Electroretinogram recording

Steiss, J.E., Siorrs, D.P., and Wright, J.C., 1992, Comparisons of electroretinograms recorded with a contact lens versus needle electrode in clinicaly normal dogs. Prog. Vet.. Compar. Ophthalmol., 2(4) 143-146. 

Fig. 7. A typical electroretinogram is recorded by placing an electrode on the cornea and monitoring the succession of electric impulses which follow the brief illumination of the retina with white light.

Hawlina, M., and De Villiers, P.L.G. 1992. Light-emitting diodes and half-cell electrodes in expeiimenml recording of electroretinogram c-wave. Doc. Qphthal. 81 227-237. 

Kommonen, B., Karhunen, U., and Raitta, C. 1988. Effects of thiopentone halothane-nitrous oxide anaesthesia compared to ketamine-xylazine anaesthesia on the dc recorded dog electroretinogram. Acta Vet Scand. 29 23-33. 

Sieving, P.A., Fishman, G.A., and Maggiano, J.M. 1978. Corneal wick electrode for recording bright flash electroretinograms and early receptor potentials. Arch. Qphthal. 96 899-900. 

Textorius, 0., and Gottvall, E. 1992. The c-wave of the direct-cuirent-recorded electroretinogram and the standing potential of the albino rabbit eye in response to repeated series of light stimuli of different intensities. Doc. Qphthal. 80 91-103. 

Reference electrode. In recording the electroretinogram, voltage differences are measured between the cornea and some other part of the body. The corneal electrode is the active electrode and the other one is the reference electrode. The reference electrode, in dog and cat, is placed on the ear of the animal. Scarcity of fur in that area allows a good contact between sMn and electrode. Needle electrode can be used also. 

The electroretinogram (ERG) is composed of responses of many different retinal cell types. Many studies have been made to separate the ERG into components and to link different components to different retinal structures. In theese studies, authors used microelectrodes and intact eyes of laboratory animals (Heynen and van Norren, 1985). However, in most clinical situations or during the course of toxicity studies, this technic is not suitable because it does not allow long-term studies on the same animal. Our first goal was to find a technic that permit to record global ERGs from the same animal at different times. 

Sato, S., Sugimoto, S., and Chiba, S., 1982, A procedure for recording electroretinogram and visual evoked potential in conscious dogs. J. Pharmacol. Methods, 8 173-181. 

Satoh, H., Fukuda, N., Kuriki, H., Maki, Y., Nomura, M., Saji, Y., and Nagawa, Y., 1980, A procedure for recording electroretinogram (ERG) in conscious monkeys, and effect of some drugs (author s transl.), Nippon Yakurigaku Zasshi, 76(7) 581-594. 

In the present study, we examined ocular toxicity of ofloxacin ophthalmic solution (3 times daily for one year application) in beagle dogs with pigmented eyes. In order to investigate the effects of melanin-bound ofloxacin on retinal function and the effect of ofloxacin on central nerve system, electroretinogram (ERG) was recorded and behavior of dogs was observed during test periods. 

Electroretinogram (ERG). Two fine tungsten-wire electrodes are used for recording. The recording electrode is inserted in the cornea and the reference electrode placed in the thorax. Light stimuli can be supplied by a variety of sources placed 2-20 cm from the fly eye. Electrical responses to light represent the summed extracellular activity from the photoreceptor field (Hotta and Benzer 1969 Pak et al. 1969 Kelly and Suzuki 1974). 

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