A New Technique Using a 4-0 Nylon Thread as a Guide for Easy and Precise Tube Insertion of Ahmed Glaucoma Valve Implant Into Ciliary Sulcus

We present a new technique for inserting the tube of the Ahmed glaucoma valve (AGV) (model FP7; Rancho Cucamonga, CA: New World Medical) implant into the ciliary sulcus, easily and precisely, using a 4-0 nylon thread as a guide. An 88-year-old woman received AGV implantation for secondary angle recession glaucoma with underlying pseudoexfoliation syndrome in her left eye. She had a history of trauma with mild intraocular lens (IOL) oscillation and poor mydriasis, with maximum pupil diameter of 3.5 mm. Ciliary sulcus tube insertion in such patients sometimes becomes difficult, however, using a 4-0 nylon thread as a guide, precise insertion was achieved easily in the following way. A 4-0 nylon thread was placed into the anterior chamber through a 1 mm incision opposite the site of the AGV implant. Subsequently, a 23G needle was inserted into the sclera 2 mm from the corneal limbus in the same quadrant as AGV implants. The tip of the 23G needle proceeded horizontally to the iris, through the sclera and ciliary body, and into the ciliary sulcus. At the center of the pupil, the 4-0 nylon thread was introduced into the lumen of the 23G needle. Subsequently, the 23G needle, together with the 4-0 nylon thread in the lumen was withdrawn out of the eye. The 4-0 nylon was then inserted into the tube lumen of the AGV implant. Finally, by using 4-0 nylon as a guide, the Ahmed tube was inserted into the ciliary sulcus precisely without much difficulty.