Occasionally, an eye drop or pill may be discontinued for as long as two weeks before the surgery. It is particularly important to discontinue the use of aspirin, or any pills containing aspirin, at least 7 days before surgery, since use of aspirin can cause undesirable bleeding at the time of surgery. To relax the patient and reduce discomfort, a trabeculectomy is usually done under local anesthesia. An injection of local anesthetic through the eyelid numbs the eye completely so that it will not move during surgery, and there is no discomfort. Sometimes a general anesthetic is used, in which the patient is put to sleep for the operation.
Local anesthesia offers several advantages.
There may be less pain after surgery, and there is no sore throat from the airway tube used in general anesthesia. Patients quickly return to normal alertness without the nausea often felt after general anesthesia. With local anesthesia, there is less risk than with a general anesthetic, especially in the elderly or those with health problems. The surgery itself takes less than one hour in most cases. After trabeculectomy, the eye generally is covered by an eye patch and protected by a plastic shield overnight.