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Glaucoma drainage devices play an important role in the management of uncontrolled intraocular pressure and glaucoma. Although more commonly used in eyes that have been multiply-operated, recent data have suggested that long tube implants that shunt aqueous to a posterior reservoir can be helpful as the initial glaucoma surgical procedure in selected patients. One of the complications associated with glaucoma drainage devices is progressive endothelial cell loss and corneal edema, which can lead to corneal decompensation and need for subsequent keratoplasty. Progressive endothelial cell dysfunction and death typically results from close proximity or contact of the intraocular portion of the silicone tube to the corneal endothelium. This process often takes years to initiate corneal dysfunction. Since this late surgical complication is well-known, most surgeons endeavor to position the anterior segment portion of the tube well away from the corneal endothelium, often along the surface of the iris, or in some cases, in the ciliary sulcus.
In this article, Bochmann and Azuara-Blanco (1696) report a single case in which a tube abutting the cornea was repositioned through the use of a permanent anterior segment prolene suture passed across the anterior segment and designed to move the flexible tube towards the iris surface. This technique, a modification of the anterior chamber retaining suture technique described by Wilson and Moster (Wilson RM, Moster MR. The chamber retaining suture revisited. Ophthalmic Surg 1990: 21: 625-627), proved useful in this particular case which had undergone multiple prior intraocular surgeries. The current article nicely describes the application of this technique to reposition the errant silicone tube.
The best way to manage tube-cornea contact is to take all intraoperative steps necessary to prevent it. For eyes with tube-cornea contact, there are several surgical alternatives. For many of these eyes with progressive decompensation, repositioning of the tube into the ciliary sulcus or vitreous cavity before or at the same time as keratoplasty may be the best long-term solution. However, for certain patients for whom additional incisional surgery may not be warranted or possible, repositioning of the tube using the technique described by Bochmann and Azuara-Blanco may be a simple and elegant solution to an otherwise difficult problem.