Evaluation of two different operations to implant the Ahmed glaucoma valve in patients with refractory glaucoma

AIM:To evaluate the efficacy and safety of Ahmed glaucoma valve(AGV)implantation surgery using different methods. METHODS:This was a retrospective study of patients with refractory glaucoma in whom AGV implantation was performed between June 2011 and September 2014. According to the method of tube insertion into the anterior chamber, the sample was divided into two groups, needle-generated scleral tunnel and scleral flap. The surgical success rate, intraocular pressure(IOP), number of antiglaucoma medications used, best correct visual acuity, postoperative complications, and operation duration were analyzed between the two groups. RESULTS:Compared with preoperative data, the two groups showed statistically significant decrease on IOP and the number of antiglaucoma medication used at all follow-up points(P<0.01). Differences on mean postoperative IOP, mean number of postoperative antiglaucoma medications, and best correct visual acuity were not significant between the two groups at all follow-up intervals. Kaplan-Meier survival curves showed that the success rate was 79% for the needle-generated scleral tunnel group and 80% for the scleral flap group at the follow-up endpoint of 1a. There was no significant difference between the two groups(P=0.932); however, statistically significant differences were detected when flat anterior chamber complications between the needle-generated scleral tunnel group(6%)and the scleral flap group(24%)were compared(P=0.032). CONCLUSION:AGV implantation may be an effective method in managing refractory glaucoma, since the two methods have similar efficacy. However, the needle-generated scleral tunnel technique application could greatly decrease the incidence of flat anterior chamber complications and decrease the duration of the operation.