The role of thrombophilia in patients with retinal vein occlusion and no systemic risk factors.

Objective: The role of thrombophilia in the etiology of retinal vein occlusion (rVO) has not been adequately clarified. The aim of this study was to examine the prevalence of thrombophilia among RVO patients with and without systemic risk factors and among patients younger and older than 50 years.

Design: Prospective case-control study.

Participants: One hundred and twenty one patients with RVO, including 92 with acquired risk factors (hypertension, hyperlipidemia, and diabetes mellitus) and 29 without these factors. The control group included 60 persons matched for age, sex, and risk factors.

Methods: All participants were screened for Leiden mutation (FV Leiden), hyperprothrombinemia (20210 G/A mutation) and deficiency of protein C, S, and antithrombin.

Results: The prevalence of FV Leiden was significantly higher among RVO patients without risk factors (24.1%) than among controls without risk factors (0%; p = 0.034) and among RVO patients with acquired disorders (4.3%; p = 0.001). No significant differences were found in the prevalence of the other investigated thrombophilic factors. In all, 37.9% patients without acquired risk factors were positive for at least 1 thrombophilic factor compared with 7.6% RVO patients with acquired risk factors (p < 0.001) and 8.3% of the controls (p < 0.001). There was no significant difference in the prevalence of thrombophilic disorders among RVO patients according to age.

Conclusions: FV Leiden is significantly more frequent among RVO patients without acquired risk factors. Thrombophilia plays a much more important role in the pathogenesis of RVO in patients without acquired risk factors. Screening for thrombophilia is thus indicated only for patients in whom these factors have been excluded.