Surgical Outcomes of Additional Ahmed Glaucoma Valve Implantation in Refractory Glaucoma

Sung Ju Ko, MD; Young Hoon Hwang, MD; Sang Il Ahn, MD; Hwang Ki Kim, MD


J Glaucoma. 2016;25(6):e620-e624. 

In This Article


A total of 23 patients (10 female, 13 male) who had undergone a second AGV surgery on 1 eye were included in the study. All of the 23 eyes had previously implanted AGV. Patient characteristics at the time of the second AGV surgery are summarized in Table 1. The mean (SD) age was 44.5 (14.5) years (range, 15 to 68 y). Ten patients (43%) were diagnosed with uveitic glaucoma, 9 (39%) with neovascular glaucoma, and 4 (17%) with other secondary glaucoma. Six patients (26%) had undergone previous trabeculectomy, 8 (35%) had undergone previous cataract surgery, and 4 (17%) had received retinal surgery. The mean (SD) follow-up period was 37.8 (14.2) months (range, 8 to 60 mo).

The implantation location and AGV type used are presented in Table 2. In the initial AGV surgery, the most common implantation site was the superotemporal area. In all of these cases, the tube tip was placed in the anterior chamber. The most common implantation site for the second AGV implantation was the inferotemporal area. In these cases too, the tube tip was placed in the anterior chamber. The FP7 AGV was more commonly used (17 out of 23 eyes) than the FP8 AGV (6 out of 23 eyes) in the first AGV surgery. In the second AGV implantation, the FP8 AGV was predominantly used (21 out of 23 eyes).

Table 3 summarizes the IOP, IOP-lowering medication, and VA data. Following the implantation of a second AGV, the mean IOP decreased from 39.3 to 15.2 mm Hg after 12 months and to 18.5 mm Hg at the final follow-up visit, respectively (P<0.001). The mean (SD) reduction in IOP was 24.1 (9.5) mm Hg after 12 months and 20.8 (11.8) mm Hg at the final follow-up visit. The mean IOP at 12 months and the final follow-up were significantly lower than the IOP before the second AGV was implanted (Fig. 1, P<0.001). The mean number of IOP-lowering medications used after the second AGV implantation was significantly lower than before the implantation (1.3 at 12 mo and 1.7 at the final follow-up visit, versus 2.8 preimplantation; P<0.001). No significant change in VA was observed as a result of the AGV implantation (P>0.05).

Figure 1.

Intraocular pressure (IOP) before surgery (pre-OP) and during follow-up visits after the implantation of an additional Ahmed glaucoma valve.

The survival analysis yielded success rates of 87%, 70%, and 52% at 1, 2, and 3 years, respectively (Fig. 2). At follow-up, the surgery was judged to have been a failure in 8 of the patients (34.8%) (Table 4): 7 (30.4%) failed to meet the IOP criteria and 1 (4.3%) experienced loss of light perception. Three eyes (13.0%) developed bullous keratopathy. The presence of 2 AGVs in the same eye did not result in diplopia or ocular movement limitation in any of the patients. In addition, other complications, such as hypotony, phthisis, valve exposure, or endophthalmitis were not found during the follow-up period. The results of the Cox proportional hazard model analysis indicated that prior trabeculectomy was a significant risk factor for failure (relative risk, 1.78; 95% confidence interval, 0.54–3.41; P=0.027). Age, type of glaucoma, and preoperative IOP were not significantly associated with success (P>0.05).

Figure 2.

Kaplan-Meier survival curves showing 87%, 70%, and 52% survival rate at 1, 2, and 3 years, respectively.