Letter to Editor Bilateral Optic Disc Edema in a Patient with Lead Poisoning Paolo Pigatto1,2, MD; Gianpaolo Guzzi3, DDS 1Clinical Dermatology, IRCCS Istituto Ortopedico Galeazzi, Milano MI, Italy 2Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy 3Italian Association for Metals and Biocompatibility Research – AIRMEB, Milan, Italy J Ophthalmic Vis Res 2021; 16 (3): 524–525 Dear Editor, In their important contribution as a “Case Report”, Abri Aghdam et al[1] described a man with bilateral optic disc edema due to lead (Pb) poisoning and complicated by opium addiction.[1] This is an excellent description of papilledema induced by Pb overexposure,[1] which is a rare but serious optic nerve damage attributed to systemic Pb toxicity.[2, 3] However, we would like to emphasize the role of whole-blood in diagnosing the Pb poisoning. The patient’s serum contained very high levels of Pb, which was 164 µg/dL.[1] In humans, the normal blood Pb level is zero.[4, 5] We wonder whether whole-blood Pb concentrations were determined. In our view, the serum is not the primary and proper indicator medium as a biomarker of Pb exposure. In fact, serum alone (with no red blood cells) does not adequately reflect the 2% of the total body burden of the Pb, which is found in the circulating whole- blood.[4, 5] Correspondence to: Gianpaolo Guzzi, DDS. Italian Association for Metals and Biocompatibility Research – AIRMEB (not-for-profit organization), Via A. Banfi, 4, 20122 Milan, Italy. E-mail: gianpaolo_guzzi@fastwebnet.it Received: 13-02-2021 Accepted: 13-04-2021 Access this article online Website: https://knepublishing.com/index.php/JOVR DOI: 10.18502/jovr.v16i3.9450 In toxicology, the whole-blood Pb concentrations have been used in conjunction with urinary Pb levels as a primary measure of Pb exposure in humans.[6] Toxicological studies suggest that exposure to Pb during developmental periods may lead to long- term visual deficits both in in vitro and in animal models.[7] Toxic optic neuropathy may be the unique clinically significant alteration in patients with Pb poisoning.[2, 3] Fortunately, Pb poisoning is a rare circumstance not commonly encountered by ophthalmologists.[8–11] Consistent with this notion, Pb and other toxic metals (i.e., organic mercury, thallium) are to be considered “neurotoxicants”, primarily due to toxic effects on the optic nerve.[12–14] With regard to the issue of toxic optic neuropathy, over the past two decades, we have noticed only one case in which papilledema was associated with overexposure to nickel salts. Their interesting case report[1] reminds us that Pb poisoning is a topic of growing interest among ophthalmologists[15] and conveys the fact that the eyes can be injured due to Pb intoxication. This is an open access journal, and articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given and the new creations are licensed under the identical terms. How to cite this article: Pigatto P, Guzzi G. Bilateral Optic Disc Edema in a Patient with Lead Poisoning. J Ophthalmic Vis Res 2021;16:524–525. 524 © 2021 Pigatto and Guzzi. THIS IS AN OPEN ACCESS ARTICLE DISTRIBUTED UNDER THE CREATIVE COMMONS ATTRIBUTION LICENSE | PUBLISHED BY KNOWLEDGE E http://crossmark.crossref.org/dialog/?doi=10.18502/jovr.v16i3.9450&domain=pdf&date_stamp=2019-07-17 https://knepublishing.com/index.php/JOVR Lead Poisoning and Papilledema; Pigatto and Guzzi Financial Support and Sponsorship Nil. Conflicts of Interest There are no conflicts of interest. REFERENCES 1. Abri Aghdam K, Zand A, Soltan Sanjari M. Bilateral optic disc edema in a patient with lead poisoning. J Ophthalmic Vis Res 2019;14:513–517. 2. Boudouresques J, Guillot P. [Papilledema, solitary manifestation of lead poisoning]. Mars Med 1957;94:693– 695. 3. Viaud M, Greau H, Colas J, Baron A, Lhermitte R. [Lead poisoning encephalopathy with papilledema; value of treatment with chelating agents; report of a case]. Rev Otoneuroophtalmol 1958;30:191–198. 4. Guzzi G, Spadari F, Bombeccari GP, Pigatto PD. Maxillofacial gunshot wounds and diagnostic tests for lead in the blood. 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Toxic optic neuropathy. Indian J Ophthalmol 2011;59:137–141. 12. Grzybowski A, Zulsdorff M, Wilhelm H, Tonagel F. Toxic optic neuropathies: an updated review. Acta Ophthalmol 2015;93:402–410. 13. Saldana M, Collins CE, Gale R, Backhouse O. Diet-related mercury poisoning resulting in visual loss. Br J Ophthalmol 2006;90:1432–1434. 14. Pamphlett R, Kum Jew S, Cherepanoff S. Mercury in the retina and optic nerve following prenatal exposure to mercury vapor. PLoS One 2019;14:e0220859. 15. Phelps J. Headliners: lead exposure and vision. Environ Health Perspect 2005;113:A163. JOURNAL OF OPHTHALMIC AND VISION RESEARCH VOLUME 16, ISSUE 3, JULY-SEPTEMBER 2021 525