What is a common issue with long-term benzalkonium chloride exposure on the ocular surface?

• A. Ocular surface toxicity and dry eye symptoms.
• B. Increased tear production.
• C. Improved corneal healing.
• D. Systemic hypotension risk.

Answer: (A)

Long-term exposure to benzalkonium chloride on the ocular surface tends to damage the surface rather than enhance it. This preservative acts like a detergent on epithelial cells and the tear film, disrupting the lipid layer, harming goblet cells that produce mucins, and triggering inflammation. Over time, this leads to tear-film instability, reduced mucin quality and quantity, and surface irritation that manifests as dry eye symptoms such as burning, stinging, grittiness, and fluctuating vision. Because of the epithelial toxicity and inflammatory changes, healing can be delayed rather than improved. Systemic hypotension isn’t a typical ocular surface issue, and increased tear production isn’t expected with chronic exposure.