Efficacy and Safety of Temporary in situ Stenting of Ahmed Glaucoma Valve in Eyes with High Risk of Hypotony

Introduction and Objective: To describe a novel technique for providing external ligation of the Ahmed glaucoma valve (AGV) to prevent hypotony in eyes at high risk with a 4/0 nylon stent suture and report outcomes compared to ligation with an absorbable vicryl suture and no ligation in terms of efficacy and safety. Methods: This was a retrospective cohort study investigating the efficacy and safety of in situ stenting compared to an absorbable ligature and the standard care, in high risk eyes, of hypotony. It included 116 patients; 34 in Group A (ligation + stent), 27 in Group B (ligation – stent), and 55 in Group C (no ligation). Results: The mean age (in years) of the participants was 53.94±19.01 in Group A, 44.85±29.92 in Group B and 52.62±24.47 in Group C, 59% (n = 20), 63% (n = 17) and 60% (n = 33) were males, respectively. The follow-up period was at least 6 months (Group A: 9.1 ±4.2 months, Group B: 9.6±3.4 months and Group C: 10.2±6.4 months). The mean baseline Snellen VA (LogMAR) was 1.82±1.34, 1.30±0.98 and 1.34±1.07 and the mean baseline IOP was 32.50±9.48, 28.22±7.12 and 28.33±10.63 mmHg, in Groups A, B and C, respectively. The failure rates, by the Kaplan Meier Survival curve, were higher 27.3% in Group C (no ligation) compared to 20.6% in Group A (ligation + stent) and 18.5% in Group B (ligation – stent) yet not found to be statistically significant (p = 0.4; log rank test). There was lower hypotony 2.9% in Group A and lower complications 25.9% in Group B but no statistical significance was found amongst the groups. Conclusion: In conclusion, temporary nylon in situ stenting of AGV had lower rates of hypotony. Furthermore, lower failure and complication rates were observed in vicryl only ligated AGV, then nylon in situ stented AGV and lastly in standard AGV controls.