The ophthalmic toxicology of dichlorøomethane

The toxic hazard to the eye from dichloromethane (DCM) as liquid or vapour has been assessed rabbits. 0.1 ml DCM caused inflammation of the conjunctiva and eyelids persisting for up to 2 weeks; keratitis and iritis occurred in two-thirds of the animals. Corneal thickness, measured in vivo, increased by a maximum of 59% at 6 h, returning to normal by 9 days. 0.01 ml DCM produced similar, but less persistent effects on the conjunctiva and eyelids; keratitis was minor. Corneal thickness increased by up to 43% at 6 h, returning to normal by 9 days. Intraocular tension increased by 33% at 1 h, returning to control values by 3 days. 10-min exposures to DCM vapour at concentrations up to 17 500 mg/m3 produced no macroscopic changes, but small increases in corneal thickness and intraocular tension occurred, which were related to the degree of exposure. The mean peak increases in corneal thickness were 13% for 17 500 mg/m3 and 5% for 1750 mg/m3; corresponding values for increases in intraocular tension were 18% and 11%. Both corneal thickness and intraocular tension returned to normal by 2 days. Treatment with a decongestant preparation (Vasocon-A), containing an antihistamine and an alpha-adrenergic sympathomimetic, reduced both the inflammatory response and the rise in intraocular pressure caused by a splash contamination of the eye with liquid DCM.