Transscleral cyclophotocoagulation with MicroPulse(R) laser versus Ahmed valve implantation in patients with advanced primary open-angle glaucoma

Purpose To compare the efficacy of transscleral cyclophotocoagulation with MicroPulse(R) laser (Iridex, Silicon Valley, California, USA) with 3000 mW to Ahmed valve implantation in eyes with advanced stage of primary open-angle glaucoma. Methods In a prospective observational clinical study, 30 patients (30 eyes) with advanced open-angle glaucoma were randomized for either micropulse transscleral cyclophotocoagulation with 3000 mW or Ahmed valve implantation. Fifteen eyes were treated with transscleral cyclophotocoagulation with MicroPulse(R) laser with 3000 mW (group A) and 15 eyes with Ahmed valve implantation (group B). As inclusion criteria are included the diagnosis of advanced primary open-angle glaucoma, an intraocular pressure above 21 mmHg, cup-to-disk ratio 0.9-1.0, failure to meet the target IOP with either maximal tolerated local medical therapy (2-4 antiglaucoma agents) or systemic therapy (acetazolamide). The follow-up time of the study was 12 months. An absolute success was defined the achievement of IOP between 6 and 15 mmHg and at least 30% reduction of the IOP from baseline under reduced or the same number of antiglaucoma agents after the surgical procedure without following glaucoma surgeries and as qualified success the achievement of IOP between 6 and 18 mmHg and at least 20% reduction of the IOP from baseline regardless of the number of postoperative antiglaucoma agents. The efficacy was evaluated by estimating the absolute success rate and the qualified success rate using the Kaplan-Meier survival analysis. Results A reduction of the intraocular pressure > 30% was achieved in 33.3% of group A and in 73.3% of group B during the follow-up period of 12 months. A statistically significant decrease in the number of eye drops was observed in both groups (p < 0.01). 53.3% of the eyes of group A underwent additional anti-glaucoma procedures to achieve target intraocular pressure. The number of the local medications that were administered 12 months after the ocular surgery was 2 (+/- 1.3) in group A and 0.57 (+/- 0.9) in group B, compared to 3.2 (+/- 0.78) in group A and 3.33 (+/- 0.7) in group B administered prior to the surgery (p: 0.016). 8 eyes (53.33%) in group A were referred for additional treatment due to an acute postoperative rise in IOP (5 eyes: mTS-CPC, 1 eye: canaloplasty, 2 eyes: AGV implantation). No further anti-glaucoma procedures were necessary in group B. Conclusion The Ahmed valve implantation achieves a more efficient decrease of the intraocular pressure as well as of the number of antiglaucoma agents than the transscleral cyclophotocoagulation with MicroPulse(R) diode laser 3000 mW. Additionally, the Ahmed valve implantation showed better results in terms of absolute and qualified success rates in the treatment of advanced primary open-angle glaucoma.