Neuro-ophthalmologic findings in patients with rhombencephalosynapsis.

Rhombencephalosynapsis is a rare, sporadic, posterior fossa malformation characterized by agenesis of the cerebellar vermis, dorsal fusion of the cerebellar hemispheres, and fusion of the dentate nuclei and superior cerebellar peduncles. Ophthalmologic findings in patients with rhombencephalosynapsis have not been described in detail. Optic nerve and chiasmal hypoplasia were reported in two patients. Strabismus has been noted in several patients; however, specific details were not provided. We describe the association of A-pattern strabismus and superior oblique overaction with rhombencephalosynapsis.