Purpose: To retrospectively evaluate the efficacy and long-term complications of the Ahmed glaucoma valve (AGV) in refractory glaucoma.
Materials and methods: Seventy-eight eyes with glaucoma refractory to conventional surgical procedures (filtration surgery and diode laser cyclophotocoagulation) underwent AGV implantation between May 2006 and August 2018. The criteria for success were defined as an intraocular pressure (IOP) less than 18 mmHg and a decrease of at least 20% from the preoperative IOP. The criteria for failure were an IOP greater than 18 mmHg or less than 5 mmHg, an increase in medical treatment, a decrease of less than 20% of the initial IOP, the need for another glaucoma surgery, or a decrease in visual acuity attributable to the valve.
Results: IOP decreased from 31.0 ± 9.0 mmHg to 17.2 ± 7.2 mmHg (mean follow-up 32.5 months), for a mean IOP lowering of 44.5% (p < 0.001). Medical treatment was significantly reduced from 5.3 ± 1.5 to 2.8 ± 1.9 (p < 0.0001). The cumulative success rates were 59.4% at 3 years and 45.1% at 5 years. Encapsulation of the filtration bleb was the most common short-term complication (32.1%). Relevant long-term complications were bleb fibrosis with elevated IOP (12.8%) and corneal decompensation (10.2%).
Conclusion: The AGV is an effective procedure in the long-term for controlling IOP in refractory glaucoma, with limited incidence of complications. These results suggest that the AGV might be considered earlier in the surgical strategy for glaucoma not controlled after one well-performed conventional filtration surgery.
Keywords: Ahmed glaucoma valve; long-term outcomes; postoperative complications; refractory glaucoma; tube shunts.