Multifocal electroretinography in isolated arterially perfused bovine eye

Aim: To develop an isolated arterially perfused bovine eye as an in vitro model for studying retinal electrophysiology using multifocal electroretinography (mfERG). Methods: Fresh bovine eyes were cannulated through the ophthalmic artery and perfused with oxygenated Krebs' solution at 37°C within 15 min postmortem. Multifocal ERG was recorded using the VERIS 1.0 (Visual Evoked Response Imaging System). Results: The mfERG waveform of in vitro bovine eyes had a typical trough (negative wave, N1) and peak (positive wave, P1) similar to those of human mfERG. The implicit times (peak latencies) for N1 and P1 were 20 and 42 ms respectively, and the average response amplitude (N1P1) was 55 nV. The implicit times of N1 and P1 were maintained for more than 4 h. The mfERG responses were affected proportionately by the stimulus intensity. Without a neutral density filter, the mean response amplitude was about 55 nV, which was diminished to 26,18 and 10 nV under neutral density filters of 0.4, 1.0 and 1.4, respectively. Partial occlusion of the pupil completely abolished mfERG responses from the corresponding part of the retina. Conclusions: Isolated arterially perfused bovine eye may be used as an experimental model to study retinal electrophysiology using mfERG. The in vitro eye may offer a convenient and easily obtainable alternative to live animals, particularly for drug screening and invasive studies.