Eating a diet of junk food was enough to make one teenage boy lose his sight. That’s according to a case study published in a medical journal. Scientists from the University of Bristol examined the case of a young patient whose extremely picky eating led to blindness. The unidentified patient told doctors he had only eaten french fries, Pringles potato chips, white bread, and slices of processed ham and sausage since elementary school. He first visited a doctor at age 14, complaining of tiredness, according to a case report published in the Annals of Internal Medicine. Doctors discovered low vitamin B12 levels and anemia, treating the patient with vitamin B12 injections and offering dietary advice. One year later there were signs of hearing loss and vision symptoms…and by the age of 17, his vision had worsened to the point of blindness. Doctors say the patient’s extreme diet led to nutritional optic neuropathy…and that the boy’s vision damage is permanent. Researchers warn that nutritional optic neuropathy could become more common due to the consumption of junk food.