Sheath Fenestration for AION

Because of the bleak natural history described in the most completely documented natural history studies, non-arteritic ischemic optic neuropathy (NAION) has been considered to be an irreversible cause of visual loss. While the prognosis of NAION has been agreed upon to be grim, the most carefully examined histopathologic material does not support the concept of an end-stage white matter infarction. These studies demonstrate preservation of a large number of axons, patent blood vessels without evidence of occlusion or recanalization,' and retrolaminar intraneural edema as well as fluid accumulation within the retrobulbar subarachnoid space.