Can vitrectomy help to understand the vitreous role in intermediate uveitis and Behçet's disease with vitritis without retinal detachment? 400 vitrectomies were decided because of vitreous changes but, over all, if macular changes were seen clinically or on the angiogram in 58 Behçet's disease and 342 intermediate uveitis including 59 children cases. Visual acuity, clinical, angiographical and visual field controls, recurrences, reduction of the medical treatment and growth were followed during 1 to 9 years. The vitrectomy products were compared to those of other inflammatory origin vitreous, the both representing 149 cases. Vitrectomy at the early stage of only posterior interface changes prevent the macular edema but this one is irreversible. The preexisting angiographical lesions have not regressed but they are generally quiet. The RD incidence is lower even if it is possible after vitrectomy, in 1.2% of the cases (1% in late vitrectomies). Recurrences and further medical treatment are reduced. This psychological point of view is important. Thus, vitrectomy at alone posterior interface change stage avoid ocular complications. Its pathogenic role in intermediate uveitis is not demonstrated; it seems more a secondary than a primary process.