Normal clinical electroretinography parameters for poodle, Labrador retriever, Thai ridgeback, and Thai Bangkaew

Abstract

The purpose of the present study was to establish normal electroretinogram (ERG) parameters using 56 normal eyes of four dog breeds common in Thailand: poodle, Labrador retriever, Thai ridgeback, and Thai Bangkaew. Standard ERG findings were bilaterally recorded using a handheld multi-species ERG unit with an ERG-jet lens electrode for 28 dogs under preanesthesia with diazepam, anesthesia with propofol, and anesthesia maintenance with isoflurane. There were significant differences in the mean values of ERG amplitudes and implicit times among the four dog breeds (p < 0.05) except for the b-wave implicit time of the photopic 30 Hz flicker response with 3 cd.s/m2 (p = 0.610). Out of the four breeds, Thai Bangkaew had the longest implicit time (p < 0.001) of scotopic low intensity responses, b-wave of scotopic standard intensity responses (3 cd.s/m2), a-wave of the higher intensity response (10 cd.s/m2), and a-wave of the photopic single flash response (3 cd.s/m2). For the b/a ratio, only the ratio of the Cone response was significantly different among the different breeds. In this summary, normal ERG parameters for four dog breeds were reported. Data from the investigation supported the hypothesis that determination of breed-specific limits of normality for ERG responses is necessary for individual clinics and laboratories.

Electroretinography in eight species of neotropical deer

“…Another factor to consider is that the corneal electrode used is made for dogs, which have different corneal curvature and globe size when compared with deer. 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 (Sussadee et al, 2015). There was a significant difference of the average body weights for each species in the present study.…”

Normal Clinical Electroretinography Parameters of Healthy Pharaoh Hounddogs

“…The skull of pharaoh hounds resembles a blunt wedge, and is long and chiseled with only a slight stop and a snout of good length (Coile, 2005). The variations of skull conformation between poodles, Labrador retriever s, Thai Bangkaews, and Thai ridgebacks might be the cause for breed-specific differences in ERG parameters (Sussadee et al, 2015).…”

“…All of that contribute to interfere with the values obtained from ERG recording; therefore, the investigations aiming to establish a normal range still continue. It is recommended each laboratory or clinic to establish a technical procedure that provide reproducible ERG results under specific conditions in order to use the data for diagnostic purposes Sussadee et al, 2015).…”

<b>Padronização do eletrorretinograma de campo total em cães da raça Yorkshire Terrier</b>

“…Esse resultado era esperado e é compatível com estudos de eletrorretinogramas na medicina humana, onde as amplitudes de todas as respostas também apresentam diminuição de valores com a progressão da idade (MCCULLOCH et al, 2015 (GÓES et al, 2015). Outro estudo, que compara quatro raças de cães, também corrobora a variação de amplitude entre diferentes raças (SUSSADEE et al, 2015). Assim, torna-se importante a padronização de respostas entre diferentes raças na análise do exame.…”

“…Estudos anteriores indicam a faixa etária como elemento essencial na normatização do exame (SAFATLE et al, 2010a;GÓES et al, 2015), assim como ocorre na eletrorretinografia humana (MCCULLOCH et al, 2015). A raça também mostra-se importante, conforme apurado por Sussadee et al (2015). O uso de fármacos para possibilitar a execução do exame com menor interferência elétrica, decorrente de movimentações musculares, também interfere nos valores obtidos (FREEMAN et al, 2013).…”