Brief summary: This study compares the long-term efficacy and safety of interferon (IFN) α2a and cyclosporine (cyclosporin A, CsA) following suppression of acute attack by high-dose oral glucocorticosteroid in patients with refractory Behçet`s uveitis (BDU). Half of the participants will receive IFNα2a while the other half will receive CsA.