Comparison of polypropylene and silicone Ahmed valve survival 2 years following implantation in the first 2 years of life

Abstract

Aim: To compare the 2-year survival rates of polypropylene and silicone Ahmed glaucoma valves (AGVs) implanted during the first 2 years of life.

Methods: Retrospective analysis of polypropylene and silicone AGV implantation during the first 2 years of life in children with 2 years’ postoperative follow-up. Patients with prior aqueous drainage device implantation were excluded.

Results: Forty-two eyes of 36 children were reviewed. Thirty-one eyes received a polypropylene AGV (six S1, 25 S2), and 11 eyes received a silicone AGV (11 FP7). The average survival time (maintenance of intraocular pressure ≤22 mm Hg with (or without) medications and without significant complications) was significantly longer (p = 0.001 by the logrank test) for the silicone group (23.36 months, standard error (SE) 1.64, 95% confidence interval (CI) 20.16 to 24.00 months) than for the polypropylene group (19.10 months, SE 1.53, 95% CI 16.1 to 22.12 months). Cumulative probabilities of survival at 2 years by Kaplan to Meier analysis were 90.9% (SE 8.7, 95% CI 70 to 100%) and 54.8% (SE 8.9, 95% CI 23 to 87%), respectively (p = 0.001 by the logrank test). All eyes implanted with silicone AGVs had the diagnosis of congenital glaucoma, which was independently associated with 2-year survival.

Conclusions: Two years after surgery, silicone AGVs survived longer than polypropylene AGVs. However, all eyes that received silicone AGVs in our cohort had congenital glaucoma, which had a better survival than other paediatric glaucoma diagnoses. A study of silicone AGV implantation in other paediatric glaucoma diagnoses is needed to determine whether or not silicone AGVs independently have a better survival after implantation in the first 2 years of life.