Material and Methods: This retrospective, noncomparative study includes the medical records of one eye of each 13 patients who underwent an AGV removal.

Results: A total of 324 eyes received an AGV between April 2002 and March 2017 and 21(6.48%) of them had tube exposure. Eight eye of the 21 were successfully repaired by different methods but 13 of them underwent an implant explantation.For the 13 patients, average 2.2±0.4(2 or 3 times) repairing procedures were performed for each patient which include conjunctival pedicle fl aps or double layer amniotic membrane graft with/without pericardial patch graft but they required an explantation within 2 months after the last attempt because of recurrent tube erosion.The mean time with the AGV was 38.30±36.94(4-114)months.The mean intraocular pressure(IOP)value was 13±7(3-30)mmHg just before the explantation,and 26±1 (range;3-50) mmHg at the fi rst postoperative morning following the explantation without antiglaucomatous therapy. The mean follow-up period after the removal was 22±14(6-57) months.The mean IOP value was 22±10(5-42) mmHg with/without medical treatment at the last visit.

Conclusions: A tube exposure, which can be considered as both an early and a late complication,is the main reason for an explantation.In this series, uveitis is the most common diagnosis for the valve implantation; hence, it is correct to say that uveitic cases are the most common groups of patients,who not only have a risk of exposure, but also have encountered failure in primary repair of exposure. AGV explantation is a safe and saviour procedure in all tube exposure. Keywords : Refractory glaucoma, glaucoma drainage implants, Ahmed glaucoma valve explantation, tube exposure