Blindness Caused by a Junk Food Diet

Background: Popular media have highlighted the risks for poor cardiovascular health, obesity, and cancer associated with junk food, but poor nutrition can also permanently damage the nervous system, particularly vision.

Objective: To alert clinicians of visio risks associated with a diet restricted to junk food.

Case Report: A 14-year-old boy presented to his family practitioner with tiredness. He was a “fussy eater” but was otherwise well and took no medications. Tests found macrocytic anemia and low vitamin B12 level but no antibodies to intrinsic factor or tissue transglutaminase. He was treated with vitamin B12 injections and dietary advice.

At age 15 years, he developed sensorineural hearing loss and was referred to an otolaryngologist. Magnetic resonance imaging (MRI) showed no structural abnormalities. Shortly afterward, he developed vision symptoms. Findings of a slit-lamp examination by an ophthalmologist were normal. No cause was found.
At age 17 years, he was referred to a neuro-ophthalmologist after 2 years of progressive vision loss. Findings were consistent with optic neuropathy: Visual acuity was 20/200 bilaterally, he read 8 of 17 Ishihara color plates with either eye, pupil responses and slit-lamp examination findings were normal, and he had bilateral central visual field defects and loss of retinal nerve fibers affecting the optic discs temporally and maculopapillar bundles. There were delayed P100 responses in visual evoked potentials with normal amplitudes (Figure). He had brisk reflexes, but findings of a neurologic examination were otherwise normal.