Anterior ischemic optic neuropathy. V. Optic disc edema an early sign
S. S. Hayreh
Four unusual patients had bilateral anterior ischemic optic neuropathy
(AION). In all four cases, AION developed in the first eye with the classic
presentation. The fellow eye had symptomless optic disc edema (ODE) with no
subjective or objective visual loss initially, but the classic AION
clinical picture developed later on. The findings indicate that symptomless
ODE may precede the visual loss in AION and could constitute the earliest
sign of this disease. Since ODE in AION is due to axoplasmic flow stasis
that, by itself, does not produce visual loss (this is produced by
disruption of visual impulse transmission), this would suggest that mild
optic nerve head ischemia interferes with axoplasmic flow without
disrupting the visual impulse; however, more severe ischemia would disrupt
both. Possible effects of various grades of acute optic nerve head ischemia
are discussed.
