COMPLICATIONS OF GLAUCOMA FILTRATION SURGERY

As with all intraocular operations, glaucoma filtration surgery can be complicated by anesthetic problems, inadvertent deleterious technical manipulations, difficult intraocular hemorrhage, and postoperative infection. In addition to these rare but potentially devastating general complications, there are a host of less serious but much more common intraoperative and postoperative complications. Approximately 60% of patients can be expected to suffer some level of complication after filtration surgery [1]. Many of these complications are mild and transient, requiring nothing more than careful observation; some are more serious and may lead to failure of the filtration procedure or even irreversible visual loss [2]. Many of the complications characteristic of filtration surgery derive from the somewhat schizophrenic demands placed on the healing filtered eye. The relatively large surgical entry sites must be sealed watertight throughout the postoperative period. This is accomplished by a combination of meticulous surgical closure and adequate healing. At the same time, the internal fistula must remain open and function as a controlled leak if the operation is to be successful. This controlled leak is maintained by a combination of proper surgical technique and a lack of healing. The regions of the eye that are expected to heal watertight within hours and those required to leak at a controlled rate for years are within millimeters of each other. In the uncomplicated filter, the requisite areas of the eye leak and heal in concert. More often than not, however, the balance between leaking and healing is tipped too far in one direction or the other during some phase of the healing process. Fortunately, effective and timely management of these problems usually leads to a successful operation.