Anterior Ischemic Optic Neuropathy After Dental Extraction: Response

Dr. Harvey has questioned why we did not suggest that our patient's ischemic optic neuropathy was related to the use of systemic anesthetic agents rather than due to the local block given for dental anesthesia. We did not discount the possibility of the systemic effects of anesthesia and discussed these in the final 3 paragraphs of our report. We emphasized that our patient had no cardiovascular findings to suggest the systemic effects from anesthesia.

Letters to the Editor Anterior Ischemic Optic Neuropathy After Dental Extraction: Response D r. Harvey has questioned why we did not suggest that our patient's ischemic optic neuropathy was related to the use of systemic anesthetic agents rather than due to the local block given for dental anesthesia. We did not discount the possibility of the systemic effects of anesthesia and discussed these in the final 3 paragraphs of our report. We emphasized that our patient had no cardiovascular findings to suggest the systemic effects from anesthesia. Dr. Harvey continued by citing literature that focused on typical spontaneous and perioperative ischemic optic neuropathy, not the focus of our report. We disagree that ischemic optic neuropathy is a "well-documented" side effect of general anesthetics. He cited a review of perioperative visual loss to assert that intravenous anesthetics cause ischemic optic neuropathy (1). That article does not provide well-documented proof of systemic anesthetics as the cause of ischemic optic neuropathy but does briefly allude to the possibility with the following statement "The use of vasoconstricting agents to correct intraoperative hypotension has also been suggested to promote optic nerve ischemia"(1). He implied that we should have concluded that disturbed autoregulation, a phenomenon one of us has previously suggested may be important in the development perioperative Letters to the Editor: J Neuro-Ophthalmol 2019; 39: 288-289 ischemic optic neuropathy (2), was the culprit for our patient's optic neuropathy. It is likely that there is no single risk factor for all cases of ischemic optic neuropathy. Although autoregulation may be important, there remains no satisfactory way to definitively prove its importance or lack thereof in ischemic optic neuropathy. Speculation that impaired autoregulation is the cause of ischemic optic neuropathy in every patient may limit the study of alternative contributing factors. Although we cannot be certain of the precise mechanism, we maintain that the most likely cause of our patient's ischemic optic neuropathy was likely related to the effects of the local anesthetic block. Rod Foroozan, MD Elizabeth Kravitz, BSA Department of Ophthalmology, Baylor College of Medicine, Houston, Texas The authors report no conflicts of interest. REFERENCES 1. Berg KT, Harrison AR, Lee MS. Perioperative visual loss in ocular and nonocular surgery. Clin Ophthalmol. 2010;4:531- 546. 2. Buono LM, Foroozan R. Perioperative posterior ischemic optic neuropathy: review of the literature. Surv Ophthalmol. 2005;50:15-26. 289 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited.