Macular ischaemia in posterior uveitis.

The commonest cause of visual morbidity in patients with posterior uveitis is cystoid macular oedema, which usually responds to immunosuppressive treatment. However, a small group of patients do not have a satisfactory visual outcome despite apparently adequate therapy. In a retrospective study of 345 angiograms of 135 patients with active non-occlusive retinal vasculitis 12 patients were identified by independent masked review as showing macular ischaemia on their fluorescein angiograms. Four patients had Behçet's disease, 4 sarcoidosis, and 4 idiopathic retinal vasculitis. Follow-up of these patients for an average of 36 months (range 6-120 months) showed that visual acuity failed to improve in 4 patients and dropped by an average of three lines Snellen in the other 8. We suggest that a poor visual outcome in some patients with posterior uveitis may be predicted by the presence of macular ischaemia on fluorescein angiography and that immunosuppressive therapy should be prescribed with caution in these patients.