Letter to the Editor: A Case of Optic Nerve Atrophy with Severe Disc Cupping after Methanol Poisoning

Dear Editor, We read with great interest the interesting case report titled 'A case of optic nerve atrophy with severe disc cupping after methanol poisoning' presented by Yong Woon Shin and Ki Bang Uhm published in the last issue of Korean Journal of Ophthalmology [1]. In the description of the case, the authors mentioned that the patient had metabolic acidosis and mildly elevated methanol levels at presentation; however, only conservative therapy was performed. It seems that the patient was in the acute phase of methanol toxicity at presentation and antidotal therapy (fomepizole or ethanol in association with hypertonic sodium bicarbonate, folic or folinic acid, and even hemodialysis) should have been initiated. Was the patient managed in the ophthalmology department or was he transferred to a clinical toxicology unit for treatment? Were corticosteroids or other treatment modalities initiated for the treatment of his visual disturbance? We would like to ask the authors if the conservative therapy consisted of these modalities or not. And if these treatments were not performed for the patient, what was the reason? According to our experience [2], these treatment modalities could have improved the ophthalmologic signs and symptoms of the patient and even prevented the progression of ophthalmologic sequelae. In such cases, it is acceptable and even necessary to focus on the toxicological management of the methanol-poisoned patient rather than just focusing on the ophthalmologic signs. Furthermore, the authors did not mention anything about the visual condition of the patient during the 4-year period before re-examination of his ophthalmologic status except by history taking. According to our experience [2], patients who present with blindness may experience recovery of vision anytime between a few days until 1 month after hospital discharge which may persist for 1 to 9 months. After this period, they may re-experience reduced vision which may progress to total blindness. Finally, the authors missed the most important follow-up studies mentioned in the literature regarding ocular abnormalities after methanol poisoning, by Dethlefs and Naraqi [3], Ingemansson [4], Onder et al. [5], and Paasma et al. [6].

[1]  K. Uhm,et al.  A Case of Optic Nerve Atrophy with Severe Disc Cupping after Methanol Poisoning , 2011, Korean journal of ophthalmology : KJO.

[2]  N. Zamani,et al.  Outcomes of visual disturbances after methanol poisoning , 2011, Clinical toxicology.

[3]  R. Paasma,et al.  Methanol poisoning and long term sequelae – a six years follow-up after a large methanol outbreak , 2009, BMC clinical pharmacology.

[4]  Hongseok Yang,et al.  A Case of Toxic Amblyopia Caused by Methanol Intoxication , 2007 .

[5]  T. Kansu,et al.  Acute blindness and putaminal necrosis in methanol intoxication , 1998, International Ophthalmology.

[6]  F. Medeiros,et al.  Retinal nerve fiber layer loss after traumatic optic neuropathy detected by scanning laser polarimetry. , 2001, Archives of ophthalmology.

[7]  N. Volpe,et al.  Methanol-induced optic nerve cupping. , 1999, Archives of ophthalmology.

[8]  J. O'day,et al.  Partly reversible visual failure with methanol toxicity. , 1992, Australian and New Zealand journal of ophthalmology.

[9]  H. Savolainen,et al.  Methanol and formic acid toxicity: biochemical mechanisms. , 1991, Pharmacology & toxicology.

[10]  S. Ingemansson,et al.  CLINICAL OBSERVATIONS ON TEN CASES OF METHANOL POISONING WITH PARTICULAR REFERENCE TO OCULAR MANIFESTATIONS , 1984, Acta ophthalmologica.

[11]  C. E. Becker Methanol poisoning. , 1983, The Journal of emergency medicine.

[12]  J. Sharpe,et al.  Methanol optic neuropathy , 1982, Neurology.

[13]  S. Naraqi,et al.  Ocular Manifestations and Complications of Acute Methyl Alcohol Intoxication , 1978, The Medical journal of Australia.

[14]  K. McMartin,et al.  Methyl alcohol poisoning. IV. Alterations of the morphological findings of the retina and optic nerve. , 1977, Archives of ophthalmology.

[15]  K. McMartin,et al.  Methyl alcohol poisoning III. Ocular toxicity. , 1977, Archives of ophthalmology.

[16]  R. W. Hollenhorst Neuropathology of Vision. An Atlas , 1974 .

[17]  C. D. Benton,et al.  The ocular effects of methyl alcohol poisoning; report of a catastrophe involving 320 persons. , 1953, American journal of ophthalmology.

[18]  A. H. Keeney,et al.  Methyl alcohol poisoning. , 1951, Annals of internal medicine.

[19]  O. Roe The ganglion cells of the retina in cases of methanol poisoning in human beings and experimental animals. , 1948, Acta ophthalmologica.

[20]  W H Fink,et al.  The Ocular Pathology of Methyl Alcohol Poisoning. , 1943, Transactions of the American Ophthalmological Society.

[21]  K. McMartin,et al.  Methanol and Ethylene Glycol Poisonings Mechanism of Toxicity , Clinical Course , Diagnosis and Treatment , 2022 .