Pars Plana Ahmed Implantation Combined with 23-gauge Vitrectomy for Refractory Neovascular Glaucoma in Diabetic Retinopathy

Abstract

Purpose To evaluate the efficacy and safety of a pars plana Ahmed valve implantation combined with 23-gauge sutureless vitrectomy in the treatment of patients with medically uncontrolled neovascular glaucoma (NVG) in proliferative diabetic retinopathy (PDR). Methods The authors retrospectively reviewed the records of 11 consecutive patients with refractory NVG in PDR who underwent a 23-gauge sutureless vitrectomy combined with pars plana placement of an Ahmed valve implant. Control of intraocular pressure (IOP), pre- and postoperative best-corrected visual acuity and the development of intra- and postoperative complications were evaluated during the follow-up. Results The mean follow-up was 12.2 months (range, 8 to 25 months). Mean preoperative IOP was 35.9 ± 6.3 mmHg and mean postoperative IOP at the last visit was 13.3 ± 3.2 mmHg. Control of IOP (8 to 18 mmHg) was achieved in all patients, but 91% (10 of 11 patients) needed antiglaucoma medication (mean number of medications, 1.2 ± 0.6). Postoperative visual acuity improved in 11 eyes, and the logarithmically to the minimum angle of resolution mean visual acuity in these eyes improved from 1.67 ± 0.61 to 0.96 ± 0.67. The complications that occurred were transient hypotony in one case, transitory hypertension in two cases, and postoperative vitreous hemorrhage which spontaneously cleared in two cases. Conclusions We suggest the combination of 23-gauge pars plana vitrectomy and Ahmed valve implantation is safe and effective in PDR patients with refractory NVG.

Analysis of long-term outcomes for combined pars plana vitrectomy (PPV) and glaucoma tube shunt surgery in eyes with advanced glaucoma

“…Studies have shown an increased prevalence of displacement of the drainage tube, iritis, conjunctival erosion with tube exposure, prolapsed vitreous, corneal endothelium functional deterioration, and worsening of cataracts in tube shunts placed through the anterior chamber. 3,13,22 In contrast, an increase in retinal detachment, tube obstruction by vitreous, and hypotony are seen in tube shunts placed through the posterior segment. 2,13,22 Limitations of this current series include its retrospective design, lack of controls, and smaller sample size with 43 eyes.…”

“…3,13,22 In contrast, an increase in retinal detachment, tube obstruction by vitreous, and hypotony are seen in tube shunts placed through the posterior segment. 2,13,22 Limitations of this current series include its retrospective design, lack of controls, and smaller sample size with 43 eyes. In this study, we showed that combined PPV and glaucoma drainage tube implantation can effectively reduce IOP and the number of required glaucoma medications in eyes refractory to medical and/ or prior surgical therapy with concurrent anterior or posterior segment pathologies.…”

“…The management of eyes with glaucoma in the setting of scarred conjunctiva, 4-6 prior failed filtration surgeries, 3,17,18 corneal pathology, 19 inflammation, 20 or neovascularization 13,14 is complex. The glaucoma tube shunt has been shown to be beneficial in such cases.…”

“…2 Tube shunts are indicated in eyes with excessive conjunctival scarring that would reduce the success of a repeated trabeculectomy, [4][5][6] in eyes with irregularities in the iridocorneal angle, 5,6 in inflammatory glaucoma, 2 and in the presence of a keratoprosthesis. 1,7 In selective cases, the insertion of the drainage tube into the anterior chamber is contraindicated because of a shallow anterior chamber, [8][9][10] vitreous prolapse, pseudophakia/ aphakia, 11 complicated glaucoma with corneal disease and angle neovascularization, [12][13][14] anterior chamber pathology such as peripheral synechiae secondary to inflammation, corneal disease, previous corneal surgeries (penetrating keratoplasty or kerato prosthesis), 15,16 and failed prior trabeculectomies. 3,7,[17][18][19] In such cases, the glaucoma tube shunt can be inserted through the pars plana with simultaneous pars plana vitrectomy (PPV).…”

Refractory Glaucomas. Types and Management

“…AGV surgery with variable success rates (20.6%-70%) 93,94 . AGV has been combined with intravitreal bevacizumab injection with encouraging results 95 , and has been implanted at the time of pars plana vitrectomy [96][97][98] . TSCPC with and without the use of anti-VEGF has been shown to be effective in lowering IOP and relieving pain in advanced cases of NVG 99,100 .…”