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Objective: We explored whether vestibular derangement in patients with severe Meniere's disease is related to gaze and fixation difficulties and could explain complains of visual blurring and visual neglect., Methods: Twenty-six patients with severe Meniere's disease treated with intratympanically applied gentamicin of the affected ear were examined. Saccades (with pseudo-random timing, size and side of the step) and pursuit eye movements (PEMs; pseudo-random target trajectory made of a combination of two sinusoidal waves of different frequencies) and posturography were tested in patients. For normative data of voluntary eye movements, 45 control subjects were tested, and for posturography 29 control subjects. Severity of symptoms in Meniere patients was assessed according to the total handicap score of AAO-HNSF (1985)., Results: Saccadic eye movements and postural stability were severely deteriorated in Meniere patients, and these disturbances correlated significantly with each other. Most of PEM parameters were significantly worse in Meniere patients than in control subjects. Prolongation of saccadic latency and reduced gains due to saccadization in PEMs were characteristic features for Meniere's patients. Severity of symptoms in Meniere patients correlated with prolongation of latency in saccades and with poorer gains in PEMs. Postural instability measured with posturography correlated with saccadic latency and PEMs., Conclusion: In severe Meniere's disease, programming of oculomotor and postural responses show the same pattern of disturbance, an increased delay of processing and inaccuracy in the motor output. A fluctuant vestibular lesion with advanced severity can cause disorders of voluntary eye movements that are reflected with clinical complaints of difficulties in reading and visual scanning of surrounding.

Objective: In previous studies about the control of posture there have been controversial findings. Our aim was to examine the role of monocular and binocular vision in controlling posture in quiet stance., Methods: Twenty-eight normal subjects were tested. We used a force platform in measuring postural stability. In main experiment, postural stability was measured in four conditions: both eyes open (BEO), dominant eye open (DEO) non-dominant eye open (NDEO), and both eyes closed (BEC). In a further experiment, 11 subjects were tested in conditions where a vertical prism was placed in front of dominant eye. Prism was strong enough to cause diplopia. Our interest was to see, if diplopia affected the balance., Results: In main experiment, at level of group the body-sway in any of the three ocular (viewing) conditions did not differ from each other. At level of individuals, binocular vision was more effective on controlling posture in only half of subjects. In prism experiment, relative to normal binocular viewing the postural stability was modified in both prism conditions, but there was no difference between monocular and binocular viewing with prism., Conclusion: In quiet stance and in subjects with perfect binocular vision and stereopsis, the benefit out of binocular viewing in postural stability is subject-dependent. At the level of group, monocular vision provides equally good postural stability as binocular vision.