Corneal endothelial cell loss after Baerveldt glaucoma drainage device implantation in the anterior chamber

Intermediate-term impact on corneal endothelial cells and efficacy of Preserflo MicroShunt implantation in patients with open-angle glaucoma - a prospective study over two years

INTRODUCTION

Preserflo MicroShunt is a novel microinvasive bleb forming device for the treatment of primary open-angle glaucoma. The intermediate- and long-term success and the impact of this procedure on corneal endothelial cell density remain to be investigated.

METHODS

In this prospective observational study, 62 eyes of 55 glaucoma patients (mean age ± SD: 67.0 ± 15.0 years) receiving a Preserflo MicroShunt were included. Corneal endothelial cell density, intraocular pressure and best corrected visual acuity were assessed preoperatively and at 3, 6, 9, 12, 18 and 24 months postoperatively. Success rates, bleb revision rates and complications were analysed. Complete success was defined as an intraocular pressure reduction of ≥ 20% and achieving a target pressure of ≤ 18, ≤ 15 or ≤ 12 mmHg without antiglaucoma medication. Qualified success indicated that the criteria were reached with or without medication.

RESULTS

Corneal endothelial cells showed no significant decline over 24 months (p > 0.05). Intraocular pressure showed a substantial reduction postoperatively (p < 0.001), decreasing from 29.6 ± 8,3 mmHg to 13.0 ± 4.3 mmHg after 24 months (p < 0.001). Complete and qualified success with a target pressure ≤ 15 mmHg was achieved in 52.9% and 54.6% of cases after 24 months, respectively. Best corrected visual acuity did not change after 24 months.

CONCLUSION

Preserflo MicroShunt had no negative side effects on corneal endothelial cells and showed favourable success rates after 2 years in patients with open-angle glaucoma.

A computational fluid dynamics investigation of endothelial cell damage from glaucoma drainage devices

Glaucoma drainage devices (GDDs) are prosthetic-treatment devices for treating primary open-angle glaucoma. Despite their effectiveness in reducing intraocular pressures (IOP), endothelial cell damage (ECD) is a commonly known side-effect. There have been different hypotheses regarding the reasons for ECD with one being an induced increase in shear on the corneal wall. A computational fluid dynamics (CFD) model was used to investigate this hypothesis in silico. The Ahmed Glaucoma Valve (AGV) was selected as the subject of this study using an idealised 3D model of the anterior chamber with insertion angles and positions that are commonly used in clinical practice. It was found that a tube-cornea distance of 1.27 mm or greater does not result in a wall shear stress (WSS) above the limit where ECD could occur. Similarly, a tube-cornea angle of 45° or more was shown to be preferable. It was also found that the ECD region has an irregular shape, and the aqueous humour flow fluctuates at certain insertion angles and positions. This study shows that pathological amounts of WSS may occur as a result of certain GDD placements. Hence, it is imperative to consider the associated fluid force interactions when performing the GDD insertion procedure.

The effects of the first versus second glaucoma drainage implant surgery in patients with primary open-angle glaucoma

BACKGROUND

To investigate the outcome of non-valved glaucoma drainage implant surgery (GDIS) in primary open-angle glaucoma (POAG) patients divided in the first GDI group (patients who underwent the first GDIS) and the second GDI group (patients who underwent the second GDIS because of the failed first GDIS).

METHODS

Intraocular pressure (IOP), visual acuity (VA), visual field defect (VFD), medication score (MS), survival rate of GDIS, complications, and patient background was retrospectively analyzed. Two success criteria were set: Criteria (1) IOP reduction ≥ 20% and 5 < IOP ≤ 21, Criteria (2) IOP reduction ≥ 20% and 5 < IOP ≤ 14.

RESULTS

There were 136 eyes of 109 patients in the first GDI group and 32 eyes of 27 patients in the second GDI group. In the first GDI group and II, mean preoperative IOP was 26.7 ± 6.7 mmHg and 23.7 ± 3.5 mmHg, respectively (P = 0.09). No statistically significant difference in postoperative IOP reduction was found between the two groups (P = 0.39). At 5-years postoperative, the Criteria 1 (Criteria 2) survival rate in the first GDI group and the second GDI group was 60.4% (31.7%) and 61.2% (25.6%), respectively (Criteria 1: hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.30-1.35 [P = 0.24]; Criteria 2: HR: 0.81, 95% CI: 0.46-1.44, P = 0.48). No significant difference in VA, VFD change, MS, or complications was observed. Young patient age was the only significant factor for failure in the first GDI group (odds ratio: 0.95, 95% confidence interval: 0.91-1.00, P = 0.03).

CONCLUSION

The second GDIS may be as effective as the first GDIS for IOP reduction in POAG patients, however, there is a high risk of failure in young-age patients and the surgery may be ineffective in eyes requiring Criteria 2.

Preserflo MicroShunt: Efficacy and Endothelial Cell Density

PRCIS

A main safety concern associated with new glaucoma implants is corneal endothelial cell loss, which could even be observed in already established procedures.

PURPOSE

The purpose of this study was to evaluate the efficacy and corneal safety, especially corneal endothelial cell loss (ECL), after Preserflo MicroShunt implantation.

METHODS

A monocentric, prospective clinical observational study of patients with a follow-up of at least 12 months who underwent Preserflo MicroShunt implantation at the Department of Ophthalmology, University Hospital of Düsseldorf, Germany, between January 2020 and October 2021. Endothelial cell density (ECD), the distance between the tip of the implant and the corneal endothelium, and the success of the surgery were analyzed.

RESULTS

In total, 14 eyes of 12 patients were included. After a mean follow-up of 20±2.7 months intraocular pressure was significantly reduced by 8.2 mm Hg (P=0.0041); in 28.6% of patients, a revision surgery was necessary. Reduction of preoperative and follow-up ECD was not statistically significant (ECL of 45 cells/mm2, ECDpreoperative=2074±703.6 cells/mm2, ECDlast follow-up=2029±742.3 cells/mm2, P=0.42). A longer intracameral shunt tube length correlated significantly with a higher distance between the shunt tip and corneal endothelium (r=0.61, P=0.036).

CONCLUSIONS

Preserflo MicroShunt effectively lowered intraocular pressure without substantial ECL after a minimum follow-up period of 17 months.

Different patterns in the corneal endothelial cell loss after pars plana and pars limbal insertion of the Baerveldt glaucoma implant

PURPOSE

To assess corneal endothelial cell (CE) loss after pars plana (PP) and pars limbal (PL) insertion of a Baerveldt glaucoma implant (BGI).

DESIGN

Retrospective multicenter interventional comparative study.

METHODS

We studied central CE loss for 5 years after BGI surgery in 192 eyes.

RESULTS

The prevalence of bullous keratopathy (BK) was greater in the PL cohort than in the PP cohort (P = .003). The CE loss after simultaneous PP vitrectomy and tube insertion into the vitreous cavity was 11.9% in the first year, which was greater than that of 2.9% in eyes where the tube was inserted simply into the vitreous cavity after a prior vitrectomy (P = .046). The annual percentage CE loss after the first year decreased unidirectionally in both of those groups and was 1.3% and 1.0% in the fifth year, respectively (P < .001). For limbal insertion, the CE loss in the simple PL cohort was biphasic, decreasing from 10.5% in the first year to 7.0% in the fifth year. Simultaneous cataract and BGI surgery enhanced the CE loss slightly in the first year in the PP and PL cohorts to 13.0% and 14.0%, respectively. However, these increases were not significant (P = .816 and .358, respectively). Low preoperative CE density (P < .001) and insertion site (P = .020) were significant risk factors for the development of BK.

CONCLUSIONS

CE loss in the PL and PP cohorts was biphasic and unidirectional, respectively. The difference in annual CE loss became evident over time. PP tube implantation may be advantageous when the preoperative CE density is low.

Long-term outcomes of Baerveldt glaucoma implant surgery in Japanese patients

This study evaluated the long-term surgical outcomes of Baerveldt glaucoma implant (BGI) surgery in patients with refractory glaucoma (204 eyes/204 patients). Surgical failure was defined by: < 20% reduction in preoperative intraocular pressure (IOP), or criterion A (IOP > 21 mmHg), criterion B (IOP > 17 mmHg), or criterion C (IOP > 14 mmHg). Reoperation, loss of light perception vision, or hypotony also denoted failure. The probability of success at 5 years postoperatively using criteria A, B, and C was 72.4%, 49.7%, and 24.4%, respectively. The mean IOP decreased significantly from 32.7 ± 9.7 mmHg preoperatively to 13.1 ± 3.9 mmHg at 5 years; the mean number of glaucoma medications also decreased from 3.7 ± 1.2 to 1.8 ± 1.9 (both P < 0.01). The number of previous intraocular surgeries was significantly associated with failure in the multivariable analysis for criterion B (hazard ratio 1.30; P < 0.01) and criterion C (hazard ratio 1.19; P = 0.031). Early and late postoperative complications occurred in 82 (40.2%) and 28 (13.7%) eyes, respectively. Postoperative interventions were performed in 44 eyes (21.6%). BGI surgery resulted in significant long-term decreases in IOP and the number of glaucoma medications. BGI surgery is effective for refractory glaucoma. However, postoperative interventions due to complications are required in numerous cases.

Improvement of the loss of corneal endothelial cells by relocating the tip of the Baerveldt® implant tube from the anterior chamber to the vitreous cavity

PURPOSE

It has been reported that corneal endothelial cells (CEC) decrease faster when the tip of the Baerveldt glaucoma implant (BGI) tube is inserted into the anterior chamber than into the vitreous cavity. We investigated whether surgically relocating the tip of the BGI tube from the anterior chamber to the vitreous cavity could reduce CEC loss.

PATIENTS AND METHODS

This was a single facility retrospective cohort study. The inclusion criteria were the CEC density less than 1500 cells/mm2 and the CEC reduction ratio was greater than 10%/year. The subjects were 11 consecutive patients that could be followed > 12 months after relocation surgery. All patients were undergone vitrectomy, and the tip of tube was inserted into the vitreous cavity from the anterior chamber. We compared the intraocular pressure (IOP), reduction slope of CEC density and annual reduction rate of CEC density before and after relocation surgery. We calculated the annual reduction ratio in comparison with the preoperative CEC density (%/year).

RESULTS

The mean of period between the Baeveldt with anterior chamber insertion surgery and the relocation surgery was 33.8 ± 15.0 months. The mean of follow-up after relocation surgery was 21.8 ± 9.8 months. The relocation surgery did not significantly change IOP (p = 0.974). The mean preoperative and postoperative IOP were 13.1 ± 4.5 and 13.6 ± 4.3 mmHg. The reduction ratio of the CEC density was 15.4 ± 6.7 (%/year) before relocation surgery and significantly slower at 8.3 ± 6.5 (%/year) after relocation surgery (p = 0.024). Two patients resulted in bullous keratopathy after relocation surgery.

CONCLUSIONS

Relocating the tip of BGI tube from the anterior chamber to the vitreous cavity could reduce CEC loss.

Incidence of Blepharoptosis After Pars Plana Baerveldt 350 Glaucoma Implant Surgery by a Single Surgeon

PURPOSE

To investigate the incidence of postoperative blepharoptosis and clinical risk factors for blepharoptosis after pars plana Baerveldt 350 glaucoma implantation (BGI) by a single surgeon for refractory glaucoma.

METHODS

Twenty-four patients (30 eyes) who underwent pars plana BGI for refractory glaucoma at Toyama University Hospital between November 2019 and February 2021 were included. Patients with a preoperative margin reflex distance-1 (MRD-1) of ≥2 mm were included in the study, and a decrease in MRD-1 of ≥2 mm at 6 months postoperatively was defined as blepharoptosis.

RESULTS

The mean MRD-1 decreased significantly from 3.2 ± 0.6 mm preoperatively to 2.4 ± 1.1 postoperatively ( p < 0.01). Postoperative ptosis developed in 8 eyes (26.7%). A comparison of the ptosis (n = 8) and nonptosis (n = 22) groups showed a significant difference in the history and number of previous filtration surgeries ( p = 0.02 and p = 0.03, respectively). Those with previous filtration surgery had a higher risk of blepharoptosis after pars plana BGI compared with those without previous filtration surgery (OR: 6.43; 95% confidence interval: 1.03-40.26; p = 0.04).

CONCLUSION

Pars plana BGI is a risk factor for postoperative blepharoptosis. Particular attention should be paid to eyes that have undergone previous filtration surgery.

Effect of guided Ahmed glaucoma valve implantation on corneal endothelial cells: A 2-year comparative study

PURPOSE

To compare the effects of guided and non-guided Ahmed glaucoma valve (AGV) implantation on the corneal endothelium.

METHODS

Medical records of patients who underwent AGV implantation in the anterior chamber (AC) were reviewed retrospectively. The eyes were divided into two groups depending on the use of a guidance technique with spatula and a 4-0 nylon intraluminal stent. Specular microscopy was performed to measure corneal endothelial cell density (ECD) loss after surgery, and the rate of ECD change was calculated. Tube parameters were measured using anterior segment optical coherence tomography (AS-OCT).

RESULTS

The ECD loss during 2 years of follow-up was significantly lower in the guided AGV implantation (gAGV) group than in the non-guided implantation (ngAGV) group, and the rate of ECD change was -0.62 ± 1.23 and -1.42 ± 1.57%/month in the gAGV and ngAGV groups, respectively (p = 0.003). The mean tube-cornea distance (TCD) and mean tube-cornea angle (TCA) were significantly greater in the gAGV group than in the ngAGV group. The frequency of tube repositioning within 2 years after surgery was 0% in the gAGV group and 12.66% in the ngAGV group (p = 0.005).

CONCLUSIONS

The use of a guidance technique can reduce corneal endothelial loss during the first 2 years after AGV implantation in the AC. The tube was positioned at a more distant and wider angle from the cornea in the eyes of the gAGV group, which may have contributed to the reduced need for tube repositioning to prevent corneal decompensation.

A Novel Tube Insertion Technique for Glaucoma Drainage Device Implantation

PURPOSE

Early hypotony after non-valved glaucoma drainage device (GDD) implantation for complex glaucomatous eyes with labile aqueous production can lead to significant visual morbidity. We therefore sought to report the early postoperative outcomes of a novel surgical technique that allows atraumatic insertion of non-valved GDDs through a much smaller 25-gauge scleral track, to minimize entry site leakage and improve safety.

METHODS

Retrospective case series of 15 consecutive cases undergoing non-valved GDD insertion into the anterior chamber using a previously unreported technique.

RESULTS

All eyes underwent successful GDD insertion using our novel technique, with no intraoperative complications. The mean preoperative intraocular pressures (IOP), at day 1, week 1 and week 3 were 31.4, 22.4, 23.7, and 25.6 mm Hg, respectively. A statistically significant IOP reduction was achieved at day 1, week 1 and week 3 postoperatively ( P <0.05) without any observed leakage at the scleral entry site. One eye (6.7%) with complex panuveitic glaucoma developed early hypotony (5 mm Hg) with shallow choroidal detachments on day 1. This was successfully managed with 1 intracameral ophthalmic viscoelastic device injection given at the slit-lamp and no further intervention.

CONCLUSIONS

This novel single needle-docking intraocular insertion manoeuvre is an easily adoptable technique to make GDD insertion through a smaller 25-gauge water-tight scleral track more efficient and less traumatic. The technique reduces scleral distortion and therefore improves surgical safety particularly in eyes with complex secondary glaucoma.

Changes in corneal endothelial cell density after initial Ex-PRESS drainage device implantation and its relating factors over 3 years

BACKGROUND/OBJECTIVES

To investigate changes in corneal endothelial cell density (CECD) after initial Ex-PRESS surgery in Japanese patients with open-angle glaucoma (OAG) followed-up for 36 months.

SUBJECTS/METHODS

Corneal specular microscopy was used to examine preoperative and postoperative (3, 6, 12, 24 and 36 months) CECD and CECD changes were analysed. Kaplan-Meier survival curve was used to examine CECD maintained at 95% level, and Cox proportional hazards model was used to detect the risk factors for CECD loss. Intraocular pressure (IOP) changes during the course were also examined.

RESULTS

A total of 79 eyes of 79 patients (standalone surgery, 24 cases; combined cataract surgery, 55 cases) were investigated. Preoperative CECD (mean ± SD) was 2521 ± 305 cells/mm² and 2429 ± 366 (P = 0.003, adjusted for Bonferroni correction), 2462 ± 332 (P = 0.002), 2457 ± 317 (P < 0.001), 2433 ± 333 (P < 0.001), and 2387 ± 352 (P < 0.001) at 3, 6, 12, 24 and 36 months, respectively. The decrease rate was calculated as 1.8%/year. Further, 95% maintenance CECD at 36 months was 50.0% (95% confidence interval, 37.1-63.0%). Both univariate and multivariate Cox proportional hazard models showed that a low preoperative CECD was a significant risk factor for CECD loss. Baseline IOP of 19.3 ± 5.8 mmHg decreased at all measurement points (P < 0.001) after surgery.

CONCLUSION

CECD after initial Ex-PRESS surgery in 36 months might not be clinically problematic. However, longer-term follow-up is necessary, and regular CECD measurement should be performed, especially in patients with low CECD.

Five-year follow-up of corneal endothelial cell density after transscleral ab interno glaucoma gel stent implantation

Purpose

This study investigates the course of the endothelial cell density over a period of 5 years after XEN45 implantation (XEN45µm, Allergan Plc., USA) with or without combined cataract surgery.

Methods

This is a prospective, cross-sectional, monocentric, non-randomized clinical trial with the intention to treat a population of the University Eye Clinic Glaucoma Service Salzburg. One hundred and fifty-five eyes with preoperative central corneal endothelial cell counts were subjected to XEN45 implantation with (combined surgery group) or without (solo surgery group) combined cataract surgery. Endothelial cell density was measured at 3 corneal positions. XEN45 location parameters were determined with anterior segment OCT and gonioscopy.

Results

In the combined surgery group, a significant reduction of central endothelial cell count was found at years 2 and 4 when compared to baseline (p = 0.001 and p = 0.02, n = 86), whereas at years 1, 3, and 5, no change was detected (all p > 0.09). The median reduction of endothelial cell count was − 79 (95% CI: − 183 to − 9) and − 93 (95% CI: − 220 to 23) cells at years 2 and 4, respectively. In the solo surgery group (n = 69), no significant change in endothelial cell counts was detected at any time during the 5-year evaluation period (all p > 0.07). Explorative data analyses revealed that XEN45 location parameters did not significantly influence the course of endothelial cell count over time.

Conclusions

Endothelial cell loss after XEN45 implantation seems to be low. The present data suggest no impact on the position of the implant with regard to central endothelial cell counts in this study.

Tube–Iris Distance and Corneal Endothelial Cell Damage Following Ahmed Glaucoma Valve Implantation

The most significant factor for endothelial cell loss should be readily identified, since prevention is the most crucial treatment. Here, we investigate risk factors for corneal endothelial cell density (ECD) decline following Ahmed glaucoma valve (AGV) implantation and determine the optimal cut-off values. This study included 103 eyes (95 patients) with glaucoma that underwent AGV implantation between January 2006 and January 2021 at a single medical center (Severance Hospital). We conducted consecutive t-tests between two groups separated by the ECD change rate to determine the survival state of the enrolled patients. Associations were evaluated using univariable and multivariable linear regressions. Optimal cut-off values for identified risk factors were analyzed using a Cox proportional hazards model and a receiver operating characteristic (ROC) curve based on logistic regression. Mean follow-up duration was 4.09 ± 2.20 years. After implementing consecutive t-tests, only patients with an ECD change rate greater than −6.1%/year were considered to have survived. Tube–iris distance (TID) was the only statistically significant factor identified in both the univariable and multivariable linear regressions. The cut-off value determined from the consecutive Cox regression method was 0.33 mm (smallest p-value of 0.0087), and the cut-off value determined from the ROC method was 0.371 mm (area under the receiver operating characteristic curve [AUC], 0.662). Patients with short TIDs showed a better ECD prognosis following AGV surgery; we suggest optimal TID cut-off values of 0.33 mm and 0.371 mm based on the implemented Cox regression and ROC methodology, respectively.

Corneal Endothelial Cell Loss in Patients After Minimally Invasive Glaucoma Surgery: Current Perspectives

Minimally invasive glaucoma surgery (MIGS) is a rapidly expanding category of surgical glaucoma treatment options that offer a superior safety profile compared with traditional approaches for reducing intraocular pressure. However, MIGS may cause corneal endothelial cell loss; therefore, it has been receiving increasing attention. This systematic review aimed to evaluate and compare the rate and degree of corneal endothelial loss after MIGS. First, this paper presents an overview of the theoretical effectiveness of MIGS, the fundamental aspects regarding the roles of endothelial cells, and the effect of cataract surgery on the quality and count of endothelial cells. Further, we detail the various surgical techniques involved in MIGS, the development of these techniques over the time, and clinical aspects to consider with respect to the endothelial cell count. We discuss in detail the COMPASS-XT study, which was based on data collected over 5 years, reported that withdrawal of the CyPass Micro-Stent (Alcon Laboratories) yielded increased corneal endothelial cell loss. Generally, MIGS procedures are considered safe, with the incidence of complications ranging from 1% to 20% depending on the surgery type; however, there is still need for studies with longer follow-up. Thus, an adequate count of endothelial cells in the central cornea portion is recommended as necessary for candidate patients for MIGS.

Corneal Edema and Keratoplasty: Risk Factors in Eyes With Previous Glaucoma Drainage Devices

PURPOSE

To assess risk factors contributing to corneal decompensation following glaucoma drainage device (GDD) implantation.

DESIGN

Retrospective case control study.

METHODS

Records of 1610 eyes that underwent GDD implantation between June 1, 2009, and April 1, 2020, at the Johns Hopkins Wilmer Eye Institute were reviewed. Seventy-nine eyes (5%) developed corneal decompensation, of which 46 underwent keratoplasty. These 79 cases were matched with 220 controls. Cox proportional hazard models with robust standard error estimates to account for clustering at the matched-pair level were used to assess risk factors for corneal decompensation. Kaplan-Meier survival analysis analyzed time to corneal decompensation.

RESULTS

The mean (SD) age of cases and controls was 68 (12.3) and 60.5 (15.9) years, respectively. The mean time from GDD implantation to corneal decompensation was 32 months, and the cumulative probability of developing decompensation at 3, 6, and 9 years was 4.7%, 9.2%, and 14.8%, respectively. Final visual outcomes in cases were worse, with a final mean ± SD visual acuity (logMAR) of 1.96±1.25 relative to a mean±SD visual acuity of 1.11±1.36 in controls (P < .001). In the multivariable model, significant risk factors for corneal decompensation were increased age (adjusted hazard ratio [AHR] 1.39, 95% CI 1.18, 1.63; P ≤ .001), history of Fuchs dystrophy or iridocorneal endothelial syndrome (AHR 9.18, 95% CI 5.35, 15.74; P ≤ .001), and postoperative complications such as hypotony (AHR 3.25, 95% CI 1.85, 5.72; P ≤ .001) and tube-cornea touch (AHR 6.37, 95% CI 3.77, 10.75; P ≤ .001).

CONCLUSIONS

The risk of postoperative corneal decompensation is persistent over time. Patients receiving GDDs, particularly those with advanced age, preexisting corneal pathology, and postoperative complications, should be counseled regarding their increased risk for corneal decompensation.

Three-Year Outcomes of Pars Plana Ahmed and Baerveldt Glaucoma Implantations for Neovascular Glaucoma in Japanese Eyes

PRCIS

Tube shunt implantation through the pars plana was effective for neovascular glaucoma (NVG) for at least 3 years, with few serious postoperative complications observed.

PURPOSE

The aim was to report 3-year outcomes of pars plana Ahmed and Baerveldt glaucoma implantation for NVG in Japanese eyes.

PATIENTS AND METHODS

This study examined 41 eyes of 39 patients who underwent tube shunt implantation through the pars plana with the Baerveldt glaucoma implant (BGI group, 26 eyes) or Ahmed glaucoma valve (AGV group, 15 eyes) for NVG and who were followed up for over 3 years at Osaka Medical College between January 2009 and April 2016. Outcome measures were intraocular pressure (IOP, mm Hg) at presurgery and at 6 months and 1, 2, and 3 years postoperative. Postoperative failure was defined as an IOP of >21 mm Hg or <5 mm Hg, further glaucoma surgery, or no light perception.

RESULTS

Mean IOPs at presurgery and at 3 years postoperative were 34.8±9.1 and 15.6±4.6 in the AGV group, and 36.9±9.2 and 12.8±5.5 in the BGI group. Mean antiglaucoma medication scores at 3 years postoperative were 1.3±1.4 in the AGV group and 0.4±0.8 in the BGI group (P=0.05). The number of eyes with a probability of failure at 6 months and at 2 and 3 years postoperative was 2, 3, and 4, respectively, in the BGI group, and 0, 1, and 2, respectively, in the AGV group.

CONCLUSION

Findings for NVG cases showed tube shunt implantation through the pars plana was effective. Equivalent good IOP reductions were noted in both groups, with the BGI group requiring fewer postoperative antiglaucoma medications compared with the AGV group. Furthermore, both groups exhibited few serious postoperative complications.

Corneal endothelial cell density loss following glaucoma surgery alone or in combination with cataract surgery: A systematic review and meta-analysis

TOPIC

Corneal endothelial cell density (ECD) loss following glaucoma surgery with or without cataract surgery.

CLINICAL RELEVANCE

Corneal ECD loss may occur due to intraoperative surgical trauma in glaucoma surgery or postoperatively with chronic endothelial cell trauma or irritation.

METHODS

Trabeculectomy, glaucoma filtration surgery or microinvasive glaucoma surgery in participants with ocular hypertension, primary and secondary open angle glaucoma, normal tension glaucoma and angle-closure glaucoma were included. Pediatric populations and participants with pre-existing corneal disease were excluded. Laser treatments and peripheral iridotomy were excluded. Electronic databases searched in December 2021 included MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov and The International Prospective Register of Systematic Reviews (PROSPERO), FDA PMA and FDA 510(k).

RESULTS

39 studies were included in quantitative synthesis. 12 months following suprachoroidal MIGS mean ECD loss was 282 cells/mm² (95% Confidence Interval (CI) 220 to 345; p <0.00001; Chi² = 0.06; I² = 0%; 2 studies; very low certainty). Mean ECD loss after Schlemm's canal implantable devices was 338 cells/mm² (95% CI 185 to 491; p<0.0001; Chi² = 0.08; I² = 0%; 2 studies; low certainty) at 12 months. When compared to phacoemulsification alone, Schlemm's canal implants combined with phacoemulsification showed statistically significant mean ECD reduction at 24 months; mean difference of ECD was -19% (95% CI -37% to -2%; p=0.03; Chi² = 3.04; I² = 34%; 3 studies; low certainty). Mean ECD loss was 64 cells/mm² (95% CI 21 to 107; p=0.004; Chi² = 4.55; I² = 0%; 6 studies; low certainty) following Schlemm's canal procedures (without implantable devices) at 12 months. At 12 months the mean ECD loss after trabeculectomy was 33 cells/mm² (95% CI -38 to 105, p=0.36, Chi² = 1.17; I² = 0%; moderate certainty). At 12 months mean ECD loss was 121 cells/mm² (95% CI 53 to 189; p=0.0005; Chi² = 3.00; I² = 0%; 5 studies; low certainty) after Express implantation. When compared to control fellow eye, aqueous shunt surgery reduced ECD by 5.75% (95% CI -0.93 to 12.43; p=0.09 Chi² = 1.32; I² = 0%; low certainty) and 8.11% ECD loss (95%CI 0.06 to 16.16 p=0.05; Chi²= 1.93; I²=48%) at 12 and 24 months, respectively.

CONCLUSIONS

Overall there is low certainty evidence to suggest that glaucoma surgery involving long-term implants has a greater extent of ECD loss than glaucoma filtration surgeries without the use of implants. The results of this review support long-term follow-up (beyond 36 months) to assess ECD loss and corneal decompensation following implantation of glaucoma drainage implants.

The long-term postoperative effect of the Baerveldt glaucoma drainage device and of a trabeculectomy on the corneal endothelium

PURPOSE

To determine whether the postoperative corneal endothelial cell density (ECD) differs between glaucoma patients who underwent Baerveldt implant (BGI) surgery and patients who underwent a trabeculectomy (TE) over 5 years ago.

METHODS

Cross-sectional, observational study including 34 patients who underwent TE and 36 patients who underwent BGI surgery 5-11 years ago, as part of a randomized clinical trial. None of the patients had a history of intraocular surgery prior to their glaucoma surgery. Central and peripheral ECD was measured by using a non-contact specular microscope.

RESULTS

Central and peripheral ECD in the TE group was 2285 ± 371 cells/mm² (mean ± SD) and 2463 ± 476 cells/mm² , respectively. Central and peripheral ECD in the BGI group was 1813 ± 745 cells/mm² and 1876 ± 764 cells/mm² , respectively. The central and peripheral ECD was statistically significantly higher in the TE group than in the BGI group (p = 0.001 for both). Additional intraocular surgical interventions were more prevalent in the BGI group (23) than in the TE group (5) (p < 0.001). In a subanalysis, without eyes that had undergone additional surgical interventions, only the peripheral ECD was statistically significantly higher in the TE group compared with the BGI group (p = 0.011). For the BGI group, a longer postoperative period resulted in a lower central ECD (r = -0.614, p = 0.004).

CONCLUSION

Long-term ECD in eyes that underwent a BGI was considerably lower compared with eyes that underwent a TE, mainly in the peripheral cornea. This suggests that BGI causes a larger decrease of ECD than TE. Additionally, the decrease after BGI appears to continue for a longer period than after TE.

Corneal Endothelial Cell Loss in Glaucoma and Glaucoma Surgery and the Utility of Management with Descemet Membrane Endothelial Keratoplasty (DMEK)

The corneal endothelium has a crucial role in maintaining a clear and healthy cornea. Corneal endothelial cell loss occurs naturally with age; however, a diagnosis of glaucoma and surgical intervention for glaucoma can exacerbate a decline in cell number and impairment in morphology. In glaucoma, the mechanisms for this are not well understood and this accelerated cell loss can result in corneal decompensation. Given the high prevalence of glaucoma worldwide, this review aims to explore the abnormalities observed in the corneal endothelium in differing glaucoma phenotypes and glaucoma therapies (medical or surgical including with new generation microinvasive glaucoma surgeries). Descemet membrane endothelial keratoplasty (DMEK) is increasingly being used to manage corneal endothelial failure for glaucoma patients and we aim to review the recent literature evaluating the use of this technique in this clinical scenario.

Three-year outcome of sulcus fixation of Baerveldt glaucoma implant surgery

PURPOSE

The purpose of this study was to evaluate the 3-year surgical outcome of the sulcus fixation of Baerveldt glaucoma implant (BGI), focusing on corneal damage.

METHODS

This prospective observational study included 37 patients who underwent a median of two previous glaucoma surgeries and sulcus fixation of BGI for the first time. Each patient's intraocular pressure (IOP), glaucoma drug score, corneal endothelial cell density (ECD), and logMAR-converted best-corrected visual acuity (VA) were measured preoperatively and postoperatively until 36 months after surgery. Complete success was defined as reduced IOP (5-21 mmHg and >20% rate), without corneal damage (postoperative development of decompensation, unmeasurable ECD, or reduction in ECD of >20%), without loss of light perception, and without additional surgery requirement. Qualified success was defined by excluding the corneal criteria from complete success.

RESULTS

A total of 51% (19/37) patients experienced complete treatment success, whereas 86% (32/37) had qualified success. The median IOP (glaucoma drug score) decreased from 26 mmHg (5) to 15 mmHg (2) at three years postoperatively. The median postoperative ECD (reduction rate) decreased from 1838 cells/cm² preoperatively to 1587 cells/mm² (14%) at one year, 1358 cells/mm² (26%) at two years, and 1228 cells/mm² (33%) at three years postoperatively. One month after surgery, the VA was significantly reduced from preoperative values but did not decline after that.

CONCLUSION

Sulcus fixation of BGI was effective for IOP reduction. However, ECD decreased over time.

Corneal Endothelial Cell Loss After PRESERFLO™ MicroShunt Implantation in the Anterior Chamber: Anterior Segment OCT Tube Location as a Risk Factor

INTRODUCTION

To analyze the effects of PRESERFLO on corneal endothelial cell density (ECD).

METHODS

Forty-six eyes that underwent PRESERFLO implantation were followed up for 12 months. Specular microscopy was performed preoperatively and at 1, 3, 6, and 12 months postoperatively to measure central ECD and mean monthly reduction (MMR). Anterior segment optical coherence tomography (AS-OCT) was applied to measure the tube-endothelium (TE < 200 μm, 201-500 μm, > 500 μm) distance. The relationship between TE distance and ECD was analyzed with a linear mixed-effects model.

RESULTS

Central ECD decreased significantly at 1 year (7.4%, p = 0.04), with an MMR of -15 ± 25 cells/mm². Regarding TE distance groups, there was an 18% ECD reduction in the < 200 μm group vs. 1% in the > 500 μm group (p = 0.08). Endothelial cell loss was related to TE distance (mean 482.9 ± 238 μm), with a higher rate at 1 month in comparison to 12 months for the same tube position in the anterior chamber (-174.8 ± 65.2 cells/mm² at 1 month vs. 30.2 ± 11.3 cells/mm² at 12 months, p < 0.01). From month 6, tubes located > 600 μm from the endothelium showed EC loss close to zero.

CONCLUSIONS

The PRESERFLO implant is associated with a loss of EC from the immediate postoperative period that continues over time at lower rates. A shorter TE distance appears to cause more severe ECD loss.

Evaluation of the Effect of the First Generation iStent on Corneal Endothelial Cell Loss-A Match Case-Control Study

Glaucoma is the leading cause of irreversible blindness worldwide. The only proven factor in slowing the progression of glaucomatous neuropathy is lower intraocular pressure (IOP), which can be achieved with pharmacology, laser therapy, or surgery. However, these treatments are associated with various adverse effects, including corneal endothelial cell loss (CECL). In recent years, several novel surgeries for reducing the IOP, collectively referred to as minimally invasive glaucoma surgery (MIGS), have been developed, one of which is the iStent. However, the long-term effects of such surgeries remain unknown. We compared a group of patients with open-angle glaucoma and cataract who underwent phacoemulsification alone with a group of patients with similar demographic and clinical characteristics who underwent simultaneous phacoemulsification and iStent implantation. Overall, 26 eyes of 22 subjects who underwent a combined phacoemulsification-iStent procedure and 26 eyes of 24 subjects who underwent cataract surgery were included. Before surgery, endothelial cells accounted to 2228.65 ± 474.99 in iStent group and 2253.96 ± 404.76 in the control group (p = 0.836). After surgery, their number declined to 1389.77 ± 433.26 and 1475.31 ± 556.45, respectively (p = 0.509). There was no statistically significant difference in CECL between the two groups 18–24 months after surgery, despite increased manipulation in the anterior chamber and the presence of an implant in the trabecular meshwork in those with an iStent implant. Thus, iStent bypass implantation is a safe treatment in terms of CECL for mild-to-moderate open-angle glaucoma.

Anterior Chamber Versus Ciliary Sulcus Ahmed Glaucoma Valve Tube Placement: Longitudinal Evaluation of Corneal Endothelial Cell Profiles

PRCIS

An Ahmed glaucoma valve (AGV) tube in the ciliary sulcus (CS) is safer for the endothelium. At 4 years of follow-up, there was a significant decrease in endothelial cell count only with anterior chamber (AC) placement.

PURPOSE

Corneal endothelium (CE) damage is one of the most feared long-term complications that can result from glaucoma drainage devices. Nonetheless, there is a lack of studies evaluating longitudinal changes in CE cells. This study aims to compare CE changes after AGV implantation in eyes with AC or CS tube placement.

MATERIALS AND METHODS

This was a retrospective, nonrandomized, longitudinal study of pseudophakic eyes with open-angle glaucoma and medically uncontrolled intraocular pressure that received an AGV. Eyes with additional glaucoma surgeries performed during follow-up were excluded. The main outcome measure was endothelial cell density (ECD), which was evaluated 1 year±2 months and 4 years±2 months postoperatively. The average endothelial cell size (AS) and the distance from the tube tip to the cornea were also evaluated.

RESULTS

Twenty-six eyes from 26 patients, with a mean age of 73±10 years, were included. The tube was placed in the AC in 15 eyes and in the CS in 11 eyes. The eyes with tube placement in the AC showed a significant AS increase (P=0.007) and ECD decrease (P=0.034), whereas eyes with tube placement in the CS had no significant AS (P=0.575) or ECD (P=0.445) change. In the eyes with tube placement in the AC, there was no correlation between DTC and ECD (P=0.260) or AS (P=0.428) changes.

CONCLUSIONS

Tube placement in the AC seems to lead to significant CE cell loss over time, compared with tube placement in the CS.

Minimally Invasive Glaucoma Surgical Techniques for Open-Angle Glaucoma: An Overview of Cochrane Systematic Reviews and Network Meta-analysis

IMPORTANCE

Glaucoma affects more than 75 million people worldwide. Intraocular pressure (IOP)-lowering surgery is an important treatment for this disease. Interest in reducing surgical morbidity has led to the introduction of minimally invasive glaucoma surgeries (MIGS). Understanding the comparative effectiveness and safety of MIGS is necessary for clinicians and patients.

OBJECTIVE

To summarize data from randomized clinical trials of MIGS for open-angle glaucoma, which were evaluated in a suite of Cochrane reviews.

DATA SOURCES

The Cochrane Database of Systematic Reviews including studies published before June 1, 2021.

STUDY SELECTION

Reviews of randomized clinical trials comparing MIGS with cataract extraction alone, other MIGS, traditional glaucoma surgery, laser trabeculoplasty, or medical therapy.

DATA EXTRACTION AND SYNTHESIS

Data were extracted according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines by one investigator and confirmed by a second. Methodologic rigor was assessed using the AMSTAR 2 appraisal tool and random-effects network meta-analyses were conducted.

MAIN OUTCOMES AND MEASURES

The proportion of participants who did not need to use medication to reduce intraocular pressure (IOP) postsurgery (drop-free). Outcomes were analyzed at short-term (<6 months), medium-term (6-18 months), and long-term (>18 months) follow-up.

RESULTS

Six eligible Cochrane reviews were identified discussing trabecular bypass with iStent or Hydrus microstents, ab interno trabeculotomy with Trabectome, subconjunctival and supraciliary drainage devices, and endoscopic cyclophotocoagulation. Moderate certainty evidence indicated that adding a Hydrus safely improved the likelihood of drop-free glaucoma control at medium-term (relative risk [RR], 1.6; 95% CI, 1.4 to 1.8) and long-term (RR, 1.6; 95% CI, 1.4 to 1.9) follow-up and conferred 2.0-mm Hg (95% CI, -2.7 to -1.3 mm Hg) greater IOP reduction at long-term follow-up, compared with cataract surgery alone. Adding an iStent also safely improved drop-free disease control compared with cataract surgery alone (RR, 1.4; 95% CI, 1.2 to 1.6), but the short-term IOP-lowering effect of the iStent was not sustained. Addition of a CyPass microstent improved drop-free glaucoma control compared with cataract surgery alone (RR, 1.3; 95% CI, 1.1 to 1.5) but was associated with an increased risk of vraision loss. Network meta-analyses supported the direction and magnitude of these results.

CONCLUSIONS AND RELEVANCE

Based on data synthesized in Cochrane reviews, some MIGS may afford patients with glaucoma greater drop-free disease control than cataract surgery alone. Among the products currently available, randomized clinical trial data associate the Hydrus with greater drop-free glaucoma control and IOP lowering than the iStent; however, these effect sizes were small.

Endothelial Cell Density After XEN Implant Surgery: Short-term Data From the Italian XEN Glaucoma Treatment Registry (XEN-GTR)

PRECIS

XEN implant was associated with low endothelial cell density (ECD) reduction. In fact, when combined with phacoemulsification, the reduction in ECD was similar to that expected after phacoemulsification alone.

PURPOSE

The purpose of this study was to assess the impact of XEN implant, either alone or in combination with phacoemulsification, on ECD.

METHODS

Multicenter, prospective, observational study conducted on consecutive open-angle glaucoma patients, who were enrolled in the Italian XEN Glaucoma Treatment Registry and have complete endothelial cell count data at baseline and at 6 months after implantation. The primary endpoint was the mean percentage change in ECD between baseline and month 6.

RESULTS

The study included 108 open-angle glaucoma eyes (68 in the XEN-solo and 40 eyes in the XEN+phaco groups) and 60 control eyes (phaco-solo group). As compared with baseline, mean (95% confidence interval, CI) ECD reduction was -5.6% (-7.0% to -4.9%), -11.3% (-13.8% to -10.9%), and -13.0% (14.8% to -11.8%) in the XEN-solo, XEN+phaco, and phaco-solo groups, respectively (P=0.0004, <0.0001, and <0.0001, respectively). As compared with the XEN-solo group, the ECD reduction was significantly greater in the XEN+phaco group (mean difference=5.7%; 95% CI: 4.1%-7.3%, P<0.0001) and in the phaco-solo group (mean difference=7.4%; 95% CI: 5.7%-9.1%, P<0.0001). ECD reduction was similar in XEN+phaco and phaco-solo groups (P=0.9). In absolute terms, ECD reduction was significantly greater in the XEN+phaco (mean difference=169±306, P=0.021) and in the phaco-solo (mean difference=192±302, P=0.0022) groups than in the XEN-solo group.

CONCLUSIONS

The mean ECD reduction 6 months after XEN implantation was low. The ECD reduction in the XEN+phaco group was larger than in the XEN-solo group but was similar to that observed in the phaco-solo group.

Effects of Miosis on Anterior Chamber Structure in Glaucoma Implant Surgery

We investigated changes in anterior chamber (AC) structure after miosis in phakic eyes and pseudophakic eyes with glaucoma. In this prospective study, patients scheduled for glaucoma implant surgery were examined using anterior segment optical coherence tomography before and after miosis. Four AC parameters (AC angle, peripheral anterior chamber (PAC) depth, central anterior chamber (CAC) depth, and AC area) were analyzed before and after miosis, and then compared between phakic and pseudophakic eyes. Twenty-nine phakic eyes and 36 pseudophakic eyes were enrolled. The AC angle widened after miosis in both the phakia and pseudophakia groups (p = 0.019 and p < 0.001, respectively). In the phakia group, CAC depth (p < 0.001) and AC area (p = 0.02) were significantly reduced after miosis, and the reductions in PAC depth, CAC depth, and AC area were significantly greater than in the pseudophakia group (all p < 0.05). Twenty-five patients (86.2%) in the phakia group and 17 (47.2%) in the pseudophakia group had reduced CAC depth (p = 0.004). Although miosis increased the AC angle in both groups, AC depth decreased in most phakic eyes and a substantial number of pseudophakic eyes. Preoperative miosis before glaucoma implant surgery may interfere with implant tube placement distant from the cornea during insertion into the AC.

The Effects of Glaucoma and Glaucoma Therapies on Corneal Endothelial Cell Density

A healthy corneal endothelium is required for corneal clarity. Both the glaucoma disease state and its various forms of treatment can have adverse effects on the corneal endothelium. Both the presence of glaucoma and the magnitude of intraocular pressure elevation are related to endothelial cell loss (ECL). Topical medical therapy, laser procedures, and both traditional surgeries-trabeculectomy and tube-shunts-and newer minimally invasive glaucoma surgeries have variable effects on ECL. This review will summarize the reported effects of glaucoma and its treatment on ECL. Concerns for corneal endothelial cell health should be part of the decision-making process when planning glaucoma therapy for lowering intraocular pressure, with added caution in case of planned device implantation in eyes with preexisting ECL and low endothelial cell density at high risk for corneal endothelial decompensation.

Efficacy and Safety of the Susanna Glaucoma Drainage Device After 1 Year of Follow-up

PRECIS

This study found a rate of failure of 13.6% of the new Susanna Glaucoma Drainage Device (SGDD) after 1 year of follow-up. Severe complications occurred in 1 patient (4.5%).

PURPOSE

The purpose of this study was to determine the success and complications rates of the SGDD implant in refractory glaucoma.

PATIENTS AND METHODS

This is a retrospective study. Medical records from all consecutive refractory glaucoma patients (failed trabeculectomies with the use of adjunctive mitomycin) followed in a private clinical practice were included in the study. All patients had undergone SGDD implant surgery from September 2016 to July 2019 were included. All surgeries were done by the same surgeon (R.S.). Primary outcome was surgical failure, defined as intraocular pressure (IOP) >18 mm Hg and/or <20% IOP reduction from baseline, IOP<5 mm Hg, reoperation for glaucoma, need of implant removal or loss of light perception vision. Secondary outcomes included mean IOP, use of supplemental medical therapy, and complications.

RESULTS

In all, 22 eyes were analyzed. Mean patient age was 63±15 years (range: 27 to 87 y). Mean IOP decreased from 23±7 to 11±8 mm Hg (P<0.001, paired t test) at an average of 18±9 months after the tube implant. The mean SD number of glaucoma medications was reduced from 3.3±1 to 1.5±1.2 at the last postoperative visit (P<0.01, paired t test). No early postoperative complications occurred. There was 1 case of late persistent hypotony in a patient with previous endocyclophotocoagulation that was solved with tube ligature with silk 8-0. Failure because of high IOP occurred in 2 cases. There was no extrusion or erosion of the tube and the plate.

CONCLUSION

The SGDD presented a 13.6% failure rate (86.4% success rate) with very few complications, being an efficient and safe alternative for refractory glaucoma.

Effect of shunt type on rates of tube-cornea touch and corneal decompensation after tube shunt surgery in uveitic glaucoma

PURPOSE

To evaluate the effect of tube shunt type [Ahmed (AGV) versus Baerveldt (BGI)] on the frequency of tube-cornea touch and corneal decompensation after tube shunt surgery.

METHODS

This retrospective comparative study included 145 eyes of 130 patients with uveitic glaucoma who underwent AGV (75 eyes) or BGI (70 eyes) implantations. Electronic medical records were reviewed to document demographic factors, intraocular pressure (IOP) reduction, frequency of tube-cornea touch, corneal decompensation, and need for subsequent corneal transplantation.

RESULTS

The mean follow-up was 27.7±3.3 months for AGV and 32.8±3.8 months for BGI (p=0.30). Tube-cornea touch was observed in 5 eyes after BGI and 1 eye in the AGV group (p=0.08). The BGI group reported a significantly higher rate of corneal decompensation (9 versus 0; p=0.001) and transplantation (6 versus 0; p=0.01) compared to the AGV group. Previous trabeculectomy was a significant risk factor for corneal complications in eyes undergoing BGI implantation (odds ratio [OR]= 8.17, 95% confidence interval [CI]=1.78-37.45, p=0.007).

CONCLUSION

Similar rates of tube-cornea touch were observed in both shunt types; BGI shunts were associated with a greater incidence of corneal complications and transplantation as compared to AGV in this retrospective series of uveitic glaucoma cases.

Corneal Endothelial Cell Changes After Phacoemulsification Combined with Excisional Goniotomy with the Kahook Dual Blade or iStent: A Prospective Fellow-Eye Comparison

Purpose

To characterize changes in endothelial cell density and morphology following phacoemulsification combined with either excisional goniotomy with the Kahook Dual Blade (KDB-phaco) or first-generation iStent trabecular microbypass implantation (iStent-phaco).

Setting

A single clinical practice.

Methods

Twenty-one adult subjects from one center with visually significant cataract and mild-moderate open-angle glaucoma underwent KDB-phaco or iStent-phaco in one eye and the alternate procedure in the fellow eye as part of a prospective, multicenter, randomized trial. Specular microscopy and pachymetry were performed before and 6–29 months after surgery. Parameters analyzed included change from baseline of endothelial cell density (ECD), the coefficient of variation (CV), the percent of hexagonal cells (%HEX), and central corneal thickness (CCT).

Results

Baseline ECD, CV, %HEX, and CCT were similar between groups. A mean (standard deviation) of 18.2 (5.8) months postoperatively (range 12.5–28.7 months), the change from baseline in ECD was −90 ± 226 cells/mm² (−3.4%) in KDB-phaco eyes (p=0.083) and −239 ± 247 cells/mm² (−9.0%) in iStent-phaco eyes (p<0.001); the change in iStent-phaco eyes was significantly greater than in KDB-phaco eyes (p=0.013). The magnitude of Endothelial Cell Loss (ECL) was not correlated with length of postoperative follow-up time in either group. No significant differences in change from baseline in CV, %HEX, or CCT were noted with the exception of a decrease in %HEX in iStent-phaco eyes (p=0.017). No eyes manifested corneal edema, decompensation, or other cornea-related complications.

Conclusion

Both KDB-phaco and iStent-phaco are associated with postoperative ECL, with iStent-phaco producing significantly greater ECL than KDB-phaco. The clinical significance of these findings is unclear, and future studies are warranted to more robustly characterize long-term effects of glaucoma surgical procedures—with and without permanent implants—on ECD and corneal health and to develop evidence-based guidelines for the pre- and post-operative evaluation of corneal health in eyes undergoing glaucoma surgery.

Impact of Phacoemulsification Combined with XEN Gel Stent Implantation on Corneal Endothelial Cell Density: 2-Year Results

INTRODUCTION

Corneal integrity has long been a preoccupation of glaucoma surgeons considering glaucoma drainage device surgery or antimetabolite-enhanced trabeculectomy. Despite having demonstrated a good safety profile and significant intraocular pressure-lowering capacities, the impact of XEN gel stents on endothelial density was never specifically investigated. The purpose of this study is to assess the effect of XEN gel stents on central endothelial cell density (ECD) over 24 months. To achieve this, we compared the effect on ECD of combined XEN surgery with that of a standard phacoemulsification procedure.

METHODS

This was an investigator-initiated, retrospective study, conducted at a single tertiary glaucoma center. Patients with primary or secondary open-angle glaucoma who underwent XEN implantation combined with phacoemulsification between January 2015 and June 2016 were retrospectively enrolled. Patients who had undergone standalone phacoemulsification over the same period of time were enrolled to form the control group of this comparative study. The primary outcome measure was the ECD. Patients who had undergone standalone XEN implantation and patients for whom both a baseline and 24-month ECD could not be obtained were excluded from the analysis. Percentages of ECD reductions were calculated for each studied eye, and the mean of ECD reductions was calculated for each group as well as for subgroups.

RESULTS

Thirty-two eyes of 23 patients (mean age=76.0±7.9 y, 60% female) underwent standalone phacoemulsification (n=15) or combined XEN surgery (n=17) and had an ECD both at baseline and 24-month postoperatively. Mean baseline ECDs were 2568±491 versus 2379±335 cells/mm, respectively (P=0.21). In the combined XEN surgery group, 58.8% of eyes (n=10) required at least 1 mitomycin C (MMC)-enhanced needling revision to maintain their target intraocular pressure. In the standalone phacoemulsification group, ECD decreased by a mean 14.5%, from 2567.7±491.2 to 2196.1±591.9 cell/mm (P=0.072). In the combined XEN surgery group, ECD decreased by a mean 14.3%, from 2378.8±334.7 to 2039.6±451.1 cell/mm (P=0.018). The difference in percentage reduction of ECD between the 2 groups was not statistically significant (P=0.226). Within the combined XEN surgery group, the ECD decreased by a mean of 15.4% in patients who did not undergo needling revisions and by 13.1% in patients who underwent the MMC-augmented procedure (P=0.485). In the 3 patients who underwent >1 needling revision, a 21.3% reduction in ECD was observed, but the difference was not statistically significant (P=0.653). Neither the time of the first needling (P=0.452), the patients' age (P=0.285), or sex (P=0.308) was statistically associated with ECD loss.

DISCUSSION

The present study demonstrated that the XEN gel implant combined with phacoemulsification produces 24-month ECD loss of a similar magnitude to that observed following standalone phacoemulsification. MMC-augmented needling revisions do not appear to have an impact on ECD.

Relationship between Tube Parameters and Corneal Endothelial Cell Damage after Ahmed Glaucoma Valve Implantation: A Comparative Study

PURPOSE

We compared the clinical factors, including anterior chamber tube parameters, in patients with and without corneal endothelial cell damage after Ahmed glaucoma valve (AGV) implantation.

METHODS

In this retrospective and comparative case series, patients who underwent AGV implantation were enrolled consecutively. Serial specular microscopy was performed before and after AGV implantation. Patients were divided into two groups depending on whether there was a significant decrease in corneal endothelial cell density (ECD), which was determined by each patient's rate of ECD change (%/year), calculated using linear regression analyses. Tube parameters such as the tube-cornea distance (TCD) and tube-cornea angle (TCA) were measured with anterior segment optical coherence tomography. Clinical factors related to the rate of ECD change were evaluated with regression analyses and compared between the two groups. The tipping point at which tube parameters became significantly associated with the rate of ECD change was identified with broken stick regression analyses.

RESULTS

There were 30 eyes (32.3%) with ECD damage (group 1) and 63 eyes (67.7%) without damage (group 2). The mean rate of ECD change (%/year) was -18.82 ± 22.97 and 2.14 ± 2.93 in groups 1 and 2, respectively (p < 0.001). The TCA was the only clinical factor associated with the rate of ECD change (regression coefficient, β = 1.254, p < 0.001). The tipping point in the TCA was 26.70° (95% confidence interval, CI: 23.75-29.64°). The mean TCD (mm) was 0.98 ± 0.38 and 1.26 ± 0.39 (p = 0.002), and the mean TCA (degrees) was 28.67 ± 7.79 and 36.35 ± 5.35 (p < 0.001) in groups 1 and 2, respectively.

CONCLUSIONS

A wider TCA was protectively associated with the rate of ECD change, and the TCA was significantly narrower in patients with ECD damage. When inserting a tube into the anterior chamber, surgeons should therefore try to secure a wide TCA of about 30°. In patients with a narrow TCA after AGV implantation, increased attention should be directed toward whether ECD decreases continuously.

Corneal Parameters after Tube-Shunt Implantation through the Ciliary Sulcus

PURPOSE

To monitor bilateral corneal parameters after unilateral Baerveldt 350 tube-shunt implantation (Advanced Medical Optics, Santa Ana, CA) through the ciliary sulcus.

DESIGN

Retrospective, interventional case series.

PARTICIPANTS

Patients from 1 private glaucoma practice with severe uncontrolled glaucoma treated with sulcus tube-shunt implantation in 1 pseudophakic eye.

METHODS

Specular microscopy data were collected before and after unilateral sulcus tube-shunt implantation from the surgical and the glaucomatous fellow eyes.

MAIN OUTCOME MEASURES

Central corneal endothelial cell density (CECD), coefficient of variation (CV), percent of hexagonal cells, central corneal thickness (CCT), intraocular pressure (IOP), IOP-lowering medications, visual acuity, and complications.

RESULTS

Forty-six patients (mean age, 69.9 years; standard deviation [SD], 4.6 years; range, 20-88 years; male gender, 41.3%) were identified. After surgery, IOP and the number of IOP-lowering medications decreased significantly by 42.3% (P < 0.0001) and 32.1% (P < 0.0001), respectively, in the surgical eye group. Preoperative CECD measured 1807 cells/mm² (SD, 172 cells/mm²) and 1825 cells/mm² (SD, 172 cells/mm²) in the surgical and fellow eyes, respectively (P = 0.92), and compared with baseline, it decreased by 8.6% (P = 0.17) and 3.1% (P = 0.65), respectively, by 24 months. Preoperative CV, percent of hexagonal cells, and CCT were similar in both groups and remained stable. All corneal parameters remained unchanged in a subgroup of 15 patients with low preoperative CECD (1273 cells/mm²; SD, 99 cells/mm²). Best-corrected visual acuity remained stable in both groups. Hyphema occurred in 23.9% of the surgical eyes and resolved with no intervention. We found no sight-threatening complications or corneal failures during follow-up.

CONCLUSIONS

Tube-shunt implantation through the ciliary sulcus in pseudophakic eyes appears relatively safe to the corneal endothelium, demonstrating a small and nonsignificant decline in central CECD compared with baseline and with glaucomatous fellow eyes. No significant disruption to corneal endothelial cell morphologic features, increased corneal thickness, or corneal failures were found during the 24-month follow-up period. A prospective head-to-head comparison to assess the effects of the various methods of tube-shunt implantation on the corneal endothelium is needed.

Determinants of corneal endothelial cell loss after sulcus placement of Ahmed and Baerveldt drainage device surgery

AIM

In patients who underwent multiple intraocular surgeries, we evaluated determinants of decreased corneal endothelial cell density (CECD) after sulcus placement following Ahmed and Baerveldt drainage device surgery.

METHODS

We retrospectively reviewed consecutive patients with glaucoma who underwent sulcus placement with an Ahmed glaucoma valve or a Baerveldt glaucoma implant. We compared presurgical and postsurgical CECD and risk factors for decreased CECD.

RESULTS

We examined 41 eyes of 41 patients. Postsurgical CECD measurements were assessed 2.0±1.0 times during a median follow-up period of 28 months. The mean intraocular pressure (IOP) decreased from 28.4±11.6 mmHg to 12.2±5.3 mmHg 24 months after the operation. At 24 months, CECD decreased 14.6±5.4% after considering the variability in the number and time points of CECD determinations. History of prior surgery and higher preoperative IOP were significantly associated with a trend for a time-dependent decrease in CECD.

CONCLUSIONS

Risk factors for decreased CECD after sulcus placement during Ahmed and Baerveldt drainage device surgery included the number of previous intraocular surgeries and higher presurgical IOP.

Effect of glaucoma drainage implant surgery on corneal topography: a prospective study

PURPOSE

To study the effect of glaucoma drainage implant (GDI) surgery on corneal topography during the first postoperative year.

METHODS

Twenty-one adult glaucoma patients were implanted with a Molteno3 or a Baerveldt 250 GDI. Corneal topography measurements were taken preoperatively and at 6 and 12 months after surgery. Untreated opposite eyes served as controls.

RESULTS

In the surgical group, the mean ± SD simulated average keratometry values were 44.36 ± 1.69 D, 44.08 ± 1.29 D (p = 0.266) and 44.15 ± 1.32 D (p = 0.554) before and 6 and 12 months after surgery, respectively. The corresponding simulated keratometry astigmatism values were 1.11 ± 1.11 D, 1.20 ± 1.01 D (p = 0.687) and 1.16 ± 0.71 D (p = 0.177). Posterior astigmatism and posterior average keratometry remained unchanged after GDI surgery as well. The mean ± SD central corneal thickness (CCT) was 530 ± 46 μm, 535 ± 56 μm (p = 0.049) and 536 ± 45 μm (p = 0.080) at 0, 6 and 12 months, respectively. A trend towards increased corneal thickness (CT) in response to GDI surgery was also seen in both the average peripheral and the tube-quadrant peripheral CT values. At 12 months postoperatively, the mean endothelial cell density (ECD) had decreased by 8% centrally and by 9% peripherally. Corneal topography parameters, CT and ECD did not significantly change in the control group during follow-up.

CONCLUSION

Glaucoma drainage implant (GDI) surgery did not significantly alter corneal keratometry parameters and thus seems to be an astigmatically neutral procedure. However a slight, although seemingly transient, increase in CCT was observed after GDI implantation.

Ab interno implantation of glaucoma drainage devices tubes in the posterior chamber

Background

Glaucoma drainage device (GDD) implantation in the anterior chamber are associated with corneal complications. We describe a novel technique to implant GDD tubes in the posterior chamber of pseudophakic eyes.

Methods

Ten patients with glaucoma who required GDD tube implantation were included.

Results

The new technique begins with the passage of one of two straight needles existing at each end of a 10–0 Polypropylene suture through the GDD tube. A 23-gauge needle then is inserted at an angle 180° away and passed from the anterior to the posterior chamber and finally through the sclera. The two suture straight needles from the 10–0 Polypropylene suture are positioned in the lumen of the 23-gauge needle. The 23-gauge needle is then extracted from the eye by passing the 2 needles through the lumen. The suture remains inside the posterior chamber, and the tube is inserted into the posterior chamber by pulling on the suture from the other side. No intra-operative complications were found such as bleeding, vitreous tube placement, bent tubes, etc.

Conclusions

This surgical procedure to implant a tube into the posterior chamber of the pseudophakic eyes is uncomplicated and facilitates the insertion of the flexible tube into the posterior chamber. This eliminates the tendency of the tube to enter the vitreous as the tube is always placed in the posterior chamber away from the cornea.

Trial registration

Current Controlled Trials ISRCTN14276553 (31th May, 2019) Retrospectively registered.

Improved Interchangeability with Different Corneal Specular Microscopes for Quantitative Endothelial Cell Analysis

Introduction

During our clinical practice and research, we encountered an interchangeability problem when using the SP-2000P and SP-3000P TopCon corneal specular microscopes (CSMs) (TopCon Medical Systems, Tokyo, Japan) regarding the endothelial cell count (ECC). We describe a method to improve interchangeability between these CSMs.

Methods

Five consecutive good-quality endothelial cell photographs were obtained in 22 eyes of 11 subjects. An ECC comparison between the two CSMs was performed after (I) gauging and calibration by the manufacturer, (II) adjustment of the magnification, (III) correction after external horizontal and vertical calibration.

Results

There was a statistically significant difference between the ECC of the SP-2000P and SP-3000P at the start. The SP-2000P counted an average of 500 cells/mm² more than the SP-3000P (p=0.00). After correction for magnification and determining a correction factor based on external calibration, the difference between the ECC of the SP-2000P and the SP-3000P was then found to be 0.4 cells/mm² and was not statistically significant (p=0.98).

Discussion

We propose a method for improving interchangeability, which involves checking magnification settings, re-checking magnification calibration with external calibration devices, and then calculating correction factors. This method can be applied to various specular or confocal microscopes and their associated endothelial cell analysis software packages to be able to keep performing precise endothelial cell counts and to enable comparison of ECCs when a CSM needs to be replaced or when results from different microscopes need to be compared.

Evaluating glaucoma surgeries in the MIGS context

The challenges of glaucoma management are many: the disease is chronic, progressive, often asymptomatic, and very often, the quality of life and costs of treatment is unacceptable to the patient. This is true for both medical therapy and conventional glaucoma surgery. The choice of therapy, especially the transition from the former to the latter, is now being bridged by Minimally Invasive Glaucoma Surgeries (MIGS). Choosing from the several options now available in the surgical armamentarium requires a deeper understanding of the available modalities. This review aims to provide an overview of the decision-making process, keeping in mind age, type of glaucoma, life expectancy, socioeconomic status, patient expectations, and coexisting cataract.

Corneal Endothelial Cell Loss and Morphometric Changes 5 Years after Phacoemulsification with or without CyPass Micro-Stent

PURPOSE

To characterize long-term changes in corneal endothelial cells after phacoemulsification with or without supraciliary Micro-Stent (Alcon) implantation in eyes with open-angle glaucoma (OAG) and visually significant cataract.

DESIGN

Three-year safety extension of a 2-year randomized clinical trial.

METHODS

Patients from the multicenter Study of an Implantable Device for Lowering Intraocular Pressure in Glaucoma Patients Undergoing Cataract Surgery (COMPASS) trial who underwent Micro-Stent implantation plus phacoemulsification (n = 282) or phacoemulsification alone (n = 67) were analyzed post hoc. Specular microscopy was used to assess endothelial cell loss (ECL), including changes from baseline in endothelial cell density (ECD), coefficient of variation, and percentage of hexagonal cells.

RESULTS

Preoperative ECDs in the microstent group (2,432.6 cells/mm² [95% confidence interval [CI], 2,382.8-2,482.4 cells/mm²]) were similar to those in the control group (2,434.5 cells/mm² [95% CI, 2,356.5-2,512.4 cells/mm²]) groups. ECL at months 48 and 60 was greater in the Micro-Stent group than in the control group. At month 60, the mean percent of changes in ECD was -20.4% (95% CI, -23.5% to -17.5%) in the Micro-Stent group and -10.1% (95% CI, -13.9% to -6.3%) in the control group. No statistically significant between-group changes from baseline in cellular morphology were observed. Nine adverse events were possibly related to ECL, including 3 eyes with transient focal corneal edema and 4 eyes that required Micro-Stent trimming due to protrusion.

CONCLUSIONS

In eyes with OAG, ECL after phacoemulsification is acute and stabilizes after 3 months, whereas ECL after phacoemulsification plus Micro-Stent implantation proceeds for at least 5 years. Clinical findings associated with ECL in these eyes were uncommon (3.3% of implanted eyes), suggesting that ECL is generally a subclinical phenomenon.

Effects of Baerveldt Glaucoma Implant Surgery on Corneal Endothelial Cells of Patients with No History of Trabeculectomy

Purpose

Persistent corneal edema is a serious potential complication of Baerveldt glaucoma implant (BGI) surgery. A trabeculectomy reduces the density of corneal endothelial cells. We investigated the effect of BGI surgery on corneal endothelial cells of patients with no history of trabeculectomy.

Methods

We retrospectively analyzed 85 eyes of 85 patients who underwent BGI surgery and were followed-up for ≥12 months. We used new criteria for surgical failure. We defined persistent corneal edema or needed additional surgery for changing the tube position due to remarkable reduction in corneal endothelial cells as failure. We compared surgical outcomes with new criteria and the rates of corneal endothelial cell density (ECD) loss after BGI surgery between the anterior chamber insertion (AC) group (n=23) and vitreous cavity insertion (VC) group (n=63).

Results

The mean pre-operative ECD values of the AC and VC groups were not significantly different at 2309 ± 498 and 2204 ± 556 (p=0.426). The ECD reduction rate in the AC group was significantly faster than in the VC group. The mean post-operative IOP values significantly decreased in both groups. However, the VC group's surgical outcomes were significantly better than the AC group's (p=0.0241) with the new criteria.

Conclusion

The mean of ECD did not decrease significantly after BGI surgery in VC group patients with no history of trabeculectomy. BGI surgery insertion to the vitreous cavity was safe and had much less effect on the ECD decrease compared to insertion to the anterior chamber.

The Quest for the Holy Grail of Glaucoma Surgery: Does Cypass Herald the End?

How to cite this article: Bhartiya S, Shaarawy T. The Quest for the Holy Grail of Glaucoma Surgery: Does Cypass Herald the End?. J Curr Glaucoma Pract 2018;12(3):99-101.

Changes in symmetry of anterior chamber following routine cataract surgery in non-glaucomatous eyes

Background

To assess minimum and maximum changes in anterior chamber dimensions following routine cataract surgery in non-glaucomatous eyes.

Methods

Forty-two eyes (42 participants) underwent routine cataract surgery with same surgeon and were assessed preoperatively, 1, 3, 6 and 12 months postoperatively. Primary outcome measure: Angle-to-angle diameter (AAD) (at 0-180^o, 45-225^o, 90-270^o, 135-315^o), Anterior-chamber-angle (ACA) (at 0^o, 45^o, 90^o, 135^o, 180^o, 225^o, 270^o and 315^o) and central anterior chamber depth (ACD) at all visits. Secondary outcome measures: relationship to axial length (AL).

Results

The mean AAD and ACA increased post-operatively in all meridians at all visits postoperatively. At 12 months, there was a maximum change in AAD in horizontal meridian (506.55 ± 468.71 μm) and least in vertical meridian (256.31 ± 1082.3 μm). The mean percentage increase in ACA postoperatively was least at 90^o (5% increase compared to 29–35% elsewhere). Central ACD deepened at all postoperative visits and this did not change over 12 months. There was no correlation between AAD, ACA and ACD with AL at any visit.

Conclusion

The AAD, ACA and ACD increases following cataract surgery in non-glaucomatous eyes, but at 12 months increase in AAD is least in vertical compared to horizontal meridian. Also, ACA was narrower (only 5% increase) superiorly compared to elsewhere (29–35% increase in ACA). This may have implications with regards to surgeries performed in the anterior chamber and corneal endothelial cell loss.