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What is Local anaesthetic usually used for retrobulbar block - and explain in detail?
Ans. is 'a' i.e., BupivacaineRetrobulbar anaesthesiao In this technique local anaesthetic is injected behind the eye into the cone formed by extraocular muscles.o Retrobulbar injection is given with a special needle which is having a rounded tip. This needle penetrates the lower lid at the junction of the middle and lateral one third of the orbit (usually. 5 cm medial to the lateral canthus).o Choice of local anaesthetic varies, but lidocaine 2% and bupivacaine 0.75% are most common,o To enhance the retrobulbar spread of local anaesthetic Hyaluronidase, a hydrolyzer of connective tissue polysaccharide is frequently added.o A properly placed retrobulbar injection is effective within second and blocks all extraocular muscles except the superior oblique muscle, affects the ciliary ganglion (resulting in pupillary dilatation) and anesthetizes the entire globe.