The determination of dark adaptation time using electroretinography in conscious miniature Schnauzer dogs.
The optimal dark adaptation time of electroretinograms (ERG's) performed on conscious dogs were determined using a commercially available ERG unit with a contact lens electrode and a built-in light source (LED-electrode). The ERG recordings were performed on nine healthy Miniature Schnauzer dogs. The bilateral ERG's at seven different dark adaptation times at an intensity of 2.5 cd.s/m(2) was performed. Signal averaging (4 flashes of light stimuli) was adopted to reduce electrophysiologic noise. As the dark adaptation time increased, a significant increase in the mean a-wave amplitudes was observed in comparison to base-line levels up to 10 min (p < 0.05). Thereafter, no significant differences in amplitude occurred over the dark adaptation time. Moreover, at this time the mean amplitude was 60.30 +/- 18.47 microV. However, no significant changes were observed for the implicit times of the a-wave. The implicit times and amplitude of the b-wave increased significantly up to 20 min of dark adaptation (p < 0.05). Beyond this time, the mean b-wave amplitudes was 132.92 +/- 17.79 microV. The results of the present study demonstrate that, the optimal dark adaptation time when performing ERG's, should be at least 20 min in conscious Miniature Schnauzer dogs.
Yu
Hyung-Ah
HA
Department of Veterinary Surgery and Ophthalmology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul 151-742, Korea.
Jeong
Man-Bok
MB
Park
Shin-Ae
SA
Kim
Won-Tae
WT
Kim
Se-Eun
SE
Chae
Je-Min
JM
Yi
Na-Young
NY
Seo
Kang-Moon
KM
D000818:Animals; D003623:Dark Adaptation / Q000502:physiology*; D004285:Dogs / Q000502:physiology*; D004596:Electroretinography / Q000662:veterinary*; D008297:Male; D012160:Retina / Q000502:physiology*; D013997:Time Factors