Nutritional optic neuropathy (aka deficiency optic neuropathy) is a dysfunction of the optic nerve resulting from improper dietary content of certain nutrients essential for normal functioning of the nerve fibers. Most commonly, it results from folic acid and vitamin B complex deficiency associated with malnutrition or poor dietary habits, incorrectly applied vegetarian diet, or chronic alcohol abuse. Obese patients after bariatric surgery constitute another risk group of optic neuropathy. Nutritional optic neuropathy is characterized by painless, gradually progressing, bilateral and symmetrical decrease in visual acuity, which can be accompanied by the color vision dysfunction. Progression of the neuropathy is associated with optic nerve atrophy, manifesting as complete disc pallor. Treatment of nutritional neuropathy includes dietary supplementation, aimed at compensating for the deficient nutrients. The treatment is mostly based on folic acid, vitamin B complex, and protein replacement, as well as eliminating risk factors of neuropathy. Early treatment commencement, prior to irreversible optic nerve atrophy, is a prerequisite of effective treatment. We would like to highlight this problem by presenting the case of a young woman in whom chronic use "water-based" diet resulted in anemia and bilateral nutritional optic neuropathy.