Noncorneal Complications

Most glaucoma specialists advocate the use of 5-fluorouracil (5-FU) and mitomycin-C (MMC) in various concentrations during the intraoperative and postoperative periods to help inhibit postoperative scarring, the primary cause of filtration surgery failure. Although the increased use of antifibrotic agents as adjunctive therapy to guarded filtration surgery has improved the likelihood of operative success, there are many additional complications associated with this class of medications. It is the nature of filtration surgery as it is performed today that successful drainage of aqueous comes with a price. Any adjunct that improves the intraocular pressure (IOP)-lowering success of surgery must be assessed in light of this increased risk. A leaking bleb is one of the most common complications seen after trabeculectomy and may occur at any point postoperatively. This complication has been reported with an incidence ranging between 17% and 42% according to one review. More recent estimates have been somewhat lower, at between 8% and 14.6%. The longer the postoperative follow-up, the greater the cumulative likelihood of bleb leakage. It is imperative that the bleb be checked periodically for leaks, primarily through examination and standard Seidel testing. Use of antifibrotic therapy is associated with increased formation of thin-walled cystic blebs, which are more likely to result in both short-term and long-term complications. The timing of a bleb leak will dictate management. Many early postoperative bleb leaks resolve without intervention but can significantly decrease the likelihood of trabeculectomy success. Early postoperative bleb leaks are often attributed to surgical technique and can generally be avoided by use of appropriate blunt instruments and careful attention to surgical detail. The simple use of nontoothed forceps when handling the conjunctiva can prevent small buttonhole conjunctival tears, which often result in early postoperative bleb leaks. However, even with careful manipulation, friable conjunctival tissue can be prone to small tears. While some have advocated the use of light cautery, or even tissue adhesives to close bleb leaks, the use of such techniques has diminished in the antifibrotic era. Intraoperative suturing of buttonholes is definitive.