A British teenager has gone blind after several years of a diet completely lacking in fruit and vegetables, according to medical journal Annals of Internal Medicine.

Researchers from Bristol Eye Hospital 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).

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.

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 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.”