Effect of adjunctive viscogonioplasty on drainage angle status in cataract surgery: a randomized clinical trial

Background To compare the anatomic effects of phacoemulsification (Phaco) versus combined phacoemulsification and viscogonioplasty (Phaco-VGP) on drainage angle status in primary angle-closure glaucoma (PACG) using anterior segment optical coherence tomography (AS-OCT). Design Prospective, randomized clinical trial. Participants Sixty-seven eyes of 57 patients with the diagnosis of PACG. Method Patients were randomized to undergo Phaco alone (33 eyes) or Phaco-VGP (34 eyes). Patients were examined postoperatively on day 1, week 1 and week 6. Indentation gonioscopy and AS-OCT were performed preoperatively and at 6 weeks after surgery. Main Outcome Measures Angle and anterior segment parameters by AS-OCT and amount of peripheral anterior synechiae (PAS) by gonioscopy. Results Sixty-five eyes of 55 patients completed the trial. The mean extent of PAS was significantly reduced from 127.7 to 95.0 degrees (P<0.001) by Phaco alone, and from 174.0 to 77.3 degrees (P<0.001) by Phaco-VGP. Phaco-VGP resulted in significantly greater reduction in PAS extent (P=0.002). Angle-opening distance and trabecular-iris space-area measured by AS-OCT increased significantly after Phaco alone and Phaco-VGP (P<0.001 for both). Although the change was higher in the Phaco-VGP group, this did not reach statistical significance. Anterior chamber depth (ACD) increased, and lens vault (LV) decreased after both procedures. The amount of change in ACD and LV was not significant between the two groups. Conclusion Both Phaco alone and Phaco-VGP resulted in widening of the drainage angle, deepening of the anterior chamber and reduction of intraocular pressure (IOP) and PAS extent in PACG eyes. Phaco-VGP resulted in significantly more reduction of PAS. However, it seems that additional VGP has no significant effect on short-term IOP.