Tear matrix metalloproteinase 9 immunoassay positivity reflects the severity of conjunctivochalasis

An objective indicator for diagnosing and evaluating the therapeutic efficacy of conjunctivochalasis (CCh) treatments is not available. Therefore, we investigated the correlation between CCh severity and the matrix metalloproteinase-9 (MMP)-9 point-of-care (POC) semi-quantitative test to determine its suitability for diagnosing and evaluating CCh. We conducted a prospective study comprising healthy participants and patients with evaporative dry eyes and CCh. The participants underwent CCh severity, tear break-up time, Schirmer test, ocular staining score, tear meniscus height, and tear MMP-9 evaluations. The MMP-9 test results were classified into negative and weakly, moderately, and strongly positive. We included 108 participants; 54 participants had CCh and 54 did not. The MMP-9 positivity rate was significantly higher for patients with ≥ CCh grade 2 than those without CCh (p < 0.001). Of the CCh-negative participants, 75.9% were MMP-9-negative, and 24.1% were moderately/strongly positive. Conversely, 37.0% of CCh-positive patients were MMP-9-negative, and 63.0% were moderately/strongly positive. Furthermore, MMP-9 positivity significantly differed among the CCh severity groups (p < 0.001). Finally, there was a positive correlation between CCh severity and MMP-9 positivity (p < 0.001, R = 0.420). The tear MMP-9 positivity correlated with CCh severity. Therefore, the MMP-9 POC test may help diagnose CCh and evaluate its severity after treatment.