Electroretinography in the western gray kangaroo (Macropus fuliginosus)

Abstract

To perform electroretinography on normal anesthetized western gray kangaroos (Macropus fuliginosus). Animals studied Six captive western gray kangaroos. The kangaroos were anesthetized using a combination of ketamine and medetomidine via a remote drug delivery system, then were maintained on isoflurane after endotracheal intubation and reversal of the medetomidine with atipamazole. After a minimum of 20 min of dark adaptation, electroretinograms were obtained using a handheld electroretinography (ERG) machine using a single flash protocol at three light intensities: 10 mcd.s/m(2), 3000 mcd.s/m(2), 10 000 mcd.s/m(2). At 10 mcd.s/m(2) the mean b-wave amplitude and implicit time was 102.0 μV (SD ± 41.3 and 95% CI 68.9-135.1) and 78.4 ms (SD ± 8.3 and 95% CI 71.8-85.0). At 3000 mcd.s/m(2) the mean a-wave amplitude and implicit time was 69.9 μV (SD ± 20.5 and 95% CI 53.5-86.3) and 17.6 ms (SD ± 1.5 and 95% CI 16.4-18.8) and the mean b-wave amplitude and implicit time was 175.4 μV (SD ± 35.9 and 95% CI 146.7-204.1) and 74.1 ms (SD ± 3.5 and 95% CI 71.2-76.9). At 10 000 mcd.s/m(2) the mean a-wave amplitude and implicit time was 89.1 μV (SD ± 27.1 and 95% CI 67.5-110.8) and 16.8 ms (SD ± 1.0 and 95% CI 16.0-17.0) and the mean b-wave amplitude and implicit time was 203.7 μV (SD ± 41.4 and 95% CI 170.6-236.8) and 75.4 ms (SD ± 3.3 and 95% CI 72.8-78.1). Electroretinography outside of the typical clinical setting is feasible using a portable ERG system and allows for quick analysis of retinal function in exotic species.