Paraquat causes chronic ocular surface toxicity.

We describe a case of topical exposure to a commercial solution of paraquat. Chronic, severe ocular surface destruction resulted, probably due to absorption of the herbicide into the surface tissues, facilitated by a surfactant present in the preparation, and to intracellular redox cycling of the paraquat cation. Ocular paraquat toxicity is described and explained in the context of the toxicity of systemic absorption.