Cutting Edge Glaucoma - Issue 2

18 • CUTTING EDGE - GLAUCOMA cost of therapy using disposable illuminated microcatheter is a limiting factor, especially in the context of the developing world. In a prospective study from India, illuminated microcatheter- assisted circumferential trabeculotomy achieved comparable results to primary CTT with MMC [55]. Hence, it appears that primary CTT may be the procedure of choice for advanced cases of PCG in developing countries. Following failed angle surgery investigators have compared CTT to GDD. Helmy et al . reported their results of CTT versus AGV (FP8) in children with PCG (80% parental consanguin- ity) who had failed previous goniotomy or trabeculotomy [56]. They included 66 eyes with 33 eyes in each group. Success rates were 97% at 1 year in both groups, which decreased to 61% in the CTT group and 66% in the AGV group at 4 years. They concluded that AGV had slightly better long-term survival; however, doing a CTT first would allow a future implant in these patients. In their series 24.2% of the eyes in AGV group had hypertensive phase. Our results show a 90% success rate in PCG with the Ahmed device following failed CTT at 1 year [57]. With regard to the surgical outcomes of GDD surgery in the developing world, Al-Mobarak et al . have reported their results with AGV in PCG and secondary glaucoma and found success rates of 54.8% at 2 years with polypropylene implant versus 90.9% with silicone implant [58]. They also found poor success rates with AGV when MMC was used (31.3% at 2 years), although there may have been selection bias between the two groups. Better outcomes have been reported by Balekudaru et al . from India with AGV (both silicone and polypropylene) in refractory pediatric glaucoma, with cumulative success rates of 97% at 1 year and 80% at 2 years [59]. Reoperations for tube-related complications were needed in 12.6% of eyes and 13% of eyes needed repeat surgery for IOP control. In their study, post-keratoplasty glaucoma was a significant risk factor for failure. In our unpublished data, the success rates with silicone AGV implantation are 91% in refractory PCG and 83% in secondary glaucomas with 4-year follow-up; our success rates with AADI are 91% at 1 year and 81% at 2 years (unpublished data). A recent study by Kaushik et al . from India has prospectively studied the outcomes of the AADI implant in refractory pediatric glaucomas and reported success rates of 81.7% at 2 years [60]. Although PCG accounts for the majority of pediatric glaucomas, glaucoma following con- genital cataract surgery is the next most common childhood glaucoma and is important in the developing world [61–64]. Mandal et al . reported complete success probability with trabeculecto- my with or without MMC (IOP between 6 and 21 mmHg without medication/additional surgery/ sight-threatening complication) in only 37% eyes, and an additional 21% eyes had qualified success after a mean follow-up of 2 years [65]. So this group of patients has a higher risk of failure of trabeculectomy and may need GDD or other surgery. Refractory Childhood Glaucomas in Developing Countries Some children with glaucoma have a poor surgical prognosis with uncontrolled IOP despite surgery and/or with maximum tolerated medical treatment. The majority of studies show surgical failure is higher in eyes with greater severity of disease at presentation and increases with time.