We thank Dr Cullen for his interest in our editorial and thoughtful comments. With regard to the expressed notion that hyperemia and edema should indicate optic nerve head ischemia, one should recognize that in bona fide ischemic optic neuropathy such as in giant cell arteritis that Dr Cullen refers to in an earlier article from his Singapore series on ischemic optic neuropathy (ION),1 it is pallor rather than hyperemia that is the predominant sign. We believe that the noted hyperemia in so-called nonarteritic anterior ischemic optic neuropathy (NAION) is indicative of an altogether different process at hand.

A 92-year-old woman had her right eye removed for a submacular choroidal melanoma. Four weeks before surgery her vision was counting fingers and intraocular pressure 17 mm Hg. The tumor measured 14.6×9.6 mm and was 4.4 mm thick. The nasal portion of the optic disc was visible and interpreted as normal (Fig A). In the laboratory, the eye was opened horizontally. Histologically, cavernous degeneration of the optic nerve was located nasally (N) opposite the melanoma (Figs B and C). Pial septi were widely dilated.

Katz and associates are most appreciative of the new concept we propose in our editorial. That it is dynamic shear force injury due to epipapillary membrane vitreoglial separation from peripapillary and papillary axons that leads to pathology, heretofore described as nonarteritic anterior ischemic optic neuropathy (NAION). Their eloquent appraisal of our editorial and examples of other English misnomers is music to our ears.

We read with relish the editorial of Parsa and Hoyt arguing for a change in prism through which we see what we had heretofore called nonarteritic anterior ischemic optic neuropathy (NAION).1 Their elegant and cogent summary of consequences and associations of vitreopapillary traction, when collated as they have done, convincingly argue their point. As the English horn is neither English nor a horn, so too, NAION is not ischemic, at least, not primarily so.

Parsa and Hoyt1 in their editorial state that nonarteritic anterior ischemic optic neuropathy (NAION) is not ischemic in nature, but is primarily owing to vitreous traction of the optic disc. They go on to state, “What is the evidence for ischemia in this entity?”