Inherited and acquired thrombophilia in adults with retinal vascular occlusion: a systematic review and meta-analysis

Background: Retinal vascular occlusion is a leading cause of sight loss. Both retinal artery occlusion (RAO) and retinal vein occlusion (RVO) have been associated with hypercoagulable states; however, the burden of thrombophilia in these patients is unclear. Objectives: This study aims at estimating the prevalence of inherited and acquired thrombophilias in adults with RAO or RVO, through a systematic review and meta-analysis of the literature. Patients/methods: Pubmed and EMBASE were systematically searched from inception to 29th February 2020. All studies reporting prevalences of Factor V Leiden (FVL) and Prothrombin (F-II) G20210A mutations, MTHFR C677T and PAI 4G polymorphisms, Antithrombin III (AT-III), Protein C (PC) and Protein S (PS) activity deficiencies, hyperhomocysteinemia and antiphospholipid (APL) antibodies in adults with RAO or RVO were included. Pooled prevalences and 95% Confidence Intervals (CI) were calculated. Results: Ninety-five studies were included; FVL and F-II mutations were found in 6% (95%CI: 5-8%) and 3% (95%CI: 2-4%) of individuals with RVO, respectively, while AT-III, PC and PS activity deficiencies were found in less than 2%. The MTHFR C677T and PAI 4G homozygous polymorphism were observed in 13% (95%CI: 10-17%) and 23% (95%CI: 16-31%) of RVO, respectively; 8% presented APL antibodies. Similar findings were observed in individuals with RAO. Conclusions: Compared to healthy subjects, patients with retinal vascular occlusion showed similar prevalences of inherited and acquired thrombophilias. These findings do not support routine thrombophilia screening in individuals with RAO or RVO.