Effect of retrobulbar versus subconjunctival anaesthesia on retrobulbar haemodynamics.

AIM To investigate the effect of retrobulbar and subconjunctival anaesthesia on retrobulbar haemodynamics by colour Doppler imaging. METHOD 39 patients (mean age 71 (SD 9) years; 19 females, 20 males) undergoing planned cataract surgery were included in the prospective study. Colour Doppler imaging (Siemens Sonoline Sienna, Germany) was performed before, directly after either subconjunctival (16 patients) or retrobulbar (23 patients) anaesthesia, and after cataract surgery to measure the peak systolic (PSV) and end diastolic velocities (EDV) in the ophthalmic artery (OA), central retinal artery (CRA), and central retinal vein (CRV). RESULTS After retrobulbar anaesthesia there was a significant reduction of the PSV and of the EDV in all investigated vessels. After surgery the flow velocities increased again. Subconjunctival anaesthesia had no significant effects on retrobulbar haemodynamics. CONCLUSION Retrobulbar anaesthesia induces a high reduction of velocity in the retrobulbar vessels in contrast with subconjunctival anaesthesia. Therefore subconjunctival anaesthesia should be preferred particularly in patients with problems of the ocular perfusion (for example, glaucoma).