Adverse effects of BAK in glaucoma medications

Abstract

Benzalkonium chloride (BAK) is a common preservative found in glaucoma medications used to increase shelf‐life, prevent bacterial contamination, and enhance ocular penetration. Its detergent properties kill microorganisms by disrupting cell membranes and causing cell lysis. Unfortunately BAK also has potentially harmful cytotoxic effects, particularly for the ocular surface, with evidence of BAK‐induced apoptosis of conjunctival and corneal epithelial cells, decreased density of conjunctival goblet cells, delayed corneal wound healing and reduced density of corneal nerved. It may also affect deeper ocular structures including the lens and trabecular meshwork, with BAK shown to cause apoptosis of human trabecular meshwork cells in culture. Clinical consequences may include increased risk of ocular surface disease, reduced adherence, and with long‐term use, reduced success of glaucoma surgery.