Retrobulbar Block

Definition

Retrobulbar block is a regional anesthetic nerve block used in intraocular procedures. In retrobulbar injection, local anesthetic is injected behind the eye, into the muscle cone of the extraocular muscle, which is located inside the orbital space, the area located behind the globe of the eye. Injection of local anesthesia provides akinesia of the extraocular muscles by blocking cranial nerves II, III, and VI, which prevents movement of the globe. Retrobulbar block also provides sensory anesthesia of the cornea, uvea, and conjunctiva by blocking the ciliary nerves.

Usual retrobulbar block includes either 1–2% lidocaine (Xylocaine) and 0.5–0.75% bupivacaine (Marcaine). Lidocaine enables quick anesthesia but has shorter duration, whereas bupivacaine has a longer duration but also takes longer time to achieve anesthesia. A mixture of both compounds is ideal to achieve quick and long-lasting (up to 2–3 h) anesthesia. The volume of liquid injected is between 4 and 6 cc, and up to...