You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is A chronic tobacco chewer came to OPD with diminution of vision. Which of the following nutritional supplement can be provided to him: and explain in detail?
Vitamin B12 is used for tobacco associated amblyopia. Tobacco associated amblyopia Seen in men doing heavy smoking, drinking and diet deficient in protein and vitamin B complex. Toxic agent involved is cyanide. B/L centrocecal scotomas are seen. Vitamin B12, 1000 microgram i.m injection weekly.