Thrombophilia – a risk factor of retinal vein occlusion?

Introduction
To evaluate thrombophilia as a risk factor of retinal vein occlusion in comparison with a control group and a general polish population.

Material and methods
Fifty nine consecutive patients with retinal vein occlusion were enrolled in this study. The diagnosis of retinal vein occlusion was based on the presence of typical findings in the eye fundus, fluorescein angiography, and optical coherence tomography. Control group consisted of 59 subjects matched for age, sex, body mass index (BMI), medications, and cardiovascular risk factors. In all patients the following thrombophilic factors were evaluated: factor V mutation, 20210A prothrombin mutation, MTHFR (methylenetetrahydrofolatereductase) mutation C677T, protein C and free protein S level, antithrombin activity, factor VIII activity, anty-β2 glikoprotein I antibodies level, anticardiolipin antibodies level, the presence of lupus anticoagulant, total homocysteine concentration.

Results
In both groups with retinal vein occlusion and control group a high incidence of factor V Leiden was observed: 10.2% and 15.6%, respectively. In one patient the presence of 20210A prothrombin mutation was noted and in one the deficiency of free S protein was observed. Antiphospholipid antibodies were present in 11.8% of cases and factor VIII concentration > 150% in 3% of patients with retinal vein occlusion. In 8.5% of patients with retinal vein occlusion genotype TT MTHFR was present. Hyperhomocysteinemia was found in 5 cases with retinal vein occlusion (8.5%) and in 7 in a control group (11.9%). In a venous blood of patients with retinal vein occlusion homocysteine level was lower by 14.5% as compared with a control group (9.4 [7.0–11.3] vs. 11.0 [9.4–12.8] μmol/l, p = 0.001).

Conclusions
The results of thrombophilia screening in patients with retinal vein occlusion showed no statistical differences as compared with a control group matched for age, sex, and cardiovascular risk factors. However patients with retinal vein occlusion showed statistically significant lower serum homocysteine concentration as compared with a control group. Two times higher prevalence of factor V Leiden was observed in patients with retinal vein occlusion than in Polish general population.