Biodegradable collagen matrix implant versus mitomycin-C in trabeculectomy: five-year follow-up

Background: Clinical studies comparing trabeculectomy augmented with Ologen implant (OLO) versus trabeculectomy plus mitomycin-C (MMC) show contradictory results. To obtain long-term data, we report an extended 5-year follow-up trial evaluating the safety and efficacy of OLO as adjuvant compared to low-dosage MMC in trabeculectomy. Methods: Forty glaucoma patients (40 eyes) assigned to trabeculectomy with MMC or Ologen. Primary outcome: target IOP at <= 21, <= 17 and <= 15 mmHg; complete and qualified success endpoint rates. Secondary outcomes: visual acuity (VA), mean deviation (MD), bleb evaluation, according to Moorfields Bleb Grading System (MBGS); spectral domain OCT (SD-OCT) bleb examination; number of glaucoma medications; frequency of postoperative complications. Results: The mean preoperative IOP was 26.7(+/- 5.2) in MMC and 27.3(+/- 6.0) in OLO eyes. Mean 60-month percentage reduction in IOP was significant in both groups [40.9 (+/- 14.2) and 42.1(+/- 13.3) P = 0.01], with an endpoint value of 15.2 (+/- 3.2) and 15.8 (+/- 2.3) mmHg in MMC and OLO, respectively. Complete success rates at <= 21 mmHg target IOP were 65 % and 70 %, at <= 17 mm Hg 60 % and 55 %, and at the = 15 mm Hg target IOP 35 % and 45 % in MMC and OLO, respectively. The Kaplan-Meier curves did not differ both for complete and qualified success at any target IOP, with no significant endpoint intergroup difference at <= 15 mm Hg (log-rank P = 0.595). The intergroup MBGS scores differed due to reduced central and peripheral vascularity in MMC group (P = 0.027; P = 0.041). SD-OCT analysis denied differences in bleb height between MMC vs OLO (140.5 +/- 20.3 mu vs 129.2 +/- 19.3 mu respectively; P = 0.079). Mean antiglaucoma medications were significantly reduced (P < 0.0005) from 2.5 (+/- 0.3) to 1.2 (+/- 0.4) in MMC and from 2.6 (+/- 0.2) to 1.4 (+/- 0.3) in OLO group, with no intergroup differences (P = 0.08). Six (30 %) cystic thin avascular blebs without oozing were recorded in the MMC group and 2 (10 %) in the OLO group, without intergroup difference (P = 0.235). Conclusions: Our extended follow-up results confirm that Ologen implant yields efficacy and long-term success rates quite similar to MMC, with at least equivalent safety.