Pars plana vitrectomy and panretinal photocoagulation combined with trabeculectomy for successful treatment of neovascular glaucoma

Background: Treatment of neovascular glaucoma (NVG) must be focused on the reduction of intraocular pressure (IOP) and prompt application of pan retinal photocoagulation (PRP). A combination of complete PRP during vitrectomy with trabeculectomy should theoretically be a better method to lower the IOP rapidly in eyes with NVG. The purpose of our study is to assess the efficacy of combining pars plana vitrectomy and PRP with trabeculectomy assisted by mitomycin C (MMC) on NVG eyes secondary to diabetic retinopathy. Methods: Twenty-five eyes with NVG associated with diabetic retinopathy had pars plana vitrectomy, followed by PRP and trabeculectomy with MMC. The eyes were divided into two groups: nine eyes with vitreous hemorrhage, fibrovascular membrane and/or retinal detachment were placed in the Proliferation group; and 16 eyes without vitreous hemorrhage, fibrovascular membrane, or retinal detachment were placed in the PC (photocoagulation) group. These eyes had vitrectomy performed so that PRP could be safely performed from ora to ora. The surgical outcome in the two groups was assessed by Kaplan-Meier survival analysis. The criteria for success were a postoperative intraocular pressure (IOP) <= 21 mmHg and a preservation of light perception. Results: In the Proliferation group, Kaplan-Meier life-table analysis showed that the success rate was 55.6% after 1 year and 18.5% after 2 years. The success rate in the PC group was 81.2% from 1 to 3 years after surgery. The surgical outcome was significantly better in the PC group than in the Proliferation group (P=0.009). In the Proliferation group, four eyes had preoperative vitreous hemorrhage, three eyes had a fibrovascular membrane, and two eyes had a retinal detachment. Three of four eyes with vitreous hemorrhage achieved good IOP control. On the other hand, the IOP of all eyes with retinal detachment and fibrovascular membrane were not lowered significantly. Conclusion: Complete PRP combined with trabeculectomy with MMC can effectively reduce the elevated IOP in eyes with NVG. However, this combined treatment is not effective in eyes with proliferative membranes and retinal detachments.