Local anaesthetic techniques and pulsatile ocular blood flow

Aim-To compare pulsatile ocular blood flow (POBF) and intraocular pressure (IOP) between eyes of patients receiving either peribulbar (with and withou t balloon compression) or subconjunctival local anaesthesia (LA). Methods-30 eyes of 30 patients undergoing cataract surgery by phacoemulsifi cation were investigated in a study of parallel group design. Ten patients had peribulbar LA and 10 minutes compression with a Honan's balloon (group A). A further 10 patients who received peribulbar LA alone (group B) acted as controls for the effects of balloon compression. Ten other patients were given subconjunctival LA (group C). POBF and IOP were measured using a mod ified Langham pneumatonometer. Three measurements were made in each eye, th e first recording immediately before LA, the second 1 minute after, and the third 10 minutes after LA. Results-No significant change in POBF or IOP was recorded in eyes receiving subconjunctival LA. In the peribulbar groups (A and B), there was a drop i n median POBF of 252 and 138 mul/min respectively 1 minute after LA, which was statistically significant in both groups (p<0.01). By 10 minutes, POBF tended to return to baseline levels, but remained significantly reduced in group B (p<0.05). In addition, there was a significant (p<0.05) reduction i n IOP (mean drop of 4.82 mm Hg) in group A following peribulbar LA with bal loon compression. Conclusions-POBF was significantly reduced after peribulbar LA but was unch anged after subconjunctival LA. Balloon compression reduced IOP and improve d POBF following peribulbar LA. The findings may have clinical implications in patients with compromised ocular circulation or significant glaucomatou s optic neuropathy.