#4 Clinical Guideline for Assessing Flash Visual Evoked Potentials in Laboratory Dogs and Normal Data for Beagle Dogs
Visual evoked potentials (VEPs) are useful to evaluate the visual pathway integrity from ganglion cells of the retina to the visual cortex. VEP could be applied to evaluate the effects on optic nerve function following ophthalmologic treatments and in toxicity studies. The aims of this research were to design a clinical protocol for testing flash-VEPs during sedation and dissociative anaesthesia in laboratory dogs, and to propose updated normal data for beagles.
The Flash-VEP technique was used in 12 beagle dogs after dark adaptation, pupil dilation and an anaesthetic protocol. Two tests were performed for each eye after monocular stimulation. Flash-VEP waveforms consisted of 2 positive (P1, P2) and 2 negative (N1, N2) peaks sequenced as P1, N1, P2, and N2, where P2 was the most prominent peak. Peak times (ms) and peak-to-peak amplitudes (V) were measured to evaluate the time from light stimulation of retina to cortical response and their electrical intensity, respectively. No statistically significant difference was observed between right and left eye data from all dogs (Students t test, p<0.05), with the exception of P2 peak times.
The protocol described allows clinicians to accurately record Flash-VEP in dogs. These results are reliable and reproducible, and could be valuable for other laboratories and future studies as standard background data to compare with when testing VEP in beagle dogs.