Purpose: To evaluate the clinical results and the risk factors related to time to failure of the Ahmed Glaucoma Valve implant (New World Medical, Inc., Rancho Cucamonga, CA), an aqueous shunting device with a unidirectional valve mechanism, in pediatric patients.
Design: Retrospective, noncomparative, interventional case series.
Participants: We studied 35 Ahmed Glaucoma Valve implants in 35 eyes of 29 patients less than 15 years of age (median, 2.4 years; range, 0-14.8 years).
Methods: Thirty-five Ahmed Glaucoma Valve implants were placed in eyes of pediatric patients with refractory glaucoma between December 1994 and March 1999.
Main outcome measures: Time after surgery without failure, intraocular pressure reduction, risk factors related to time to failure, and postoperative complications were evaluated.
Results: The cumulative probabilities of success according to Kaplan-Meier analysis 12 and 24 months after implantation were 70.1% +/- 8.5% and 63.7% +/- 9.9%, respectively. Intraocular pressure was reduced from a preoperative mean of 28.8 +/- 4.5 mmHg to 18.1 +/- 2.4 mmHg by postoperative month 18. Shallow anterior chambers of different grades developed in nine eyes (25.7%) on the first postoperative day; this was associated with choroidal detachment in four eyes. Nine eyes (25.7%) experienced malposition, causing failure in six eyes. In three other eyes (8.5%), the average intraocular pressure at the last two follow-up examinations was more than 22 mmHg. Congenital glaucoma and surgical experience were significantly associated with time to failure.
Conclusions: The 12- and 24-month success rates of the Ahmed Glaucoma Valve implant in our study confirm its viability in the management of refractory infantile glaucoma. The complications related to overfiltration during the immediate postoperative period appear to be less severe than those associated with other drainage devices and resolve spontaneously. Diagnosis, number of previous glaucoma procedures, and the surgeon's experience seem to be related to the survival of the Ahmed Glaucoma Valve implant.