Intraluminal stenting versus external ligation of Ahmed glaucoma valve in prevention of postoperative hypotony

AIM: To compare intraluminal stenting and external ligation of Ahmed glaucoma valves (AGV) for refractory glaucoma management and postoperative hypotony prevention. METHODS: This randomized prospective blind study included 30 eyes of 25 patients (age range: 44-56y) with refractory glaucoma. This study was conducted from September 2018 to January 2020. The study included two groups, AGV with intraluminal stenting group (n=15 eyes) and AGV with external ligation group (n=15 eyes). Follow-up period was one year postoperatively. The primary outcome was intraocular pressure (IOP) and its association with the number of postoperative glaucoma medications. IOP <= 21 mm Hg without medications indicated complete success while IOP <= 21 mm Hg with medications indicated qualified success; and IOP<6 mm Hg was defined as hypotony. RESULTS: After a year of follow-up, IOP was significantly reduced in the intraluminal stenting group than in the external ligation group (11.67 +/- 0.89 vs 14.2 +/- 4.0 mm Hg, respectively, P=0.024). Postoperative hypotony was more common in the external ligation group (2 cases, 13.33%) than in the intraluminal stenting group (1 case, 6.67%). CONCLUSION: Application of intraluminal stenting or external ligation during AGV surgery usually prevents postoperative hypotony (transient and persistent) that occurs in conventional AGV surgery.