First evidence of microplastic pollution in human trabecular meshwork and its association with intraocular pressure in glaucoma.

Microplastics (MPs), as pervasive environmental pollutants, have been documented in various human tissues, yet their presence within ocular structures, particularly the trabecular meshwork (TM), and potential pathophysiological roles remain unexplored. To address this, our study aimed to provide the first quantitative evidence of MP pollution in the human TM and investigate its correlation with intraocular pressure (IOP) in primary open-angle glaucoma (POAG). We employed a multi-modal analytical strategy, integrating Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) for polymer quantification, Laser Direct Infrared Spectroscopy (LD-IR) for particle characterization, and Scanning Electron Microscopy (SEM) for morphological assessment, to examine trabeculectomy samples from 20 POAG participants under stringent contamination control protocols. Our analysis consistently identified MPs in all TM specimens, with Py-GC/MS data revealing polyamide 66 (PA66, median: 62.03 mg/kg), polyvinyl chloride (PVC, 59.4 mg/kg), and polypropylene (PP, 33.65 mg/kg) as the predominant polymers. Furthermore, LD-IR analysis revealed a diverse profile of 14 polymer types and showed that 76.9% of the detected particles were under 50 μm in size, a dimension relevant to TM pore architecture. Most importantly, after adjustment for confounders such as age and medication use, the total MP burden demonstrated strong and significant correlations with both the maximum recorded IOP prior to any treatment (Spearman's ρ = 0.735, P < 0.001) and the preoperative IOP (ρ = 0.797, P < 0.001). Thus, this work establishes the novel finding of MP accumulation in the human TM and links this environmental exposure to elevated IOP in glaucoma, thereby suggesting a previously unrecognized etiological pathway and underscoring the imperative for further investigation into MP-induced trabecular dysfunction and the mitigation of plastic pollution.