What substance, when metabolized from methanol, can cause blindness?

When methanol is metabolized in the body, it is converted into several toxic byproducts, one of which is formic acid. This substance is particularly harmful and is responsible for the severe metabolic acidosis and ocular toxicity associated with methanol poisoning.

Formic acid can lead to retinal damage and ultimately result in visual impairment or blindness. The mechanism by which formic acid induces these effects is thought to involve the inhibition of mitochondrial respiration, which causes cellular damage, particularly in the optic nerve and retina. This is why recognition of formic acid as a significant metabolite is crucial in the context of methanol toxicity.

Acetic acid is also a metabolite of methanol but does not have the same toxic effects related to vision. Oxalic acid is associated with ethylene glycol metabolism rather than methanol. Ethylene glycol itself leads to different repercussions within the body, primarily kidney injury and metabolic acidosis, rather than directly causing blindness via its metabolites.