A teenage boy has gone blind after living on a diet of Pringles, fries, plain white bread, and occasional processed meat.
The boy from Bristol, England, described in the Annals of Internal Medicine, first began experiencing health problems at 14 years old. He began to suffer problems with his hearing, for which he and his family sought medical treatment. Poor vitamin intake due to his diet was quickly identified as the problem.
"His diet was essentially a portion of chips from the local fish and chip shop every day," Dr Denize Atan, who treated him at Bristol Eye Hospital, told BBC News. "He also used to snack on crisps – Pringles – and sometimes slices of white bread and occasional slices of ham, and not really any fruit and vegetables."
He was diagnosed with a vitamin B12 deficiency. The vitamin, found mainly in fish, meat, dairy, and eggs, is crucial for brain function as well as forming red blood cells, new DNA, proteins, hormones, and fats. If left unchecked, vitamin B12 deficiency can lead to optic neuropathy, progressive, painless vision loss often associated with reduced color vision, as well as other strange conditions.
The boy, described as a "fussy eater" by doctors but otherwise well, was given supplements and advice on how to improve his diet.
The teenager suffered from Arfid (avoidant restrictive food intake disorder), a sometimes debilitating eating disorder where sufferers limit their intake based on appearance, texture, presentation, taste or past negative experiences with the same food. People with the condition, who often also suffer from anxiety, may limit their food intake at a detriment to their health.
Against medical advice, he did not continue with his supplements. Three years later, he returned to the doctor, this time for loss of vision.
"He had blind spots right in the middle of his vision," said Atan. "That means he can't drive and would find it really difficult to read, watch TV or discern faces."
He now meets the criteria for being registered legally blind and is unable to drive, though his functional peripheral vision means he is able to walk around unaided. Again, his poor diet was found to be the cause of his problems.
"He explained this as an aversion to certain textures of food that he really could not tolerate, and so chips and crisps were really the only types of food that he wanted and felt that he could eat," Dr Atan explained to the BBC.
If nutritional optic neuropathy is caught early enough, it can be treated. However the teenager's eyesight had deteriorated quickly, according to his mother, and nobody had spotted any other obvious signs of poor health.
"He has always been skinny so we had no weight concerns," she said. "You hear about junk food and obesity all the time – but he was as thin as a rake."
Despite his outward signs of good health, he was severely malnourished and had suffered a loss of minerals in his bones, and referred to mental health services for his eating disorder.
"[His initial doctors] said it was all in his head. By the time they realised what was wrong it was too late to save his sight," his mother told doctors at the eye hospital.
“The whole ordeal has been very traumatic. I want to scream about what we have gone through."