Comparative analysis of visual evoked potentials obtained using Tomey EP-1000 and Diopsys Nova in healthy participants

BACKGROUND: A visual evoked potential test is a common method of electrophysiological examination in ophthalmology. There are no published Russian scientific comparative studies of the results of the visual evoked potential test obtained using different devices. AIM: The work aimed to perform a comparative analysis of visual evoked potentials obtained using Tomey EP-1000 and Diopsys Nova in healthy participants. METHODS: The study included a total of 15 patients (30 eyes). The following parameters of visual evoked potentials were assessed: N75/N80 (Tomey EP-1000), P100, and N135 peak latency and P100 and N135 peak amplitude. RESULTS: The means of the evaluated parameters obtained using Diopsys Nova were higher than those obtained using Tomey EP-1000, except for P100 peak amplitude. A Bland–Altman analysis showed that the mean difference between the P100 peak amplitude values recorded using Diopsys Nova and Tomey EP-1000 was −0.3 μV, and agreement limits of the evaluated parameters varied quite greatly (−5.66 to 4.99 μV). The P100 peak latency varied even greatly and the mean difference between measurements was 3.5 ms, with the quite wide limit of agreement (−4.29 to 11.35 ms). CONCLUSION: The mean latencies of N70 (pattern 32), P100 (patterns 32 and 64), and P135 (pattern 32) peaks obtained using Diopsys Nova were statistically significantly higher than those recorded using Tomey EP-1000. The obtained results demonstrated that the used measurement methods were inconsistent. However, the performed study is greatly limited by the small sample size, which is a key for interpreting the results. Therefore, to demonstrate that the two methods are consistent, the sufficient sample size should be determined.