In a study of enucleated human eyes, the authors investigated the effect of scleral buckling on the ocular pressure-volume relationship. Intraocular pressure was recorded continuously during intravitreal infusion of saline solution before and after the application of encircling silicone elements. Scleral buckling produced a marked reduction in ocular rigidity, with reversibility of the effect on removal of the buckling elements. Similar results were obtained during incremental intravitreal air injection. The authors propose that the greater extensibility of silicone compared with sclera and the induced alterations in ocular shape are the primary factors responsible for the observed change in ocular rigidity. The clinical implications of these findings for intravitreal gas injection are discussed.