BACKGROUND: 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). METHODS: 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. RESULTS: 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 microV 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%. CONCLUSIONS: 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.
BACKGROUND: 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). METHODS: 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. RESULTS: 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 microV 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%. CONCLUSIONS: 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.