Documenta Ophthalmologica

, Volume 120, Issue 3, pp 273–289

Serial multifocal electroretinograms during long-term elevation and reduction of intraocular pressure in non-human primates

  • T. Michael Nork
  • Charlene B. Y. Kim
  • Gregg A. Heatley
  • Paul L. Kaufman
  • Mark J. Lucarelli
  • Leonard A. Levin
  • James N. Ver Hoeve
Original research article

DOI: 10.1007/s10633-010-9231-4

Cite this article as:
Michael Nork, T., Kim, C.B.Y., Heatley, G.A. et al. Doc Ophthalmol (2010) 120: 273. doi:10.1007/s10633-010-9231-4

Abstract

The purpose of this study was to evaluate the relationship between elevations of intraocular pressure (IOP) and the multifocal electroretinogram (mfERG) in non-human primates. Experimental glaucoma was induced in 4 rhesus and 4 cynomolgus monkeys by laser trabecular meshwork destruction (LTD) in one eye. To evaluate the contribution of ganglion cells to mfERG changes, one monkey of each species had previously underwent unilateral optic nerve transection (ONT). After ≥44 weeks of elevation, the IOP was reduced by trabeculectomy in 2 non-transected animals. In the intact (non-transected) animals, there was an increase in the amplitude of the early mfERG waveforms (N1 and P1) of the first-order kernel (K1) throughout the period of IOP elevation in all of the rhesus, but not all of the cynomolgus monkeys. A species difference was also present as a decrease of the second-order kernel, first slice (K2.1) in all of the cynomolgus monkeys but only in 1 of the rhesus monkeys (the 1 with the ONT). Similar IOP effects on the mfERG were seen in the ONT animals. Surgical lowering of IOP resulted in a return of the elevated K1 amplitudes to baseline levels. However, the depressed K2.1 RMS in the cynomolgus monkeys did not recover. These results demonstrate species-specific changes in cone-driven retinal function during periods of elevated IOP. These IOP-related effects can occur in the absence of retinal ganglion cells and may be reversible.

Keywords

Experimental glaucomaMultifocal electroretinogramOptic nerve transectionTrabeculectomy

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • T. Michael Nork
    • 1
  • Charlene B. Y. Kim
    • 1
  • Gregg A. Heatley
    • 1
  • Paul L. Kaufman
    • 1
  • Mark J. Lucarelli
    • 1
  • Leonard A. Levin
    • 1
    • 2
  • James N. Ver Hoeve
    • 1
  1. 1.Department of Ophthalmology and Visual SciencesUniversity of Wisconsin School of Medicine and Public HealthMadisonUSA
  2. 2.Department of OphthalmologyUniversity of MontrealMontrealCanada