Microplastic contamination in commercial eyedrop products: detection and characterization study

Microplastics (MPs) have become an emerging contaminant of concern, yet their presence in ocular formulations and products remains poorly understood. This study employed a dual-method approach (water dilution and Fenton digestion) coupled with micro-FTIR analysis to investigate the MP contamination in 21 commercial eyedrop products in Malaysia. Our findings demonstrate widespread contamination, with 81% of samples containing detectable MPs. They are predominantly composed of polystyrene (PS) (52%), polyamide (PA) (19%), and polyethylene (PE) (14%). The particle abundance varied significantly across classes of eyedrops. Specifically, one lubricant eyedrop reported a mean concentration of 3 particles/ml, representing the highest concentration among all categories. Morphological characterization revealed diverse particle shapes, including irregular fragments (most common), fibers, and pellets. The area of MPs detected ranged between 369 to 36,388 µm². The pollution load assessment indicated that the lubricant eyedrops showed extreme contamination levels (MPCF = 15). The calculated daily microplastic exposure (DME) suggests a potential emission of up to 2.704 million MP particles daily among lubricant users in the general Malaysian population. Glaucoma patients in rural areas are potentially exposed to 0.049 million particles daily and urban areas at 0.137 million. These results provide the first evidence of MP contamination in eyedrops in Malaysia, highlighting a previously unrecognized route of human exposure. The findings emphasize the need for improved manufacturing standards and regulatory oversight to minimize plastic contamination in ocular products. While these findings suggest MPs are present in many eyedrop products, further research would be needed to understand any potential health implications.