Contact lens microplastics: rapid Py-TOFMS quantification and ocular health risk assessment

Microplastics (MPs) released from contact lenses during wear can persistently contact the ocular surface through tear circulation, thereby posing a threat to ocular health. Combining thermal analysis with mass spectrometry enables accurate quantitative detection of low-concentration MPs from contact lenses, supporting exposure risk assessment. In this study, a hyphenated device consisting of a mini-pyrolyzer and a time-of-flight mass spectrometer (Py-TOFMS) was developed to enable rapid quantitative detection of MPs released from contact lenses. Compared with conventional Py-GC/MS, which typically requires approximately 30 min per sample, the proposed Py-TOFMS method eliminates the GC separation step and completes the analysis in 15 min, thereby simplifying the detection workflow and reducing the risk of sample loss and contamination. Py-TOFMS exhibited good limit of detection (LOD = 0.09 μg) and limit of quantification (LOQ = 0.27 μg), along with good linearity (R² ≥ 0.98). This study systematically simulated daily use conditions, including soaking, heating, and ultraviolet (UV) radiation. All tested contact lenses were found to release MPs, with the most significant release occurring under UV exposure. Furthermore, by combining optical microscopy and infrared spectroscopy to observe the morphological distribution of MPs and the aging effect of contact lenses, a preliminary systematic assessment was conducted on the potential ocular health risks associated with the release of MPs from contact lenses. This study reveals that UV exposure poses the most significant risk of MPs release from contact lenses, underscoring the urgency of assessing the potential health risks associated with ocular exposure to MPs.