Determining role of the optic vesicle in orbital and periocular development and placement.

Nine patients with aberrations in development and placement of the eyes and periocular structures who also had serious defects in central nervous system development were evaluated in order to better understand normal ocular development. Included were an incompletely developed twin stillborn infant who lacked both eyes and the nose, a stillborn infant with cyclopia hypognathia, 6 spontaneous abortuses with varying degrees of holoprosencephaly, and a 17-year-old male with a serious defect in central nervous system development whose right eye was positioned laterally above the right ear. In all cases, evidence indicates that orbital and periocular structures are determined by the underlying optic vesicle rather than independently derived as has been suggested by previous studies.