Detailed description: Both CsA and IFNα2a have been shown to be effective for long-term control of BDU, however, randomized prospective comparative studies are scarce, particularly in East Asian populations. Our preliminary data gave us the impression that IFNα2a might be more effectiveness than CsA in long-term control of refractory BDU, and this study aimed to compare their effectiveness and safety profiles in a well-designed prospective study. Refractory BDU is defined as relapse of posterior or pan- uveitis with at least 10mg daily prednisone (or equivalent) and one traditional immunomodulatory treatment (IMT) agents. The acute attack is controlled with large dose oral corticosteroid (60mg daily prednisone) for 4 weeks, and then the patients are randomly assigned to the IFN arm and the CsA arm, in which patients are treated with IFNα2a (3×10^6 IU qd for 4 weeks and qod thereafter) and CsA (100mg bid), respectively, along with a fixed tapering regimen of corticosteroid. Patients were followed up until relapse, or for 12 months.