Assessment of the dark-adaptation time required for recovery of electroretinographic responses in dogs after fundus photography and indirect ophthalmoscopy

Tuntivanich, Nalinee; Mentzer, Anita; Eifler, Danielle M.; Montiani‐Ferreira, Fabiano; Forcier, Janice Q.; Johnson, Cheri A.; Petersen‐Jones, Simon M.

doi:10.2460/ajvr.2005.66.1798

Cited by 15 publications

(19 citation statements)

References 2 publications

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“…To determine the actual stimulus intensity used in this study, the instruments’ output would have had to be measured by a time‐integrated photometer which was not available in the participating clinics. Though not measured in this study, two studies using Retinographics report the instrument's output to range from −2.6 to 0.86 log cd s/m 2 for the −30 and +5 dB settings, respectively . Of course, it is possible that the stimulator output of our instruments differed from these values, and from each other.…”

Section: Discussionmentioning

confidence: 82%

Electroretinography is a prognostic indicator for postoperative vision in dogs undergoing retinal reattachment surgery

Hoffman

Sisler

Pappania

et al. 2017

Veterinary Ophthalmology

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Section: Discussionmentioning

confidence: 82%

Electroretinography is a prognostic indicator for postoperative vision in dogs undergoing retinal reattachment surgery

Hoffman

Sisler

Pappania

et al. 2017

Veterinary Ophthalmology

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“…The former may be intensity of the light stimulus used, filter and amplifier settings, conductor characteristics of the electrodes, and position of the electrodes [23,35]. The latter may be the level of dark-adaptation [34], exposure to bright light prior to the ERG recordings [31], and level of anesthesia or sedation [11,33]. Other variables that affect ERGs are breed of dog, age and the degree of pupil dilation [1].…”

Section: Discussionmentioning

confidence: 99%

Comparison of Two Electroretinography Systems Used in Dogs: The HMsERG and the RETIport

Jeong

Son

Park

et al. 2011

The Journal of Veterinary Medical Science

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ABSTRACT. The purpose of the study was to compare two different electroretinography (ERG) instruments used on the same animal in a laboratory setting. Retinal function in both eyes of 12 healthy miniature schnauzers was evaluated under general anesthesia. Scotopic and photopic ERGs were recorded by the HMsERG and the RETIport using the Dog Standard Protocol recommended by the European College of Veterinary Ophthalmologists (ECVO). The waveforms of the ERGs obtained by the two ERG units were similar to those described in previous studies. The 90% reference ranges using the multiple of medians (MoM) showed that the changes in ERG parameters obtained by the HMsERG unit were very similar to those of the RETIport for most ERG responses, except for a few. The results demonstrate that the two ERG systems are comparable for evaluating retinal function in dogs. Further, the results also show that it is necessary to establish ERG system-specific limits of normality in each laboratory or clinic in order to obtain a correct diagnosis, for example by using a graphical representation of the 90% reference range.

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“…The pupils were dilated with 0.5% tropicamide (eye drops, two times, 15 min intervals; Samil, Korea). After producing mydriasis, animals were dark-adapted for 20 min [4,10,12,15]. ERG examination was then performed under general anesthesia using a combination of 40 µg/kg medetomidine hydrochloride (Orion Pharma, Finland) and 4 mg/kg ketamine hydrochloride (Yuhan, Korea) intravenously [6,8,12].…”

Section: Methodsmentioning

confidence: 99%

“…After producing mydriasis, animals were dark-adapted for 20 min [4,10,12,15]. ERG examination was then performed under general anesthesia using a combination of 40 µg/kg medetomidine hydrochloride (Orion Pharma, Finland) and 4 mg/kg ketamine hydrochloride (Yuhan, Korea) intravenously [6,8,12]. The ground electrode was placed over the external occipital protuberance and the reference electrode was placed approximately midpoint between lateral canthus and ipsilateral ear pinna [8].…”

Section: Methodsmentioning

confidence: 99%

The normal electroretinogram in adult healthy Shih Tzu dogs using the HMsERG

et al. 2009

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Electroretinography (ERG) is a reliable diagnostic tool for the diagnosis of retinal disease. It measures electric potentials occurring in the retina in response to light stimulation. In this study, we examined the normal electroretinogram using the Handheld Multispecies ERG (HMsERG) in Shih Tzu dogs. ERG recordings were performed in twelve eyes of six healthy Shih Tzu dogs. Dogs were anesthetized with a combination of medetomidine and ketamine. Proparacaine eye drops were also applied as a topical anesthetic. Tropicamide eye drops were applied for mydriasis. After 20 min of dark adaptation, we recorded the amplitudes and implicit times of the b-waves of the rod, standard rod and cone (Std R&C), high-intensity rod and cone (Hi-int R&C), and cone systems, and responses of the cones and inner retina by flicker light stimulation (cone flicker). Results showed that mean the amplitudes of a-waves of Std R&C, Hi-int R&C, and the cone responses were 141.25 µV, 173.00 µV, and 12.92 µV, respectively. The b-waves of the rod responses ranged from 141.58 to 155.25 µV; the Std R&C was 314.75 µV, the Hi-int R&C was 329.42 µV, the cones were 37.75 µV, and the flicker responses were 64.08 µV. The b/a ratios for the Std R&C, Hi-int R&C, and the cone response were 2.29, 1.94, and 3.71, respectively. Mean implicit time of the a-wave of the Std R&C was 15.12 ms, of Hi-int R&C was 13.42 ms, and of the cone response was 7.22 ms. The b-wave of the rod responses ranged from 68.12 to 72.68 ms, of Std R&C were 37.28 ms, of Hi-int R&C were 41.90, of the cone responses were 38.12 ms, and of the cone flicker responses were 22.80 ms. We believe that these parameters can be used as reference "normal" ERGs ranges for Shih Tzu dogs using the HMsERG under medetomidine and ketamine anesthesia.

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Assessment of the dark-adaptation time required for recovery of electroretinographic responses in dogs after fundus photography and indirect ophthalmoscopy

Abstract: Results suggest that at least 60 minutes of dark adaptation should be allowed before ERGs are performed in dogs after fundus photography or indirect ophthalmoscopy.

Cited by 15 publications

References 2 publications

Electroretinography is a prognostic indicator for postoperative vision in dogs undergoing retinal reattachment surgery

Electroretinography is a prognostic indicator for postoperative vision in dogs undergoing retinal reattachment surgery

Comparison of Two Electroretinography Systems Used in Dogs: The HMsERG and the RETIport

The normal electroretinogram in adult healthy Shih Tzu dogs using the HMsERG

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