Generally-speaking, a blunt 25G needle is used (Atkinson retrobulbar needle Eagle Labs, Rancho Cucamonga, California). The technique can include also injecting 2 cm³ of the anesthetic agent into the eye’s internal canthus. It is advisable to associate a small quantity of hyaluronidase (5 U\mL, that is 0.5–1 mL in the 10 mL syringe) to facilitate the diffusion of the anesthetic agent. Akinesia of the orbicularis muscle is achieved by slowing injecting 1.5 mL of anesthetic in front of the orbital septum.

In the event the surgeon opts for peribulbar anesthesia, four periconic injections should be performed in the four quadrants to allow a better distribution of the anesthetic agent.

Sub-Tenon anesthesia has the advantage of not increasing the intraorbital pressure, due to the small quantity of anesthetic agent injected (1.5 mL) and the disadvantage of a greater haemorrhage risk. Several different quadrants have been proposed for the injection: supero-temporal, internal canthus and infero-nasal.

In all cases of injected anesthesia, the block can be achieved by using 2% carbocaine (or 2% lidocaine) possibly in association with 0.50% Marcaine (1:1) if the procedure is expected to last longer than normal.

Digital eye massage consents better diffusion of the anesthetic solution and reduces the intraocular pressure (IOP); this is an important phase in the preparation of the patient for surgery. However, many surgeons do not apply this technique because they believe it induces an additional transitory IOP increase—dangerous for patients affected by glaucoma; pressure values are maintained at between 30 and 40 mm Hg for approximately 20 min.