I found it:
Why are vertebrate nervous systems crossed?
Med Hypotheses 1995 Nov 45:5 471-5
Contralateral central nervous control may be an evolutionary consequence of
dependence on the image-forming eye, especially in large organisms. As a
result of the topological transformation of the visual stimulus in the
pupillary eye, the external environmental hemispace impinges directly upon
the contralateral internal organismal hemispace. Selective pressure leads to
the development of central connections capable of the most rapid and precise
functional association of the internal milieu with the organism's
environment. The consequence is contralateral central sensorimotor control.
Previous hypotheses are discussed, including those based on bilaterality,
binocularity the optic chiasm and avoidance behaviors.