Orbital hydrocephalus: a proven cause for optic atrophy

A 4-year-old boy with bilateral optic sheath enlargement and progressive op tic atrophy and blindness is presented. Computed tomography demonstrated hy drocephalus and enlargement of the optic nerve sheath complex. The child di ed during an attempted repair of hypoplastic atrioventricular valves. Autop sy demonstrated a patulous perioptic subarachnoid space and optic atrophy. This condition has been described in the literature but has not had radiolo gic-pathologic correlation. With the availability of magnetic resonance ima ging, this diagnosis may be made prospectively, thus, it is important for t he radiologist to be aware of this entity because optic atrophy and blindne ss may be prevented by early diagnosis and surgery.