AIM: To assess the serum levels of matrix metalloproteinase 2(MMP-2)and tissue inhibitor of matrix metalloproteinases 2(TIMP-2)in patients with high myopia(HM), and to investigate the relationship between their levels and axial length(AL).

METHODS: HM patients(13 eyes)(group A)and age-matched healthy volunteers with normal axial length eyes(13 eyes)(group B)who acted as controls were recruited. Blood samples were collected from all subjects in the early morning hours after an overnight fast. MMP-2 and TIMP-2 levels were measured by specific immunoassays(enzyme-linked immunosorbent assay).

RESULTS: The serum MMP-2 and TIMP-2 levels were decreased in the eyes of patients with HM compared with those of controls(P=0.027 and P=0.048, respectively).The median MMP-2 level was 10.21 pg/ml(range,9.26-11.49 pg/ml)in the group A and 11.56 pg/ml(range, 11.03-15.14 pg/ml)in the control group. The median TIMP-2 level was 79.69 pg/ml(range, 72.86-93.89 pg/ml)in the group A and 93.16 pg/ml(range, 87.54-100.97 pg/ml)in the control group.

There was no significant difference between the two groups in TIMP2/ MMP2(P=0.216)ratio. MMP-2 and TIMP-2 levels were negatively correlated with AL(r₁=-0.512, P₁=0.007; r₂=-0.604, P₂=0.001). No correlation was observed between the ratio TIMP2/ MMP2 and AL(r=0.385, P=0.052).

CONCLUSION: This pilot study reveals that the levels of MMP-2 and TIMP-2 could be detected in the serum. The levels of serum MMP-2 and TIMP-2 were decreased in the eyes with elongated axis, and their levels were nevatively correlated with AL.