Blindness seen in methanol poisoning is due to?
**Core Concept**
Methanol poisoning is a toxic condition caused by excessive ingestion of methanol, leading to severe metabolic acidosis, visual disturbances, and potential blindness. The pathophysiology involves the metabolism of methanol to its toxic metabolites, formic acid and formaldehyde.
**Why the Correct Answer is Right**
The correct answer involves the formation of formic acid, a potent inhibitor of mitochondrial cytochrome c oxidase enzyme. This enzyme plays a crucial role in the electron transport chain, leading to impaired cellular respiration and energy production. The accumulation of formic acid in the retina causes selective damage to the retinal ganglion cells, resulting in visual disturbances and potentially permanent blindness. The optic nerve is particularly susceptible to the toxic effects of formic acid, leading to the characteristic visual symptoms of methanol poisoning.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the correct mechanism of methanol-induced blindness. While methanol itself is toxic, its metabolites, particularly formic acid, are responsible for the visual disturbances.
* **Option B:** This option is incorrect because it does not accurately describe the pathophysiology of methanol-induced blindness. Methanol poisoning does not primarily cause blindness through the inhibition of glycolysis.
* **Option C:** This option is incorrect because it does not specify the correct mechanism of methanol-induced blindness. While methanol poisoning can cause metabolic acidosis, it is the formation of formic acid that directly leads to visual disturbances.
**Clinical Pearl / High-Yield Fact**
Methanol poisoning is a classic example of a toxic condition that can be treated with fomepizole, a specific inhibitor of alcohol dehydrogenase, the enzyme responsible for the first step in methanol metabolism. Early recognition and treatment of methanol poisoning are critical to prevent the formation of toxic metabolites and minimize visual damage.
**Correct Answer: C. Formic acid inhibition of mitochondrial cytochrome c oxidase enzyme.**