MMP2 and snowflake vitreoretinal degeneration: The results indicate that endogenous TIMP-4 increased in response to the high level of MMPs activity and confirmed the role of MMPs in the progression of SVD [57].Single nucleotide polymorphism in MMP-2-1306 T/C is being considered a direct risk factor for the occurrence of isolated lacunar infarction, a form of SVD [228].