The Effect of Tube Ligature on the Safety and Efficacy of Ahmed Glaucoma Valve Surgery.

PRECIS In this matched case-control study, ligature of the Ahmed Glaucoma Valve was associated with a reduction in the rate of postoperative complications without affecting the surgical success rate or the visual outcome following the procedure. PURPOSE To compare the safety and efficacy of Ahmed Glaucoma Valve (AGV) surgery with and without tube ligation. MATERIALS AND METHODS This was a retrospective matched case-control study. A review was performed of patients that underwent AGV surgery with tube ligation between June 2015-December 2017 (ligated AGV group). Cases were matched with controls that underwent AGV surgery without tube ligation (non-ligated AGV group). Data were compared on postoperative intraocular pressure (IOP), the number of glaucoma medications, surgical success rates, complications, and vision. RESULTS There were 49 eyes in the ligated AGV group, and 98 eyes in the non-ligated AGV group. Baseline characteristics were similar between groups except for the number of glaucoma medications (3.72±0.55 in the ligated AGV group vs. 3.92±0.92 in the non-ligated AGV group; P<0.01). At 18 months, IOP was 16.7±6.3▒mmHg in the ligated AGV group and 17.3±8.0▒mmHg in the non-ligated AGV group (P=0.76). Additionally, the mean number of glaucoma medications was 2.38±1.10 in the ligated AGV group and 1.68±1.51 in the non-ligated AGV group (P=0.56). The overall success rate at 12 months was similar between groups (P=0.84). The overall rate of complications was statistically lower in the ligated AGV group (28.6%) compared to the non-ligated AGV group (73.5%) (P<0.01). The mean change in logMAR acuity was similar between groups (P=0.50). CONCLUSION Tube ligation in AGV surgery may be an effective measure that reduces the rate of postoperative complications without affecting the success rate or visual outcomes of the surgery.