Cutting Edge Glaucoma - Issue 2

CHILDHOOD GLAUCOMA SURGERY IN DEVELOPING COUNTRIES • 11  clarity and diameter of the cornea permit, goniotomy may be attempted by surgeons who are trained and competent in performing the surgery. Trabeculotomy Ab Externo Trabeculotomy ab externo was simultaneously and independently described by Burian [20, 21] and by Smith [22] in 1960 and is our preferred angle surgical technique due to a number of advantages [19, 23] over goniotomy in the management of childhood glaucomas in our part of the world. The popularity of trabeculotomy ab externo as an initial procedure in the surgical manage- ment of PCG has been championed by a number of authorities [23, 24]. Trabeculectomy with or Without Antiscarring Therapy Trabeculectomy is a procedure that most ophthalmologists are familiar with and is technically easier than goniotomy or trabeculotomy. Hence some surgeons in developing countries perform only trabeculectomy. However, many others do not consider it as a first-line procedure for PCG in view of the higher incidence of complications and lower success rates reported in the early litera- ture [25–27]. Nevertheless, several subsequent reports documented successful results following primary trabeculectomy for PCG that are comparable to goniotomy or external trabeculotomy [28–32]. In refractory PCG following failed angle surgery or combined trabeculotomy-trabeculec­ tomy (CTT), trabeculectomy with mitomycin C (MMC) [33, 34] may be an option. Combined Trabeculotomy-trabeculectomy (Ab Externo) The prevalence of children presenting with glaucoma and opaque corneas precluding goniotomy, coupled with encouraging reports of primary trabeculectomy in PCG, prompted Indian surgeons to combine trabeculotomy ab externo with trabeculectomy as the initial surgery for PCG in the Indian patient population [35]. In mild forms of PCG, i.e., mild angle anomaly and corneal haze, we perform trabeculotomy ab externo in isolation. However, in most cases of PCG with megalo- cornea and associated significant corneal edema, we prefer CTT. In secondary childhood glauco- mas, if Schlemm canal is technically possible to explore, we perform CTT. However, if Schlemm canal is difficult to dissect or is anatomically absent, we perform trabeculectomy alone. Surgical Technique: 1. A limbus-based conjunctival flap is raised 7 mm from the superior limbus with blunt-tipped Westcott scissors and plain forceps. The dissection is normally done in the episcleral plane. Hemostasis is meticulously maintained throughout the dissection of the conjunctival flap with bipolar wet-field cautery. 2. Retracting the conjunctival flap gently toward the pupil, light cautery is applied on the sclera to outline the sides of a 4-mm equilateral triangle with its base at the limbus. The authors prefer