A pattern electroretinogram (PERG) can be recorded when the eye wearing the electrode is occluded and the stimulus is viewed with the other eye. We find that this phenomenon occurs when an Arden gold foil electrode is used, but not when either an ERG-Jet lens or a scleral lens electrode is used. Therefore, a corneal-type electrode should be used in PERG recording situations where the fellow eye is not occluded.