Risk Factors for Failure of Tube Shunt Surgery: A Pooled Data Analysis

Ab-Externo XEN Gel stent implantation effectively treated refractory glaucoma with prior failed shunt tube

PURPOSE

To assess the efficacy of a gelatin stent (XEN 45 Gel Stent; Allergan) implant in advanced glaucoma eyes that have failed prior aqueous shunt implantation.

METHODS

We retrospectively reviewed 6 patients with refractory glaucoma, defined as persistently high IOP (> 21 mmHg) despite taking at least 3 IOP-lowering medications subsequent to undergoing a glaucoma drainage device (GDD) with or without a second GDD or cilioablative procedure. Eyes with previous failed GDD underwent subconjunctival 0.3 cc (0.4 mg/ml) mitomycin C, tenonectomy, and placement of an ab- externo XEN stent. The outcome measures included change in IOP and the number of glaucoma medications. Success was defined as patients achieving an IOP ≤ 18 mmHg with a percentage reduction of 25% or 15 mmHg and 40% mean IOP reduction from baseline while taking the same number or fewer medications.

RESULTS

All six eyes with age of 77.6 ± 7.82 years who underwent XEN implantation following previous GDD surgery had primary open-angle glaucoma. The IOP decreased significantly from 32.33 ± 5.99 to 12.67 ± 3.27 mmHg (p < 0.001) with a follow-up of 13.9 ± 2 (11.7-16.7) months. Visual acuity and visual field remained stable after XEN placement. Compared to the baseline number of medications of 4.2 ± 0.8, all medication was discontinued except in one eye on two drops at the end of the follow-up. The overall surgical success rate was 100%. No complications, needling, or additional procedures were required.

CONCLUSION

This study described successful implantation of the XEN stent following failed GDD. XEN Gel stent implantation associated with mitomycin C and tenonectomy can be considered a viable surgical option for patients with a history of previously failed tube shunt requiring further IOP lowering.

Celastrol alleviates subconjunctival fibrosis induced by silicone implants mimicking glaucoma surgery

Subconjunctival fibrosis is critical to the outcomes of several ophthalmic conditions or procedures, such as glaucoma filtering surgery. This study aimed to investigate the anti-fibrotic effect of celastrol on subconjunctival fibrosis and to further reveal the underlying mechanisms. We used celastrol-loaded nanomicelles hydrogel hybrid as a sustained-release drug. A rabbit model of subconjunctival fibrosis following silicone implantation was used for in vivo study, and TGF-β1-induced human pterygium fibroblast (HPF) activation as an in vitro model. The effects of celastrol on inhibiting TGF-β1-induced migration and proliferation of HPFs were evaluated by scratch wound assay and CCK-8, respectively. Immunofluorescence and western blotting were used to examine the effect of celastrol on the expression of α-SMA, collagen I, fibronectin, and the targets of the Hippo signaling pathway. We found that in vivo celastrol treatment reduced the expression of YAP and TAZ in subconjunctival tissue. Moreover, celastrol alleviated collagen deposition and subconjunctival fibrosis at 8 weeks. No obvious tissue toxicity was observed in the rabbit models. Mechanistically, celastrol significantly inhibited TGF-β1-induced proliferation and migration of HPFs. Pretreatment of HPFs with celastrol also suppressed the TGF-β1-induced protein expression of α-SMA, collagen I, fibronectin, TGF-βRII, phosphorylated Smad2/3, YAP, TAZ, and TEAD1. In conclusion, celastrol effectively prevented subconjunctival fibrosis through inhibiting TGF-β1/Smad2/3-YAP/TAZ pathway. Celastrol could serve as a promising therapy for subconjunctival fibrosis.

Incidence and Outcomes of Hypertensive Phase After Glaucoma Drainage Device Surgery

PURPOSE

To describe the incidence, risk factors, clinical characteristics, and long-term outcomes of a hypertensive phase (HP) after glaucoma drainage device (GDD) implantation.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Eyes that underwent implantation of their first GDD from January 2010 to October 2020 at a tertiary care center.

METHODS

Hypertensive phase was defined as intraocular pressure (IOP) >21 mmHg occurring at 2 consecutive visits in the first 90 days after the date of surgery for Ahmed Glaucoma Valve (AGV) or in the first 90 days after tube opening for Baerveldt Glaucoma Implant (BGI). Generalized estimating equations and Fisher exact tests were used to evaluate risk factors for HP and risk factors for failure of GDD surgery after occurrence of a HP.

MAIN OUTCOME MEASURES

Incidence and risk factors for HP. Overall surgical success rates, defined as the absence of failure criteria: IOP >21 mmHg, ≤5 mmHg, or <20% reduction below baseline IOP after 3 months for 2 consecutive visits, with or without adjunctive ocular hypotensive therapy; additional glaucoma surgery; or loss of light perception.

RESULTS

Among 419 eyes of 360 patients that underwent GDD implantation, 42 (10.0%) eyes developed HP. Onset of HP was 20.8 ± 10.5 days after AGV and 11.7 ± 20.3 days from the date of tube opening after BGI. Mean IOP during HP was 26.5 ± 3.2 mmHg with peak IOP of 30.0 ± 5.9 mmHg. Median follow-up duration was 21.5 months after onset of HP. Younger age and neovascular glaucoma were significant risk factors for HP occurrence in a multivariable model. Resolution of HP occurred in 32 eyes (76.2%) after a mean duration of 48.0 ± 53.0 days. Additional surgery with a second GDD or cyclophotocoagulation was performed for 12 eyes (28.6%). The overall success rate among eyes with a HP was 52.6% at 2 years, which was significantly lower than that observed among control eyes that did not experience HP (76.3%), P < 0.01.

CONCLUSIONS

The incidence of HP was 10.0%. Younger age and neovascular glaucoma were significant risk factors for HP in the multivariable model. The risk of surgical failure after HP is significantly higher compared to eyes that did not experience HP.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Evaluation of machine learning approach for surgical results of Ahmed valve implantation in patients with glaucoma

BACKGROUND

Ahmed valve implantation demonstrated an increasing proportion in glaucoma surgery, but predicting the successful maintenance of target intraocular pressure remains a challenging task. This study aimed to evaluate the performance of machine learning (ML) in predicting surgical outcomes after Ahmed valve implantation and to assess potential risk factors associated with surgical failure to contribute to improving the success rate.

METHODS

This study used preoperative data of patients who underwent Ahmed valve implantation from 2017 to 2021 at Ajou University Hospital. These datasets included demographic and ophthalmic parameters (dataset A), systemic medical records excluding psychiatric records (dataset B), and psychiatric medications (dataset C). Logistic regression, extreme gradient boosting (XGBoost), and support vector machines were first evaluated using only dataset A. The algorithm with the best performance was selected based on the area under the receiver operating characteristics curve (AUROC). Finally, three additional prediction models were developed using the best performance algorithm, incorporating combinations of multiple datasets to predict surgical outcomes at 1 year.

RESULTS

Among 153 eyes of 133 patients, 131 (85.6%) and 22 (14.4%) eyes were categorized as the success and failure groups, respectively. The XGBoost was shown as the best-performance model with an AUROC value of 0.684, using only dataset A. The final three further prediction models were developed based on the combination of multiple datasets using the XGBoost model. All datasets combinations demonstrated the best performances in terms of AUROC (dataset A + B: 0.782; A + C: 0.773; A + B + C: 0.801). Furthermore, advancing age was a risk factor associated with a higher surgical failure incidence.

CONCLUSIONS

ML provides some predictive value in predicting the outcomes of Ahmed valve implantation at 1 year. ML evaluation revealed advancing age as a common risk factor for surgical failure.

Glaucoma Tube Outcomes with and without Anti-VEGF in Patients with Age-related Macular Degeneration

PURPOSE

To compare glaucoma tube outcomes of wet age-related macular degeneration (AMD) eyes receiving anti-VEGF injections versus dry AMD eyes and no anti-VEGF.

DESIGN

Retrospective clinical cohort study.

PARTICIPANTS

Patients with wet AMD and a history of anti-VEGF within a year prior or after stand-alone glaucoma tube surgery and eyes with dry AMD and no history of anti-VEGF with at least 6 months of follow-up. Eyes with neovascular glaucoma or anti-VEGF for reason other than wet AMD were excluded.

METHODS

A Kaplan-Meier analysis compared survival for wet versus dry AMD eyes. Failure was defined as intraocular pressure (IOP) > 21 mmHg or < 20% IOP reduction from baseline or IOP ≤ 5 mmHg for 2 consecutive postoperative visits starting at month 3, additional glaucoma surgery, or no light perception. Complete success was defined as no failure or medications at final follow-up. Hypertensive phase was defined for valved tubes as IOP > 21 mmHg within 3 months of surgery after a reduction to < 22 mmHg during the first postoperative week. Intraocular pressure, percent reduction in IOP, number of glaucoma medications, and early (< 1 year) and late (> 1 year) complications were compared through 5 years.

MAIN OUTCOME MEASURES

Survival analysis, IOP, number of medications.

RESULTS

Baseline IOP, number of medications, or tube type were not significantly different between wet (n = 24) and dry AMD eyes (n = 54). No wet AMD eyes failed versus 10 (18%) dry AMD eyes (P = 0.03). Five-year survival was estimated as 100% for wet AMD and 72% for dry AMD (P = 0.04). Wet AMD eyes had lower IOP (10.6 vs. 12.7 mmHg, P = 0.05), greater IOP reduction (60% vs. 49%, P = 0.04), fewer medications (1.2 vs. 2.1, P = 0.02), and more complete success (50% vs. 15%, P = 0.001) at final follow-up (32 vs. 36 months, P = 0.42). Fewer wet than dry AMD eyes experienced hypertensive phase (0/10 [0%] vs. 4/10 [40%], P = 0.04). There were no significant differences in early or late complications.

CONCLUSIONS

Exposure to anti-VEGF may influence postoperative wound healing and capsule formation which may improve glaucoma tube surgical outcomes. Prospective data is needed to consider perioperative administration of anti-VEGF for glaucoma tube surgery.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Comparing Outcomes of Tube Versus Trabeculectomy Among Patients With Angle-closure Glaucoma

PURPOSE

Compare outcomes of tube shunt surgery (Tube) and trabeculectomy with mitomycin C (Trab-MMC) in patients with angle-closure glaucoma (ACG).

DESIGN

Retrospective nonrandomized comparative study.

PARTICIPANTS

A total of 80 eyes from 80 patients with ACG who underwent either Tube (N = 50) or Trab-MMC (N = 30) between January 2015 and January 2022 at Massachusetts Eye and Ear.

METHODS

Reviewed and analyzed 390 visits from patient charts.

MAIN OUTCOME MEASURES

Kaplan-Meier (KM) success rates, intraocular pressure (IOP), medication burden, best-corrected visual acuity (BCVA), adjusted hazard ratios (HRs), and complications.

RESULTS

Baseline demographics were similar between both groups, except for a higher proportion of patients with pseudophakia and prior incisional ocular surgery in the Tube group. The Trab-MMC procedure had significantly higher KM complete success (CS) rates than the Tube procedure, but similar qualified success (QS) rates. Under QS, the cumulative probability of survival was 87% in the Tube group and 83% in the Trab-MMC group at year 1 (P = 0.77), and 75% in the Tube group and 58% in the Trab-MMC group at year 2 (P = 0.14). Under CS, the cumulative probability of survival was 13% in the Tube group and 59% in the Trab-MMC group at year 1 (P < 0.001), and 11% in the Tube group and 41% in the Trab-MMC group at year 2 (P < 0.001). Both Tube and Trab-MMC procedures resulted in significant patterns of IOP and medication reduction from baseline up to 2 years with mean IOP reduced to 12.6 ± 5.9 mmHg on 2.8 ± 1.4 medications after Tube and 12.1 ± 6.6 mmHg on 2.4 ± 1.7 medications after Trab-MMC. Patients who underwent Trab-MMC required less IOP-lowering medications at every follow-up visit up to year 1, but a similar number at year 2. No significant differences were found in IOP reduction, BCVA, or complication rates between groups.

CONCLUSIONS

We demonstrate that Trab-MMC confers similar IOP reduction and QS rates to Tube placement in patients with ACG. Trab-MMC, however, demonstrated greater medication burden reduction up to 1 year, and more favorable CS rates up to 2 years, while still maintaining similar complication rates to Tube.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Risk Factors for Failure in Glaucoma Patients Undergoing Microshunt Implantation

PURPOSE

To evaluate risk factors for failure of Microshunt in glaucoma patients.

DESIGN

Multicenter retrospective cohort study.

METHODS

The study included 220 eyes from 220 consecutive glaucoma patients undergoing Microshunt implantation at six glaucoma units. Four intraocular pressure (IOP) success criteria were defined: (A) IOP ≤21 mm Hg with ≥20% IOP reduction; (B) IOP ≤18 mm Hg with ≥20% IOP reduction; (C) IOP ≤15 mm Hg with ≥25% IOP reduction; and (D) IOP ≤12 mm Hg with ≥30% IOP reduction from baseline. Kaplan-Meier analysis was used to estimate success rates according to the criteria above, and multivariable Cox models were used to identified risk factors for failure according to criterion A.

RESULTS

Success rates varied based on different criteria, ranging from 43.3% to 62.5% (overall success for criteria D and A, respectively) and from 35.3% to 44.4% (complete success for criteria D and A, respectively) at 1-year follow-up. Higher intraoperative MMC concentration was associated with reduced risk of failure to maintain complete (0.4 vs 0.2 mg/mL: hazard ratio [HR] = 0.441, P < .001) and overall (0.4 vs 0.2 mg/mL: HR = 0.360, P = .004) success. For complete success, other risk factors for failure were pseudoexfoliation glaucoma/pigmentary glaucoma (HR = 1.641, P = .004), primary angle closure glaucoma (HR = 1.611, P < .001), and previous non-glaucomatous ocular surgeries (HR = 2.301, P = .002). For overall success, other risk factors for failure were lower preoperative IOP (for 1-mm Hg increase, HR = 0.934, P = .005), higher number of preoperative antiglaucoma agents (HR = 1.626, P < .001), and Microshunt combined with cataract surgery (HR = 1.526, P = .033).

CONCLUSIONS

This study identified risk factors for Microshunt failure, highlighting the importance of high intraoperative MMC dose and careful patient selection to optimize surgical success.

Difficult decisions, filtration surgery, and the heartbreak of the numerator

A 70-year-old man had progressive and severe glaucoma in each eye. He was intolerant to dorzolamide, brimonidine, and netarsudil. Each eye had prior selective laser trabeculoplasty (SLT) as well as phacoemulsification plus minimally invasive glaucoma surgery (MIGS) 6 years before current presentation (iStent [Glaukos Corp.] in the right eye and Cypass [Alcon Laboratories, Inc.] in the left eye). Postoperative acuities were 20/20 and 20/25 in the right and left eyes, respectively. When his left eye progressed with loss of central acuity despite peak intraocular pressures (IOPs) in the middle to upper teens, neuro-ophthalmology consultation was obtained (Figure 1JOURNAL/jcrs/04.03/02158034-202401000-00017/figure1/v/2023-12-22T124801Z/r/image-tiff). That workup included magnetic resonance imaging scan and hematologic screening, but all results were negative, and the neuro-ophthalmic consultant concluded that the vision loss was likely on the basis of glaucoma. Accordingly, a trabeculectomy was performed in the left eye achieving consistent IOPs in the range of 7 to 10 mm Hg without medications, rending the left eye stable since the filtration surgery nearly 2 years previously. The right eye continued to progress both subjectively and objectively, and on recent examination, the IOP measured 20 mm Hg and 09 mm Hg in the right and left eyes, respectively (Figure 2JOURNAL/jcrs/04.03/02158034-202401000-00017/figure2/v/2023-12-22T124801Z/r/image-tiff). Medications included timolol and latanoprostene bunod in the right eye only. Central corneal thickness was 526 μm and 527 μm in the right and left eyes, respectively. The visual acuity now measured 20/25 in the right eye and 20/250 in the left eye. The vertical cup-to-disc ratio was 0.9 in the right eye and 1.0 in the left eye. Gonioscopy revealed a wide open angle in each eye with a patent sclerostomy superiorly in the left eye. The conjunctiva and sclera were healthy and without scarring in the right eye. The bleb in the left eye was diffuse, lightly vascularized, and seidel negative. Axial length (AL) was 26.88 μm in the right eye and 26.77 μm in the left eye. The patient was in good health and was not anticoagulated. An extensive discussion ensued about the best course of action for the right eye. How would you proceed in managing definite progression in this individual's right eye, knowing that he had lost fixation in his left eye at similar pressures?

Surgical safety and efficacy of a multi-stent system, the comet stent, in Baerveldt glaucoma implant surgery: a prospective pilot study

PURPOSE

This study aimed to introduce a new technique for lowering intraocular pressure (IOP) using a multi-stent system after the implantation of a Baerveldt glaucoma implant (BGI) and evaluate its clinical effectiveness.

STUDY DESIGN

Prospective case series.

METHODS

Six patients with uncontrolled refractory glaucoma were enrolled between December 2021 and May 2022. Six 6-0 nylon sutures were preoperatively inserted into the tube of a BGI. These sutures were named "comet stents" (CSs). BGI implantation was performed, and the CSs were removed one-by-one whenever the IOP rose during the follow-up period. IOP was measured 30-60 min after the removal of each CS, and the reduction in IOP was recorded to assess the effect of CS removal. IOP reduction and the effect of CS removal on IOP reduction were evaluated for 6 months. The cut and trimmed stented tubes were examined with scanning electron microscopy, and the ratio of the patent cross-sectional area to the total luminal area (PCSA, %) and the luminal area occupation rate per stent (%) were calculated.

RESULTS

The mean (±standard deviation) IOP decreased from 31.5 ± 2.8 mmHg at the baseline to 14.8 ± 8.3 mmHg at 1 month, 8.8 ± 4.7 mmHg at 3 months, and 9.2 ± 3.4 mmHg at 6 months. The IOP reduction induced by CS removal ranged from 0 to 19 mmHg. The mean PCSA was 52.7 ± 1.7%, and the mean luminal area occupation rate per stent was 7.9 ± 0.3%.

CONCLUSION

The use of CSs is an effective technique for controlling IOP in a step-by-step manner after BGI surgery.

Short-Term Outcomes of Trabeculectomy With or Without Anti-VEGF in Patients With Neovascular Glaucoma: A Systematic Review and Meta-Analysis

Objectives

The aim of this study was to compare the safety and efficacy of trabeculectomy alone or combined with intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents for the treatment of neovascular glaucoma.

Methods

We conducted a systematic review and meta-analysis to compare the effects of trabeculectomy alone or combined with intravitreal injections of anti-VEGF agents for the treatment of neovascular glaucoma. We searched four databases (PubMed, Cochrane Library, Embase, and Web of Science) up to January 2023 and extracted data on three surgical outcomes: postoperative intraocular pressure, success rate and complications. We used a random-effects model to calculate pooled relative risk (RR) or standardized mean difference (SMD) estimates and 95% confidence intervals (CIs). We assessed publication bias using Begg and Egger tests.

Results

We included seven studies with 353 eyes. Compared to trabeculectomy alone, trabeculectomy with anti-VEGF had a lower risk of postoperative complications (RR, 0.60; 95% CI, 0.41-0.89) and higher success rate (RR, 1.19; 95% CI, 1.02-1.40). The intraocular pressure reduction was significantly greater in the trabeculectomy with anti-VEGF augmentation group than the trabeculectomy group from 1 week (SMD, -1.36; 95% CI, -2.76 to 0.04) to 6 months (SMD, -0.79; 95% CI, -1.50 to -0.07) after surgery.

Conclusions

According to current evidence, adding intravitreal injection of anti-VEGF agents to trabeculectomy may improve the short time outcomes of patients with neovascular glaucoma.

10-Year Clinical Outcomes of Tube Shunt Surgery at a Tertiary Care Center

PURPOSE

To report 10-year clinical outcomes of tube shunt (TS) surgery at a tertiary care center.

DESIGN

Retrospective cohort study.

METHODS

Eyes were included that underwent a first TS surgery between January 2005 and December 2011 at a tertiary referral eye hospital and with at least 10 years of follow-up. Demographic and clinical data were collected. Failure was defined as reoperation to lower intraocular pressure (IOP), IOP > 80% of baseline for two consecutive visits, or progression to no light perception.

RESULTS

Eighty-five eyes of 78 patients were included in the Study Group; 89 eyes were selected as a Comparison Group. Mean follow-up was 11.9 ± 1.7 years. Fifty-one valved (60%), 25 non-valved (29%), and nine unknown (11%) TS were placed. At the final visit, mean IOP was reduced from 29.2 ± 10.4 mmHg on 3.1 ± 1.2 medications to 12.6 ± 5.8 mmHg on 2.2 ± 1.4 (p<0.001 for each). Forty-eight eyes (56%) failed; 29 eyes (34%) underwent additional glaucoma surgery; eight eyes (10%) progressed to no light perception; and 34 eyes (40%) also required TS revision. Best corrected visual acuity (BCVA) logMAR (minimal angle of resolution) worsened from 0.8 ± 0.7 (20/125) to 1.4 ± 1.0 (20/500) at the last visit (p<0.001). Average visual field MD was -13.9 ± 7.5 dB at baseline and -17.0 ± 7.0 dB at last follow-up (P=0.0605).

CONCLUSIONS

Many eyes maintained IOP control 10 years following TS, but 56% met failure criteria, 39% had substantial vision loss, and 34% underwent additional surgery. Outcomes did not differ with TS model. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Ocular surface and glaucoma, a mutual relationship. Practical suggestions for classification and management

The chronic use of glaucoma medications could improve the development of an ocular comorbidity, the glaucoma therapy-related ocular surface disease. This could be related to the exposure of the conjunctiva to preservatives, but also active compounds such as prostaglandin analogues may improve the risk of ocular surface inflammation. Inflammation has a negative impact on tolerability and adherence to eyedrops and to the outcome of filtration surgery as well. A stratification of glaucoma patients based not only on visual field progression but also on glaucoma therapy-related ocular surface disease would be desirable for a strategic management. Early diagnosis, individualized treatment, and safe surgical management should be the hallmarks of glaucoma treatment. One of the main issues for the proper and successful management of patients is the right timing, effectiveness and safety for both medical and surgical treatment options leading to a precision medicine in glaucoma disease as the best modern treatment.

Outcomes of vitrectomy, complete pan-retinal photocoagulation, and endoscopic cyclophotocoagulation surgery after anti-VEGF treatment in neovascular glaucoma

Purpose

To establish a comprehensive treatment strategy and evaluate the efficacy of combination of anti-vascular endothelial growth factor (VEGF) injection, pars plana vitrectomy (PPV), endoscopic pan-retinal photocoagulation (PRP), and endoscopic cyclophotocoagulation (ECP) surgery for neovascular glaucoma (NVG) patients.

Methods

This retrospective study included 30 patients (30 eyes) who were suffering from NVG and treated with PPV & PRP & ECP (ECP group, 16 eyes), or Ahmed glaucoma valve implantation (Ahmed group, 14 eyes). The intraocular pressure (IOP), number of postoperative anti-glaucoma medications, best-corrected visual acuity (BCVA), successful rate of surgery, and postoperative complications were recorded and statistically analyzed at the time points of preoperative, 1-day, 1-month, 3-months, 6-months, and 12-months after operation.

Results

An obvious reduction in IOP and number of postoperative anti-glaucoma medications were observed in both the ECP group and Ahmed group after operation (P ​< ​0.05), and the ECP group showed a significantly lower IOP compared to the Ahmed group at the 6-months (P ​= ​0.014) and 12-months (P ​= ​0.047) postoperative time points, while there was no significant difference of medication number between the two groups except for 1-day after surgery. The BCVA showed no marked difference between the two groups preoperatively and postoperatively (P ​> ​0.05), while it was significantly improved in ECP group at 3-months (P ​= ​0.001), 6-months (P ​= ​0.004), and 12-months (P ​= ​0.010) time points comparing with preoperative BCVA. The surgical success rates in ECP group were also slightly higher than Ahmed group. And the complications after operation showed no marked differences.

Conclusions

The comprehensive treatment of PPV, endoscopic PRP, and ECP surgery for NVG patients after anti-VEGF injection can control IOP effectively and be friendly to patients' BCVA without obvious serious complications throughout a 12-months follow-up period.

Ahmed Glaucoma Valve Implantation to Reduce Intraocular Pressure: Updated Perspectives

Trabeculectomy and glaucoma drainage device implantation are the most commonly performed glaucoma surgeries worldwide. Although trabeculectomy is the gold standard, at the present time there is an increase in the use of glaucoma drainage devices. The Ahmed glaucoma valve is one of the most widely used glaucoma drainage devices worldwide. Corneal endothelial cell loss and eventually corneal decompensation is one of the serious complication of glaucoma drainage device implantation. To avoid this, drainage tube can be inserted into the ciliary sulcus instead of the anterior chamber, especially in eyes with high risk for corneal decompensation. Tube/plate exposure, hypertensive phase, endophthalmitis, cataract formation, diplopia and ocular hypotony are the other potential complications that can develop after Ahmed glaucoma valve implantation.

Bleb geometry and morphology after Preserflo Microshunt surgery: Risk factors for surgical failure

PURPOSE

To investigate the possible risk factors for treatment failure in patients who had undergone Preserflo Microshunt (PMS) implantation, using anterior-segment optical coherence tomography (AS-OCT) to analyze the internal structures of the bleb.

METHODS

The PMS blebs of 54 patients were evaluated with AS-OCT. A mathematical model was used to calculate the total filtering surface of the episcleral fluid cavity (EFC) and the hydraulic conductivity (HC) of the bleb wall. Complete and qualified success were defined as IOP between 6 and 17 mmHg with or without glaucoma medication. The relation between baseline characteristics and probability of bleb success was analyzed by bivariate and multivariate logistic regression. The main outcome measures were mean bleb wall thickness (BWT), reflectivity (BWR), HC, mean horizontal and vertical diameter and total filtering surface (TFS) of the EFC.

RESULTS

Blebs from 74% patients were considered as complete success and 26% as failure. BWR and BWT increased linearly up to the first year in both groups. BWR was higher in the group failure (p = 0.02) and BWT in the group success (p<0.001). EFC was wider and shorter in the success group (p = 0.009, p = 0.03). Higher TFS showed a negative correlation with IOP (r = -0.4, p = 0.002). Higher baseline IOP was associated with success of PMS by multivariate analysis (p = 0.01). Mean HC, 0.034 ± 0.008 (μL/min)/mm2/mmHg, was negatively correlated with bleb surface (r = -0.5, p<0.0001) and wall´s thickness (r = -0.3, p = 0.01).

CONCLUSIONS

AS-OCT revealed that successful PMS blebs could show either thick hyporreflective walls or wide filtering surfaces with thin capsules. A higher baseline IOP increased the probability of surgical success.

Defining the role of ab externo Xen gel stent in glaucomatous eyes with prior failed surgical intervention

PURPOSE

To evaluate the safety and efficacy of Xen45 Gel stent (Xen; Allergan) in eyes that have failed prior surgical intervention, compared to traditional glaucoma drainage device (GDD) or continuous-wave cyclophotocoagulation (CPC). Since this population has low expected success rates with additional surgery, it is vital to compare to standard-of-care surgical options.

METHODS

Retrospective, single-center, case-control study of ab externo transconjunctival Xen shunt in eyes that have previously undergone trabeculectomy and/or GDD surgery. Postoperative data were collected for 18 months. Failure was defined as no light perception, additional glaucoma surgery required, or intraocular pressure (IOP) of < 6 mmHg after 6 weeks postoperatively.

RESULTS

Eighteen Xen eyes and 36 control eyes matched on both glaucoma type and previous glaucoma surgeries were included. Seventy-two percent had primary open angle glaucoma, 11% uveitic, 6% primary angle closure, 6% pseudoexfoliation, and 6% pigmentary glaucoma. Fifty-six percent of eyes in each group had prior trabeculectomy, 28% of Xen and 31% of control eyes had prior GDD, and 17% of Xen and 14% of control eyes had both. Baseline medicated IOP was lower in the Xen group (21.8 ± 7.2) compared to controls (27.5 ± 9.4, P = 0.043). The cumulative failure rate at year 1 was 17% for Xen and 20% for controls (P = 0.57). Mean survival time was 14.1 (± 1.5) months and 11.4 (± 0.6) months for controls. There was no difference in minor complication rates between groups (P = 0.65), but the Xen group had a significantly lower rate of serious complications (P = 0.043) defined as vision threatening or requiring surgical intervention in the operating room. When censored for additional glaucoma procedures, there were no differences at year 1 in IOP, change in IOP, number of IOP-lowering medications, or number of medications reduced from baseline.

CONCLUSIONS

The Xen shunt provides a reasonable alternative to current standard of care, with a similar failure rate at year 1, with a noninferior IOP reduction compared to GDD and CPC, and a preferred safety profile.

Results from the Primary Tube Versus Trabeculectomy Study and translation to clinical practice

PURPOSE OF REVIEW

The Primary Tube Versus Trabeculectomy (PTVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube shunt surgery and trabeculectomy with mitomycin C (MMC) in eyes without previous incisional ocular surgery. This article reviews results from the PTVT Study and suggests how they may be translated to clinical practice.

RECENT FINDINGS

Tube shunt surgery had a higher failure rate than trabeculectomy with MMC in the PTVT Study, and the difference was statistically significant at 1 year but not at 3 years and 5 years. Both surgical procedures reduced intraocular pressure (IOP) to the low teens throughout 5 years of follow-up. Mean IOPs were lower after trabeculectomy with MMC compared with tube shunt implantation, and the differences were statistically significant during the first postoperative year and at 3 years. The greater IOP reduction after trabeculectomy with MMC was achieved with significantly fewer glaucoma medications relative to tube shunt placement. Surgical complications were common in the PTVT Study, but most were transient and self-limited. The incidence of early postoperative complications was significantly higher after trabeculectomy with MMC than tube shunt surgery. The rates of late postoperative complications, cataract progression, and vision loss were similar with both surgical procedures. Serious complications producing vision loss and/or requiring a reoperation to manage the complication developed more frequently after trabeculectomy with MMC compared with tube shunt surgery, and the difference was statistically significant at 1 year but not at 3 years and 5 years postoperatively.

SUMMARY

Tube shunt implantation and trabeculectomy with MMC are both viable surgical options for managing glaucoma in patients without previous incisional ocular surgery. Results from the PTVT Study support further expansion of tube shunt use beyond refractory glaucomas.

Follow-up studies of the classical landmark studies in Glaucoma

PURPOSE OF REVIEW

It was not until the nineteen nineties that there was scientific evidence for the primary treatment concept of glaucoma, lowering intraocular pressure. The treatment concept of lowering intraocular pressure is now proven by randomized controlled clinical trials (landmark studies). This review provides an overview of the follow-up studies to these landmark studies from the last 18 months.

RECENT FINDINGS

The 20-year data of the ocular hypertension treatment study showed a 49% incidence of primary open-angle glaucoma. The data of this landmark study was used for developing different machine learning algorithms. Bilateral disease, disc hemorrhages, and higher intraocular pressure (IOP) were risk factors for visual field deterioration in the United Kingdom Glaucoma Treatment Study. The Advanced Glaucoma Intervention Trial and the Collaborative Initial Glaucoma Treatment Study identified demographic factors, comorbidity, and clinical variables associated with visual field damage. Analysis was performed on Chinese subsets from the Laser in Glaucoma and Ocular Hypertension Study (LiGHT). Looking at all the follow-up studies to the tube shunt landmark studies, preoperative IOP, neovascular glaucoma, Ahmed implantation, and younger age were predictors of failure. A follow-up study to the Effectiveness in Angle-Closure Glaucoma in Lens Extraction Study showed that patients were ten times more likely to maintain a drop-free target IOP after lens extraction than after laser iridotomy. A superior location for iridotomy results in significantly more significant angle widening than temporal or nasal locations, as shown by a follow-up study to the Zhongshan Angle Closure Prevention Trial using OCT and gonioscopy.

SUMMARY

The number of published follow-up studies to the landmark studies in glaucoma show the ongoing development of clinical questions in management of glaucoma.

Treatment Outcomes in the Primary Tube Versus Trabeculectomy Study after 5 Years of Follow-up

PURPOSE

To report 5-year treatment outcomes in the Primary Tube Versus Trabeculectomy (PTVT) Study.

DESIGN

Multicenter randomized clinical trial.

PARTICIPANTS

A total of 242 eyes of 242 patients with medically uncontrolled glaucoma and no previous incisional ocular surgery, including 125 patients in the tube group and 117 patients in the trabeculectomy group.

METHODS

Patients were enrolled at 16 clinical centers and randomly assigned to treatment with a tube shunt (350-mm2 Baerveldt glaucoma implant) or trabeculectomy with mitomycin C (MMC) (0.4 mg/ml for 2 minutes).

MAIN OUTCOME MEASURES

The primary outcome measure was the rate of surgical failure, defined as intraocular pressure (IOP) > 21 mmHg or reduced < 20% from baseline, IOP ≤ 5 mmHg, reoperation for glaucoma, or loss of light perception. Secondary outcome measures included IOP, glaucoma medical therapy, and visual acuity.

RESULTS

The cumulative probability of failure after 5 years of follow-up was 42% in the tube group and 35% in the trabeculectomy group (P = 0.21; hazard ratio = 1.31; 95% confidence interval = 0.86-2.01). At 5 years, IOP (mean ± standard deviation) was 13.4 ± 3.5 mmHg in the tube group and 13.0 ± 5.2 mmHg in the trabeculectomy group (P = 0.52), and the number of glaucoma medications (mean ± standard deviation) was 2.2 ± 1.3 in the tube group and 1.3 ± 1.4 in the trabeculectomy group (P < 0.001).

CONCLUSIONS

Trabeculectomy with MMC and tube shunt surgery produced similar IOPs after 5 years of follow-up in the PTVT Study, but fewer glaucoma medications were required after trabeculectomy. No significant difference in the rate of surgical failure was observed between the 2 surgical procedures at 5 years.