Combined surgery or trabeculectomy alone for patients with uncontrollable PACG

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• Marc D. Myers, O.D.

Primary angle closure glaucoma (PACG) is a debilitating, sight-threatening disease that is commonly found in the Asian population. Although initial treatment may be obtained with laser peripheral iridotomies, the patient more often than not will require additional surgeries, such as cataract extraction and/or a trabeculectomy to obtain adequate intraocular pressure (IOP) control. This retrospective study examined the long-term efficacy and safety of cataract surgery in conjunction with trabeculectomy versus trabeculectomy alone.

The researchers reviewed the charts of 99 Asian patients with PACG who either had cataract surgery with trabeculectomy (combined group) or trabeculectomy alone (trabeculectomy group) between January 1997 and February 2002. The combined procedure was performed on 75 individuals, whereas 24 had trabeculectomy alone. The combined group had either a trabeculectomy with extracapsular cataract extraction (46.7%) or phacotrabeculectomy (53.3%). Pre- and postoperative visual acuity, IOP, and number of glaucoma medications were collected. Evaluations were given at 1 day, 1 week, 1 month, 2 months, 3 months, and then at 6-month intervals for the next 3 years.

The trabeculectomy group needed additional surgery postoperatively, such as cataract surgery (42%), combined trabeculectomy and cataract surgery (8%), and cyclophotocoagulation (2%). The combined group did not need additional surgery. There was no statistical difference between the 2 groups in mean IOP at each of the follow-up periods. Comparing preoperative IOPs with the 3-year postoperative pressures, the combined group showed decreases from 22.9 mmHg to 11.9 mmHg, and the trabeculectomy group showed decreases from 25.4 mmHg to 12.0 mmHg. Visual acuity improved in the combined group and remained stable throughout the study. The visual acuity of the trabeculectomy group fluctuated for 2 months immediately after surgery, then progressively decreased over the remaining 3 years. The number of medications for both groups decreased from an average of 1.9 preoperative to 0.6 postoperative; there was no statistical difference between the 2 groups.

The study concluded that the 2 groups were similar in long-term IOP-lowering effects. One major drawback is more than half of the trabeculectomy group needed additional surgery. Researchers recognized limitations because of the size of the study and the lack of diversity of the patient base. In addition, the initial surgical treatment was not randomized, and the indication for surgery may have differed between the 2 groups. Furthermore, the combined group had a slightly shorter follow-up period compared with the trabeculectomy group. The researchers hope these findings may be useful to other physicians deciding to perform combined surgery or trabeculectomy alone for patients with uncontrollable PACG.