A teenager in the UK has gone blind and deaf after eating only chips and sausages for a decade.
Doctors say his illness was caused by a serious vitamin deficiency, with health experts pointing to the case as a sombre reminder that having a poor diet doesn't only affect your weight and heart, but also your vision.
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The teen, now aged 19, stopped eating normally when he was around seven years old, his mother told the Independent.
"The first we knew about it was when he began coming home from primary school with his packed lunch untouched," his mother, who didn't want to be named, said.
"I would make him nice sandwiches and put an apple or other fruit in and he wouldn't eat any of it. His teachers became concerned too."
From that time on, she said, he ate only chips, Pringles, sausages, processed ham and white bread.
Despite his bad diet, he was "as thin as a rake", the mother said, so the family had no concerns about his weight.
However, when the boy was aged around 14, he began to lose his hearing, and then eventually his sight, too.
"His sight went downhill very fast – to the point where he is now legally blind," his mother said.
"We are told the damage is irreversible; it's been a nightmare."
According to the Independent, the boy was later diagnosed with an eating disorder called avoidant-restrictive food intake disorder (ARFID). Those suffering from ARFID avoid food with a certain texture, smell, taste or appearance, or only eat food at a certain temperature.
His diet caused him to be deficient in vitamin B12, vitamin D and copper. The lack of nutrition then caused severe damage to his optic nerve, resulting in a condition known as optic neuropathy.
Dr Denize Atan, who cared for the boy, said the damage is permanent.
"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," she told the Daily Mail.
"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.
"It's the most serious case I've ever seen of blindness caused by junk food."
Dr Atan said the case was a lesson for parents to be vigilant in making sure their children were eating a balanced diet.
"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."
Despite the damage caused by the teen's diet, Dr Atan said he still had not changed his eating habits.