Intermediate uveitis defines the group of diseases formerly called pars planitis or chronic cyclitis. Its frequency amounts to 10-20% of all uveitis cases. The anamnesis is vague. The clinical symptoms mainly involve the vitreous. The visual acuity is variable, depending of the involvement of the retina. A slight inflammation of the anterior chamber is possible, but no synechiae are present. The vitreous shows a positive Tyndall and cells, snow balls, eventual plaques on the pars plana. Serious cases are complicated by a retinal vasculitis, which often leads to cystic macular edema and papillary edema. Schisis and retinal holes are more seldom. A complicated cataract can develop. The most valuable complementary tests are fluorescein angiography and electroretinography, useful to detect retinal damage. Aetiological investigations give mostly poor results and are not very useful. Differential diagnosis has to be made, among others, from Fuchs' heterochromic cyclitis and from acute cellular infiltration of the vitreous in case of retinochoroiditis or candida endophthalmitis. Treatment of intermediate uveitis can be only local and discrete when only the vitreous is involved. If the retina is damaged, systemic steroids or immunodepressive cytostatic drugs might be indicated. Despite the duration of the disease, its prognosis remains rather good. Only about 15% of the cases end up with visual impairment to 1/10 or less, while more than half of the cases maintain a visual acuity higher than 0.6, even after three years of disease progress.