Early Postoperative Intraocular Pressure is Associated with Better Pressure Control after XEN Implantation

Carlo Alberto Cutolo, Michele Iester, Alessandro Bagnis, Chiara Bonzano, Letizia Negri, Sara Olivari, Francesca Cappelli, Valeria Testa, Daniele Sindaco, Chiara Pizzorno, Riccardo Scotto, Michela Saccheggiani, Carlo Enrico Traverso

Research output: Contribution to journalArticlepeer-review


Précis: Gel stent implantation is a bleb-forming surgery designed to achieve predictable pressure drop. An early low intraocular pressure is associated with the long-term success of the procedure. Purpose: To identify the variables associated with the success of the XEN procedure. Patients and Methods: This was part of a prospective, uncontrolled, consecutive case series study. Patients with primary open-angle glaucoma or pseudo-exfoliative glaucoma were included. All the patients underwent surgical Xen implant procedure with MMC subconjunctival injection 20 minutes before surgery. Success criteria were an off-medication IOP of 6 to 16▒mmHg 12 months after surgery; no additional glaucoma surgery; no visual threatening complications, no visual acuity loss greater than 1 Snellen line. One eye per patient was considered for statistical analysis. A univariate Cox's proportional hazard regression analysis was performed to identify potential risk factors for surgical failure. Then, a multivariate cox model was built. Results: 123 patients were recruited in this study: 93 patients underwent Xen implantation alone whereas 30 the combined procedure with phacoemulsification and IOL implantation. Univariate cox regression showed that the day after surgery IOP greater than 9▒mmHg was associated with surgical failure (P=0.02) and a postoperative number of needlings greater or equal to 2 in the follow-up was also predictive of surgical failure (P<0.01). These data were confirmed by a multivariate model too. At 1-year the surgical success criteria were 76% in the group with 24-hour IOP below or equal to 9▒mmHg, while it was 43% when above 9▒mmHg (P=0.026). Conclusion: Our study shows that an early IOP below or equal to 9▒mmHg is predictive of the efficacy of the procedure during 1-year follow-up, while more than two needlings are predictive of failure.

Original languageEnglish
JournalJournal of Glaucoma
Publication statusAccepted/In press - Jan 1 2020


  • Glaucoma
  • Prognostic factors
  • Surgery
  • Xen implant

ASJC Scopus subject areas

  • Ophthalmology


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