Hyperlipidaemia
Hyperlipidaemia (cholesterol > 6.5 mmol/l) is the predominant association in
the younger age group (< 50 years) of patients with retinal vein occlusion and is
associated in up to 50% of older patients.11
Diabetes mellitus
Diabetes mellitus (table 1) is associated with retinal vein occlusion. This may
be due to an increase of other cardiovascular risk factors (e.g. 70% of type II
diabetics are hypertensive).10,12,13
Glaucoma
Current evidence suggests an association between central retinal vein occlusion
and glaucoma.7,14 One study suggests that BRVO is associated with glaucoma 12
Thrombophilia
Factor V Leiden and other such abnormalities have been implicated in RVO but
their aetiology is unclear. Deficiency or abnormal activity of various factors
have been identified in patients with RVO including protein S,C, anti-thrombin
3, activated protein C resistance, hyperhomocysteinaemia and the presence of
lupus anticoagulant or anti-cardiolipin antibody deficiency.15 Thombophilia
and the other rarer associations e.g. oral contraceptive pill, and optic disc
vasculitis assume more importance in the younger patients (<50 years).16,17
Other Important Observations
Myeloproliferative disorders occur in 1% of patients presenting with retinal
vein occlusion.9