Live Science6%
Diagnostic dilemma: Junk-food diet caused a teen's permanent blindness 5%
By Mindy Weisberger4%
7/15/2026, 10:00:00 AM
BS Summary: This article contains 14 faulty reasoning types, including Recency Bias, Hasty Generalization, and Ambiguity (Equivocation), with Post Hoc (False Cause) as the most egregious example at 13.7% saturation with 51 hits. Analysis detected 328 faulty-reasoning hits from 371 analyzed words, generating a BS Score of 20.7% and a BS Rank of 5% (15,108 of 15,884 articles). This article is better (less manipulative) than 95.10% of the article peer group.
A teen's nutrient-poor diet led to irreversible vision problems.
A 17-year-old boy in the United Kingdom was referred to a neuro-ophthalmologist because he felt unusually tired.
His doctor described him as a fussy eater, noting that his diet consisted of fast-food french fries, white bread, potato chips, sausages and processed ham.
The teen had avoided most foods since elementary school due to texture issues.
Tests revealed the teen had mild anemia and low levels of vitamin B12, which is essential for red blood cell and nervous system health.
His doctor prescribed B12 injections and advised him on dietary changes.
Later, at age 15, the teen began experiencing vision problems.
An eye exam showed no abnormalities, and the cause of the worsening vision loss remained unknown.
When he was 17, his doctor referred him to a neuro-ophthalmologist for further testing.
Additional vision tests showed the teen had a visual acuity of 20/200 in both eyes, which falls within the parameters of legal blindness.
The ophthalmologist was unable to determine the cause of the vision loss.
However, blood tests revealed that his red blood cells were enlarged, suggesting vitamin deficiencies.
Elevated concentrations of homocysteine and methylmalonic acid, compounds that B12 helps to break down, further indicated a B12 deficiency.
The doctors diagnosed the patient with nutritional optic neuropathy, a rare condition often caused by severe B12 and other B vitamin deficiencies.
This condition leads to atrophy of the optic nerve, which relays visual information to the brain, resulting in vision loss.
The doctors prescribed supplements to correct the deficiencies and referred the teen to mental health services to address his eating disorder.
While his vision loss did not improve, it also did not worsen after treatment.
Nutritional optic neuropathy is rarely caused by dietary deficiencies alone.
Historically, cases have been linked to malnutrition from war and famine, or to restrictive diets not adequately supplemented.
More recent cases have involved vitamin deficiencies combined with smoking or alcohol and drug abuse.
The teen's case is unusual because his normal BMI masked the vitamin deficiencies.
Doctors noted that nutritional optic neuropathy should be considered in patients with unexplained vision symptoms and poor diets, regardless of their BMI.
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