OF THE EYE

Inadvertent penetration of the globe can occur in association with many ocular procedures. Most, if not all, of these incidents can be prevented with strict attention to technique. The keys to prevention are awareness of the factors likely to cause penetration and constant vigilance. Many factors are associated with inadvertent penetration of the eye. They include patient movement, posterior staphylomas, myopic eyes, and poor technique (1–3).

OFFICE INJECTIONS

Subconjunctival injection in the lower fornix is safer than sub-Tenons (infra-Tenons) or so-called periocular injection. Subconjunctival injection under the bulbar conjunctiva is potentially dangerous. Myopic eyes are more likely to be penetrated than emmetropic or hyperopic eyes because of greater ocular length, thin sclera, and staphylomas. Injections should be performed with patient supine. Viscous lidocaine provides better anesthesia than topical anesthesia. Both physicians’ hands should be braced against the patient’s facial bones with the needle entering laterally and nearly parallel to the lid margins. If the needle is directed posteriorly, the globe can be penetrated if the patient moves forward.

PRESURGICAL ANESTHESIA

Topical and intraocular anesthesia is rapidly increasing in popularity for cataract surgery. Although some straightforward core vitrectomy procedures can be performed with topical anesthesia, the extraocular muscles must be blocked for macular and complex surgery. Peribulbar anesthesia using a blunt, curved, flexible cannula and small conjunctival incision are theoretically safer than multiple injections into the anterior orbital tissue. The patient should be directed to position the eye in the primary position during retrobulbar injection. This position has been shown by Grizzard to minimize displacement and increased tension on the optic nerve, which increase the risk of penetration of the nerve (4).

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