title: Multifocal electroretinographical changes in monkeys with experimental ocular hypertension: a longitudinal study.
abstract: OBJECTIVE
  To study the time course of changes in the multifocal electroretinograms (mfERG) in monkeys with experimental ocular hypertension (OHT).
  
  
  METHODS
  The mfERGs were recorded in 12 eyes out of 6 monkeys. Two baseline measurements were used to quantify the reproducibility, the inter-ocular and the inter-individual variability of the ERG signals. Thereafter, the trabeculum of one eye of each animal was laser-coagulated in one to three sessions to induce OHT. ERG measurements were repeated regularly in a period of 18 months and the changes in ERG waveforms were quantified.
  
  
  RESULTS
  All animals displayed OHT (between 20 and 50 mmHg) in the laser-coagulated eyes. An ERG change was defined as the sum of differences during the first 90 ms between the laser-coagulated eye and the same eye before laser coagulation and between the laser-coagulated eye and the non-treated fellow eye. Three animals displayed significant changes for nearly all retinal areas and all stimulus conditions. The three remaining animals displayed significant changes only in one comparison, indicating very mild changes. The data indicate that a high stimulus contrast is more sensitive to detect changes, probably because of a better signal-to-noise ratio. Moreover, the comparisons with the fellow eye are more sensitive to detect changes than comparisons with the measurements before laser-coagulation.
  
  
  CONCLUSIONS
  OHT does not always lead to ERG changes. Comparisons with fellow eyes using high contrast stimuli are more sensitive to detect changes related to OHT.
authors.affiliation: Novartis Institutes for Biomedical Research, 4002 Basel, Switzerland. jan.kremers@uk-erlangen.de
authors.forename: Jan
authors.initials: J
authors.lastname: Kremers
authors.forename: Arno
authors.initials: A
authors.lastname: Doelemeyer
authors.forename: Elzbieta A
authors.initials: EA
authors.lastname: Polska
authors.forename: Fabrice
authors.initials: F
authors.lastname: Moret
authors.forename: Christian
authors.initials: C
authors.lastname: Lambert
authors.forename: George N
authors.initials: GN
authors.lastname: Lambrou
mesh_terms: D000818:Animals; D004596:Electroretinography; D005500:Follow-Up Studies; D007429:Intraocular Pressure; D017075:Laser Coagulation; D008252:Macaca fascicularis; D008297:Male; D023421:Models, Animal; D009798:Ocular Hypertension / Q000503:physiopathology*; D012160:Retina / Q000503:physiopathology*; D014129:Trabecular Meshwork / Q000601:surgery