Optic nerve sheath decompression for pseudotumor cerebri.

We studied optic nerve sheath decompressions for pseudotumor cerebri performed at the Kresge Eye Institute, Detroit, over the past year. Six patients (ten eyes) were operated on. Visual function improved in all ten eyes. A decision to operate was based on progressive loss of visual acuity or visual field unresponsive to medical therapy, accompanied by echographic evidence of a distended optic nerve sheath (positive 30 degrees test). Follow-up ranged from four to 11 months. Four patients underwent subarachnoid iopamidol (Isovue) contrast injection followed by orbital computed tomography. The subarachnoid space totally filled in all patients. No evidence of fibrosis or obstruction of the optic nerve sheath existed; however, leakage of dye from the optic nerve sheath could not be demonstrated. Postoperative complications included transient diplopia and transient atonic pupil (one patient each). Our results indicate that optic nerve sheath decompression improves and protects visual function in patients with pseudotumor cerebri who demonstrate progressive visual field loss and fluid in the optic nerve sheath.