Documenta Ophthalmologica

, Volume 111, Issue 2, pp 113–125

Effects of Reference Electrode Location on Monopolar-derived Multifocal Electroretinograms in Cynomolgus Monkeys

  • Charlene B. Y. Kim
  • James N. VerHoeve
  • Paul L. Kaufman
  • T. Michael Nork

DOI: 10.1007/s10633-005-4781-6

Cite this article as:
Kim, C.B.Y., VerHoeve, J.N., Kaufman, P.L. et al. Doc Ophthalmol (2005) 111: 113. doi:10.1007/s10633-005-4781-6


The purpose of this study is to determine the effect of reference electrode location on the multifocal electroretinographic waveform. Multifocal electroretinograms (mfERGs) were recorded from 20 ocularly normal cynomolgus monkeys. The corneal electrode was an ERG-jetTM referenced to an ipsilaterally (outer canthus) situated subdermal needle electrode and to the contralateral corneal electrode. Testing was monocular and recordings from both montages were obtained simultaneously. The stimulus array consisted of 103 equal-sized hexagonal elements, which subtended ±44° about the central visual axis. Mean luminance of the display was 100 cd/m2. First-order (K1) and second-order (first slice) kernels (K2.1) of the mfERG were grouped in (a) 4 rings, representing the central 56° of visual field and (b) in 15-element quadrants. The mfERG waveform measures included amplitude, implicit time, and root mean square (RMS) of the oscillatory potentials (OP) and response waveform. K1 and K2.1 ring and quadrant amplitudes were larger with the contralateral than with the ipsilateral reference, but more notably signal-to-noise ratios (S:N) of the response waveform were always larger with the ipsilateral reference. Implicit times were longer for the contralateral than ipsilateral reference montage. K1 and K2.1 implicit times in males were longer than in females. Quadrant groupings revealed generally larger K1 and K2.1 amplitudes in nasal than in temporal retina.


cynomolgus monkeysgendermultifocal electroretinogramoscillatory potentialsroot mean square



first-order kernel


second-order (first slice) kernel


multifocal electroretinogram


oscillatory potentials


root mean square


signal-to-noise ratio

Copyright information

© Springer 2006

Authors and Affiliations

  • Charlene B. Y. Kim
    • 1
    • 2
  • James N. VerHoeve
    • 1
  • Paul L. Kaufman
    • 1
  • T. Michael Nork
    • 1
  1. 1.Department of Ophthalmology and Visual SciencesUniversity of Wisconsin Medical SchoolMadisonUSA
  2. 2.Department of Ophthalmology and Visual SciencesUniversity of Wisconsin Medical SchoolMadisonUSA