A review of electroretinography waveforms and models and their application in the dog

Abstract

Electroretinography (ERG) is a commonly used technique to study retinal function in both clinical and research ophthalmology. ERG responses can be divided into component waveforms, analysis of which can provide insight into the health and function of different types and populations of retinal cells. In dogs, ERG has been used in the characterization of normal retinal function, as well as the diagnosis of retinal diseases and measuring effects of treatment. While many components of the recorded waveform are similar across species, dogs have several notable features that should be differentiated from the responses in humans and other animals. Additionally, modifications of standard protocols, such as changing flash frequency and stimulus color, and mathematical models of ERG waveforms have been used in studies of human retinal function but have been infrequently applied to visual electrophysiology in dogs. This review provides an overview of the origins and applications of ERG in addition to potential avenues for further characterization of responses in the dog.

Effect of mydriasis with topical rocuronium bromide on electroretinography in domestic pigeons (<i>Columba livia</i>)

“…ERG is generated by the summed activity of all retinal cells that consist of overlapping positive and negative component potentials originated from different stages of retinal processing [ 10 ]. The initial negative wave in response to light stimuli is known as the a-wave, followed by the positive peak known as the b-wave [ 7 , 10 , 22 ] ( Fig. 1 ).…”

“…1 ). Under the scotopic condition, the main generator of the a-wave to a low intensity stimulus is the rod photoreceptors, as the cone photoreceptors are not as sensitive to light [ 22 ]. However, in this study, the stimulus presented during the scotopic condition was strong enough to elicit a response from both photoreceptor types ( Fig.…”

“…As for the photopic condition, the a-wave was driven by cone photoreceptors because the rod photoreceptor was suppressed by the light adaptation stage ( Fig. 1C and 1D ) [ 22 ]. Aside from the photoreceptors, the bipolar cells, amacrine, and ganglion cells also contribute to the a-wave [ 10 , 22 ].…”

“…1C and 1D ) [ 22 ]. Aside from the photoreceptors, the bipolar cells, amacrine, and ganglion cells also contribute to the a-wave [ 10 , 22 ]. In both dark- and light-adapted conditions, the main generator of the b-wave is the ON-bipolar cells [ 10 ].…”

Characterization of Scotopic and Mesopic Rod Signaling Pathways in Dogs Using the On-Off Electroretinogram

“…Few studies have addressed canine responses to the On-Off ERG, although the technique has been used in the study of some canine inherited retinal degenerations (38)(39)(40)(41)(42)(43)(44). The dog exhibits a predominantly negative Off-response of the E-type retina (45). The purpose of this study was to determine baseline features of the On-and Off-response in phenotypically normal dogs as well as to assess postreceptoral pathways and changes with increasing background luminance in the canine retina.…”