Vitamin deficiency causing optic atrophy -

Ans. is 'b' i.e. Vitamin B Nutritional optic atrophyo The exact mechanism by which nutritional deficits damage the optic nerve has not been elucidated. Although the etiology is likely multifactorial, most clinicians agree that in patients who abuse ethanol and tobacco, malnourish- ment is often present and undemutrition, rather than direct toxicity, is the principal cause of the visual loss. Specific deficiencies of vitamin B-12 (cyanocobalamin), thiamine (vitamin B-1), other B-complex vitamins (riboflavin, niacin, and pyridoxine), and folic acid, as well as reduced systemic levels of other proteins with sulfur-containing amino acids, may play a role.Causes of optic atrophyo Compressive - secondary to papilledema, tumor, bony growth (fibrous dysplasia, osteopetrosis), thyroid eye disease, chiasmal (pituitary etc), optic nerve sheath meningioma, disc drusen, increased intraocular pressure (glaucoma)o Vascular - arteritic and non-arteritic ischemic optic neuropathy, diabeteso Inflammatory - sarcoid, systemic lupus, Behcet's, demyelination (MS), etc.o Infectious - viral, bacterial, fungal infections - herpes, TB, bartonella, etc.o Toxic & nutritional - many medications such as ethambutol, amiodarone, methanol, vitamin deficiency etc.o Metabolic - diabeteso Neoplastic - lymphoma, leukemia, tumor, gliomao Genetic - Autosomal dominant optic atrophy (OPA1), Leber's hereditary optic atrophy, Leber's hereditary optic neuropathy, as a late complication of retinal degneration.o Radiation optic neuropathyo Traumatic optic neuropathy