Trabeculectomy and phacotrabeculectomy, with mitomycin-C, show similar two-year target IOP outcomes

Background: To determine the efficacy and safety of trabeculectomy with mitomycin-C (trabMMC) compared with that of single-site phacotrabeculectomy with mitomycin-C (phacotrabMMC) in glaucoma patients at increased risk for filtering surgery failure. Methods: Eighty-five consecutive eyes that underwent trabMMC and 105 consecutive eyes that underwent phacotrabMMC were retrospectively compared up to 2 years postoperatively with respect to intraocular pressure (IOP), number of glaucoma medications, and surgical complication rates. The primary outcome was the difference in the cumulative proportion of patients meeting the target IOP range at 2 years. Secondary outcomes included mean postoperative IOP, mean IOP drop from baseline, mean number of glaucoma medications, and surgical complication rates. Results: Baseline characteristics were similar in the 2 groups and most patients had advanced glaucoma with a similar upper limit of the target IOP range (15.5 ± 2.6 mm Hg for trabMMC vs. 15.3 ± 2.1 mm Hg for phacotrabMMC, p = 0.56). Loss to follow-up was significant in both groups (almost 50% over 2 years). A statistically similar proportion of patients achieved their target IOP range at 1 and 2 years in both groups: the cumulative success rate at 2 years was 29.04% and 22.91 % (p = 0.44) without add-on glaucoma therapy, 25.38% and 25.22% (p = 0.60) with the use of up to 2 glaucoma medications, and 30.01% and 25.17% (p = 0.81) with the use of any number of glaucoma medications, in the trabMMC and phacotrabMMC groups, respectively. Mean postoperative IOP was also similar between the 2 groups at almost all follow-up times up to 2 years (13.56 ± 4.92 mm Hg in trabMMC vs. 13.98 ± 4.74 mm Hg in phacotrabMMC at 2 years, p = 0.67). The mean IOP drop from baseline was significantly greater in the trabMMC group throughout the study period (-10.87 ± 8.33 mm Hg in trabMMC vs. -6.15 ± 7.01 mm Hg in phacotrabMMC at 2 years, p = 0.003); however, baseline IOP was also higher in the trabMMC group (26.1 mm Hg vs. 20.3 mm Hg, p < 0.0001). Serious postoperative complication rates were similarly low between the 2 groups. Interpretation: TrabMMC and phacotrabMMC may be equally safe and effective in bringing IOP to within an acceptable target range over 2 years in advanced glaucoma patients at increased risk for filtering surgery failure, although trabMMC appears to be associated with greater IOP lowering from baseline.