Inter-session repeatability of electroretinography and visual evoked potentials of the Celeris system

The Celeris system (Diagnosys LLC) offers a streamlined alternative to the gold-standard Espion system for high-throughput electroretinography (ERG) and visual evoked potentials (VEP) in preclinical studies. This study evaluated its inter-session repeatability of ERG and VEP measurements in healthy rodent retinae.

Twenty-five wild type Brown Norway rats underwent ERG and VEP testing across two sessions. Dark-adapted ERG a- and b-waves (flash stimulus of 10 cd s/m²), and the photopic negative response (PhNR) (flash stimulus of 3 cd s/m²) were recorded. VEPs (flash stimulus of 3 cd s/m²) were recorded from implanted screw electrodes in the skull. Pearson's correlation coefficient (ρ), Bland-Altman with 95% limits of agreement (LOA) and a novel cumulative distribution plot were used to assess inter-session agreement.

Intersession dark-adapted a-wave showed a correlation of ρ = 0.73, (P < 0.0001), LOA: -106.4 to 113.9 µV, and 90% of measurements fell within - 24.8 to 58.0% variation (90% range). Intersession dark-adapted b-wave amplitudes showed ρ = 0.65, (P < 0.001), LOA: - 402.5 to 437.4 µV, and 90% range: - 33.7 to 72.6%. Inter-session PhNR-B (base-to-trough) and PhNR-P (peak-to-trough) amplitudes showed ρ = 0.66 and 0.72 respectively; LOA: - 26.7 to 31.1 µV and - 98.9 to 100.1 µV respectively; 90% ranges: - 58.2 to 59.3%, and - 45.6 to 60.9%, respectively. Inter-session VEP P2 amplitude showed ρ = 0.67, (P < 0.001), LOA: 78.5-72.8 µV, and 90% range: - 52.2 to 67.9%. Inter-session VEP implicit time showed ρ = 0.48, (P < 0.05), LOA: - 39.4 to 38.3 ms, and 90% range: - 39.2% to 16.7%.

The study reported the inter-session repeatability of the ERG and VEP tests using the Celeris system. These data facilitate the study design and sample size calculation for future preclinical studies using the Celeris, and serve as a reference for future comparison with other systems, protocols and species.