Purpose: To compare the intraocular pressure-lowering effect and safety of viscocanalostomy and trabeculectomy with mitomycin C.
Methods: Twenty-five patients with bilateral primary open-angle glaucoma were enrolled in a prospective clinical study. The eyes of each patient were randomly assigned to receive viscocanalostomy in one eye and trabeculectomy with mitomycin C in the other eye. The patients were followed up for 12 months. At each visit, best-corrected visual acuity, intraocular pressure, and the appearance of the surgical wound, anterior chamber, and indirect ophthalmoscopy were recorded.
Results: The mean baseline intraocular pressure was 25.0+/-2.2 mmHg in viscocanalostomy-treated eyes and 24.8+/-2.6 mmHg in trabeculectomy-treated eyes. The mean postoperative intraocular pressure was 15.3+/-1.7 mmHg, 17.1+/-1.5 mmHg, and 17.1+/-1.5 mmHg in viscocanalostomy-treated eyes and 11.7+/-4.4 mmHg, 11.8+/-4.6 mmHg, and 12.6+/-4.3 mmHg in trabeculectomy-treated eyes at 3-, 6- and 12-month intervals, respectively. The mean intraocular pressure in viscocanalostomy-treated eyes was significantly higher than that in trabeculectomy-treated eyes at every visit (P<0.0001). At 12 months, 16 viscocanalostomy-treated eyes (64%) and 22 trabeculectomy-treated eyes (88%) achieved an intraocular pressure of less than or equal to 20 mmHg without medication; there was a significant difference between the two groups (P=0.0240). There were fewer complications in viscocanalostomy-treated eyes. Complications included four cases of shallow anterior chamber (16%) and five of hypotony (20%) in trabeculectomy-treated eyes, against intraoperative microperforation of Descemet's membrane in one of viscocanalostomy-treated eye (4%).
Conclusion: Trabeculectomy with mitomycin C may be more effective than viscocanalostomy in lowering intraocular pressure in patients with primary open-angle glaucoma, while eyes undergoing viscocanalostomy experience a lower incidence of complications. Further investigation of more cases is needed.