Scientists raise concern over safety of common eye drop ingredient

Researchers report that benzalkonium chloride results in mitochondrial dysfunction – a defect which has been linked to Parkinson’s disease and cancer


Chemicals found in common household products, including eye drops, have been linked to inhibited mitochondrial function and impaired hormone response.

A study published in Environmental Health Perspectives analysed the cellular impact of quaternary ammonium compounds or “quats” used as antimicrobial agents.

Scientists surveyed a collection of 1600 compounds used in household products and pharmaceuticals, using multiple measures to analyse mitochondrial function.

Researchers found that quats as a class inhibited mitochondrial function and estrogen signalling.

The authors note that this is a concern because mitochondrial dysfunction has emerged as a potential contributing mechanism for several health problems, including cardiac diseases, diabetes, obesity, Alzheimer’s disease, Parkinson’s disease and cancer.

Study author, Sandipan Datta, highlighted to OT  that one of the quats used in the study, benzalkonium chloride (BAK), is one of the most popular preservatives used in eye drops.

“Further clinical studies are needed in order to assess the effect of these quats in humans but caution should be exercised while using or prescribing quat-containing eye drops,” he emphasised.

Dr Datta shared that a previous study found BAK results in injury to the ocular surface, and repeated use of BAK can cause the chemical to reach the retina.

“Although this study was done in animals the same thing could be happening in humans who use eye drops containing BAK for a long time,” he explained.