ISCHEMIC-INJURY OF OPTIC-NERVE AXONS - THE NUTS AND BOLTS

Anterior ischemic optic neuropathy is the most common cause of persist ent monocular visual loss in persons over the age of 50. At the heart of this form of optic neuropathy is a sequence of cytoplasmic and memb rane events that culminate in axonal destruction. Early depletion of A TP is followed by membrane depolarization, influx of Na+ and Ca2+ via specific voltage-gated channels and reverse operation of the Na+/Ca2exchange protein. Toxic Ca2+ overload is the ultimate consequence of t hese events. Preventing or modulating any of these well-defined steps mitigates against the development of anoxic injury. Translating these molecular insights about how optic nerve axons are damaged by ischemia -like conditions into clinical gains remains the challenge for the fut ure. (C) 1997 Wiley-Liss, Inc.