Rare Optic Neuropathy in a Jamaican Couple Linked to Cassava Root Consumption

ABSTRACT

We report central visual loss with selective papillomacular bundle damage in a Jamaican couple, husband and wife, with long-term cassava root consumption. The two cases presented independently with gradual central visual loss. Examination revealed bilateral temporal pallor of the optic nerve head and automated static perimetry demonstrated a central or caecocentral scotoma in each patient. Optical coherence tomography findings are described. The only mutual risk factor, reported independently, was long-term cassava consumption. Cessation of cassava intake and vitamin supplementation resulted in partial recovery of visual function. As thiocyanate levels in urine were not measured, the aetiology in these patients is not definitively confirmed, but chronic cassava consumption should be considered in similar cases as a rare cause of potentially reversible optic neuropathy.

KEYWORDS:

• Cassava
• cyanide
• toxic optic neuropathy
• central scotoma
• papillomacular bundle