# Tear matrix metalloproteinase 9 immunoassay positivity reflects the severity of conjunctivochalasis

## TL;DR

This study shows that a tear test for MMP-9 can indicate the severity of conjunctivochalasis, a common eye condition.

## Contribution

The study introduces tear MMP-9 immunoassay as a potential diagnostic and severity evaluation tool for conjunctivochalasis.

## Key findings

- MMP-9 positivity was significantly higher in participants with CCh grade 2 or higher.
- There was a positive correlation between CCh severity and MMP-9 positivity (R = 0.420).
- MMP-9 POC test results varied significantly across different CCh severity groups.

## Abstract

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.