J Vet Sci.  2015 Mar;16(1):67-74. 10.4142/jvs.2015.16.1.67.

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

• Sussadee M
• Phavaphutanon J
• Kornkaewrat K
• Thayananuphat A

• KMID: 2160822
• DOI: http://doi.org/10.4142/jvs.2015.16.1.67

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.

Keyword

electroretinogram; Labrador retriever; poodle; Thai Bangkaew; Thai ridgeback

MeSH Terms

Animals
Dogs/genetics/*physiology
Electroretinography/veterinary
Reference Values
Retina/*physiology

Figure

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  Fig. 1 Photograph of the electroretinogram (ERG) setup using a handheld multi-species electroretinograph with a 5-year-old Thai Bangkaew.

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  Fig. 2 Comparison of normal ERG traces for the four dog breeds: scotopic low intensity responses (Rod1~Rod5) observed 4, 8, 12, 16, and 20 min after dark conditions (A~E); scotopic standard intensity responses (Std R&C; F), higher intensity responses (Hi-int R&C; G), photopic single flash responses (Cone; H), and photopic flicker responses (Flicker; I). The flash onset stimulus is indicated by arrows.

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  Fig. 3 Mean and standard error (SE) of amplitudes recorded for the four dog breeds. Letters a, b, and c indicate significant differences among the breeds. ERG amplitudes of all responses were significantly different among the breeds (p < 0.05).

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  Fig. 4 Mean and SE of implicit times recorded for the four dog breeds. Letters a, b, and c indicate significant differences among the breeds (p < 0.05). Implicit times of all responses were significantly different among the breeds except for Flicker (p = 0.610).

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  Fig. 5 Mean and SE of the b/a ratio recorded for the four dog breeds. Letters above the columns (a and b) indicate significant differences among the breeds. There was no statistical difference in the b/a ratio of the Std R&C (p = 0.476) and Hi-int R&C (p = 0.214) responses. A significant difference (p = 0.035) was observed for the b/a ratio of the Cone.

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