The somatic component of schizophrenia: a dissociation of the goals of visual attention and bifoveal fixation?

Abstract 

The presence of disorders of eye movements is today regarded as ‘the strongest candidate for a genetically transmitted biological trait marker of schizophrenic disorders’ (1). The present study is based on the experience, rather than the behaviour, of one patient in a search for a method of objectifying his visual problems. This method was found to be a simple test, which demonstrates a disturbance of fixation: while one eye accommodated on the figure without vergence, the other, vergent, eye fused with the image of the related background.

The disorder had been misdiagnosed as ‘exophoria’ in conventional ophthalmological examinations, because prevailing ophthalmological theory accepts only one mode of vision; according to the most recent researches, however, it is necessary to distinguish two complementary modes of vision – one for panorama and one for detail – which differ in their coordination of vergence and accommodation.

This new bimodal theory of vision – presented here for the first time – made it possible to understand the cause of the disorder as asubstitution of sighting for fixation, due either to a disinhibition of panorama vision during fixation vision, or to an interchange of ipsilateral temporal and contralateral nasal projections from the retina, both associated with a fixation disparity. After correction of the patient's fixation disparity according to an unusual method, the dissociation of the visual goals was remedied and the mental disturbances of the patient vanished.

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