Effect of Postoperative Trimming of the Tube Portion of Ahmed Glaucoma Valve on Corneal Endothelial Cell Loss.

Abstract

We reduced the tube length through a small limbal incision in eyes that underwent Ahmed glaucoma valve (AGV) implantation and found that the rate of corneal endothelial cell (CEC) density was markedly reduced from -12.2% per year to -3.5% per year after this simple procedure. The aim was to evaluate the effect of postoperative tube tip trimming (TT) after AGV implantation on CEC loss. In this retrospective cohort study, a total of 75 eyes from 67 patients (41 eyes in the AGV implantation only group (AGVG: mean follow-up, 42.2±13.8 mo) and 34 eyes in the TT after AGV implantation group (TAGVG: mean follow-up, 64.9±18.5 mo) were analyzed. TT was performed through a small limbal incision at a mean of 41 months after AGV implantation. Both groups were followed up for at least 1 year and underwent at least 2 specular microscopic examinations after AGV implantation and/or TT. In the AGVG, CEC density was reduced from 2247.0±527.3 to 1665.7±643.3 cells/mm2 (P<0.001). In the TAGVG, it was reduced from 2383.1±619.4 to 1552.9±700.9 cells/mm2 before TT (mean 41 mo of follow-up) and after TT, to 1394.6±654.7 cells/mm2 (mean 26 mo of the follow-up). The reduction rate of CEC density before TT was -12.2±6.5% per year, and this rate was significantly reduced to -3.5±6.9% per year after TT in the TAGVG (P=0.002). The probability of corneal failure defined as a 15% reduction in CEC density was significantly reduced after TT in TAGVG (P=0.038). Tube TT after AGV implantation markedly reduced the rate of CEC loss without serious complications in eyes with AGV implantation.