Between the two extremes noted above, that is, those patients with good glaucoma control and those with uncontrolled glaucoma that poses an immediate threat to vision, there is a third group of patients with borderline glaucoma status and visually significant cataracts. For these patients, a combined procedure may be indicated. There is often a fine line of judgment involved in selecting these cases, although the following situations are some in which a combined approach might be preferred: (a) glaucoma under borderline control, despite maximum tolerable medical therapy and laser trabeculoplasty; (b) adequate IOP control, but significant drug-induced side effects; (c) adequate IOP control on well-tolerated medical therapy, but advanced glaucomatous optic atrophy; or (d) uncontrolled glaucoma, but an urgent need to restore vision or when two operations are not feasible.
The rationale for a combined procedure, as opposed to cataract surgery alone, in eyes with good IOP control but advanced damage, is the risk of a transient pressure rise in the early postoperative period, as previously discussed. Even if laser trabeculoplasty has achieved good IOP control, it may still be necessary to combine glaucoma surgery with the cataract extraction, because a good response to laser therapy before cataract surgery does not guarantee postoperative pressure control (47). Studies have shown that the early postoperative pressure rise is significantly less after a combined procedure than after cataract extraction alone (14,15), and this was probably the primary benefit of the combined surgery during the era of extracapsular cataract surgery, when long-term glaucoma control following combined procedures was less predictable. However, with the advent of small incision cataract surgery and the adjunctive use of antimetabolites with the filtering surgery (discussed later in this chapter), the long-term results of combined procedures have improved (48,49) and the relative indications for this surgical option have expanded. Nevertheless, there is still a role for each of the three basic surgical options, the selection of which depends not only on the status of the individual patient, but also on the results that each surgeon experiences with the various operations.
Cataract extraction by phacoemulsification or ECCE, combined with IOL implantation and trabeculotomy, has been found to be a safe and effective treatment for patients with coexisting glaucoma and cataract (50,51). Several retrospective studies have found that the postoperative complication rate and IOP were lower when trabeculectomy was combined with phacoemulsification than with ECCE after 1 to 2 years of follow-up (52,53), and that ECCE may be a risk factor for unsatisfactory late IOP control and filtering bleb appearance. The frequency of fibrin formation and the incidence of an IOP spike of more than 25 mm Hg were lower in one study after the phacoemulsification than after the ECCE (54). More frequent IOL dislocation has been found when trabeculectomy was combined with ECCE than when it was combined with phacoemulsification (55).
Small-incision cataract surgery can be readily combined with trabeculectomy in patients with open angle glaucoma (56,57,58,59). Phacoemulsification and PC IOL implantation, combined with trabeculectomy, is usually associated with a significant improvement in visual acuity, and with lowering of the IOP and the number of glaucoma medications (60). A retrospective analysis of phacoemulsification with PC IOL implant, combined with mitomycin-C–augmented trabeculectomy with fornix-based conjunctival flaps, has shown that the filtering blebs were large, diffuse, and noncystic, achieving good control of IOP and improvement of visual acuity (61).
