JJ Lee, et al. AHMED VALVE WITH TUBE LIGATION AND STENTS B D A C Fig. 1. Ahmed glaucoma valve implant surgery with ligation of silicone tube and external stents. (A) A limbus-based scleral flap was created with a Beaver knife. (B) The AGV plate was placed in the sub-Tenon’s space in the supero-temporal quadrant. (C) The silicone tube and 3 strands of 8-0 Nylon were ligated with 8-0 Vicryl, and the ligature was tightened until the internal lumen of the tube collapsed. (D) The lengths of the exposed 8-0 Nylon strands were kept to about 5 mm to minimize corneal irritation. M aterials and M ethods A retrospective chart review was conducted on consecutive patients who underwent AGV implantation by a single surgeon (K.H.P.) at Seoul National University Hospital from January, 2001 to July, 2004. This study was approved by the hospital Institutional Review Board as a retrospective chart review study which does not require informed consent from the patients. All 95 eyes of 90 patients with a minimum of 12 months of follow-up were included. The following information was gathered from the charts: age, gender, race, eye laterality, glaucoma diagnosis, previous operation history, visual acuity, IOP, number of antiglaucoma medications, and postoperative complications. After administering retrobulbar and facial nerve blocks, the affected eye was prepared with povidone-iodine and draped. A 6-0 black silk suture was placed through the midstromal cornea at the 12 o’clock position and used for traction. A fornix-based conjunctival flap was then created between two adjacent recti (superotemporal or nasal), the recti were identi- fied, but not isolated. The AGV (model S2) was then irrigated with a balanced salt solution to prime the valve mechanism. A limbus-based scleral flap was created with a rectangle of 4×4 mm. The plate was placed and fixed to the sclera with 8-0 Nylon sutures 8 to 9 mm posterior to the limbus. As an external stent, 3 strands of 8-0 Nylon were put just beside the silicone tube and the ligation of both tube and stent was done with 8-0 Vicryl. The ligature was tightened until the internal lumen of the silicone tube collapsed (Fig. 1). The tube was then positioned over the cornea to measure the required length so as not to cross the pupil margin, and its tip was trimmed so that the bevel on the tip faced the corneal endothelial surface. The anterior chamber was entered through the limbus under the scleral flap with a 23-gauge needle. The AGV tube was then placed into the anterior chamber parallel to the iris plane through the needle track. The scleral flap was then sutured to cover the AGV tube. The conjunctiva and Tenon’s capsule were closed with 8-0 Vicryl sutures. No anti-metabolites were used intra- or postoperatively. The external stents consisting of 3 strands of 8-0 Nylon were exposed through the conjunctival wound. The exposed stents could be removed with a forceps during slit lamp examination between 1 day and 1 month 87