Evaluation of Human Corneal Barrier Function and Its Change by Benzalkonium Chloride

Abstract

Purpose: : Evaluation of human corneal barrier function and its change by exposure to benzalkonium chloride using corneal trans-epithelial electric resistance (TER) measurement.

Methods: : Corneal TER was measured using electrodes placed on the cornea and in the conjunctival fornix. The corneal electrode was surrounded by insulation to ensure that the electrical current passed through the corneal epithelium. Corneal TER change was then monitored during exposure to 0.02% benzalkonium chloride for 30 seconds. Slit lamp observation was performed before and after exposure.

Results: : Human corneal TER was 621 ± 30 ohm-cm² (n=3). After exposure to 0.02% benzalkonium chloride, corneal TER significantly decreased to 397 ± 76 ohm-cm² (p<0.01) in 10 seconds and 258 ± 29 ohm-cm² (p<0.001) in 30 seconds. The results agreed with those in rabbit cornea. After benzalkonium chloride exposure, superficial punctate keratopathy was observed; this epithelial change disappeared within 24 hours.

Conclusions: : The corneal TER measurement method was useful for evaluating human corneal barrier function. Acute corneal epithelial dysfunction by 0.02% benzalkonium chloride occurred within 10 seconds.

Keywords: cornea: epithelium • electrophysiology: clinical • drug toxicity/drug effects