To the Editor.
—In their article in the December 1991 issue of the Archives, Rizzo and Lessell1 reported considerable overlap between the clinical profiles of optic neuritis and anterior ischemic optic neuropathy (AION). The experience of the Optic Neuritis Treatment Trial (ONTT) provides further support for the existence of this overlap.2One of the major clinical features that have been cited for many years as differentiating optic neuritis from AION is the pattern of visual field defects. Among the patients entered into the ONTT, we were surprised to find a high incidence of altitudinal and other nerve fiber bundle types of field defects that, prior to the ONTT, we felt were more typical of AION. Rizzo and Lessell's findings were similar.The ONTT experience and that of Rizzo and Lessell also clearly indicate overlap between AION and optic neuritis in the course of visual loss, the presence of
Beck RW. Optic Neuritis or Anterior Ischemic Optic Neuropathy?. Arch Ophthalmol. 1992;110(10):1357. doi:10.1001/archopht.1992.01080220019002