Changes in Electroretinogram Parameters after Panretinal Photocoagulation in Diabetic Retinopathy

Abstract

Objective: This study was performed to evaluate the effect of panretinal photocoagulation (PRP) on parameters of electroretinograms (ERG). Methods: Retrospective study was performed on 58 eyes of 29 patients with proliferative diabetic retinopathy (PDR) who underwent PRP. ERG was performed in each patient before and after PRP, and each ERG parameters were compared between the preand post-PRP state. Also, the results of ERG performed after PRP were compared between two groups: one group showing obvious new vessels regression and the other group showing poor regression after PRP. Results: Marked reduction in amplitude and delay in implicit time were observed in all patients (P<0.05). The results also showed larger reduction of amplitude and delay in implicit time in b-wave than a-wave (P<0.05). There were no significant differences in ERG parameter changes after PRP between the group showing obvious new vessel regression and the group showing poor new vessel regression after PRP (P>0.05). Conclusion: PRP in diabetic retinopathy patients may affect not only the outer retina but also the cells within the inner nuclear layer, causing changes in ERG parameters. However, ERG was not a good indicator for representing the amount of new vessel regression in PDR.