Pediatric Glaucoma: Angle Surgery and Glaucoma Drainage Devices

Abstract

The goniotomy procedure is elegantly simple and requires minimal equipment; however, preparationfor this procedure is essential for its success. In the operating room, gonioscopic examination of the filtration angle prepares the surgeon for the upcoming procedure by redefining the target trabecular meshwork (TM) and by confidently assuring the presence of an adequate view of the angle for surgery. Of note, the view of the angle during surgery rarely equals the examination view qualitatively, something to take into account when planning for surgery.

The two most common causes of poor angle visualization in young children with glaucoma are diffuse epithelial edema and localized stromal edema associated with breaks in Descemet’s membrane. During the gonioscopic exam, the presence of epithelial edema can be quan­tified by back focusing on the epithelium and noting the intensity of epithelial microcysts present in light reflected from the iris. Only the corneal opacification secondary to epithelial edema is corrected by removal of epithelium (stromal edema is not improved by this maneuver). When necessary the epithelium is carefully peeled off to create a clear window on the surgeon’s side of the cornea extending to the visual axis. This procedure is performed after selecting a meridian for knife entry that allows an optimal view to either side of any stroma opacity.