Prophylactic retinal detachment with laser photocoagulation is ineffective for some vitreo-retinopathies in which vitreous traction is predominant (non traumatic giant retinal tears, Wagner Stickler's syndrome, Marfan's syndrome...). Twenty eyes were operated by prophylactic episcleral circular buckling. In eighteen cases, the fellow eyes had previously presented a retinal detachment. We performed two types of encircling buckle. We only observed minor operative complications, without any functional consequences, attesting to the innocuity of this type of treatment. But we have to wait for vitreous detachment to know the efficacy of this prophylactic treatment. This detachment occurs at different time in each vitreoretinopathy, but with a specific rate of retinal detachment for each pathology.