Effects of Stimulus Intensity for Electroretinogram in Conscious Miniature Schnauzers

Abstract

The aim of this study was to determine the most effective light intensity for flash electroretinogram (ERG) examination in conscious dogs using ERG equipment with a contact lens electrode with a built-in LED light source. ERG was performed on the bilateral eyes of ten clinically healthy Miniature Schnauzers at 6 different intensities (0.025, 0.079, 0.25, 0.79, 2.5 and 7.9 cd⋅s/m2) after dark adaptation for 20 min. With the increase in stimulus intensity, the most significant increase in a and b-wave amplitudes were observed at 2.5 cd⋅s/m2 (p<0.05). As the intensity of light was increased, the implicit times of both waves significantly decreased. Therefore, the most effective intensity of stimulus was 2.5 cd⋅s/m2 in the conscious Miniature Schnauzers. This suggests that this procedure would be applicable for evaluation of retinal function in conscious dogs, especially in high-risk patients.