Yes—though it is uncommon and typically warrants careful evaluation. Because vitamin B12 is crucial for the nervous system, deficiency can, in some cases, affect the optic nerve (optic neuropathy) and lead to visual problems. A typical presentation described in the medical literature is painless, bilateral, progressively reduced vision and impaired color perception. It can begin subtly and be mistaken for routine fatigue, so B12 assessment becomes more relevant when visual changes coexist with neurological symptoms (numbness, balance issues), anemia signs, malnutrition, or long-term dietary/absorption risk factors. A critical reality: most blurred vision is not caused by B12 deficiency—refractive errors, dry eye, migraine, and metabolic fluctuations are far more common. Still, B12-related optic neuropathy should not be dismissed because early diagnosis and treatment may reduce the risk of permanent damage. Diagnosis is typically based on blood tests (B12 and, when appropriate, MMA/homocysteine), plus eye and neurological assessment. Treatment is tailored to the cause (dietary deficiency, malabsorption, medication-related issues); it is not always as simple as “take a supplement.” Seek urgent care if vision loss is rapidly progressive, markedly asymmetric, accompanied by pain/flashes, or associated with neurological symptoms. Bottom line: B12 deficiency can affect vision, but it is not a routine explanation—it requires proper clinical workup and management.