The analysis of electroretinography of diabetes mellitus

In order to get deeper understanding of Diabetic Retinopathy(DR), we analyzed and evauated the results of the amplitude and latency of F-ERG a-wave, b-wave and the total amplitudes of oscillatory potentials(OPs).

F-ERG of 105 eyes from 55 cases of DM were diagnosed by the medical department from July 1997 to July 1998. The 105 eyes were examined by ophthalmoscope and fluorescing in angiography and divided into there groups: 22 eyes with DM without DR(NDR), 56 eyes with background DR(BDR) and 27 eyes with proliferate DR(PDR). In addition, 30 eyes were regard as normal control group(NCG). We used VATA-2000 type vision electrophysiological instrument and inter-national standard for clinical ERG to do measure meat and recording automatically by computer.

1. The proportion of eyes number of invisible wave of a-wave, b-wave of F-ERG and Ops increased with the development of DR. 2. There were significant differences(P < 0.01) in the latency of a-wave between NCG and BDR and statistical significance(P < 0.05) between BDR and NDR. There were significant differences(P < 0.01) in the amplitude of b-wave among NCG and BDR, NCG and PDR, NDR and BDR, NDR and PDR. 3. The total amplitudes of OPs lowered with progressions of DR. There were significant differences(P < 0.01) in tota amplitudes of OPs between NCG and NDR, NCG and BDR, NDR and BDR, statistical significance(P < 0.05) between NDR and PDR. 4. There was no correlation between each index and the duration of the disease (P < 0.05).

The amplitude of a-wave, b-wave, and total amplitudes are the targets for early diagnosis of DR. The combined analyses of the three indexes of ERG can determine the severity, curative effect, and prognosis of the disease.