Iodate induced toxic retinopathy: a case report

BACKGROUND: Iodine deficiency is a common preventable cause of intellectual and developmental disabilities. Iodine in the form of potassium iodate is added to the common salt under the National Iodine Deficiency Disorder Control Program in India. Overdose of iodate can lead to retinal toxicity. CASE PRESENTATION: We hereby present a case of a 34 year old male patient who presented to us 10 years following iodate ingestion. There was widespread outer retinal atrophy, foveal atrophy and sub-retinal fibrosis noted on fundus evaluation. The fundus fluorescein angiogram was suggestive of window defects while the scotopic electroretinogram showed diminished amplitude pointing towards a grave prognosis. CONCLUSIONS: Excessive ingestion of potassium iodate can lead to outer retinal atrophy due to its toxicity to the retinal pigment epithelium and photo-receptors. The degree of damage is dependent on the ingested dose.