The efficacy of optic nerve sheath decompression for anterior ischemic optic neuropathy and other optic neuropathies.

First proposed by De Wecker! in 1872 as a treatment for neuroretinitis, optic nerve sheath decompression (or fenestration) is an operation that has caused much controversy. This surgical therapy was not seriously considered until Davidson" and Smith, Hoyt, and Newton" reintroduced it in 1969 as an alternative therapy for chronic disk edema. Over the next 19 years, however, only about 60 cases of optic nerve sheath decompression were described in the literature.v" This operation was not widely accepted until 1988, when Brourrnan, Spoor, and Ramocki.? Sergott, Savino, and Bosley." and Corbett and associates" simultaneously published their series of cases for which they used optic nerve sheath decompression as a treatment for pseudotumor cerebri. Keltner" stated the operation had merit and recommended that it be performed soon after failure of medical therapy for pseudotumor cerebri. Now, as optic nerve sheath decompression has finally become accepted as an effective and safe surgical treatment to limit visual loss in pseudotumor cerebri. great controversy surrounds its use as a treatment for anterior ischemic optic neuropathy. In 1989, Sergott and associates" suggested that optic nerve sheath decompression might improve the visual course in the progressive form of anterior ischemic optic neuropathy, a variant of anterior ischemic optic neuropathy that is characterized by progressive deterioration of visual function over several weeks." The relatively prolonged cadence of progressive anterior ischemic optic neuropathy suggested that surgical intervention might be of benefit. Sergott and associates'" used optic nerve sheath decompression in 14 eyes of 14 patients with progressive anterior ischemic optic neuropathy. They described visual improvement in 12 of these 14 eyes, compared with no improvement in 12 untreated eyes that were similarly afflicted. Other investi-