10. Night blindness (nyctalopia) and photophobia. People with some nutrient deficiencies (most notably, vitamin A) can become the victims of some bizarre eye problems, such as night blindness, a condition that permits people to see okay in the day time but to have very poor eyesight at night or in the absence of bright light. In some extreme cases, people may even become sensitive to any light in general (photophobia) or go blind permanently.
Conclusion
The sad fact is that vitamin deficiencies are very common these days, even in developed countries. In general, these deficiencies may not necessarily lead to severe medical problems or, less likely, death; they can, however, help open the door for more sinister medical complications. One egregious example is the weakening of the immune system.
Because vitamin deficiencies do occur more often than some people assume, they should always be considered by medical personnel, especially if certain key symptoms are observed. For your part, make sure that you get regular blood work, eat a balanced diet, and stay alert for any unusual signs and symptoms.
References & Resources
1. Yater, Wallace Mason. (1989). Fundamentals of Internal Medicine. New York: Appleton Century Crofts.
3. http://www.healthsupplementsnutritionalguide.com/vitamin-deficiency-symptoms.html