Patient Position: Supine, with the head flat.

Indications: Anesthesia for the majority of surgical procedures in and around the eye (e.g., cataract extraction, glaucoma filtering procedures, iris surgery, trans-par-plana vitrectomy, or orbital exploration [combined with second injection in the superior nasal quadrant]).

Needle Size: A 30-gauge short needle and a 27-gauge, 31-mm needle.

Local Anesthetic Solution: Half 0.5% or 0.75% bupivacaine, half 2% lidocaine, plus 100 to 150 IU/10 mL hyaluronidase.

Volume: 2 mL plus 5 to 7 mL.

Approach and Technique: The proper technique begins with the patient’s arrival for surgery. Apprehension in anticipation of eye surgery is common and should be expected. The concept of a needle being stuck behind the eye is frightening; therefore, sedation should be given upon arrival and not delayed until just before administration of the retrobulbar injection. Patients need to have their fears allayed during the preparation and waiting period and not so much at the actual time of the injection, which if done properly causes little pain.

The technique of the block is of paramount importance, and strict attention to detail minimizes the risk for complications. Instruct the patient to keep both eyes open and to look straight ahead. Visualize the globe and orbit as divided into four quadrants (Fig. 18-1). Using a 30-gauge short needle and a 10-cc syringe containing the anesthetic agent, raise a skin wheal 8 to 10 mm posterior to the lid margin so as to be inferior to the tarsal plate and in the center of the inferior temporal quadrant (Fig. 18-2A). Without being withdrawn, the needle is turned and directed through the skin, posteriorly toward the back of the orbit without angulation. It is inserted to the hilt, and with the laxity of the lid and further posterior pressure, the hilt indents the lid, thereby advancing the needle tip past the equator of the globe and into the retrobulbar space. During insertion of the needle, approximately 2 mL of anesthetic agent is injected, and the needle is then withdrawn. Moderate digital
pressure is applied to the globe and orbit through the closed lid for approximately 3 to 5 minutes. A 27-gauge, 31-mm disposable needle is placed on the same syringe, and the lower lid is immobilized by the needle tip so that it is at the level of the equator of the globe prior to penetrating the skin (Fig. 18-2B). The needle is guided along the previously anesthetized tract, angulated only slightly toward the apex of the orbit, and advanced carefully to the hilt and into retrobulbar space. After negative aspiration for blood, 5 to 7 mL of the local anesthetic mixture is injected. In the case of trans-par-plana vitrectomy or orbital exploration, a complete akinesia of the extraocular muscles and total anesthesia is indicated. This may require a supplemental injection in the superior nasal quadrant. For that purpose, the same 27-gauge, 31-mm needle is introduced at the level of the skin of the upper lid just below the superior orbital rim at the 1:30 position (Fig. 18-3). The needle is
directed posteriorly along the roof of the orbit to a depth of 2.5 cm, where an additional 2 to 3 mL of anesthetic solution is injected. It is important not to slant the needle toward the apex of the orbit since the optic nerve is nasally located in the orbit and may be damaged.