Blood tests showed the unnamed patient from Bristol in the United Kingdom had both macrocytic anemia and low levels of B12, according to a new report.
He was treated with injections and some much-needed dietary advice, although this turned out to only be the beginning of his problems.
The case report, put together by researchers from Bristol Eye Hospital, said the boy's vision had become progressively worse to the point of blindness by age 17.
Optic nerve damage
Tests showed the teen had developed damage to his optic nerve, leading to him developing a condition called nutritional optic neuropathy (NON).
"By the time his condition was diagnosed, the patient had permanently impaired vision," the report, published in Annals of Internal Medicine, said.
He had just 20/200 vision in both eyes, making him legally blind.
The young man also suffered from hearing loss and bone weakness, showing the severe effects a poor diet can have.
"The patient confessed that, since elementary school, he would not eat certain textures of food," the report explained.
The teenager avoided certain textures and chose to only eat French fries, white bread, Pringles, sausages and processed ham slices - although there was a reason for this.
The now 19 year old was found to have an eating disorder called ARFID (avoidant-restrictive food intake disorder) which causes sufferers to often avoid food with a certain texture, smell, taste or appearance.
This article originally appeared on 7NEWS