Local anesthesia is used for eye surgeries when an additional level of anesthesia is required.
If a surgery is complex or expected to last 30-60 minutes or more, numbing medicine may be injected around the eye. This is referred to as a “retrobulbar block” and is often used during full-thickness corneal transplants or vitrectomy surgery. The injection is given in the preoperative area under deep sedation and is closely monitored by an experienced nurse anesthetist.
The deep sedation causes the patient to fall asleep for a few moments while the block is administered. The patient continues to breathe on their own during this time, so no breathing tube is required. After the block is administered, the patient wakes up and is taken to the operating room.
The surgery proceeds with the patient awake but relaxed, and still carefully monitored. After surgery, an eye patch is typically placed and left in place until the morning.
Until the block completely wears off, local anesthesia causes complete numbness of the eye, the inability to move the eye, and decreased vision. The numbing effects of the medication may last for several hours.
The risks of local anesthesia include a slight chance of damage to the eye or surrounding structures from the needle used to administer the anesthetic. There is an extremely remote chance of the anesthetic medication reaching the fluid around the brain, which could lead to loss of consciousness and the need for supportive measures until the anesthetic dissipates.