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Shu Kachi, Shunsuke Yasuda, Hiroaki Ushida, Ruka Uetani, Mineo Kondo, Hiroko Terasaki; Changes In Implicit Times of 30 Hz Flicker Electroretinograms After Photocoagulation In Eyes With Central Retinal Vein Occlusion. Invest. Ophthalmol. Vis. Sci. 2012;53(14):946.
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© ARVO (1962-2015); The Authors (2016-present)
Neovascular glaucoma (NVG) is a vision-threatening complication of central retinal vein occlusion (CRVO). The ischemia caused by CRVO leads to an increase of vascular endothelial growth factor (VEGF) resulting in neovascularization. Photocoagulation (PC) is performed to prevent the NVG by reducing the ischemia. The implicit times of 30 Hz flicker electroretinograms (ERGs) have been shown to be significantly correlated with the ocular VEGF level. The aim of this study was to determine whether there is any change in the implicit times of the 30 Hz flicker ERGs after PC in eyes with a CRVO.
The medical records of 29 consecutive patients with macular edema secondary to CRVO and had received an intravitreal injection of bevacizumab at the Nagoya University Hospital from December of 2008 to December of 2010 were reviewed. The 30 Hz flicker ERGs were recorded and the aqueous humor was collected just before the injection of bevacizumab. The VEGF concentration in the aqueous humor was measured by ELISA, and the correlations between the difference in implicit time of the affected eye and the fellow eye and the VEGF concentration was calculated. The 30 Hz flicker ERGs were recorded in 9 of 29 patients after PC. For these patients, the implicit times before and after the PC were compared.No patient developed neovascularization in the iris or angle.
The mean VEGF concentration of the affected eyes was 620 pg/ml, and the implicit time of affected eye was 3.40 msec longer than that of the fellow eye in 30 CRVO patients (P <0.0001; Wilcoxon signed rank test). The VEGF concentration was significantly correlated with difference of the implicit times (p = 0.02; ρ = 0.44; Spearman Rank Correlation coefficient). The mean VEGF concentration of the affected eyes was 667 pg/ml in 9 patients that the ERGs were recorded after PC, and the difference of the implicit times between the affected and fellow eye changed from 4.68 to 1.48 after PC (P = 0.02; Wilcoxon signed rank test).
The implicit time of 30 Hz ERG was longer in affected eyes compared with the fellow eyes in CRVO patients, however the difference decreased by PC treatment. The efficacy of PC for CRVO patients might be evaluated by determining the implicit times of the 30 Hz ERG.
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