Risk Management

Inform Cataract Patients of Anesthesia Risks

By Monica L. Monica, MD, PhD, and Daniel A. Long, MD

Argus, May, 1994

When informing patients about the risks and benefits of cataract surgery, the ophthalmologist should also discuss the type of anesthesia that will be used and its potential problems. Risks and complications may occur with either local or general anesthesia. This article will address the concerns of patients and ophthalmologists with regard to local anesthesia, including seventh nerve akinesia.

The federal mandate of 1986 requiring that all Medicare-reimbursed cataract surgery be done in an outpatient setting prompted ophthalmologists to seek anesthesia that would allow a safe and rapid recovery after surgery. Less invasive techniques such as the use of topical rather than injected anesthetic agents became desirable in short-stay facilities where early ambulation is required.

Currently, most cataract surgery is performed under local anesthesia and involves one or more of the following: retrobulbar anesthesia, peribulbar block or topical anesthesia.

Retrobulbar Anesthesia

Retrobulbar anesthesia has been routinely used for cataract surgery for many years. It affords a complete loss of orbital sensation, an eye that remains immobile throughout the operative procedure, and postoperative pain control lasting up to several hours. When securing preoperative consent, the ophthalmologist must communicate to the patient the risks of retrobulbar injections, including orbital hemorrhage, perforation of the globe and damage to the optic nerve. Rather than surprise a patient on the day of surgery, tell the patient in advance that surgery may have to be canceled and rescheduled if a complication such as a retrobulbar hemorrhage occurs.

As part of the informed consent process, ophthalmologists warn patients of possible loss of vision or blindness following cataract surgery. This warning is particularly significant should an anesthetic agent be inadvertently injected into the optic nerve sheath, or if the circulation to the optic nerve and retina is compromised from an injection that injures the ophthalmic artery.

Peribulbar Block

A peribulbar block, an alternative to retrobulbar anesthesia, offers the advantages of less pain from injection and no loss of vision in the immediate postoperative period. But it requires a longer waiting period for the anesthetic agent to take effect and a possible ecchymosis of the skin of the eyelid. Penetration of the globe has been known to occur with the use of small-bore sharp disposable needles.

Topical Anesthesia

Recently, ophthalmologists have been returning to a technique that was popularized during the early 1900s the use of topical anesthetic agents, employed particularly when the surgical incision is being made through clear cornea. Agents of choice are proparacaine or tetracaine. Tetracaine penetrates deeper into the cornea and is less toxic on the corneal epithelium. Both agents allow a rapid recovery and avoid the risks associated with injecting anesthetics around or behind the globe. The disadvantages of topical anesthetic agents include a less profound anesthesia (such as when agents like Miochol are used for myosis after the IOL is placed), an eye that may move at an inappropriate time, and possible sensitivity to the medication.

The authors have used topical anesthesia for clear cornea cataract surgery in more than 300 cases and have followed the patients for up to one year. In addition to avoiding the risks associated with injections, patients need little, if any, medication for preoperative sedation. They are alert before, during and after the procedure, and are immediately ambulatory and able to leave the surgery area. Good communication is essential when topical anesthesia is used for cataract surgery. The ophthalmologist must give the patient thorough preoperative instructions, including:

They will be fully awake throughout the procedure and will be expected to communicate with the surgeon about any anxiety or discomfort they feel.

They may be required to move their eyes as directed by the surgeon or to keep it still and focused on a light throughout the surgery.

If necessary, the surgeon may give them a sedative during the procedure and the type of anesthesia used may change if the need arises.

Seventh Nerve Akinesia

Regional blocks of the seventh nerve often are used prior to cataract surgery. Patients should be forewarned of complications that may occur, most of which are not severe. If a Van Lint block is used, the authors believe that it should be done prior to the retrobulbar block to avoid the possibility of penetrating the globe in case the retrobulbar injection proptoses the eye. With Atkinson akinesia, care must be taken because hemorrhage from the superficial temporal blood vessels may occur when the injection is made along the zygomatic arch.

The O’Brien method blocks the facial nerve over the condyle of the mandible but, due to anatomic variations, sometimes does not accomplish complete akinesia. The Spaeth modification of the O’Brien technique is often more successful since it catches the nerve at the edge of the mandible before it divides into its branches.

Finally, the Nadbeth technique blocks the facial nerve after its emergence from the stylomastoid foramen. It is successful and easy to perform but occasionally leaves patients with a bitter taste in their mouths, something that should be mentioned prior to surgery. A few patients have reported dysphoria as well as swallowing and respiratory difficulties following Nadbeth blocks. Thin patients are more prone to complications. A long needle with a deep injection and the use of hyaluronidase should be avoided when injecting at the stylomastoid foramen.

Just as anesthesiologists are expected to communicate the risks of standby or general anesthesia to patients prior to cataract surgery, the operating surgeon is responsible for discussing and reviewing aspects of local anesthesia before surgery. An informed patient is more cooperative and suffers less anxiety before, during and after surgery.