The Effects of Different Anesthetic Agents on Short Electroretinography Protocol in Dogs

The purpose of this article was to investigate the effects of sedatives and general anesthetics, such as tiletamine-zolazepam, medetomidine, and isoflurane on the short ERG protocol. Six healthy mongrel dogs were assessed by a convenient short ERG protocol with the owners' consent. The amplitudes of a-wave and b-wave, as well as the implicit time of ERG under different anesthesia statuses, were recorded and analyzed. The amplitudes of ERG waves were not significantly different between tiletamine-zolazepam and medetomidine groups, except in b-wave after 5 min dark adaptation (140 ± 42 μV in tiletamine-zolazepam and 101 ± 32 μV in medetomidine, p<0.01). The amplitude of ERG recorded in isoflurane (5 ± 3 μV of a-wave and 12 ± 6 μV of b-wave under light adaptation; 41 ± 19 μV of b-wave after 1 min dark adaptation; 28 ± 15 μV of a-wave and 58 ± 32 μV of b-wave after 5 min dark adaptation) were significantly different from tiletamine-zolazepam (8 ± 2 μV of a-wave and 24 ± 9 μV of b-wave under light adaptation; 117 ± 44 μV of b-wave after 1 min dark adaptation; 59 ± 18 μV of a-wave and 140 ± 42 μV of b-wave after 5 min dark adaptation), except in a-wave after 1 min dark adaptation (39 ± 13 μV in tiletamine-zolazepam and 34 ± 17 μV in isoflurane). Comment-General anesthesia had significantly lower amplitudes in the dark-adapted group compared with the sedation group. Therefore, tiletamine-zolazepam is a desirable choice for the short ERG protocol in dogs.