Factors influencing the reduction in corneal endothelial cells after Ex-Press® surgery

Systematic Literature Reviews Comparing the Long-Term Safety Outcomes for the Port Delivery System with Ranibizumab (PDS) Versus Other Ocular Implants

OBJECTIVES

To determine whether the types and rates of post-surgical complications associated with the Port Delivery System with ranibizumab (PDS) are comparable with those reported for other ocular implants that cross the sclera.

METHODS

Systematic literature reviews were conducted to determine the long-term (≥ 18-month) safety of ocular implants that cross the sclera in clinical trials and real-world studies. Complication types and rates were compared with those reported for the PDS in phase III clinical trials (Archway, Pagoda, and Pavilion).

RESULTS

Sixteen clinical trials (24 publications) and 43 real-world studies were identified reporting 30 complications in eyes with 15 implant types and 8 ocular diseases. Implants were associated with an acceptable, well-characterized safety profile, with most complications resolving spontaneously or with treatment. Device-related complications were reported in 0.7% (0.0-5.0%) of study eyes in clinical trials and 1.3% (0.0-14.5%) of eyes in real-world studies. Rates of conjunctival complications were 2.1% (0.0-22.8%) and 2.2% (0.9-4.6%), respectively. The overall types and rates of adverse events of special interest reported for the PDS in phase III trials (cataract, conjunctival bleb, vitreous hemorrhage, conjunctival erosion, conjunctival retraction, endophthalmitis, implant dislocation, retinal detachment, and hyphema) were within the ranges reported for other ocular implants.

CONCLUSIONS

The rates of complications reported in phase III clinical trials for the PDS were within the ranges reported for other ocular implants that cross the sclera. This suggests that the long-term safety of the PDS is consistent with other ocular devices established in ophthalmology clinical practice.

TRIAL REGISTRATION

PROSPERO international prospective register of systematic reviews: CRD5202234129, CRD42022343129.

Corneal endothelial density loss in patients after gonioscopy‑assisted transluminal trabeculotomy

PURPOSE

To compare short-term changes in corneal endothelial cells after gonioscopy-assisted transluminal trabeculotomy(GATT).

METHODS

This retrospective comparative study included 138 patients(138 eyes), and 98 of these patients underwent GATT procedure and 40 underwent SLT procedure as a control group. Changes in the corneal endothelium in patients who underwent GATT and SLT were analyzed retrospectively. Endothelial changes in the central cornea were examined using specular microscopy before and 6 months after the GATT and SLT procedure. Intraocular pressure(IOP), number of glaucoma medications, and side effects were evaluated at visits before and after two methods.

RESULTS

One hundred and thirty-eight eyes of 138 patients with a mean age of 62.9±12.7 years in the SLT group and 62.5±11.8 years in the GATT group were included in this study. Pre-procedure mean ± SD IOP was 27.7±3.6 mmHg and 27.4±5.3 mmHg (p=0.173) 2.8±0.5 and 2.9±0.8 (p=0.204) glaucoma drugs are in the SLT and GATT group, respectively. The mean corneal endothelial cell density (CECD) in the SLT group was 2433.1±581.4 cells/mm2 before the procedure and 2435.1±585 cells/mm2 6 months after the procedure, a change of 0.1±0.6% which was not statistically significant (p>0.967).The mean CECD at baseline in the GATT group was 2443.4±508.2 cells/mm2 and decreased to 2290.2±527.7 cells/mm2 6 months after this procedure, representing a cell loss of 6,2±9,1% (p<0.001).

CONCLUSION

GATT caused more CECD damage than SLT at the sixth month after the procedure. Considering the loss of CECD in candidates for GATT, sufficient number of endothelial cells in the central cornea is recommended.

Corneal endothelial cell loss after EX-PRESS surgery depends on site of insertion, cornea or trabecular meshwork

PURPOSE

Previously, we reported that the Ex-press® shunt (EXP) was associated with more rapid reduction in corneal endothelial cells when inserted into the cornea rather than the trabecular meshwork (TM). We compared the reduction rate of corneal endothelial cells between the corneal insertion group and TM insertion group.

METHODS

This was a retrospective study. We included patients who had undergone EXP surgery and were followed for > 5 years. We analyzed the corneal endothelial cell density (ECD) before and after EXP implantation.

RESULTS

We included 25 patients in the corneal insertion group and 53 patients in the TM insertion group. One patient in the corneal insertion group developed bullous keratopathy. The ECD decreased significantly more rapidly in the corneal insertion group (p < 0.0001), in whom the mean ECD decreased from 2227 ± 443 to 1415 ± 573 cells/mm2 at 5 years with a mean 5-year survival rate of 64.9 ± 21.9%. By contrast, in the TM insertion group, the mean ECD decreased from 2356 ± 364 to 2124 ± 579 cells/mm2 at 5 years, and the mean 5-year survival rate was 89.3 ± 18.0%. The decrease rate of ECD was calculated as 8.3%/year in the corneal insertion group and 2.2%/year in the TM insertion group.

CONCLUSIONS

Insertion into cornea is a risk factor for rapid ECD loss. The EXP should be inserted into the TM to preserve the corneal endothelial cells.

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.

Long-Term Changes in Corneal Endothelial Cell Density after Ex-PRESS Implantation: A Contralateral Eye Study

Our purpose is to evaluate long-term changes in corneal endothelial cells after Ex-PRESS shunt implantation for the treatment of glaucoma in Chinese patients by comparison with the contralateral eye. In this retrospective observational study, glaucoma patients with a single eye undergoing Ex-PRESS shunt implantation surgery were consecutively enrolled. For each patient, the clinical assessment, including corneal endothelial cell density (CECD) before surgery and at 6, 12 months, and at last follow-up (2.43 ± 0.63 years) after surgery was reviewed. The operated eyes were in the study group and the unoperated contralateral eyes were used as the control group to compare the CECD change. A total of 48 subjects (age, 51.02 ± 17.96 years) were included. The follow-up period was 2.08~3.17 years, with an average of 2.43 ± 0.63 years. At the last follow-up after the surgery, the CECD decrease in the operated eyes (5.0%) was similar to that in the contralateral eyes (3.2%) (p = 0.130). There were no significant differences in CECD reduction between the two groups at baseline and each postoperative follow-up (6 months, 12 months and at the last follow-up) (all p > 0.05). The average IOP reduction after the surgery was 50.8%, and the number of IOP-lowering medications was significantly reduced (p < 0.05). In addition, visual acuity showed no significant differences during follow-up (p > 0.05). In this study, we found that the CECD reduction of Ex-PRESS shunt-implanted Chinese eyes was similar to that of contralateral eyes without surgery.

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.

Ex-PRESS® surgery versus trabeculectomy for primary open-angle glaucoma with low preoperative intraocular pressure

PURPOSE

To compare surgical outcomes between Ex-PRESS® surgery (EXP) and trabeculectomy (Trab) for primary open-angle glaucoma (POAG) with low preoperative intraocular pressure (IOP).

PATIENTS AND METHODS

This was a retrospective non-randomized study. We included POAG patients with preoperative IOP ≤ 16 mmHg who were taking tolerance glaucoma medications. We compared the surgical outcomes, postoperative IOP, number of glaucoma medications, reduction rate of corneal endothelial cell density (ECD), visual acuity, and postoperative complications between POAG patients who underwent EXP (34 eyes) or Trab (38 eyes) and could be followed up for > 2 years.

RESULTS

Both surgeries significantly decreased the IOP (p < 0.001): At 2 years, EXP provided decreases from 13.4 ± 2.3 to 10.2 ± 3.1 mmHg, and Trab provided decreases from 13.5 ± 2.0 to 8.9 ± 3.2 mmHg. No significant differences were observed in the postoperative IOP (p = 0.076), number of postoperative medications (p = 0.263), success rate (p = 0.900), reduction rate of ECD (p = 0.410), or difference in visual acuity (p = 0.174). The reduction rate of IOP was significantly high in the Trab group (p = 0.047).

CONCLUSIONS

Both surgeries significantly decreased IOP and were useful surgical methods for low-IOP glaucoma. Our results suggest that trabeculectomy can decrease IOP more than Ex-PRESS surgery but might have more complications.

The surgical management of glaucoma: A review

After a long period of little change, glaucoma surgery has experienced a dramatic rise in the number of possible procedures in the last two decades. Glaucoma filtering surgeries with mitomycin C and glaucoma drainage devices remain the standard of surgical care. Other newer surgeries, some of which are minimally or microinvasive glaucoma surgeries, target existing trabecular outflow, enhance suprachoroidal outflow, create subconjunctival blebs, or reduce aqueous production. Some require the implantation of a device such as the iStent, Hydrus, Ex-PRESS, XEN and PRESERFLO, whilst others do not-Trabectome, Kahook dual blade, Ab interno canaloplasty, gonioscopy-assisted transluminal trabeculotomy, OMNI and excimer laser trabeculotomy. Others are a less destructive variation of an established procedure, such as micropulse transscleral cyclophotocoagulation, endoscopic cyclophotocoagulation and ultrasound cycloplasty. Cataract surgery alone can be a significant glaucoma operation. These older and newer glaucoma surgeries, their mechanism of action, efficacy and complications are the subject of this review.

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.

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.

Ex-Press® versus Baerveldt implant surgery for primary open-angle glaucoma and pseudo-exfoliation glaucoma

PURPOSE

To compare surgical outcomes between Ex-Press^® (EXP) and Baerveldt glaucoma implant (BGI) surgeries for primary open-angle glaucoma (POAG) and pseudo-exfoliation glaucoma (PEXG) patients.

PATIENTS AND METHODS

This was a retrospective single-facility study. The inclusion criteria were that the patient's preoperative intraocular pressure (IOP) was > 21 mmHg and the post-surgery follow-up was > 1 year. We recruited 161 patients who had undergone a trabeculectomy with EXP (89 eyes) or BGI surgery (72 eyes). We compared these groups' postoperative IOP values and postoperative glaucoma medications, the reduction rate of corneal endothelial cell density (ECD), surgical outcomes, complications, the hospital stay duration, and the number of visits within 3 months post-surgery.

RESULTS

Both the EXP and BGI surgeries could significantly decrease the IOP. When the surgical success was defined postoperative IOP ≤ 21 mmHg, the surgical outcome of BGI was significantly better than EXP (p = 0.0148). When the surgical success was defined postoperative IOP ≤ 18, 15 , and 12 mmHg, the surgical outcomes between BGI and EXP surgeries were not significantly different (p = 0.0815, p = 0.331, and p = 0.910). The mean ECD reduction rate was significantly faster in the EXP group. The BGI patients had significantly shorter stays in the hospital and fewer visits within 3 months post-surgery (p < 0.0001).

CONCLUSIONS

BGI surgery could provide comparable surgical outcomes as EXP surgery for POAG or PEXG patients with high preoperative IOP. BGI surgery has some advantages: fewer post-surgery visits, less postoperative interventions, and a lower ECD reduction rate.

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.