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Strong alcoholic beverages (e.g. moonshine) are reported to have caused blindness amongst some people.

How exactly can alcohol make someone go blind?

Is that because different forms of "rubbing" and homemade alcohol: ethanol, methanol, isopropyl and moonshine cause damage to the optic nerve?


Disclaimer: I am interested in what exactly is the biological process of certain alcohols on the optic nerves and what in particular triggers the blindness.

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  • $\begingroup$ It'd be better if you cite such a report. $\endgroup$ – another 'Homo sapien' May 25 '16 at 9:07
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    $\begingroup$ Why do you first talk about homemade alcohol (moonshine) and then about rubbing alcohol? Both have no connection. Can you please clarify this? $\endgroup$ – Chris May 25 '16 at 10:27
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    $\begingroup$ Methanol is probably the culprit in those cases. As little as 30mL of pure methanol can kill a person. While it's pretty safe to handle as long as you don't drink it, my lab here in Japan won't let me use it outside a hood designated for toxic substances. The reason it's so toxic is because it gets metabolized to formic acid. $\endgroup$ – user137 May 25 '16 at 10:44
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    $\begingroup$ @user137 As long as you do not drink it or pour it in large quantities over your skin (it will be taken up to some amount) you are pretty safe. This is the typical overreaction of safe guard measures. $\endgroup$ – Chris May 25 '16 at 11:01
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    $\begingroup$ @WYSIWYG I got the information from Wikipedia, " The conversion to formate via ALDH proceeds completely, with no detectable formaldehyde remaining. Formate is toxic because it inhibits mitochondrial cytochrome c oxidase, causing hypoxia at the cellular level, and metabolic acidosis, among a variety of other metabolic disturbances." This suggests that the formaldehyde doesn't stick around long enough to be an issue, and that formate itself is also toxic. Wikipedia could be wrong though. $\endgroup$ – user137 May 25 '16 at 14:34
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Methanol is rapidly absorbed not only after oral ingestion but by inhalation or after cutaneous exposure and becomes oxidised in the liver to formaldehyde and to formic acid, metabolites which are more toxic than methanol itself and which inhibit mitochondrial ATP production.

Histopathologically, circumscribed myelin damage behind the lamina cribrosa of the optic nerve has been reported. The electrophysiological changes following acute methanol ingestion suggest that methanol affects photoreceptors, Muller cells, and the retrolaminar portion of the optic nerve.

Source : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1771266/

Several years ago there were numerous cases of blindness and death due to Methanol in Estonia.

If you ask : What exactly happened?

Waste from wood (sawdust, shavings), and other cellulose-containing materials (paper, rags, etc.) can be processed by applying excessive heat and acids, resulting in degraded cellulose into sugar (glucose). Sugar obtained is fermented to get ethanol. However as a side-effect, some methanol is produced as well. This compound is not safe to drink. Basically, someone sold it (illegally) as an ethanol drink (I am not sure if they stole it and tried to monetize it this way.).

There was a (stupid) joke that somewhat popularized knowing about this problem:

(roughly translates to) "Guys, let's drink faster, it is getting dark."

Other impurities in the alcohol could have similar effect, but I can confirm at least the methanol part.

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    $\begingroup$ You can perhaps add that the toxicity is because of formaldehyde which is formed by oxidation of methanol in the body. $\endgroup$ – WYSIWYG May 25 '16 at 13:27

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