Healthy vision relies on a range of factors, from genetics to a healthy diet. Nutritional deficiencies, including a vitamin B-12 deficiency, has the potential to cause vision problems. Although double vision is not a common symptoms for a vitamin B-12 deficiency, the neurological problems caused by a lack of this vitamin could result in double vision. Talk to your doctor if you develop visual problems in order to determine what is causing your symptoms.
Vitamin B-12 Physiology
Vitamin B-12 primarily comes from animal-based foods, such as eggs, dairy products and meat. Your body needs vitamin B-12 to make nucleic acids, which are the building blocks for DNA. You also need vitamin B-12 to speed many chemical reactions, to make red blood cells and to make a substance known as myelin. Myelin forms a protective sheath around nerves and allows nerve signals to be conducted more quickly.
Double Vision Causes
The eyes normally move together to send the brain signals, which the brain can then form into a single image. If both of your eyes are not moving in a concerted effort, the brain will interpret the signals into two different images, resulting in double vision or diplopia. One thing that can cause diplopia is if one of your eyes cannot move properly; this can be due to a neurological problem that affects the cranial nerves that control eye movement.
Vitamin B-12 Deficiency and Diplopia
If you have a vitamin B-12 deficiency, your body will have trouble making myelin, which can ultimately cause neuropathy. This can affect the cranial nerves, resulting in vision problems due to difficulty in moving your eyes. Although double vision is not a common manifestation of a vitamin B-12 deficiency, a 2010 article in "Case Reports in Medicine" details a case of double vision in a young man caused by a vitamin B-12 deficiency.
If you experience double vision or other vision problems, talk to your doctor. If your double vision is not treated, your eye may begin to ignore visual signals from one of your eyes, resulting in the loss of vision in one eye. Your doctor can determine if your double vision is due to a lack of vitamin B-12 by doing blood tests. Talk to your doctor before taking vitamin B-12 or other supplements and do not attempt to diagnose vision problems on your own.