December 2002
Volume 43, Issue 13
Free
ARVO Annual Meeting Abstract  |   December 2002
ERG-Threshold in Man Compared to Cat (In Vivo/In Vitro)
Author Affiliations & Notes
  • KF Jost
    Neurophysiology Laboratory Ophthalmology University Hospital Zurich Switzerland
  • G Niemeyer
    Neurophysiology Laboratory Ophthalmology University Hospital Zurich Switzerland
  • Footnotes
    Commercial Relationships   K.F. Jost, None; G. Niemeyer, None.
Investigative Ophthalmology & Visual Science December 2002, Vol.43, 1816. doi:
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      KF Jost, G Niemeyer; ERG-Threshold in Man Compared to Cat (In Vivo/In Vitro) . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1816.

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Abstract

Abstract: : Purpose: To record and compare the scotopic threshold response (STR) in humans and in cats (in vivo and in perfused eyes). Method: In humans 13 ERG series of 7 healthy volunteers were recorded using a LKC UTAS 3000. Dark adaptation was 60 min, pupils were dilated. In cats, ERGs were recorded from 4 anesthetized and artificially ventilated cats. A reference electrode was either positioned on the sclera or in the subcutaneous tissue. A Ganzfeld-Grass stimulator was used. In vitro arterially perfused, fully dark adapted eyes from 5 cats, enucleated under deep anesthesia and analgesia, were used to record the vitreo-scleral ERG (Niemeyer G.: Prog Ret Eye Res 20/3, 2001). Intensity-response series to 50 ms light pulses from a Xenon source included thresholds of STR and b-wave. Results: The STR of the two species examined in vivo and partly in vitro were both graded corneal-negative potentials with similar waveform, maximum amplitude and dynamic range. In vitro, lower intensities sufficed to elicit measurable STRs, using pulses instead of flashes and a reference electrode at the posterior pole. Threshold intensities are as follows:  

Conclusions: Threshold intensity values of the human ERG were found to be remarkably close to those of the anesthetized cat. Pentobarbital/Gallamine anesthesia with artificial ventilation obviously does not reduce retinal sensitivity. In vitro, under the particular conditions of the perfused cat eye, threshold intensities were observed to be clearly lower than those measured in anesthetized cats.

Keywords: 394 electrophysiology: non-clinical • 396 electroretinography: non-clinical • 395 electroretinography: clinical 
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