Outcomes of Ahmed Glaucoma Valve Implantation in Children With Primary Congenital Glaucoma

Abstract

To evaluate the long-term efficacy of intraocular pressure reduction and complications of Ahmed glaucoma valve (AGV) implantation in children with primary congenital glaucoma. Methods:The medical records of patients with primary congenital glaucoma who underwent AGV implantation with a minimum follow-up of 6 months were reviewed. The primary outcome measure was cumulative probability of success, defined as intraocular pressure greater than 5 mm Hg and less than 23 mm Hg and at least a 15% reduction from the preoperative intraocular pressure, without serious complications, additional glaucoma surgery, or loss of light perception.Results: Thirty eyes of 19 children with primary congenital glaucoma who underwent AGV implantation with a minimum follow-up of 6 months were reviewed. The children had a mean (SD) age of 1.8 (2.6) years, a mean (SD) preoperative intraocular pressure of 28.4 (6.7) mm Hg, and a mean (SD) follow-up time of 57.6 (48.0) months. The cumulative probability of success was 63% in 1 year and 33% in 5 years. After a second AGV implantation, the cumulative probability of success was 86% in 1 and 2 years and 69% in 5 years. Hispanic ethnicity (P=.02) and being female (P=.005) were associated with increased risk of failure.Conclusions: Thirty-three percent of AGV implantations in children with primary congenital glaucoma were successful after 5 years of follow-up. With the implantation of a second AGV, the 5-year success rate increased to 69%.

The Role of Glaucoma Drainage Devices in Paediatric Glaucoma

“…8,11,12 In our experience, survival using the Kaplan-Meier analysis has been 76 % at 6 months, 63 % at 1-3 years and 55 % at 4-8 years. 27 Ou et al 14 have studied the results after an implantation of a second GDD and have found a success rate of 86 % at one and two years decreasing to 69 % afterwards in the Kaplan-Meier survival analysis.…”

“…This is one of the reasons the Ahmed glaucoma valve is preferred in children. Indeed, several authors have recommend using restrictive measures such as tube ligature even when inserting an Ahmed valve, with total 6,14,16 or partial 17 occlusion of the tube lumen using a re-absorbable ligature, or implanting the device in two phases, inserting the tube into the eye four to six weeks after the plate has been implanted. 5,6,18 In this way, aqueous outflow is prevented in the early post-operative period and delayed until an adequate fibrous capsule has formed around the plate.…”

“…5,6,8,12,14,17,21 Apart from the well-known factors involved in its development in adults, such as poor lubrication of the ocular surface, micro-movements of the tube, rubbing against the tarsal plate and previous use of MMC, in children its occurrence is even more likely to be produced by eye rubbing, which is hardly avoidable (see Figure 3). Children younger than two at the time of surgery appear to be at higher risk for this complication.…”

“…11,13 Choroidal effusion, also an hypotony related complication, has been reported in between 2.1 to 4.2 % of the cases. 6,8 With regard to endophthalmitis, there are isolated cases in many series, 5,8,12,14 and as many as 7.1 % in the series by Al Mobarak et al 13 In the Ahmed device it has been suggested that the valve mechanism and unidirectional flow may be partially protective against this complications, which has been reported almost exclusively in children, especially in those with tube exposure. 23,36,37 Therefore, regular follow-ups specifically assessing the potential exposure are needed, with immediately treatment performed should this occur.…”

Childhood glaucoma surgery in the 21st Century

“…In children, small series of sequential tube surgery in a different quadrant report reasonable success rates. 116,117 One study comparing cyclophotocoagulation with sequential tube surgery following failure of primary GDD in children suggested similar success and complication rates, although again no long-term follow-up data are available. 118 Our experience with needling and surgical revision suggests that the satisfactory IOP control is short lived especially with needling.…”