A 31-year-old woman who had lost 240 lbs following bariatric surgery 3 years ago presented with decreased vision. The patient was found to have deficiencies of folate and vitamin B 1 , and to a lesser degree vitamins B 6 and B 12 . The patient was treated with vitamin supplementation but without improvement. Bariatric surgery is known to cause B vitamin and folate deficiencies, which can lead to both serious ocular and neurological complications. This is important as the incidence of obesity increases and thus the number of bariatric procedures. It is paramount that patients undergoing these procedures and their physicians be made aware of the need for vitamin supplementation to prevent nutritional optic neuropathy.