Pons. (Medial pontine syndrome affects structures at the bottom of the diagram: the corticospinal tract, abducens nerve, and occasionally the facial nerve. Medial lemniscus is also affected, but not pictured.)
Strabismus (ipsilateral lateral rectus muscle paralysis - the affected eye looks down and towards the nose). Abducens nerve lesion localizes the lesion to inferior pons.
Depending upon the size of the infarct, it can also involve the facial nerve.
^Hubloue I, Laureys S, Michotte A (September 1996). "A rare case of diplopia: medial inferior pontine syndrome or Foville's syndrome". Eur J Emerg Med. 3 (3): 194–8. doi:10.1097/00063110-199609000-00011. PMID9023501.