**4.2.3 Retinal Vein occlusion**

Several studies have examined the relationship between hyperhomocysteinemia and retinal vein occlusion, a condition affecting approximately five out of 1000 of the general population over 64 years of age (David et al., 1988). The association between retinal vein occlusion, hyperhomocysteinemia and thermolabile MTHFR was confirmed (Janssen et al., 2005).
