| Purpose: To investigate the characteristics of flash electroretinogram(f-ERG) in type2diabetes individuals with nonproliferative diabeticretinopathy (NPDR), and its value for clinical application.Methods: A total of39outpatients with type2diabetes mellitus fromSeptember2010to March2011were recruited for this study. Based oncomplete ophthalmic examinations, patients were divided into two groups:no diabetic retinopathy (NDR) group (n=23,46eyes) and non-proliferativediabetic retinopathy (NPDR) group (n=16,32eyes). Meanwhile,age-matched healthy volunteers were enrolled as normal control group (n=15,30eyes). Full-field flash ERG tests were conducted on all participantsfollowing the standard of International Society for ClinicalElectrophysiology of Vision(ISCEV)., the implicit time and amplitude of a-and b-wave plus the b/a amplitude ratio of dark adaption0.01, dark-adaptedand light-adapted3.0ERG were recorded after filtering the oscillatorypotentials’(OPs) effect on a-and b-waveresponse. The spectral range of rod- and cone-derived OPs were determined, followed by extracting the OPsusing Fast Fourier transform, and measured the peak frequency, amplitude,implicit time and amplitude power. One-way analysis of variancesupplemented with Bonferroni post hoc correction was performed forstatistical analysis. P <0.05was regarded statistically significant.Results: NPDR group had longer implicit time and lower amplitude ofb-wave than control group in dark-adapted0.01ERG（p＜0.05）. Indark-adapted3.0ERG, amplitude of a-and b-wave in NPDR group reducedcompared with NDR group. In light-adapted3.0ERG,implicit time ofa-wave in both NDR and NPDR group prolonged compared with controlgroup（P＜0.01and P＜0.001,respectively）. Meanwhile, NDR and NPDRgroup showed longer implicit time of OPs in the cone system than controlgroup（P＜0.05）,whereas no significant difference was found in any of OPsparameters in the rod system among those groups. The peak frequency ofcone-derived OPs response was increased in NPDR group than in NDRgroup and control group, the differences were statistically significant（P＜0.05and P＜0.01,reapectively）Conclusions:1. Implicit time and amplitude of b-wave in dark-adapted0.01ERG,implicit time of a-wave in light-adapted3.0ERG, and implicit time ofcone-derived OPs could be used as stable and objective indicators for retinalfunction assessment at an early stage of DM. 2. As NPDR aggravated, significant retinal dysfunction wasdemonstrated in both cone and rod system, with the rod system beingpredominantly affected.3. The retinal dysfunction might origin from photoreceptors in diabeticpatients with NPDR, significant retinal dysfunction was demonstrated inboth photoreceptors and inner retinal layers.4. Coefficient of variation of implicit time was smaller and that ofpower of amplitude was larger among parameters in ERG test.5. Neuronal abnormalities may emerge earlier than clinically detectablevascular damage in diabetic retinopathy. |
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