Electroretinography recordings using a light emitting diode active corneal electrode in healthy beagle dogs

Abstract

Electroretinography (ERG) is a well-established diagnostic procedure for objectively evaluating retinal function. In this study, ERG in beagle dogs, which are a popular experimental animal, was performed to determine the normal range of ERG variables and assess differences between the left and right eyes. ERG findings including rod, combined rod-cone, single-flash cone, and 30-Hz flicker responses were recorded with an LED-electrode in 43 sedated beagle dogs. The subjects were divided into young (< 1 year old), adult (1~5 years old), and senile animals (≥ 6 years old). Normal ERG ranges were obtained. Significant differences in b-wave amplitude along with b/a ratio of the combined rod-cone response were found between the young and adult animals as well as young and senile dogs. No significant differences were observed between the left and right eyes. ERG variables in beagle dogs differed by age due to age-related retinal changes. Thus, we propose that normal ERG ranges should be determined according to age in each clinic and laboratory using its own equipment because each institution usually has different systems or protocols for ERG testing.

Scotopic electroretinography in fishing cat (Prionailurus viverrinus) and leopard cat (Prionailurus bengalensis)

“…A guideline for clinical ERG in dogs recommended that each laboratory should obtain its own normal baseline ERG parameters . Variations between ERGs can be due to the anesthetic technique, electrode type and position, and the age, species, and breed of the animal . A study comparing ERG in four dog breeds—Poodle, Labrador Retriever, Thai Ridgeback, and Thai Bangkaew—reported that the breed of dog was an important variable in ERG, possibly based on the variation in skull conformation .…”

Avaliação eletrorretinográfica pré e pós-operatória em cães diabéticos submetidos à facoemulsificação

“…Assim sendo, as principais manifestações clínicas do DM são: poliúria, polidipsia, polifagia e perda de peso (KANEKO et al, 1978;NELSON, 1992;NELSON, 2010 No mesmo estudo, Rand et al (2004) concluíram que a obesidade não resultou em DM tipo II nos cães, porém predispunha à pancreatite, que é um frequente fator etiológico desta doença no cão.…”

“…Ao comparar os eletrodos, podemos observar que as respostas dos testes eletrofisiológicos diferem entre si (GUM, 1980;DANTAS, 1995;KUZE;UJI, 2000;ITOH et al, 2013;PEREIRA et al, 2013).…”

“…As características de condutibilidade dos eletrodos também podem influenciar nas respostas obtidas (HÉRBERT et al, 1996;MAHEHARA et al, 2005;MENTZER et al, 2005;BELLER et al, 2007;PEREIRA et al, 2013;ITOH et al, 2013 Dentre as desvantagens do eletrodo Burian Allen podemos citar o custo, a dificuldade em obtê-lo e a variedade de tamanhos necessárias para as diversas raças de cães analisadas no estudo.…”

“…Quanto mais jovem o paciente, maiores são as amplitudes e quanto mais velho, menores são as amplitudes das respostas, semelhante ao que acontece no ERG humano (ITOH et al, 2004;NARFSTRÖM, 2006;SAFATLE et al, 2010c;ITOH et al, 2013). Atenuação das respostas ao fazer estudo comparativo entre os grupos, pode ser esperada, porém como amostra era heterogênea a comparação foi feita com o olho contralateral.…”