Infra-red and video-oculography as alternatives to electro-oculography

With the introduction of each new technique for registering eye movements, the question arises concerning whether these provide a reliable and accurat e alternative for the diagnosis of labyrinthine dysfunction when compared t o the most commonly used electro-oculographic technique. To answer this que stion we compared mean slow-phase velocity (SPV) using three different reco rding techniques: electro-oculography (EOG), video-oculography (VOG) and in frared oculography (IROG) during four different types of examinations. The examinations were the eye target tracking test (ETT), horizontal and vertic al optokinetic nystagmus (OKN) tests and the rotating chair test of the hor izontal vestibulo-ocular reflex (HVOR). For the ETT tests the VOG provided consistently higher mean SPV values with low variance, presumably because o f 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 IR OG 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. Th ese results indicate that the EOG technique despite its disadvantages of no ise, time to apply and variability of calibration still provides an inexpen sive, reliable and accurate means of measuring slow-phase eye movements.