Comparison of standard trabeculectomyversusmicrotrabeculectomy as a surgical treatment for glaucoma: a randomized clinical trial

Abstract

To determine the effect of scleral flap size on the medium-term intraocular pressure control and complication rates after augmented trabeculectomy. Prospective randomized clinical trial. Glaucoma patients undergoing primary trabeculectomy. Exclusion criteria included previous ocular surgery apart from cataract surgery, secondary glaucoma and age under 18. Patients were randomized to either standard trabeculectomy (4 × 4 mm scleral flap) or microtrabeculectomy (2 × 2 mm scleral flap), both with adjustable sutures and antimetabolites. Bleb needling was performed as required. Patients were evaluated at day 1, weeks 1, 3, 6 and months 3, 6, 12, 18 and 24 postoperatively. Vision, intraocular pressure, complications and failure (intraocular pressure ≥ 21 mmHg or not reduced by ≥20% from baseline, intraocular pressure ≤ 5 mmHg, repeat glaucoma surgery and no light perception vision). Forty-one patients were recruited; 20 had standard trabeculectomy, and 21 had microtrabeculectomy. At 2 years, the mean intraocular pressure and cumulative probability of failure was 12.4 ± 4.6 mmHg and 0.28 for standard trabeculectomy, and 11.5 ± 3.6 mmHg and 0.27 for microtrabeculectomy (P = 0.50 and 0.89, respectively). One patient in each group required Baerveldt device implantation. Vision reduced ≥2 Snellen lines in 15% in the standard trabeculectomy group and 25% in the microtrabeculectomy group, mainly from cataract (P = 0.48). Both trabeculectomy techniques achieved good intraocular pressure reduction and had similar complication rates. Scleral flap size had no significant effect on medium-term intraocular pressure control and complication profile.