Chronic papilledema from pseudotumor cerebri can cause progressive visual loss despite functioning lumboperitoneal shunts. The authors performed modified optic nerve sheath decompression in 12 patients (16 operations) with functioning lumboperitoneal shunts and progressive visual loss. All of the patients demonstrated improvement in visual function. Optic nerve sheath decompression allows release of localized cerebrospinal fluid (CSF) pressure. By performing optic nerve sheath decompression, progressive visual loss secondary to chronic papilledema can be halted and reversed.