What are the potential complications of retrobulbar anesthesia?

What are the potential complications of retrobulbar anesthesia? Are there any other blocks that are satis-factory with less morbidity?

The onset time of retrobulbar blockade is 5–10 minutes. Retrobulbar blockade has a low failure rate of less than 1% in skilled hands. However, retrobulbar anesthesia is asso-ciated with a number of complications. The recognized complications of retrobulbar blockade are:

·  Central retinal artery occlusion

·  Retrobulbar hemorrhage

·  Subdural or subarachnoid injection

·  Seizures

·  Intraneuronal injection

·  Globe puncture

·  Oculocardiac reflex

Peribulbar block is a good alternative to retrobulbar block and is associated with fewer complications. To perform a retrobulbar blockade, local anesthetic is injected into the eye’s muscle cone. Peribulbar blockade is per-formed by injecting local anesthetic around the eye.

The failure rate of peribulbar block is as high as 10%, and the onset time is 10–12 minutes, which is slower than that of retrobulbar block. An alternative to the retrobulbar and peribulbar block is the more recently popularized sub-Tenon block. The sub-Tenon block is performed somewhat similarly to a retrobulbar block. In the sub-Tenon block a blunt-tipped cannula is inserted between the fused conjunctiva and anterior Tenon capsule. It is advanced to midway between the insertion of the medial and inferior rectus muscles into a thin channel to the posterior sub-Tenon space. Success rates are reported as high as 98.8%.