General considerations in ophthalmic surgery

A vast array of surgical interventions may be performed in the treatment of ocular and periorbital disease. Because of the high technical difficulty, the subspecialist often performs a significant portion of the ophthalmic surgeries. Most procedures in ophthalmology involve microsurgery and are usually limited to the eye and orbit. Thus, typically there is minimal risk to other organs. Ophthalmic surgery offers a high probability of success, with a major positive impact on quality of life. Nevertheless, many patients with eye pathology are elderly, and some have significant systemic illness. Therefore, the risk of elective intervention must be balanced against the expected benefits, and appropriate counseling should be performed prior to surgery. Optimizing the management of medical problems preoperatively can make the surgery safer and minimize patient discomfort. Anesthesia The large majority of ophthalmic interventions can be performed under local anesthesia with intravenous sedation. In some cases, even topical anesthetics are sufficient. But there are ophthalmic surgeries that require general anesthesia, such as those that involve significant extraocular manipulation, for which the local anesthetic may not be as effective, or those that may be prolonged, as is often the case in many vitreoretinal and orbital procedures. Some periorbital or facial cosmetic interventions often necessitate general anesthesia as well. General anesthesia is also indicated in younger patients and those who may not be cooperative enough to remain motionless during surgery. In addition, general anesthetics are required in trauma cases with significant ocular laceration, where administration of local anesthetics may raise intraorbital pressure, necessitating subsequent extrusion of intraocular contents. Several choices exist in the route of administration of local ophthalmic anesthesia for intraocular surgery. The most widely used approach is injection of 3–7 mL of a mixture of lidocaine 2% and marcaine 0.75% through a retrobulbar approach using a blunted needle (Atkinson needle). This is often performed with a regional seventh nerve block to paralyze eyelid closure. The risks of local ophthalmic anesthesia are remote, but they may be significant. They include local damage through retrobulbar hemorrhage, extraocular muscle damage, and penetration of the globe or optic nerve. Systemic exposure to the injected medication through intravascular or subarachnoid injection of the anesthetic has been known to cause hypertension, seizures, apnea, or even death.