The flicker electroretinogram interocular amplitude ratio is a strong prognostic indicator of neovascularization in patients with central retinal vein occlusion

To evaluate the prognostic value of interocular amplitude ratio of flicker electroretinogram (ERG) in determining the development of neovascularization in patients with central retinal vein occlusion (CRVO). We retrospectively reviewed the data obtained from flicker ERG in 51 CRVO patients. Of these, 22 eyes which had enough follow-up to differentiate ischemic CRVO from nonischemic CRVO were included for data analysis. The flicker ERG was recorded at a 30 Hz frequency after dark adaptation, and ten sweeps were averaged. Eleven eyes were ischemic and 11 eyes were nonischemic. Three amplitude parameters had the potential to explain the type of CRVO. They were amplitude of lesion eye (p = 0.0001), interocular difference of amplitude (p < 0.0001), and interocular ratio of amplitude (p < 0.0001). Both an interocular amplitude difference of -23 mu V and interocular amplitude ratio of 60% were very good cutoff points to differentiate ischemic from nonischemic CRVO. Receiver operating characteristic curve analysis revealed that each of the two cutoff values had a sensitivity and specificity of 100%. Interocular comparison of amplitude is a good solution for avoiding the variability of ERG. An interocular amplitude ratio of flicker ERG of 60% is a succinct, useful parameter in clinical practices for differentiating ischemic from nonischemic CRVO.