Nystagmus and eye reflex sensor

[摘要] ENGLISH ABSTRACT: Nystagmus is an eye movement pattern that consists of a drifting gaze component, knownas the slow phase, followed by a corrective quick phase component. The presence ofnystagmus or the lack thereof under certain conditions can be used for various diagnosticpurposes including the diagnosis of physiological, pathological and neurological conditions.The angular velocity of the quick phase can make the detection of nystagmus a challengingtask for the untrained eye, since the quick phases are usually comparable with saccadic eyemotions. The goal is thus to develop a fully automated diagnostic tool that can identifythe presents of nystagmus in a patient's eye motions.In this thesis, an appropriate eye tracking method was selected from a number of eyetracking methods that are commonly implemented in the literature. A video-oculographygoggle concept was chosen based on criteria such as invasiveness, sampling rate, accuracyand telemedicine capability, amongst other nystagmus related necessities. A binocularvideo-oculography concept was chosen that satisfied the technical requirements andprovided a cost-effective design. An automated analysis algorithm was developed forautomatic nystagmus identification from eye motion data. The algorithm was validatedby testing the performance of the algorithm on an optokinetic nystagmus signal. Itproved to provide a reliable automatic identification of nystagmus beats, even in signalsthat contained nystagmus as well as random motion components. A statistical analysisshowed that the algorithm provided a sensitivity of 91.8% and a specificity of 96.5% forpure nystagmus signals, and a sensitivity and specificity of 87.8% and 91.1% respectivelyfor mixed signals.

[发布机构] Stellenbosch University