Background: Blind ophthalmic anaesthetic techniques may have serious complications. Aim: To assess the safety of ultrasound as a guide in ophthalmic blocks. Methods: Fifty adult patients undergoing cataract surgery under peribulbar block anaesthesia were randomly assigned to ultrasound-guided and conventional block groups. In the ultrasound-guided block group, a large amount of the standard ultrasound gel was applied to the closed eyelids. The globes were scanned in both sagittal and transverse planes. The patients were asked to look straight ahead with closed eyes without clenching the eyelids. The depth and gain were adjusted before performing the block. The primary outcome was the rate of complications. Secondary outcomes included the volume of injected anaesthetics and surgeon and patients’ satisfaction. Results: The local anaesthetic volume used was not significantly different between the two groups (7.08 ± 1.66 and 6.72 ± 1.97ml). The block onset, time and quality were comparable in both groups. No complications were reported, and there were no significant differences regarding surgeons’ or patients’ satisfaction with either procedure. Conclusion: The ultrasound-guided local ophthalmic block is as safe as the conventional method. Although its use was not superior to the conventional procedure, direct visualisation with ultrasound may be important to avoid vulnerable structures such as staphylomas.