Peribulbar anaesthetic blocks were administered to 70 patients and the intraocular pressure (IOP) measured immediately before and within 1 minute of the injections. In 10 patients IOPs were recorded at 1 minute intervals for 15 minutes after injection and then compared with the IOPs recorded in 60 patients after 5 or 10 minutes of Honan balloon ocular compression. The IOP rose significantly after injection in all patient groups and in some cases this increase was marked (over 50 mm Hg in 10 patients). The IOP showed an equivalent drop after 5 or 10 minutes of ocular compression when compared with eyes that did not receive ocular compression. The Honan balloon does not appear to be necessary to reduce IOP in the 10 minutes following peribulbar injection. Furthermore, the occurrence of IOP peaks after peribulbar anaesthesia suggests that the balloon should be used with caution in eyes in which the ocular circulation may be compromised.