A teenager has gone blind and partially deaf after years of eating a diet made up of crisps and chips.
The boy, 17, who cannot be named, went years without eating fruit or vegetables because he was a “fussy eater”.
His junk food diet consisted solely of crisps, chips, white bread and processed meats.
The case was revealed in the Annals of Internal Medicine journal after the boy was treated at Bristol Eye Hospital.
Researchers said the boy first presented to his doctor aged 14, complaining of tiredness.
Aside from being labelled a "fussy eater", the Bristol boy took no medication and had a normal body mass index (BMI).
Tests showed he had low vitamin B12 levels and macrocytic anaemia - a condition bringing larger-than-normal red blood cells.
He was given B12 injections and dietary advice, but when he returned a year later he had developed some hearing loss and impaired vision, though still no cause was found.
"By age 17, the patient's vision had become progressively worse, to the point of blindness," the report said.
Investigating the boy's nutrition, physicians found vitamin B12 and vitamin D deficiencies, a reduced bone mineral density, low levels of copper and selenium, and a high zinc level.
"The patient confessed that since elementary school, he had avoided foods with certain textures and only ate French fries, Pringles, white bread, processed ham slices, and sausage," the report said.
"By the time his condition was diagnosed, the patient had permanently impaired vision."
The report cautioned that nutrition-related optic damage should always be considered by doctors finding any patient with unexplained vision symptoms.
"The risks for poor cardiovascular health, obesity and cancer associated with junk food consumption are well known, but poor nutrition can also permanently damage the nervous system, particularly vision," the report said.
"It is rare in developed countries. The condition is potentially reversible if caught early. But if left untreated, it leads to permanent blindness."