Dependence of optokinetic nystagmus characteristics upon recording techniques

The presence of infrared recording spectacles in the visual field is shown, under certain conditions, to influence human eye movement responses to optokinetic stimulation. Electrooculographic recording of optokinetic nystagmus (OKN) of the "follow" and "stare" type were made in four normal subjects, both with and without infrared spectacles. The ratio of slow phase velocity to target velocity was computed. This measure showed that wearing the spectacles produced no statistically significant change for "follow" but a significant decrement for "stare" OKN. The latter finding suggests that the advantage of more accurate eye movement recording offered by infrared spectacles should be weighed against a possible response decrement most probably caused by a stabilized image in the visual periphery.