Graft Survival after Penetrating Keratoplasty in Cases of Trabeculectomy versus Ahmed Valve Implant

Impact of Glaucoma Surgery on Corneal Graft Survival After Keratoplasty: A Systematic Review and Meta-Analysis

PRCIS

Glaucoma surgery impacts corneal graft survival differently by procedure type, with GDDs being most effective at reducing intraocular pressure. However, graft survival rates are comparable across trabeculectomy, CPC, and GDDs. Trabeculectomy improves visual acuity best but often requires additional interventions.

PURPOSE

To investigate the impact of different glaucoma procedures on corneal graft survival and corneal endothelium health.

METHODS

We searched PubMed, Cochrane Library, Scopus, and Web of Science, to identify eligible studies. Studies were included based on predetermined criteria. The primary outcome was corneal graft survival, and secondary outcomes included intraocular pressure (IOP) control, visual acuity, antiglaucoma medications, additional glaucoma surgery, and postoperative complications. Meta-analyses were conducted using random-effects models, and heterogeneity was assessed using the ( I2 ) test.

RESULTS

Our results included 27 studies involving 905 patients were analyzed. However, there were no randomized comparative studies. The overall proportion of corneal graft survival at the last follow-up was 66.4%, with the 3 subgroups of trabeculectomy, cyclophotocoagulation (CPC), and Glaucoma drainage devices (GDD) showing similar survival rates of 66.6%, 64.8%, and 65.6%, respectively. Short-term graft survival (6 mo) was similar across groups; however, 2-year survival favored trabeculectomy. GDDs were the most effective in reducing IOP with an average reduction of 21.4 mmHg compared with 18.9 mmHg for trabeculectomy and 14.8 mmHg for CPC. CPC yielded the best improvement in visual acuity reported as BCVA. GDD required the fewest postoperative antiglaucoma medications. Trabeculectomy had the highest proportion of patients needing additional surgery for glaucoma. The most common complications were hypotony, uveitis, and tube obstruction.

CONCLUSION

There were no significant differences in corneal graft survival rates among various glaucoma surgical techniques, but these findings must be interpreted with caution due to the limitations of primary research. GDDs effectively reduced IOP and minimized the need for antiglaucoma medications. Trabeculectomy may be associated with the greatest visual acuity improvement but may carry a higher likelihood of requiring further glaucoma surgery.

A systematic review and network meta-analysis of surgical interventions for glaucoma following penetrating keratoplasty

This study aims to compare the effectiveness and safety of surgical interventions for secondary glaucoma following penetrating keratoplasty (PKP) through a network meta-analysis. PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, Scopus, and Google Scholar databases were searched for articles published from inception to July 16, 2024. We included studies that compared the effects of trabeculectomy, glaucoma drainage devices (GDDs), or cyclophotocoagulation (CPC) on graft failure, intraocular pressure (IOP), or the number of glaucoma medications required for patients with post-PKP glaucoma. Based on data synthesized from 13 cohort studies, we observed that valved GDDs are not associated with a higher risk of graft failure (risk ratio [RR], 1.49; 95% confidence interval [CI], 0.89 to 2.48) compared with trabeculectomy with antifibrotic agents. Valved GDDs demonstrated greater benefits in achieving successful IOP control (RR, 1.33; 95% CI, 1.08 to 1.64), reducing IOP from baseline (mean difference [MD], - 3.08; 95% CI, - 5.36 to - 0.81), and reducing the number of glaucoma medication usage from baseline (MD, - 0.53; 95% CI, - 0.94 to - 0.12) compared with trabeculectomy with antifibrotic agents. In conclusion, valved GDDs may be the preferred surgical option for managing post-PKP glaucoma.

Risk Factors for Progression of Graft Rejection to Graft Failure Following Penetrating Keratoplasty

PURPOSE

To analyze the risk factors for graft failure in eyes with endothelial graft rejection following penetrating keratoplasty (PK).

METHODS

Single-center, retrospective study that included patients who underwent PK at Wills Eye Hospital (2007-2018) who later presented with endothelial graft rejection, defined as clinical appearance of keratic precipitates or anterior chamber reaction. Among patients with rejection across multiple grafts, only the first PK of the first eye with documented rejection was included. The primary outcome measures were progression to graft failure, defined as irreversible and visually significant stromal edema, haze, or scarring, and acute graft failure, defined as failure within 6 months of rejection.

RESULTS

296 eyes from 296 patients were included with mean age of 54.4 ± 21.3 years. Average follow-up duration was 4.5 ± 2.9 years and rejection occurred 16.2 ± 18.7 months after transplantation. The rate of graft failure was 45.9% and the rate of acute failure was 31.4%. Predictors of failure after rejection included history of systemic autoimmune disorders (OR = 8.99, 95% CI = 2.03-39.77, p = 0.004), prior glaucoma surgery (OR = 2.73, 95% CI = 1.05-7.11, p = 0.039), and postoperative lens status as aphakia (OR = 7.59, 95% CI = 1.00-57.52, p = 0.0497). Predictors of acute graft failure after rejection included history of systemic autoimmune disorders (OR = 4.69, 95% CI = 1.20-18.33, p = 0.026), active microbial infection (OR = 3.52, 95% CI = 1.69-7.31, p = 0.001), and prior glaucoma surgery (OR = 3.50, 95% CI = 1.42-8.62, p = 0.006).

CONCLUSION

Systemic autoimmune disorders and prior glaucoma surgery predicted both overall and acute graft failure, suggesting more aggressive rejection episodes in these cohorts.

Efficacy and Safety of Ab-Interno Canaloplasty in Post-Keratoplasty Patients: 3-Year Results

Purpose

To evaluate the effectiveness and safety of ab-interno canaloplasty (ABiC) for managing intraocular pressure (IOP) in patients following keratoplasty over a three-year period.

Methods

This retrospective analysis focused on post-keratoplasty patients treated with ABiC with the iTrack microcatheter (Nova Eye Medical, Fremont, CA, USA) at a single institution. The study assessed the procedure's impact on IOP control, graft survival, and reliance on topical hypotensive medications, with additional observation for any postoperative complications. Surgical success criteria included the percentage of eyes with IOP ≤15 mmHg, IOP ≤18 mmHg, ≥20% IOP reduction, medication-free eyes, and eyes with concurrent IOP and medication reductions.

Results

ABiC was performed successfully in a cohort of 16 post-keratoplasty (7 penetrating keratoplasty and 9 endothelial keratoplasty (EK)) eyes. Preoperative mean IOP of 25.8±7.2 mmHg was significantly reduced to 13.4±2.9 mmHg (p<0.001) at 1 year postoperatively and maintained at 13.1±3.9 mmHg (p=0.009) at 3 years postoperatively. The mean number of glaucoma medications was 3.5±1.7 at baseline, 2.8±1.3 at 1 year (p=0.107), and 2.5±1.2 at 3 years postoperatively (p=0.088). Eight eyes (66.7%) maintained IOP ≤ 15 mmHg, and 10 eyes (83.3%) maintained ≥ 20% IOP reduction at 3 years. The mean IOP and medication reductions from baseline at 3 years were -49.2% and -28.6%, respectively. Graft clarity was preserved in all patients except for one case of late graft failure that necessitated a repeat EK procedure. Post-ABiC complications included transient hyphema in two patients, neither of which led to long-term adverse outcomes.

Conclusion

ABiC appears to be an effective and safe surgical intervention for sustained IOP reduction in post-keratoplasty patients. Graft survival trends are encouraging, and there was a low incidence of complications over a three-year follow-up period.

Outcomes of XEN Stent in Patients With Glaucoma and Previous Corneal Transplantation

PRCIS

The XEN stent safely and effectively controls intraocular pressure in select patients with history of corneal transplantation.

PURPOSE

Glaucoma is a common complication after corneal transplantation and can be difficult to manage in these patients. This study reports outcomes of XEN stent implantation in eyes with glaucoma in the setting of previous corneal transplantation.

PATIENTS AND METHODS

Noncomparative retrospective case series including eyes with a history of corneal transplantation and subsequent XEN stent implantation by a single glaucoma surgeon in Surrey, British Columbia, between 2017 and 2022. The analysis included patient demographics, pre and postoperative intraocular pressure (IOP), pre and postoperative glaucoma medications, peri and postoperative complications and interventions, and incidence of repeat corneal transplantation and additional glaucoma procedures to control IOP.

RESULTS

Fourteen eyes with previous cornea transplantation underwent XEN stent implantation. Mean age was 70.1 years (range: 47-85 y). Mean follow-up was 18.2 months (range: 1.5-52 mo). The most common glaucoma diagnosis was secondary open angle glaucoma (50.0%). There was a significant reduction in IOP and the number of glaucoma agents at all postoperative time points ( P < 0.05). IOP decreased from 32.7 ± 10.0 mm Hg at baseline to 12.5 ± 4.7 mm Hg at the most recent follow-up. Glaucoma agents decreased from 4.0 ± 0.7 to 0.4 ± 1.0. Two eyes required additional glaucoma surgery to control IOP, with an average time to reoperation of 7 weeks. Two eyes underwent repeat corneal transplantation, with an average time to reoperation of 23.5 months.

CONCLUSIONS

In selected patients with previous corneal transplants and refractory glaucoma, the XEN stent was safely implanted and effectively reduced IOP in the short term.

Surgical Management of Intraocular Pressure With Ab Interno Canaloplasty in Postkeratoplasty Patients: 12-Month Results

PURPOSE

The purpose of this study was to report clinical outcomes of ab interno canaloplasty (ABiC) with the iTrack microcatheter (Nova Eye Medical, Fremont, CA) for surgical management of intraocular pressure (IOP) in postkeratoplasty patients.

METHODS

This study was a single-center retrospective case series of postkeratoplasty eyes undergoing ABiC. Efficacy was evaluated based on graft survivability and mean reduction in IOP at 12 months postoperatively. Secondary end points consisted of visual acuity outcomes, number of topical hypotensive medications, and rate of complications.

RESULTS

ABiC was successfully performed in 17 eyes after keratoplasty (8 penetrating keratoplasty, 6 DSAEK, 2 penetrating keratoplasty + DSAEK, and 1 DMEK) with elevated IOP refractory to topical hypotensive medications. The baseline mean IOP was 26.2 ± 8.4 mm Hg and reduced significantly to 15.0 ± 4.21 mm Hg at 6 months and 13.0 ± 2.99 mm Hg at 12 months ( P < 0.005). The best-corrected visual acuity improved from 0.61 ± 0.55 logMAR at baseline to 0.47 ± 0.59 and 0.49 ± 0.64 at 6 and 12 months, respectively, following ABiC (not statistically significant: P = 0.6769). The baseline mean number of topical hypotensive medications was 3.7 ± 1.8 and reduced to 2.7 ± 1.4 and 2.9 ± 1.3 at 6 and 12 months, respectively ( P = 0.096). One patient developed a hyphema which required anterior chamber washout. One patient required additional glaucoma surgery 19 months after ABiC. No patients experienced graft failure.

CONCLUSIONS

ABiC is a clinically safe and effective treatment that can be performed in postkeratoplasty patients to reduce IOP for at least 1 year without any significant complications.

Surgical management of glaucoma following different keratoplasty techniques

PURPOSE

To investigate the results of surgical management of glaucoma following different keratoplasty techniques.

METHODS

Medical records of 628 cases who underwent keratoplasty were reviewed. One hundred and eighty-eight patients (29.9%) who developed post-keratoplasty glaucoma were evaluated. Patients who could not be controlled with maximal medical treatment and underwent glaucoma surgery were included in this study. Trabeculectomy, Ahmed glaucoma valve (AGV) implantation or diode laser cyclophotocoagulation (DLC) were applied.

RESULTS

Glaucoma surgery was performed in 55 (29.3%) patients who had uncontrolled post-keratoplasty glaucoma. In penetrating keratoplasty group (n = 42), DLC was applied to 30 (71.4%) eyes, AGV to 11 (26.2%) eyes, and trabeculectomy in 1 (2.4%) eye. In Descemet's membrane endothelial keratoplasty group (n = 8), DLC was applied to 4 (50%) eyes, trabeculectomy for 3 (37.5%) eyes and AGV for 1 (12.5%) eye. In deep anterior lamellar keratoplasty group (n = 5), DLC was applied to 2 (40%) eyes, trabeculectomy to 2 (40%) eyes and AGV to 1 (20%) eye. While a statistically significant decrease was found in intraocular pressure (IOP) and anti-glaucomatous medication after surgery (p < 0.05 for each), no significant difference was found in best corrected visual acuity (BCVA). During follow-up, DLC was applied as re-glaucoma surgery in 19 (34.5%) cases. A significant reduction in IOP together with number of anti-glaucomatous medications was found with re-operation; however, a significant decrease in BCVA was noted (p < 0.05 for each).

CONCLUSION

Glaucoma surgeries after keratoplasty are effective in decreasing IOP and the number of anti-glaucomatous medication. While BCVA doesn't change after the first glaucoma surgery, after re-operation significant decrease may occur.

Clinical Outcomes in Maximum Tolerated Medical Therapy in Penetrating Keratoplasty for Bullous Keratopathy

Purpose

To compare the clinical outcomes of maximum tolerated medical therapy (MTMT) in patients with penetrating keratoplasty (PKP) with those of Ahmed glaucoma valve (AGV) implantation.

Methods

The medical records were retrospectively reviewed in patients who had undergone PKP for bullous keratopathy and were treated with MTMT or AGV implantation for the management of glaucoma. A total of 18 bullous keratopathic patients were investigated between January 2010 and February 2017: 9 patients treated with MTMT and 9 patients treated with AGV implantation. Non-corrected visual acuity (NCVA), intraocular pressure (IOP), endothelial cell density (ECD), hexagonality, coefficient of variation (CV), central corneal thickness (CCT), median survival time of the graft, and the presence of epithelial keratopathy were compared between the groups at each time point or between baseline and after treatment of glaucoma in each group.

Results

There were no significant differences in the visual acuity and corneal thickness between the two groups or within each group over time. Both groups showed a significant reduction in IOP compared with the baseline IOP, and IOP reductions were greater in the AGV group than in the MTMT group (p = 0.040). Significant ECD reductions were found in each group between the baseline and 6 months (p = 0.008 in the MTMT group, p = 0.015 in the AGV group); however, no differences were found between the two groups until 12 months. The significant hexagonality reduction was found in the AGV group between the baseline and 12 months (p = 0.018). The median survival time showed no significant difference in the survival analysis.

Conclusions

Maximum tolerated medical therapy in penetrating keratoplasty for bullous keratopathy seems to similarly affect the endothelial cell density or graft survival when compared with at least 12 month-followed Ahmed glaucoma valve implantation.

Comparison of long-term outcomes of trabeculectomy and risk factors for failure in eyes post penetrating keratoplasty or Descemet's stripping endothelial keratoplasty

Purpose:

To evaluate the outcomes of trabeculectomy, graft survival, and risk factors for failure in post penetrating keratoplasty (PK) and Descemet’s stripping endothelial keratoplasty (DSEK) eyes.

Methods:

We reviewed charts of eyes that underwent trabeculectomy for post keratoplasty glaucoma PK [25 eyes] and DSEK [14 eyes] between 1993 and 2019. The demographics, clinical features, and surgical outcomes were evaluated. Success of trabeculectomy was defined as complete when the intraocular pressure (IOP) was >5 and ≤21 mmHg without antiglaucoma medications (AGM) and qualified with AGM. Clear and compact graft was considered for graft success.

Results:

Median (interquartile range [IQR] preoperative IOP in post-PK eyes and post-DSEK eyes was comparable, 32 (28–38) vs. 31.5 (25–36) mmHg, P = 0.38). Median number of preoperative AGMs was comparable (P = 0.78). Median postoperative follow-up was longer in post-PK, compared with post-DSEK, 2.5 (1.3–3.3) vs. 1 (0.3–2.9) years (P = 0.05). Kaplan–Meier survival estimates for complete and qualified success of trabeculectomy at 3 years were 23.7% and 73.3%, respectively, for PK and 45.8% and 71.6%, respectively, for DSEK. Kaplan–Meier survival estimates for graft survival were 91.8% up to 3 years for PK and 100% until 2 years and 77.8% at 3 years for DSEK. Higher IOP prior to trabeculectomy was a risk factor for failure of trabeculectomy (P = 0.03) and older age was a risk factor for graft failure (P = 0.05) in PK eyes. Number of prior corneal surgeries (P = 0.05) was associated with failure of trabeculectomy and graft failure in post-DSEK eyes.

Conclusion:

Trabeculectomy had moderate qualified success in post-PK and DSEK eyes at 3 years. Higher pretrabeculectomy IOP and higher number of prior corneal surgeries were significantly associated with failure of trabeculectomy in PK and DSEK eyes, respectively.

[Descemet membrane endothelial keratoplasty after implantation of glaucoma drainage devices]

Secondary decompensation of corneal endothelium, including transplanted, is a frequent long-term complication of glaucoma drainage surgery. According to literature data, after implantation of a glaucoma drainage device into the anterior chamber, the speed of endothelial cells density (ECD) loss increases significantly.

PURPOSE

To study the possibility of performing modified Descemet membrane endothelial keratoplasty (DMEK) with maximum graft diameter, and to assess its short-term effectiveness in the treatment of bullous keratopathy (BK) in the presence of a glaucoma drainage device in the anterior chamber.

MATERIAL AND METHODS

Modified surgery ³/₄-DMEK was performed in 9 eyes of 7 patients with BK and Ahmed glaucoma drainage using graft of maximum diameter (11±1 mm). Average follow-up time was 15.3±2.5 months (12 to 18 months).

RESULTS

No intraoperative or postoperative complications were observed. Mean ECD after 12 months amounted to 1664±346 cells/mm², which corresponds to ECD reduction of 34±9.6% (24 to 49%) in comparison to preoperative values. Mean best corrected visual acuity 12 months after surgery increased from 0.04±0.03 (0.01 to 0.1) to 0.3±0.2 (0.04 to 0.7). The last follow-up examination revealed all corneas to have preserved transparency and stable pachymetry measurements (from 488 to 548 µm).

CONCLUSION

Performing ³/₄-DMEK with a mega graft for treatment of BK after drainage surgery is technically possible. Absence of Descemet membrane (DM) donor and preservation of DM recipient in the drainage tube plane eliminates its contact with the endothelium. Maximum graft diameter should in the long term help prolong the effectiveness of the surgery.

Three-quarter DMEK in eyes with glaucoma draining devices to avoid secondary graft failure

PURPOSE

To present a case series of a modified three-quarter Descemet's membrane endothelial keratoplasty (3/4-DMEK) technique to treat pseudophakic bullous keratopathy in the presence of a glaucoma drainage device (GDD) tube in the anterior chamber by reducing the risk of donor endothelial damage due to absence of donor endothelial cells overlying the GGD tube area.

METHODS

In this prospective case series, four eyes of three patients with stable glaucoma underwent 3/4-DMEK surgery for pseudophakic bullous keratopathy after GDD insertion. The patients were followed up to 24 ± 2.5 months postoperatively.

RESULTS

No intraoperative or postoperative complications were noted. The average central endothelial cell density (ECD) was 1093 ± 74 cells/mm² at 12 months postoperatively, corresponding to an ECD decrease of 58 (±6)% as compared to preoperative values. Average best-corrected visual acuity increased from finger counting before surgery to 20/60 (logMar 0.5) at 12 months after 3/4-DMEK and remained stable up to 24 months postoperatively. All corneas remained clear at the last available follow-up.

CONCLUSION

This case series demonstrates the technical feasibility of 3/4-DMEK in eyes with pseudophakic bullous keratopathy in the presence of a GDD tube. The absence of a donor DM and donor cells above the silicone tube excludes direct tube contact with the graft. Longer term studies are needed to show the effect of this modified graft pattern and dimensions on transplant survival.

Corneal transplant survival rate in glaucoma patients with multiple previous antiglaucoma surgeries

BACKGROUND

Glaucoma can cause corneal decompensation and accelerate the failure of the graft. Previous antiglaucoma operations are one of the most important risk factors for endothelial failure.

METHODS

In this retrospective study, 40 eyes of 40 glaucoma patients with advanced corneal decompensation after glaucoma surgery were treated with keratoplasty and outcomes were assessed for 24 months.

RESULTS

16, 9 and 15 eyes underwent Descemet Membrane Endothelial Keratoplasty (DMEK), Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) and penetrating keratoplasty (pKPL), respectively. Visual acuity improved at least 2 lines in 24 of 40 eyes after the three types of keratoplasty. All 40 eyes remained pain free for the follow-up period. The mean intraocular pressure (IOP) difference was not significantly different (p > 0.05) from the preoperative values 12 and 24 months after keratoplasty. The endothelial cell density of the donor cornea decreased from 2485.6 ± 165.18 to 1291.4 ± 467.1 and 1180.4 ± 397.2/mm² (p < 0.001) after 12 and 24 months, respectively. Nine eyes (22.5%) had therapy-resistant corneal decompensation in the context of a transplant failure and were treated with a re-keratoplasty (2 re-pKPLs, 3 re-DSAEKs and 3 re-DMEKs).

CONCLUSIONS

Eyes with previous glaucoma surgery show satisfying results after keratoplasty, mainly DMEK and pKPL.

Xen Gel Stent as a minimally invasive option for intraocular pressure control after DSAEK: A case study

PURPOSE

This case study describes the implantation of a Xen45 Gel Stent in a patient that had previously undergone Descemet stripping automated endothelial keratoplasty (DSAEK). Glaucoma might worsen after corneal transplant, and while medical treatment is the first-line therapy to achieve intraocular pressure (IOP) control, a surgical approach is required when medication does not reach the target IOP.

METHODS

In 2017, the patient underwent treatment in both eyes with ocular hypotensive eye drops for pseudoexfoliative (PXF) glaucoma. In May 2017, DSAEK was performed on the right eye because of the presence of a pseudophakic bullous keratopathy. An increase in IOP, resistant to medical treatment, was observed after the corneal transplant. In November 2017, a Xen45 Gel Stent was implanted.

RESULTS

The patient had a positive outcome with a Xen45 Gel Stent implant in surgical glaucoma treatment after DSAEK. The case demonstrated excellent postoperative IOP control, stable vision and a healthy ocular graft at short-term and long-term follow-ups.

CONCLUSION

Studies with larger numbers of patients in this particular form of therapy are required. Nevertheless, Xen45 Gel Stent implantation appears to be a promising option in preventing or limiting glaucoma in patients who have previously undergone DSAEK. It is a brief, minimally invasive procedure with reduced postoperative inflammation, faster visual recovery and a lower risk of graft damage or hypotony, even in the case of PXF glaucoma.

Pars plana vitrectomy combined with penetrating keratoplasty and transscleral-sutured intraocular lens implantation in complex eyes: a case series

BACKGROUND

The aim of this study was to evaluate the clinical outcomes of pars plana vitrectomy (PPV) combined with penetrating keratoplasty (PKP) and transscleral-sutured intraocular lens (IOL) implantation (IOL-suture) in complex eyes.

METHODS

In this prospective, consecutive interventional case series, patients who underwent PKP combined with PPV and IOL implantation from July 2014 to March 2018 at Yokohama Minami Kyosai Hospital were enrolled. The postoperative best corrected visual acuity (BCVA) (converted to logarithm of the minimal angle of resolution [logMAR] units), intraocular pressure (IOP, mmHg), endothelial cell density (ECD, cells/mm²), graft survival, complications, astigmatism, and spherical equivalent (dioptres [D]) were evaluated.

RESULTS

This study included 11 eyes of 11 patients (three females and eight males; mean age, 61.8 ± 13.9 years) with an injury (n = 6) or bullous keratopathy (n = 5). The BCVA significantly improved from 1.50 ± 0.66 logMAR preoperatively to 0.78 ± 0.59 logMAR (p < 0.001) postoperatively. The baseline ECD significantly decreased from 2396 ± 238 cells/mm² preoperatively to 1132 ± 323 cells/mm² (p < 0.001) postoperatively. Despite two rejection episodes, graft survival rates were 100%. The mean follow-up period was 38.0 ± 20.5 months. Two patients required combined glaucoma surgery, and three patients underwent subsequent glaucoma surgery. Postoperative astigmatism and spherical equivalent were 3.9 ± 3.2 D and 0.29 ± 2.18 D, respectively.

CONCLUSION

The combination of PKP, PPV, and IOL-suture implantation could be a safe and effective approach for eyes requiring anterior segment surgery; however, these eyes are associated with a higher incidence of glaucoma surgery.