Ahmed glaucoma valve implantation for neovascular glaucoma after vitrectomy for proliferative diabetic retinopathy

To evaluate the safety and efficacy of Ahmed Glaucoma Valve implantation (AGVI) for the management of neovascular glaucoma (NVG) associated with proliferative diabetic retinopathy (PDR) in the vitrectomized eyes.

We reviewed the medical records of patients with NVG associated with PDR who underwent AGVI for intraocular pressure (IOP) control and compared the surgical outcome according to vitrectomy history. The main outcome measures were: postoperative IOP control, visual acuity, and complications. Success was defined as an IOP of ≤21 mm Hg and ≥6 mm Hg, without further glaucoma surgery or loss of light perception and devastating complications.

A total of 73 patients (73 eyes) were included: 42 patients with vitrectomy history before AGVI (vitrectomized group) and 31 patients without vitrectomy history (nonvitrectomized group). The cumulative probabilities of success after AGVI were 89.9% and 83.8% after 1 year, 74.8% and 74.7% after 2 years, and 62.5% and 68.5% after 3 years for the vitrectomized group and the nonvitrectomized group, respectively (P=0.9309). Cox proportional hazards regression showed the intraocular silicone oil tamponade as a risk factor for the surgical failure (odds ratio=4.543, P=0.047). Final visual acuity improved or stabilized in 33 patients (78.6%) in the vitrectomized group and 18 patients (58.1%) in the nonvitrectomized group. Complications were comparable between the groups, but surgical interventions were needed for 5 patients (11.9%) in the vitrectomized group.

Despite some complications that necessitate surgical intervention, the AGVI is a safe and effective procedure that enables successful IOP control and vision preservation in patients with NVG associated with vitrectomy for the PDR.