We evaluated the effects of peribulbar block for eye surgery on bi-hemispheric regional cerebral oxygenation (rSO2) of aged patients. In 66 adult patients, peribulbar block was performed using ropivacaine 10 mg.ml−1 with hyaluronidase 100 IU.ml−1. Cerebral oxygenation was monitored using continuous non-invasive, near-infrared spectroscopy. The rSO2 data on the side where the eye block was performed were evaluated as eye block side values, whereas the data recorded on the other side were taken as control values. Mean rSO2 values on the side where regional block was performed were not significantly different from control values (p > 0.05). Nevertheless, in several patients, a slight desaturation in the cerebral hemisphere on the block side was detected. Therefore, in aged patients, peribulbar block with ropivacaine does not significantly modify bi-hemispheric rSO2, but rSO2 monitoring during peribulbar block should be a field of future research in aged patients with brain injury or disease.