Electroretinography in dogs: a review

Abstract

Electroretinography (ERG) in the form of full-field, flash ERG is the most commonly used technique in veterinary ophthalmology for diagnosing the functioning of the outer retina. Under light stimulation spatially distributed different cell types within the retina produce time-varying electric responses. These are recorded in the form of ERG traces consisting of a series of positive and negative wavelets. The possibility of selective stimulation of individual types of retinal cells and the analysis of constituent components of ERGs are the basis for determining the source of abnormalities and diagnosis of various types of dysfunction. In many cases, the ERG allows diagnosis of hereditary retinal disorders in dogs before the appearance of behavioural and ophthalmoscopic symptoms. This review is an introduction to the electrophysiology of vision, intended for small animal practitioners, and aimed at presenting the benefits of ERG for early ophthalmic diagnostics in dogs.