Influence of benzalkonium chloride on langerhans cells in corneal epithelium and development of dry eye in healthy volunteers.

Purpose: To investigate the influence of benzalkonium chloride (BAC) on corneal Langerhans cells (LCs) and on the development of dry eye.

Methods: A randomized double-blind clinical trial was performed in 20 healthy volunteers. One eye of each subject was treated with a 0.