The authors of this prospective trial evaluated the benefits of adding trabeculectomy with mitomycin C (MMC) during phacoemulsification in patients with primary angle-closure glaucoma.
Study design
The trial enrolled 63 patients with primary angle-closure glaucoma who were randomized to undergo phacoemulsification alone (32 eyes), or phacoemulsification with concurrent MMC-augmented trabeculectomy with watertight releasable flap sutures (phacotrabeculectomy; 31 eyes). Patients were seen at 1 day, 1 week, 1 month, 3 months, 6 months, 9 months and 12 months postoperatively. Outcome measures included success rates, complications, IOP, number of eye drops and need for further procedures.
Outcomes
There was no significant difference in postoperative IOP, IOP reduction, success rates or survival times between groups. The number of glaucoma medications was significantly lower in the phacotrabeculectomy group at 1 and 3 months postoperatively, but not at any other time point.
In the phacotrabeculectomy group, 35% required 1 or more bleb needlings with 5-Fluorouracil. At final follow up, 39% of eyes in the phacotrabeculectomy group had restarted glaucoma drops, compared with 34% in the phacoemulsification alone group. One eye (3%) in the phacotrabeculectomy group required another glaucoma procedure, compared with 2 eyes (6%) in the phacoemulsification alone group, which was not a statistically significant finding.
Limitations
The practice of watertight scleral flap closure with 4 to 5 releasable sutures is not a common trabeculectomy technique, which limits the applicability of this study for most surgeons. While the goal of this technique was to eliminate hypotony as a confounding factor in the study, it may have resulted in the higher probability of trabeculectomy failure. This study was performed in Egypt, and most patients were likely of African descent (although this was not recorded). This may have led to an overestimation of trabeculectomy failure when compared with other racial groups, and also limits the applicability of this study for non-African patients. In addition, the study did not have concrete criteria for pulling the releasable sutures, and did not mention whether postoperative treatment was guided by bleb morphology.
Clinical significance
The high rates of success, regardless of the stage of glaucoma or degree of peripheral anterior synechie, is reassuring that most patients with primary angle-closure glaucoma will achieve IOP control from phacoemulsification alone, although frequently with the help of topical antihypertensives. Lens extraction can be considered first-line surgical therapy for primary-angle closure glaucoma, and may help the vast majority of patients avoid filtration surgery.