A four-year-old boy presented with photophobia, persistent eye rubbing and severe vision loss — symptoms that were ultimately traced to prolonged vitamin A deficiency caused by avoidant/restrictive food intake disorder (ARFID).
Initially, doctors suspected a neurological cause. Brain imaging ruled out intracranial masses but incidentally revealed a Chiari I malformation. However, detailed ophthalmic examination showed conjunctival injection, reduced tear film and corneal haze — signs consistent with xerophthalmia.
Blood tests confirmed severe vitamin A deficiency, with serum levels far below the normal range.
Restricted diet and delayed diagnosis
Further assessment revealed that from age one, the child consumed a highly restricted diet consisting mainly of yoghurt, crackers, french fries and apple juice. Sensory aversions to texture and temperature limited food variety.
Despite treatment with high-dose vitamin A supplementation and resolution of surface eye findings, the child’s vision did not improve. Electroretinography showed normal retinal function, but persistent optic nerve pallor indicated optic neuropathy — a rare but devastating complication of prolonged deficiency.
Later genetic testing identified a pathogenic mutation in the LZTR1 gene, confirming Noonan syndrome, which explained his developmental delays and feeding challenges.
Why early recognition matters
Vitamin A deficiency remains one of the leading causes of preventable childhood blindness globally, according to the World Health Organization. While uncommon in developed nations, it can occur in children with restrictive eating disorders such as ARFID.
Early symptoms — including nyctalopia (night blindness) and poor visual behaviour — may appear before classic ocular signs like xerophthalmia. Without prompt diagnosis, irreversible optic nerve damage can occur.
This case underscores the importance of nutritional screening in children with neurodevelopmental disorders or feeding difficulties. Clinicians are urged to maintain a high index of suspicion when unexplained vision changes occur.
Timely intervention can prevent permanent blindness — but delay, as in this case, may lead to lifelong visual impairment.