Of approximately 1500 cases undergoing retinal detachment surgery in the retinal unit at Moorfields Hospital between October 1973 and March 1978, 105 eyes in 104 consecutive patients in whom the authors used silicone oil injection for the treatment of retinal detachment with massive preretinal retraction were reviewed. A diagnosis of massive preretinal retraction was made when in our combined opinion retinal shortening and rigidity made retinal reattachment by conventional means impossible. Ninety-seven eyes (92%) had previously undergone conventional treatment for retinal detachment, and 49 (47%) had had more than one previous operation. In 69 eyes (66%) an encircling buckle was already present, in 15 eyes (14%) encirclement was undertaken at the time of silicone oil injection, but in 21 (20%) encirclement was not undertaken.