Injection location Blockade
Inferotemporal approach Lacrimal, nasociliary and frontal (supraorbital and supratrochlear) nerves
Medial approach (placed between the caruncle and the medial canthal angle) Medial branches of nasociliary (long ciliary) nerve; Infratrochlear nerve and medial components of supraorbital and supratrochlear nerves
Superomedial approach Here the needle would be in contact with a path congested with nerves, blood vessels and muscles, and this approach is therefore best avoided.
Superolateral approach This would avoid the impediments encountered in Superomedial approach. The needle is placed through the skin of the upper lid as the relevant area of conjunctiva is inaccessible.
Table 5: Various regional anaesthetic injection approaches and the resulting lockade of relevant nerves.