A review of directions of gaze during intraocular anesthetic blocks.

Safety of orbital blocks depends on operator and patient factors. Among the patient factors, the direction of gaze is important. Certain ocular structures move when the gaze is shifted. These may veer into the path of the needle, setting the stage for injury. The optic nerve with its accompanying artery swerves medially during abduction, direct up gaze, and superolateral and inferolateral gazes. These gazes are therefore risky for medial compartment blocks. In a superomedial gaze, the optic nerve shifts down and out and is likely to be injured during inferolateral needle blocks. Primary gaze is considered to be the safest for akinetic sharp needle blocks. "Tethering tests" involving extremes of gazes are dangerous. The superomedial, superior, superolateral, and inferomedial routes are perilous in all gazes. The superolateral gaze during classic Steven's sub-Tenon's block brings the optic nerve forward, rendering it vulnerable. Complications can be reduced by avoiding deep blind dissection and posterior injections.