... Figure 29-11 Chapter 029. Disorders of the Eye (Part 11) Posterior Ischemic Optic Neuropathy This is an infrequent cause of acute visual loss, induced by the combination of severe anemia ... (Fig. 29 -11) without a phase of acute optic disc edema. Many agents have been implicated as a cause of toxic optic neuropathy, but the evidence supporting the association for many is weak. The following ... gradual, painless, severe, central visual loss in one eye, followed weeks or months later by the same process in the other eye. Acutely, the optic disc appears mildly plethoric with surface capillary...