Toxic corneal epithelial edema from exposure to high atmospheric concentration of toluene diisocyanates.

Exposure to organic isocyanates in the atmosphere of a polyurethane-foam-producing company resulted in microcystic corneal epithelial edema and conjunctival injection localized primarily in the palpebral fissure. The degree of microcystic edema and decreased visual acuity appeared to be related to location, length of exposure, ventilation, temperature, and amount of chemicals and premold stored. Clearing time varied with amount of exposure. Moderate amounts of microcystic edema caused an average fall of one line in the visual acuity. Pain was absent. The toxic effect of the isocyanates on the metabolism of the corneal epithelium may be the cause of the corneal epithelial edema.