Thrombophilic factors in ischaemic and non-ischaemic idiopathic retinal vasculitis.

Two common causes of visual loss in idiopathic retinal vasculitis (RV) are retinal ischaemia and cystoid macular oedema. This study investigated whether thrombophilic factors are more prevalent in patients with ischaemic RV than non-ischaemic RV. Twenty patients with RV (10 ischaemic, 10 non-ischaemic) were prospectively recruited before starting systemic immunosuppression. Twenty-one different haemostatic parameters were tested. Seventeen patients had at least one haemostatic abnormality. Three patients had low Protein S, one had low Protein C. Three patients had positive anticardiolipin antibody titres, 1 had poor fibrinolytic activity, 3 had raised fibrinogen levels. Ten patients had raised lipoprotein (a) levels. Fibrinogen levels were higher in the smokers (p = 0.02). Although all von Willebrand's factor levels were within the normal range, they were higher in the ischaemic group (p = 0.008), in which smoking was more prevalent. This study has shown a high prevalence of thrombophilic abnormalities in RV patients, and implicates smoking in the aetiology of ischaemic RV.