This prospective study found that phacoemulsification and trabeculectomy offer similar and effective reduction of IOP in medically uncontrolled chronic angle-closure eyes without cataract. While trabeculectomy is more effective at reducing dependence on glaucoma drugs, it is associated with more complications.
Based on the findings of this study, it would appear that the standard procedure of glaucoma surgery for uncontrolled closed-angle glaucoma remains the procedure of choice, as the pressure control is better, and one would prefer to remove a cataractous lens rather than a clear one. Although the authors emphasized the greater complication rate in the trabeculectomy group, with cataract being the main complication, only 27 percent of the phacoemulsification group was able to eliminate the use of glaucoma drugs.
Subjects were 50 patients with medically uncontrolled chronic angle closure glaucoma without cataract randomized to phacoemulsification or trabeculectomy with adjunctive mitomycin C. All patients had visual acuity of 20/40 or better and angle occlusion of at least 180 degrees. After surgery, patients underwent follow-up exams every three months for two years.
Both procedures resulted in significant and comparable IOP control at 24 months (reduction of 8.4 mmHg or 34 percent for phacoemulsification vs. 8.9 mmHg or 36 percent for trabeculectomy; P = 0.76). However, the dependence on glaucoma drugs remained significant in the phaco group, with only 27 percent of eyes not requiring IOP-lowering drugs or further surgery by 24 months. On the other hand, trabeculectomy was associated with significantly more surgical complications than phacoemulsification (46 percent vs. 4 percent; P = 0.001). Eight (33 percent) of 24 trabeculectomy-treated eyes demonstrated cataract during follow-up.
Five (19 percent) of 26 eyes in the phacoemulsification group remained or became medically uncontrolled within 24 months. However, the subsequent trabeculectomies did not seem to be compromised by the prior phacoemulsification.
The authors conclude that both phaco and trab may each have a role in the management of medically uncontrolled chronic angle closure glaucoma without cataract, with specific benefits and drawbacks. By performing phacoemulsification alone, the potential complications of trabeculectomy and mitomycin C were avoided. This may be of greater significance in patients who are prone to, or do not wish to endure, such complications. However, in situations in which drug reduction is a high priority, trabeculectomy may be more suitable. It is not known whether the IOP control achieved by phacoemulsification will decay with time and whether an increasingly larger proportion of phacoemulsification eyes will require trabeculectomy with longer follow-up.