Investigating Microplastic Presence in Eye Drops Using Micro-Fourier Transform Infrared Spectroscopy.

Purpose: The ubiquity of microplastics (MPs) in daily life has raised significant health concerns, yet their pathways into the eye remain poorly understood. MPs have a multitude of direct and indirect effects on human health, with a recent murine study indicating that they may cause inflammatory and toxic damage to the ocular surface. Given the prevalence of plastic in eye drop packaging, MPs could potentially contaminate topical ocular medications and thus be absorbed into ocular and systemic tissues. This study aimed to determine the presence of MPs in commercially available eye drops.

Methods: Commercially available eye drops from 20 brands were analyzed in triplicate (n = 60) for MPs. Particles ≥20 μm were examined using micro-Fourier Transform Infrared Spectroscopy, with identities confirmed by cross-referencing with a polymer and chemical database. Particle area and appearance were also documented.

Results: Although 498 visible particles were observed, a total of 4 MPs were identified in 2 of the 60 samples, specifically poly(1-dodecne) film (n = 2) and poly(1-octene) film (n = 2). In addition, 12 additional particles, including chemical catalysts and industrial lubricants, were noted across 6 samples.

Conclusions: The study provides evidence for the presence of MPs ≥20 μm in commercial eye drops. Further investigation into eye drop packaging is essential to discern whether detected particles are manufacturing by-products or expected ingredients. Further studies using micro-Raman spectroscopy are recommended for definitive analysis of MP contamination.