<prompt> A chronic tobacco chewer came to OPD with diminution of vision. Which of the following nutritional supplement can be provided to him:Vitamin B1Vitamin B2Vitamin B6Vitamin B12  <response>: 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. BL centrocecal scotomas are seen. Vitamin B12, 1000 microgram i.m injection weekly. 