of the electroretinograms (ERGs) in eyes with a hCRVO or with a BRVO.
Methods:
The medical records of patients who had macular edema secondary to a hCRVO (7 eyes) or a BRVO (13 eyes) and had received an intravitreal injection of bevacizumab (IVB) at the Nagoya University Hospital from July 2009 to August 2012 were reviewed. ERGs were recorded according to the protocol of the ISCEV, and they were recorded before the IVB. Aqueous humor was collected before the IVB and the VEGF concentration was measured by ELISA.
Results:
The mean VEGF concentration in the aqueous humor in the hCRVO eyes was significantly higher than that in the BRVO eyes (622 vs 149 pg/mL, P<0.05). The implicit time of the 30 Hz flicker ERGs was significantly longer in eyes with a hCRVO than eyes with a BRVO (34 vs. 30 msec, P<0.05), and the amplitude of cone b-wave were significantly smaller in the hCRVO than the BRVO eyes (47 vs. 68 uV, P<0.05). There was no significant differences in the other ERG components.
Conclusions:
The significant differences in the aqueous VEGF level and in the implicit time of the 30 Hz flicker ERG between eyes with a hCRVO and BRVO suggest that the ERG findings can be used to estimate the aqueous level of VEGF and determine whether there is a risk of developing iris neovascularization in eyes with hCRVO and BRVO.
Keywords: 509 electroretinography: clinical •
748 vascular endothelial growth factor •
749 vascular occlusion/vascular occlusive disease