Clinical electroretinography in the dog with ganzfeld stimulation: A practical method of examining rod and cone function

Narfström, Kristina; Andersson, Björn-Erik; Andréasson, Sten; Gouras, Peter

doi:10.1007/bf01203863

Cited by 29 publications

(36 citation statements)

References 12 publications

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“…For this purpose the so called Ganzfeld (or 'full-field') stimulator was developed and now recommended for use in both humans and animals [22,25]. A contact lens electrode with a built-in LED together with a recording system, have been used in human and animal ERG studies during the past years [10,12,20].…”

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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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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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“…This examination is objective, non-invasive and provides information on the function of the individual retinal cell types (Gouras 1970;Aguirre 1973). An analysis of ERGs can be used to characterise vision disorders (Acland 1988;Narfstrom et al 1995;Yanase et al 1995). Flash ERG is currently used in the early diagnostics of retinal diseases (Narfstrom et al 2002;Ofri 2002;Ekesten et al 2013) and may also be useful in making decisions on cataract surgery (Ofri 2002;Ekesten et al 2013;Wilkie and Colitz 2013).…”

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Electroretinography in dogs: a review

Drazek¹,

Lew²,

Lew³

et al. 2014

Vet. Med. - Czech

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Electroretinography (ERG) in the form of full-field, flash ERG is the most commonly used technique in veterinary ophthalmology for diagnosing the functioning of the outer retina. Under light stimulation spatially distributed different cell types within the retina produce time-varying electric responses. These are recorded in the form of ERG traces consisting of a series of positive and negative wavelets. The possibility of selective stimulation of individual types of retinal cells and the analysis of constituent components of ERGs are the basis for determining the source of abnormalities and diagnosis of various types of dysfunction. In many cases, the ERG allows diagnosis of hereditary retinal disorders in dogs before the appearance of behavioural and ophthalmoscopic symptoms. This review is an introduction to the electrophysiology of vision, intended for small animal practitioners, and aimed at presenting the benefits of ERG for early ophthalmic diagnostics in dogs.Keywords: ERG; ophthalmology; PRA; retina

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“…When ERG using an external light source is used, there is the possibility of variation in stimulus among laboratories. Goldmann and Weekers developed a stimulus device called the Ganzfeld dome, which is a semicircular machine with a diffuser built inside, allowing stimulation of the entire retina [11,25]. Following the development of the Ganzfeld dome, separate recording of rod and cone responses became possible [11].…”

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“…Goldmann and Weekers developed a stimulus device called the Ganzfeld dome, which is a semicircular machine with a diffuser built inside, allowing stimulation of the entire retina [11,25]. Following the development of the Ganzfeld dome, separate recording of rod and cone responses became possible [11]. The Ganzfeld dome, however, has some defects in veterinary ophthalmological use: 1) it is a large and expensive system that is difficult to install in every animal hospital; 2) bilateral stimulating recording is difficult; 3) fixation of animals for recording is difficult; and 4) the head of the dog has to be kept within a sphere of 60 cm diameter [17,24,25].…”

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confidence: 99%

“…The LED-electrode enabled us to perform simple and reliable recording of full-field ERG. Today, the Ganzfeld dome is widely used for full-field ERG in veterinary clinics as well as in human clinics [7,11,12,14]. However, the Ganzfeld dome has some defects: 1) it is a large and expensive system that is difficult to install in every animal hospital; 2) bilateral stimulating recording is difficult; 3) fixation of the animals for recording is difficult; and 4) the dog's head need to be kept within a sphere of 60 cm diameter [17,24,25].…”

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Electroretinography Using Contact Lens Electrode with Built-In Light Source in Dogs

Maehara

Itoh

et al. 2005

The Journal of Veterinary Medical Science

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ABSTRACT. Electroretinography (ERG) is an effective method for the diagnosis of retinal disease. In the dog, dependable ERG recording is difficult without the use of an expensive device like a Ganzfeld full-field stimulator. The International Society for Clinical Electrophysiology of Vision has defined the standard flash stimulus condition (SF) and evaluation of the retina using the b/a ratio in humans. In dogs, evaluation using the b/a ratio has not been reported, whereas the intensity of SF has been defined. In this study, we performed a convenient ERG recording method using a contact lens electrode with a built-in light source (LED-electrode), and confirmed SF as reported previously. ERG recordings were performed on 15 healthy beagle dogs under sedation. We performed bilateral ERG at 12 different intensities after 30 min dark adaptation. After 10 min light adaptation, we recorded single flash cone and flicker cone response using the SF determined in this study. In this study, SF of 3.0 cd/m 2 /sec (6,000 cd/m 2 , 0.5 msec) resulted in b/a=2. The intensity for rod response that recorded only the b-wave was 0.0096 cd/m 2 /sec (80 cd/m 2 , 0.12 msec). We could achieve ERG for each response easily and smoothly under sedation, and without general anesthesia. Using an LED-electrode, we could perform more quantitative and reproducible ERG examinations than with traditional methods. We propose that the b/a ratio is the most useful parameter in ERG reporting for evaluating retinal function. KEY WORDS: canine, contact lens electrode, electroretinography, rod response, standard flash.

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Clinical electroretinography in the dog with ganzfeld stimulation: A practical method of examining rod and cone function

Cited by 29 publications

References 12 publications

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

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

Electroretinography in dogs: a review

Electroretinography Using Contact Lens Electrode with Built-In Light Source in Dogs

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