Summary.To assess the effect of chronic deprivation of visual feedback, 21 blind patients underwent clinical and electronystagmographical examination. Patients with congenital blindness were characterized by spontaneous eye movements, inability to consciously move the eyes and absence of the vestibulo-ocular reflex (VOR), whereas eye movement abnormalities were practically absent in those with blindness acquired late in life. Active visual experience, at least in early life, seems to be crucial for the development of eye movements and VOR adjustment.

Bicycling demands on both the vestibular and the visual system. Deficiencies relevant to behaviour in traffic and the possibilities to compensate for these may be estimated based on a oculographic evaluation. This should therefore be used to advise bicyclists with a visual impairment.

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It is proposed that test procedures for visual performance in traffic be altered as follows: nystagmus and abnormal head postures are admittable if sufficient binocular vision is achieved. The test may use illustrations of traffic situations containing relevant details such as traffic signs. These are to be understood by the test person on triplicate presentation.

Some people are able to abduct and adduct just one of their eyes from maximum convergence position. Such a distribution of different tonus on both sides has a binocular-symmetric innervation pattern carried out on two chronological orders and a monocular-asymmetric innervation pattern carried out on one chronological order. The latter is trainable. The voluntary nystagmus ist comparable to the muscle tremor (on coldness). It is mediated by the parasympathic-innervated reflex for near focussing. The relief of the brain stem automatism is a ‘stigma degenerationis’ and not trainable because it is a basic rhythm. An opto-kinetic nystagmus could be performed without stimulus by conditioned reflexes.

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27 children with severe brain injuries were examined by an ophthalmologist and had several paediatric examinations during an eight or ten weeks' course of rehabilitation. With highly reduced levels of consciousness they had hardly any cortical visual function but frequently had brainstem controlled reactions of eyelids, pupils and eyeballs. The development of these reactions was followed up and correlated to the recovering visual functions. Some of the palpebral reflexes seemed to be of prognostic significance to the reappearance of cortical visual functions.