A 17-year-old boy who lived on French fries, Pringles potato chips and processed ham has gone blind because of a lack of vitamins in his diet.
The fussy-eating teenager from Bristol, the United Kingdom, who is now 19, hadn't eaten a fruit or vegetable in a decade.
His only daily meal was a portion of French fries, which was accompanied throughout the day by potato chips, deep-fried sausages and the occasional ham sandwich.
The unnamed student, who has had to drop out of studying IT at college, was deficient in several key vitamins, including vitamin B12, copper and vitamin D.
He slowly lost his sight over the course of three years, starting when he was 14, due to a condition known as Nutritional Optic Neuropathy (NON).
He was a normal height and weight, but the lack of vital nutrients caused irreversible damage to the nerve in the back of his eyes, leaving him registered blind.
Speaking to the Times, he said: “I've become very isolated. When I was little I'd go out and play football with my friends. I'm too frightened to do that now.”
He believes that doctors he pleaded for advice could have helped him earlier by providing help with his diet, which they only began to question at a progressed stage.
“When I asked for help, they didn't listen to me,” he added.
His mum, who quit her pub job to look after him, told the Telegraph: “His sight went downhill very fast – to the point where he is now legally blind.
“He has no social life to speak of now. After leaving school he got into college to do a course in IT. But he had to give it up because he could not see or hear anything.
“He would love a job – but he has not been able to find anything he can do. I had to quit my job in a pub. I now look after him full-time.”
The optic nerves are made up of millions of fibres and are responsible for transferring visual information from the retina to the brain.
When the fibres become damaged due to a lack of vitamins, the optic nerve loses its ability to relay messages to the brain.
Nutritional optic neuropathy is a slow, painless condition that sees the gradual decrease in vision.
It is sometimes accompanied by colour-vision dysfunction and if left untreated leads to permanent blindness.
B Vitamins, found in whole foods and leafy vegetables, are vital to maintaining good eyesight.
Medics at Bristol Eye Hospital revealed the tale in the Annals of Internal Medicine's case reports.
Its lead author, Dr Denize Atan, told MailOnline: “He has only eaten French fries, Pringles potato chips, sausages and other processed foods since he was primary school age.
“It's the most serious case I've ever seen of blindness caused by junk food.
“He was clearly getting enough calories, but not nutrients. When the problems started he seemed, on the outside, like a healthy 14-year-old boy.
“His family actually bought him the French fries because if he didn't eat them, then he wouldn't eat anything. They tried hard to introduce veg and fruit to his diet.
“He is now registered blind and can only read the top letter on an optician chart. He also has a blind spot in the middle of his eyes.
“He has maintained his peripheral vision, so he is still able to navigate. But he has caused permanent damage to the optic nerve, which can't repair itself.”
She revealed the teenager has still not changed his diet, but is receiving treatment for an eating disorder and taking vitamin supplements.
Dr Atan added: “Doctors and families need to be aware that having a poor diet and eating Pringles all day doesn't just affect your heart and lead to obesity. It can also damage vision.”
The boy had initially gone to his GP at the age of 14 complaining of tiredness.
Tests showed he had anaemia and wasn't producing enough red blood cells to meet his body's needs.
He was treated with vitamin injections and advised to eat a varied diet with plenty of meat, fruit and vegetables.
But when his symptoms failed to subside he began experiencing hearing loss and impaired vision by the age of 15.
Puzzled medics carried out a number of tests on the boy, who had a normal BMI and was not taking medication, but no cause was found.
By 17, the patient's vision had become progressively worse, to the point of blindness.
Further medical checks discovered he had vitamin B12 deficiency and low copper and selenium levels – tell-tale signs of nutritional optic neuropathy.
By the time he was diagnosed with the condition, the patient had become permanently blind.
He was prescribed nutritional supplements that corrected his deﬁciencies and was referred to mental health services for his eating disorder.
Obesity and cancer patients are normally those most at risk of suffering from the condition.
But poor nutrition can also permanently damage the nervous system, particularly vision.
Purely dietary causes are rare in developed countries, the authors note.
Writing in the case study, they said: “Junk foods are nutritionally poor but energy-dense and cheap.
“Hence, high-energy diets correlate with high BMI, low socioeconomic status, and poor health.
“Fussy eating that is restricted to junk foods and causes multiple nutritional deﬁciencies is an eating disorder.
“Avoidant-restrictive food intake disorder is a relatively new diagnostic entity, but unlike anorexia nervosa, it is not driven by weight or shape concerns.
“Onset is in middle childhood, with lack of interest in food, heightened sensitivity to food textures, and fear of the consequences of eating.” – DAILY MAIL