The accumulation of formic acid is responsible for the presence of metabolic acidosis. Formic acid also inhibits cellular respiration leading to lactic acidosis. The ocular injury caused by methanol may be due to retinal injury, which results from intra-retinal metabolism of methanol and the accumulation of formic acid. Alternatively, it may be caused be the inhibition of normal metabolism in optic nerve calls (Jacobsen 1997).

What is so special in Formic acid accumulation which leads to blindness as a result of retinal damage (accumulation of toxic metabolites and inhibition of metabolism is a general mechanism for other toxicities also) ?