Assessment of Peripheral Anterior Synechiae Using Linear Gonio-Images Following Trabeculotomy with Trabectome

Purpose: To quantify peripheral anterior synechiae (PAS) extent after Trabectome surgery using automated gonioscopy (GS-1) and its effects on intraocular pressure (IOP) reduction. Patients and Methods: This retrospective, single-center study included patients who underwent Trabectome surgery and were followed for ≥ 6 months. GS-1 was performed at 6 and 12 months postoperatively to quantify PAS as the proportion of the angle circumference. Analysis of covariance (ANCOVA; linear regression) was performed at 6 and 12 months postoperatively, with IOP reduction rate, PAS extent, and preoperative IOP as the dependent variable, independent variable, and covariate, respectively. The 6- and 12-month PAS extents were compared using the Wilcoxon signed-rank test. The correlations of 6- and 12-month IOP reduction rates with age, preoperative IOP, preoperative score, and PAS extent were determined using Spearman's rank coefficients. Results: The data of 33 eyes (33 patients; 20 males; mean age, 68.5 ± 14.2 years) were analyzed. Trabectome surgery was performed as a standalone procedure for 28 patients and combined with cataract surgery for five. GS-1 revealed PAS in all eyes at 6 and 12 months. The mean PAS extents at 6 and 12 months were not significantly different at 40.16 ± 21.42% and 43.92 ± 20.68%, respectively (P = 0.286). Only preoperative IOP showed significant correlations with the 6- and 12-month IOP reduction rates (r = 0.641, 0.776; P = 0.002, < 0.001, respectively). ANCOVA revealed partial regression coefficients of 0.41 (P = 0.002) and 0.019 (P = 0.952) at 6 months and 0.37 (P = 0.014) and -0.180 (P = 0.623) at 12 months for preoperative IOP and PAS extent, respectively. Conclusion: Widespread PAS was detected by GS-1 at 6 and 12 months postoperatively. However, its effect on postoperative IOP reduction and prognosis appears limited. Moreover, the long-term effects remain unclear; therefore, further studies are warranted.