Aerobic responses of the cornea to ophthalmic preservatives, measured in vivo.

A micropolarographic system was used to measure the effects of several concentrations of benzalkonium chloride and thimerosal on oxygen uptake by the cornea. Although the threshold of 0.01% found for benzalkonium chloride generally agreed with other criteria (e.g., clinical and histologic) in the current literature, the threshold for thimerosal was somewhat higher, 1.0%, indicating a substantially greater aerobic activity tolerance of the cornea to initial direct exposures of that agent then to benzalkonium chloride.