Purpose:
The full field electroretinogram (fERG) is a very useful, objective, non-invasive tool to assess retinal function used extensively for research and in various animal models. The fERG is used in various porcine models of retinal diseases. To date, despite scientific need, there is lack of data regarding the properties of the normal porcine ERG and dark adaptation curve. The purpose of this study is to evaluate the dark adaptation curve of the domestic pig by means of full field electroretinogram.
Methods:
The electroretinographic responses were recorded bilaterally from six healthy female pigs, 6 months old using a contact lens electrode and a mini-Ganzfeld electroretinographic unit. The pigs were anesthetized and the ERG was recorded in response to 4 low intensity (10 mcd.s/m2) light stimuli given at a frequency of 0.1 Hz at each time (T) point: T= 5, 10, 15, 20, 25, 30, 40, 50 and 60 min of dark adaptation. Off-line analysis of the ERG was then performed.
Results:
Mean b-wave amplitude of the full-field ERG increased continuously from 5 to 25 min of dark adaptation (peak amplitude at T(25) = 204µV), and then reached a plateau until the end of the study at T = 60. No distinct a-wave was observed during the testing time.
Conclusions:
Evaluation of porcine rod function or combined rod/cone function by means of full-field ERG should be performed after a minimum 25 min of dark adaptation.
Keywords: electroretinography: non-clinical • retina