The first and second articles of this series contain a description of the techniques of scleral buckling when performed as a primary procedure, and the third article deals with difficulties in reoperations following other types of retinal surgery. This article describes techniques used when a reoperation follows a scleral buckling procedure. A more detailed discussion of the indications for procedures used in reoperations will be the subject of our next article. One of the greatest dangers in reoperating after a diathermy operation and, to less degree, after a scleral resection is that sciera treated with diathermy is edematous, Prone to rupture, and adherent to orbital Scar tissue. After a scleral buckling, on the other hand, the treated portion of the sciera is folded in and protected by the polyethylene tube. Adhesions between sclera and orbital soft tissues are less dense and easier to dissect. This reduces the danger of accidentally