Clinical electroretinography in the dog with ganzfeld stimulation: a practical method of examining rod and cone function.

We used a simple and reproducible technique with full-field electroretinography and a special-purpose computer system to test and evaluate outer retinal function in dogs. The standardized protocol included the following five basic responses: (1) a stable initial light-adapted, mainly cone derived response, (2) a dark-adapted rod response, (3) chromatically separated rod and cone responses, (4) a maximal rod and cone response and (5) an isolated cone flicker response. For evaluating the electroretinographic responses, a graphic-presentation was used that included data from the tested animal as well as normative data from dogs of the specific breed and age group, presented as the percentage of the median in which limits of normality were depicted in percentiles.