WHEREAS surface electrodes, placed around the orbit could detect eye motions and nystagmus for about the last 40 years, the photoelectric technique (PENG) was developed 14 years ago1,2 and offered a number of improvements.
Advantages
The sensing device is mounted in a goggle frame and can be placed before the patient's eye in the manner of a pair of eyeglasses. This obviates considerable time otherwise necessitated by placing three or more electrodes around the eye.In discarding the electrodes, the inconvenience caused by perspiration, tearing, or loosening of the contact is eliminated.Disturbances in the recording caused by contraction of the muscles of facial expression or by clenching the jaws are avoided.Occasional electroencephalographic (EEG) recordings which may be picked up by the electrodes will not be interfered with.Of greater significance is the fact that the photoelectric output represents a much greater electrical potential than the surface electrodes