MMP2 and cataract: As a calcium and zinc dependent proteolytic enzyme, MMPs play an important role in embryonic development, wound repair, cell migration, and so on.[31] MMP-2 affects the migration, shuttle, proliferation and growth of lens posterior capsule cells, and is closely related to the occurrence and development of cataract.[32,33] In this paper, meta-analysis was carried out to systematically analyze the relationship between multiple mutation sites of MMP-2 and cataract susceptibility, which will provide evidence-based medicine for early prevention and treatment of cataract.