MTHFR and hyperhomocysteinemia: The retrospective study analyzed 60 consecutive case series of patients with RVO, tested for CRF, hyperhomocysteinemia (HH), lupus anticoagulant, antiphospholipid antibody and 5 gene variants: factor V Leiden (G1691A), factor II (PT G20210A), 5,1-methylenetetra-hydrofolate reductase (MTHFR; 677 C > T and 1298 A > C), plasminogen activator inhibitor 1 (PAI-1; 4 G/5 G).