Long-Term Results of Ahmed Valve Implantation in Neovascular Glaucoma and the Effects of Intracameral Bevacizumab

PURPOSE: To evaluate the long-term surgical results of Ahmed glaucoma valve implantation (AGVI) and the effects of intracameral bevacizumab injection in neovascular glaucoma (NVG) after diabetic vitrectomy. METHODS: We reviewed the medical records of 57 patients with NVG after diabetic vitrectomy who underwent AGVI with or without intracameral bevacizumab injection. In each group, preoperative and postoperative intraocular pressure, the number of glaucoma medications, and best corrected visual acuity (BCVA) were compared. We analyzed the rates of surgical success, postoperative complications, and risk factors. RESULTS: The cumulative probability of success was 87.7% at 1 year, 78.8% at 2 years, 70.5% at 3 years, and 61.6% at 5 years. Intraocular pressure and the number of glaucoma medications were significantly reduced and BCVA was significantly better at all postoperative follow-up time points in both groups. There were no differences in mean intraocular pressure, the number of glaucoma medications, BCVA, or the rates of surgical success between the two groups. The incidence of hypertensive phase was significantly reduced in the intracameral bevacizumab group, but neither the surgical success rate nor intraocular pressures were different compared with the control group. CONCLUSIONS: Ahmed glaucoma valve was a good therapeutic modality for long-term treatment of NVG occuring after diabetic vitrectomy. Intracameral bevacizumab injection had no effects on the surgical results of Ahmed glaucoma valve surgery.

Systemic Risk Factors for Postoperative Vitreous Hemorrhage Following Diabetic Vitrectomy

PURPOSE: To determine the incidence of and the systemic risk factors for postoperative vitreous hemor-rhage(PVH). METHOD: The records of 503 consecutive diabetic vitrectomy cases were reviewed. RESULT: Eighty-seven eyes(17.3%) had at least one episode of PVH. Sixty-five eyes(12.9%) had PVH within 3 months after vitrectomy, and the mean onset time of the first episode of PVH was about 13 weeks after vitrectomy. The mean follow-up period was 17.2 months in non-hemorrhage group, and 21.9 months in hemorrhage group. While 34 eyes(29.6%) had spontaneous absorption of blood, 42 eyes(36.5%) required air(or gas)-fluid exchange and 39 eyes(33.9%) vitreous cavity lavage. Using univariate analysis, the factors associated with increased incidence of PVH include type 1 diabetes mellitus(p=0.01), method of glycemia control(p=0.02), anemia(p=0.04), and hypercholesterolemia(p=0.005). Multivariate analysis revealed diabetic nephropathy(p=0.02) and hypercholesterolemia(p=0.01) were the risk factors. Five eyes(1.0%) lost light perception, 7 eyes(1.4%) had rhegmatogenous retinal detachment, and 11 eyes(2.2%) had neovascular glaucoma. CONCLUSION: Vitreous hemorrhage after diabetic vitrectomy occurred in the 17.3%, three quarters of them within 3 months. About one third had spontaneous clearing, and two-thirds required reoperation. Diabetic nephropathy and hypercholesterolemia were the systemic risk factors of vitreous hemorrhage after diabetic vitrectomy.

Surgical Prognostic Factors in Proliferative Diabetic Retinopathy(PDR)

The results of diabetic vitrectomy on eyes with severe proliferative fibrovascular membranes are often disappointing, because of difficulties in removing the membranes. But we sometimes observe the regression of the proliferative fibrovascular membranes when the antero-posterior tractional force become released. Hence we compared the surgical prognosis of proliferative diabetic retmopathy according to the severity of proliferation and whether removal of antero-posterior vitreoretinal traction was complete or not. The results showed that the anatomic success rate and final visual acuities(VA) were significantly better in less-severe proliferation group(LSPG) than in severe prolif era tion group(SPG). In SPG, the anatomic success rate and VA tended to be better when we were able to remove the antero-posterior vitreoretinal adhesion completely whether the removal of preretinal membranes was complete or not. When complete removal of the diabetic fibrovascular membrane is difficult due to severe proliferation and broad adhesion, complete removal of anter-posterior traction only could be an alternative in diabetic vitrectomy.

Vitrectomy for severe proliferative diabetic retinopathy

To analyse the results of diabetic vitrectomy according to the severity of proliferation [severe (SPG) vs. less-severe proliferation group (LSPG)], and methods of the operation, which was complete removal of anteroposterior vitreous traction with or without complete removal of preretinal memebrane, we compared both groups by using anatomic success rate and postoperative visual acuities (VA). The results were as follows: The anatomic success rate and postoperative VA were significantly better in LSPG than in SPG. In SPG, anatomic success rate and postoperative VA tended to be better when complete removal of anteroposterior traction was possible than when impossible. In SPG, postoperative VA tended to be better when complete removal of preretinal membrane was possible, but the anatomic success rate was the same for each group. So, when severe proliferation (including table-top elevation of posterior retina), complete removal of anteroposterior traction only can improve the anatomic success rate of the surgery.