Pars plana Ahmed valve and vitrectomy in patients with glaucoma associated with posterior segment disease

Effectiveness of pars plana Ahmed® valve implantation in patients with refractory glaucoma

PURPOSE

To evaluate the success rate and complications of the Ahmed FP7 valve implanted via Pars Plana in a group of vitrectomized patients with refractory glaucoma and anterior segment abnormalities from January 2018 to June 2023.

METHODS

Quasi-experimental, prospective study. Eleven eyes with refractory glaucoma were included. Participants underwent a comprehensive ophthalmic examination, including assessment of intraocular pressure (IOP) reduction, visual acuity, characterization of glaucoma type, and number of antiglaucoma medications.

RESULTS

The mean baseline IOP was 37.3 ± 11 mmHg, which decreased to 13.5 ± 3.0 mmHg after one year. The qualified success rate was 63.7%, while the complete success rate was 36.3%. The most common diagnosis was neovascular glaucoma in 36.4% of cases. The most frequent postoperative complications were choroidal detachment and hypotony.

CONCLUSIONS

Our data suggest that implantation of the Ahmed FP7 valve via pars plana is an effective and safe option for patients with refractory secondary glaucoma.

Efficacy and safety of combined 27-G vitrectomy and Ahmed valve using same sclerotomy site for the tube placement: A case series

We report a retrospective case series describing the feasibility and outcomes of combined 27-G minimally invasive vitrectomy surgery (MIVS) and Ahmed® Glaucoma Valve (AGV) placement. Four eyes of four patients underwent a combined MIVS using 27-G technology and AGV implantation with the tube placement in the vitreous cavity. Preoperative and postoperative data up to 12 months were collected including the type of glaucoma, intraocular pressure (IOP), glaucoma medications, and complications. All AGVs tubes were placed in the vitreous cavity using the same sclerotomy, although a slight wound enlargement was required. After one year, IOP and glaucoma medications were reduced (41.5 ± 19.1-14.5 ± 3.1 mmHg and from 3(3-3) to 1.5 (1.5-3.5). Three patients developed cystoid macular edema. The first-reported cases of combined MIVS-27-G and AGV showed a reduction of IOP and antiglaucoma medication. Placing the tube using the same sclerotomy location is feasible but a slight enlargement may be required.

Update on Retinal Vein Occlusion

Retinal vein occlusion represents the second leading cause of retinal vascular disorders, with a uniform sex distribution worldwide. A thorough evaluation of cardiovascular risk factors is required to correct possible comorbidities. The diagnosis and management of retinal vein occlusion have changed tremendously in the last 30 years, but the assessment of retinal ischemia at baseline and during follow-up examinations remains crucial. New imaging techniques have shed light on the pathophysiology of the disease and laser treatment, once the only therapeutic option, is now only one of the possible approaches with antivascular endothelial growth factors and steroid injections being preferred in most cases. Nowadays long-term outcomes are better than those achievable 20 years ago and yet, many new therapeutic options are under development, including new intravitreal drugs and gene therapy. Despite this, some cases still develop sight-threatening complications deserving a more aggressive (sometimes surgical) approach. The purpose of this comprehensive review is to reappraise some old but still valid concepts and to integrate them with new research and clinical data. The work will provide an overview of the disease's pathophysiology, natural history, and clinical features along with a detailed discussion on the advantages of multimodal imaging and of the different treatment strategies with the aim of providing retina specialists with the most updated knowledge in the field.

Neovascular Glaucoma: An Update

Neovascular glaucoma (NVG) is a severe type of secondary glaucoma with devastating complications and generally poor visual prognosis. NVG is defined by the development of pathological neovessels over the iris and the iridocorneal angle that can block the outflow of aqueous humor, causing elevation of intraocular pressure (IOP). The pathogenesis of NVG is, in most cases, associated with ischemia of the posterior segment, which is most frequently associated with proliferative diabetic retinopathy or central retinal vein occlusion. The advanced stages of NVG are by iris and angle neovascularization, angle, and extremely high IOP, accompanied by ocular pain and poor vision. The therapeutic approach of NVG is based on the reduction of retinal ischemia by panretinal photocoagulation. Intravitreal anti-VEGF administration can contribute to the regression of neovascularization, and topical and systemic medications may be necessary for IOP control. However, if medical treatment with these agents is not enough, surgical procedures may be required to lower IOP and prevent glaucomatous optic neuropathy. Early and prompt diagnosis, with identification of the underlying etiology, can improve IOP control and final visual outcome. The aim of this study is to review current knowledge of the pathogenesis and management of NVG.

Ahmed glaucoma valve implantation for secondary glaucoma post-vitrectomy

BACKGROUND AND OBJECTIVE

Ahmed glaucoma valv (AGV) implantation is one of the successful surgical methods in secondary glaucoma that develops after pars plana vitrectomy (PPV). In our study, we aimed to evaluate the 1-year results of AGV implantation in patients with a history of PPV.

STUDY DESIGN

A total of 26 patients who underwent AGV implantation after PPV were included in our retrospective study. Fourteen of 26 patients had AGV implantation due to neovascular glaucoma (NVG) and 12 of them had secondary refractory galucoma. Data of these two groups of patients were evaluated in terms of IOP reduction, number of medication use, surgical complete and qualified success, surgical failure, and complications.

RESULTS

The mean IOP was 29.54 ± 4.87 mmHg at the preoperative of AGV implantation and 12.88 ± 4.17 at the twelfth month visit in overal group. There was no statistically significant difference between two groups in terms of IOP in preoperative and all postoperative visits (p > 0.05). The mean intervals between PPV and AGV implantation were 67 ± 34 days in NVG and 391 ± 500 days in non-NVG group (p = 0.017). In overall group, 91.7% of patients had improvement in BCVA at the twelfth month visit. Complete and qualified surgical success rates were 75%, 83.3% in NVG group and 50%, 91.7% in non-NVG group, respectively. There was no devastating complication in both groups.

CONCLUSION

AGV implantation is a safe and effective surgical method in uncontrolled IOP elevations after PPV. While surgical success and failure rates were similar between etiologies, the time required for AGV implantation after PPV was shorter in NVG etiology.

Simultaneous pars plana vitrectomy, panretinal photocoagulation, cryotherapy, and Ahmed valve implantation for neovascular glaucoma

AIM

To describe and evaluate the efficacy of Ahmed glaucoma valve implantation (AGV) combined with pars plana vitrectomy (PPV) in a single surgical act for the treatment of advanced neovascular glaucoma (NVG).

METHODS

Retrospective observational case series included 51 eyes from 50 patients with severe NVG treated with PPV, AGV, and panretinal photocoagulation and/or cryotherapy in a single surgical act during a 13-year period (2005-2018). Preoperative, intraoperative and postoperative data at day 1 and months 1, 3, 6, 21, and 24 were systematically collected. Definition of surgical success was stablished at IOP between 6 and 21 mm Hg with or without topical treatment.

RESULTS

Main indications for surgery were NVG secondary to proliferative diabetic retinopathy (39.2%) and central retinal vein occlusion (37.3%). Mean (±SD) preoperative IOP was 42.0±11.2 mm Hg decreasing to 15.5±7.1 mm Hg at 12mo and 15.8±9.1 mm Hg at 24mo of follow up. Cumulative incidence of success of IOP control was 76.0% at first postoperative month, reaching 88.3% at 6mo. Prevalence of successful IOP control at long term was 74.4% at 12mo and 71.4% at 24mo. Eye evisceration for unsuccessful NVG management was required in 1 case (2.0%).

CONCLUSION

Combination of AGV implantation and PPV in a single act may be a suitable option for severe forms of NVG in a case-by-case basis for effective IOP control and a complete panretinal photocoagulation.

Clinical outcome of a nonvalved Aurolab aqueous drainage implant in posterior segment versus anterior chamber

Purpose

To evaluate the outcome of a nonvalved Aurolab aqueous drainage implant (AADI) in the management of refractory glaucoma.

Methods

Retrospective case series of patients with refractory glaucoma underwent AADI implantation in posterior segment (PS group) or anterior chamber (AC group) with minimum follow-up of 1 year. Primary outcome criterion was success, defined as intraocular pressure (IOP) <18 or >6 mm Hg or IOP reduced to <20% from baseline, for two consecutive visits after 3 months. Failure was defined as inability to meet IOP criteria, any additional glaucoma surgery, loss of light perception, and implant explantation. Secondary outcome criteria compared groups based on mean IOP, mean glaucoma medication use, best-corrected visual acuity, and complications at each postoperative visit.

Results

In the AC and PS group of 64 patients, 32 tubes each were placed. Preoperative mean IOP was 37.41 ± 8.6 and 43.38 ± 10.3 mm Hg in AC and PS, respectively. Postoperatively IOP reduced to 14.22 ± 4.9 and 15.21 ± 8.1 mm Hg in AC and PS groups, respectively (P < 0.001). Preoperative mean antiglaucoma medication changed from 2.56 ± 0.9 and 3.44 ± 0.5 to 1.03 ± 0.9 and 1.67 ± 0.5 in AC and PS, respectively, postoperatively (P < 0.001). No significant change in VA was noted in either group. At 12 months, success rate was 84% in AC group and 72% in PS group, with PS group having 2.63 times higher hazard (risk) of failure than AC group.

Conclusion

AADI implantation in PS or AC is a safe and effective method for IOP control in refractory glaucoma with its low cost being of significance in developing countries.

Neovascular glaucoma: a review

Neovascular glaucoma (NVG) is a secondary glaucoma generally associated with poor visual prognosis. The development of new vessels over the iris and the iridocorneal angle can obstruct aqueous humor outflow and lead to increased intraocular pressure. The underlying pathogenesis in most cases is posterior segment ischemia, which is most commonly secondary to proliferative diabetic retinopathy or central vein retinal occlusion. The neovascularization process in the eye is driven by the events that alter the homeostatic balance between pro-angiogenic factors, such as the vascular endothelial growth factor and anti-angiogenic factors, such as the pigment-epithelium-derived factor. Early diagnosis of this condition through slit lamp examination of the iris, iridocorneal angle and retina can help to avoid the development of goniosynechia and obstruction of aqueous humor outflow, with consequent intraocular pressure elevation. Historically, NVG treatment was focused on reducing the posterior segment ischemic process that caused the formation of new vessels, through panretinal photocoagulation. Recently, several studies have investigated the application of intravitreal anti-VEGF therapies in NVG. If clinical treatment with the use of hypotensive topical drops is not sufficient, laser and/or surgical procedures are required for intraocular pressure control.

Combined Scleral Flap with Donor Scleral Patch Graft for Anterior Tube Placement in Glaucoma Drainage Device Surgery

Purpose. To report a new technique for anterior placement of tubes for glaucoma drainage devices to reduce the risk of tube erosions. Methods. Retrospective review of select cases of Ahmed Valve surgery combined with the novel method of a limbal-based scleral flap covered by a scleral patch graft to cover the tube at the entrance through the limbus. Intraoperative and postoperative illustrations are shown to highlight the method of tube placement. Results. In this retrospective case series, 3 patients are presented illustrating the technique. Two had neovascular glaucoma and one had primary open-angle glaucoma (POAG). On average, intraocular pressure was reduced from 39 ± 14 mmHg to 15 ± 2 mmHg and the number of glaucoma medications was reduced from 4 ± 1 to 0. Preoperative and most recent visual acuities were hand-motion (HM) and HM, 20/60 and 20/50, and 20/70 and 20/30, respectively. Conclusion. The combination of a limbal-based scleral flap with scleral patch graft to cover the tube with glaucoma drainage devices may be an effective means to reduce erosion and protect against endophthalmitis.

Outcomes of 23-Gauge Vitrectomy Combined with Phacoemulsification, Panretinal Photocoagulation, and Trabeculectomy without Use of Anti-VEGF Agents for Neovascular Glaucoma with Vitreous Hemorrhage

Purpose. To evaluate the outcomes of 23-gauge vitrectomy combined with phacoemulsification, PRP and trabeculectomy without use of anti-VEGF-agents for NVG. Methods. Eighteen eyes of 18 patients with NVG underwent 23-gauge vitrectomy combined with phacoemulsification, PRP and trabeculectomy without use of anti-VEGF agents. The preoperative BCVA ranged from light perception to 0.2. The preoperative IOP ranged from 38 mmHg to 64 mmHg with a mean of 54 ± 8 mmHg. The average follow-up time was 14.5 ± 3 months with a range from 11 to 24 months. Results. The postoperative VA increased in 14 eyes and was stable in 4 eyes at the final follow-up. The mean IOP was 12 ± 3 mmHg at postoperative day 1. The mean IOP was 15 ± 2 mmHg, 16 ± 3 mmHg, 23 ± 5 mmHg, 28 ± 4 mmHg, 22 ± 5 mmHg, 17 ± 3 mmHg, and 19 ± 4 mmHg at postoperative days 2 and 3, 1, 2, 3, and 12 weeks, and 1 year postoperatively, respectively, with a range from 10 to 30 mmHg at the final follow-up time point of one year. The IOP was significantly lower than the preoperative one 12 weeks postoperatively (p < 0.05). Conclusion. 23-gauge vitrectomy combined with phacoemulsification, PRP, and trabeculectomy without use of anti-VEGF-agents is a safe and effective method in treating NVG.

Combined pars plana vitrectomy and pars plana Baerveldt tube placement in eyes with neovascular glaucoma

PURPOSE

To describe characteristics and outcomes of combined pars plana vitrectomy and Baerveldt tube insertion procedure from 2005 to 2010 in eyes with neovascular glaucoma.

METHODS

Seventy-nine patients (89 eyes) with ≥2 months of follow-up were included. Outcome measures were visual acuity, intraocular pressure (IOP), number of glaucoma medications, and complications. Changes in mean logMAR visual acuity, IOP, and glaucoma medications were compared by a two-tailed t-test.

RESULTS

Mean patient age was 69.0 years. Forty-three (54%) were male. Mean follow-up time was 19.9 months. Most common causes of neovascular glaucoma was diabetes (n = 63 [71%]) and central retinal vein occlusion (n = 21 [24%]). Eighty-six eyes (97%) underwent a 250 mm Baerveldt drainage device and 3 (3.4%) a 350 mm Baerveldt. Forty-five (51%) 20-gauge, 12 (13%) 23-gauge, and 32 (36%) 25-gauge pars plana vitrectomies were performed. Fifty-two eyes (58%) preoperatively and 23 (33%) postoperatively received intraocular injections for rubeosis and macular edema. Mean ± standard deviation logMAR visual acuity at 18-, 24-, 36-, and 48-month follow-up time points was significantly better than preoperative vision (P < 0.05). Preoperative versus final IOP and number of glaucoma medications were significantly decreased (P < 0.05). Fourteen eyes (16%) had a final visual acuity of no light perception. Most common complications included transient ocular hypertension (n = 82 [92%]), transient hypotony (n = 20 [22%]), hyphema (n = 19 [21%]), corneal edema (n = 17 [19%]), and vitreous hemorrhage (n = 14 [16%]). The frequency of transient hypotony, vitreous hemorrhage, and rubeosis was significantly (P < 0.05) higher in 20-gauge versus 23-/25-gauge pars plana vitrectomy eyes. Nine eyes (10%) required return to the operating room after combined procedure, including 4 eyes (4.5%) for retinal detachment and 3 (3.4%) for high IOP due to tube occlusion. Three eyes (3.4%) developed endophthalmitis and 2 (2.2%) progressed to being pre/phthisical (none were enucleated).

CONCLUSION

Combined pars plana vitrectomy and Baerveldt glaucoma shunt may be a useful procedure in reducing IOP and number of glaucoma medications in eyes with neovascular glaucoma along with stabilizing visual acuity in a majority of these eyes. Further studies are warranted to verify and expand on these findings.

One-Year Feasibility Study of Replenish MicroPump for Intravitreal Drug Delivery: A Pilot Study

PURPOSE

To determine the feasibility of the surgical procedure and to collect some safety data regarding the bioelectronics of a novel micro drug pump for intravitreal drug delivery in a Beagle dog model for up to 1 year.

METHODS

Thirteen Beagle dogs were assigned to two groups. The experimental group (n = 11) underwent pars plana implantation of MicroPump; the body of which was sutured episclerally, while its catheter was secured at a pars plana sclerotomy. The control group (n = 2) underwent sham surgeries in the form of a temporary suturing of the MicroPump, including placement of the pars plana tube. Baseline and follow-up exams included ophthalmic examination and imaging. The experimental animals were euthanized and explanted at predetermined time points after surgery (1, 3, and 12 months), while the control animals were euthanized at 3 months. All operated eyes were submitted for histopathology.

RESULTS

Eyes were scored according to a modified McDonald-Shadduck system and ophthalmic imaging. Neither the implanted eyes nor the control eyes showed clinically significant pathological changes beyond the expected surgical changes. The operated eyes showed neither significant inflammatory reaction nor tissue ingrowth through the sclerotomy site compared with the fellow eyes.

CONCLUSION

This study shows that the Replenish Posterior MicroPump could be successfully implanted with good safety profile in this animal model.

TRANSLATIONAL RELEVANCE

The results of this study in a Beagle dog model are supportive of the biocompatibility of Replenish MicroPump and pave the way to the use of these devices for ocular automated drug delivery after further testing in larger animal models.