[Infrared and video oculography--alternatives to electrooculography?]

With the introduction of each new technique for registering eye movements, the question arises concerning whether these provide a reliable and accurate alternative for the diagnosis of labyrinthine dysfunction when compared to the most commonly used electro-oculographic technique. To answer this question we compared mean slow-phase velocity (SPV) using three different recording techniques:electro-oculography (EOG), video-oculography (VOG) and infrared oculography (IROG) during four different types of examinations. The examinations were the eye target tracking test (ETT), horizontal and vertical optokinetic nystagmus (OKN) tests and the rotating chair test of the horizontal vestibulo-ocular reflex (HVOR). For the ETT tests the VOG provided consistently higher mean SPV values with low variance, presumably because of the accuracy and stability of the calibration. For the horizontal OKN and VOR rotating chair tests no significant differences were found between the mean SPV obtained with the different recording techniques, although the IROG recordings were associated with a larger variance. Vertical OKN mean SPV was consistently lower with IROG and VOG techniques presumably because of non-linearities and resolution limitations inherent in these techniques. These results indicate that the EOG technique despite its disadvantages of noise, time to apply and variability of calibration still provides an inexpensive, reliable and accurate means of measuring slow-phase eye movements.