Abstract
Benzalkonium chloride (BAC) is a quaternary ammonium compound commonly
employed as a preservative in several multidose eye drops. Its use is
associated with several adverse events, particularly when used
chronically. Topically instilled BAC acts not only on superficial
structures but also reaches deeper tissues (trabecular meshwork, optic
nerve) and can be deleterious in patient under chronic treatment. In
glaucomatous patients, BAC is the primary cause of ocular surface
disease (OSD), and it can lead to significant morbidity, influence
treatment compliance, quality of life, and surgical outcomes. Clinical
and experimental evidence demonstrates that BAC causes instability of
the tear layer, loss of goblet cells, apoptosis, subclinical
neuroinflammation, and antibiotic resistance. Considering the validity
of the alternative formulations (alternative preservatives or
preservative-free formulations) it is unreasonable to persist in using
such toxic compounds and, perhaps it is time for a moratorium on the use
of BAC in eye drops.