THE NEURAL LOCUS OF BINOCULAR-RIVALRY AND MONOCULAR DIPLOPIA IN INTERMITTENT EXOTROPES

PATIENTS With intermittent exotropia (strabismus) can either fixate no rmally or allow one eye to deviate outward by as much as 60 degrees. T wo such patients (D.N. and K.C.) were studied and it was found that du ring eye deviation, binocular correspondence is maintained by complete ly 'remapping' egocentric space for the deviating eye alone using extr aretinal signals from that eye. Also, by using foveal afterimages we s howed that binocular rivalry occurs at a site earlier than this egocen tric remapping, probably in area 17 itself. And finally, consistent wi th the neural remapping hypothesis, patient K.C. also experienced mono cular diplopia; objects appeared double when viewed with the deviating eye.