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

The presence of disorders of eye movements is today regarded as 'the strong est candidate for a genetically transmitted biological trait marker of schi zophrenic disorders' (1). The present study is based on the experience, rat her than the behaviour, of one patient in a search for a method of objectif ying his visual problems. This method was found to be a simple test, which demonstrates a disturbance of fixation: while one eye accommodated on the f igure without vergence, the other, vergent, eye fused with the image of the related background. The disorder had been misdiagnosed as 'exophoria' in conventional ophthalmo logical examinations, because prevailing ophthalmological theory accepts on ly one mode of vision; according to the most recent researches, however, it is necessary to distinguish two complementary modes of vision - one for pa norama and one for detail which differ in their coordination of vergence an d accommodation. This new bimodal theory of vision - presented here for the first time - mad e it possible to understand the cause of the disorder as a substitution of sighting for fixation, due either to a disinhibition of panorama vision dur ing fixation vision, or to an interchange of ipsilateral temporal and contr alateral 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.