Glaucoma management after corneal transplantation surgeries

Current concepts and recent trends in endothelial keratoplasty

Endothelial keratoplasty (EK) is defined as an umbrella term comprising methods for selective surgical replacement of corneal endothelium and adjacent corneal tissue, which retains healthy portions of a patient's cornea while replacing diseased innermost corneal layer(s) with healthy donor tissue, to achieve corneal dehydration and transparency before the onset of irreversible stromal edema and permanent loss of corneal clarity. Recently, the pathophysiology of corneal decompensation is increasingly being researched upon. Consequent improvement in pharmacotherapy is progressively leading to reduction in the indications of EK. In addition, EK techniques have progressed towards using thinner tissue, optimizing visual outcomes. Improvements have enabled better donor tissue formulation, usage, and attachment, and surgical modifications have enhanced the tissue utilization in difficult clinical scenarios lowering failure and rejection. However, challenges are encountered in various complex clinical scenarios including eyes with prior intraocular surgery, complex anterior chamber anatomy, glaucoma, ocular surface disease etc. These complexities demand tailored surgical strategies, including modifications in graft handling, instrumentation, and postoperative management to ensure success. Attention to these details and addressing patient-specific factors can help improve outcomes in these difficult cases. The choice of procedure depends on multiple factors, including the surgeon's experience, patient's ocular anatomy, and the specific clinical scenario. This review article encompasses the recent developments in this field presenting a comprehensive picture of our modern understanding of the indications, contraindications, surgical techniques, clinical situations, community aspects and future directions pertaining to EK.

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.

Endoplasmic Reticulum-Mitochondria Crosstalk in Fuchs Endothelial Corneal Dystrophy: Current Status and Future Prospects

Fuchs endothelial corneal dystrophy (FECD) is a progressive and debilitating disorder of the corneal endothelium (CE) that affects approximately 4% of individuals over the age of 40. Despite the burden of the disease, the pathogenesis of FECD remains poorly understood, and treatment options are limited, highlighting the need for deeper investigation into its underlying molecular mechanisms. Over the past decade, studies have indicated independent contributions of endoplasmic reticulum (ER) and mitochondrial stress to the pathogenesis of FECD. However, there are limited studies suggesting ER-mitochondria crosstalk in FECD. Recently, our lab established the role of chronic ER stress in inducing mitochondrial dysfunction for corneal endothelial cells (CEnCs), indicating the existence of ER-mitochondria crosstalk in FECD. This paper aims to provide a comprehensive overview of the current understanding of how ER and mitochondrial stress contribute to FECD pathogenesis. The paper also reviews the literature on the mechanisms of ER-mitochondria crosstalk in other diseases relevant to FECD.

Artificial Intelligence in Predicting Ocular Hypertension After Descemet Membrane Endothelial Keratoplasty

Purpose

Descemet membrane endothelial keratoplasty (DMEK) has emerged as a novel approach in corneal transplantation over the past two decades. This study aims to identify predisposing risk factors for post-DMEK ocular hypertension (OHT) and develop a preoperative predictive model for post-DMEK OHT.

Methods

Patients who underwent DMEK at Gangnam Severance Hospital between 2017 and 2024 were included in the study. Four machine learning models-XGBoost, random forest, CatBoost, and logistic regression-were trained to assess feature importance and develop a predictive classifier. An ensemble of these four models was used as the final predictive model. The ensemble model identified clinically significant patients for prediction or exclusion.

Results

A total of 106 eyes from patients who underwent DMEK were analyzed, with 31 eyes (29.2%) experiencing post-DMEK OHT. The final ensemble model achieved clinically significant classification for 61 eyes (57.5%) in the total patient population. Significant risk factors identified in all four models included angle recess area (ARA), best-corrected visual acuity, donor graft size, angle-to-angle distance, crystalline lens rise, and central corneal thickness. The average accuracy, precision, recall, area under the receiver operating characteristic curve, and area under the precision-recall curve values of the ensemble model obtained by a 5-fold cross-validation were 80.2%, 60.0%, 59.7%, 82.3%, and 68.0%, respectively.

Conclusions

This study identified significant risk factors for post-DMEK OHT and highlighted the importance of ocular topographic measures in risk assessment. The development of a final machine learning model to differentiate between clinically predictable patient groups demonstrates the clinical utility of the proposed model for predicting post-DMEK OHT.

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.

Secondary Glaucoma Following Corneal Transplantation: A Comprehensive Review of Pathophysiology and Therapeutic Approaches

Corneal transplantation is a critical surgical procedure aimed at restoring vision in patients with corneal blindness or severe damage. This review focuses on secondary glaucoma, a significant postoperative complication, with the primary objective of providing a comprehensive analysis of its pathophysiology, risk factors, diagnostic challenges, and therapeutic approaches. Unlike other reviews, this work emphasizes the interplay between inflammatory responses, corticosteroid use, and structural changes in the eye that lead to elevated intraocular pressure (IOP) after transplantation. A comprehensive review of the literature was conducted, including studies on postcorneal transplantation glaucoma, to highlight both clinical outcomes and the efficacy of current management strategies. Key findings indicate that medical treatments, such as prostaglandin analogs and beta-blockers, are effective for IOP control in the early stages, while surgical interventions, like trabeculectomy, are often necessary for more advanced cases. Diagnostic challenges, such as the difficulty of accurate IOP measurement posttransplant, are underscored, along with the importance of advanced imaging techniques for the early detection of optic nerve damage. The pathophysiology of secondary glaucoma involves a complex interaction of postsurgical inflammation, steroid-induced complications, and anatomical changes that hinder aqueous humor outflow. Diagnosis requires a combination of tonometry, gonioscopy, and imaging technologies. Management strategies range from pharmacological treatments to surgical options, with a critical focus on balancing IOP control and minimizing risks to graft survival. Clinically, these findings highlight the need for proactive and tailored management of IOP in corneal transplant patients to preserve both graft function and long-term visual outcomes. Future research should focus on improving diagnostic accuracy, developing less invasive surgical techniques, and exploring personalized medicine approaches, including genetic profiling and targeted therapies.

Mechanism and treatment of secondary glaucoma after corneal transplantation: a review

Corneal transplantation is a common treatment for corneal diseases. Secondary glaucoma after corneal transplantation is the second leading cause of failure of keratoplasty. This article reviews the mechanism and treatment of secondary glaucoma after corneal transplantation.

Glaucoma drainage device implantation and cyclophotocoagulation in the management of refractory glaucoma after Descemet-stripping automated endothelial keratoplasty

AIM

To compare the surgical outcomes of glaucoma drainage device implantation (GDI) and trans-scleral neodymium:YAG cyclophotocoagulation (CPC) in the management of refractory glaucoma after Descemet-stripping automated endothelial keratoplasty (DSAEK).

METHODS

This retrospective study on observational case series enrolled 29 patients who underwent DSAEK and posterior anti-glaucoma surgery (15 with GDI and 14 with CPC). The main outcome measures were intraocular pressure (IOP), glaucoma surgery success rate (defined as IOP of 6-21 mm Hg without additional anti-glaucoma operation), number of glaucoma medications, endothelial graft status, and best-corrected visual acuity (BCVA).

RESULTS

The mean follow-up time was 34.1 and 21.0mo for DSAEK or glaucoma surgeries, both for the GDI and CPC groups. Both groups showed significant IOP reduction after glaucoma surgery. The GDI group presented a significantly higher success rate in IOP control than the CPC group (60% vs 21.4%, P=0.03). Both procedures significantly decreased the number of glaucoma medications (P=0.03). Forty percent and 57% of cases in the GDI and the CPC group, respectively, experienced endothelial graft failure during follow-up (P=0.36). Significantly worse BCVA after surgery was observed in the CPC group but not in the GDI group.

CONCLUSION

Both GDI and CPC significantly decrease IOP in eyes with glaucoma after DSAEK. GDI is preferable to CPC in refractory glaucoma cases after DSAEK, as it manifests a significantly higher success rate for IOP control, similar endothelial graft failure rate, and relatively preserves BCVA than CPC.

Classifications of anterior segment structure of congenital corneal opacity in infants and toddlers by ultrasound biomicroscopy and slit-lamp microscopic photographs: an observational study

BACKGROUND

The structural features have an impact on the surgical prognosis for congenital corneal opacity (CCO). The structural classification system of CCO, however, is lacking. Based on data from ultrasound biomicroscopy (UBM) findings in infants and toddlers with CCO, this research proposed a classification system for the anterior segment structure severity.

METHODS

Medical records, preoperative UBM images and slit-lamp photographs of infants and toddlers diagnosed with CCO at University Third Hospital between December 2018 and June 2022 were reviewed. According to the anterior segment structural features observed in UBM images, eyes were classified as follows: U1, opaque cornea only; U2, central anterior synechia; U3, peripheral anterior synechia combined with angle closure; and U4, aniridia or lens anomaly. The opacity appearance and corneal vascularization density observed in slit-lamp photographs were assigned grades according to previous studies. The extent of vascularization was also recorded. The corresponding intraocular anomaly classifications and ocular surface lesion severity were analysed.

RESULTS

Among 81 eyes (65 patients), 41 (50.6%) were right eyes, and 40 (49.4%) were left eyes. The median age at examination was 6.91 months (n = 81, 1.00, 34.00). Two (2.5%) of the 81 eyes were classified as U1, 20 (24.7%) as U2, 22 (27.2%) as U3a, 11 (13.6%) as U3b and 26 (32.1%) as U4. Bilateral CCO eyes had more severe UBM classifications (P = 0.019), more severe dysgenesis (P = 0.012) and a larger angle closure (P = 0.009). Eyes with more severe UBM classifications had higher opacity grades (P = 0.003) and vascularization grades (P = 0.014) and a larger vascularization extent (P = 0.001). Eyes with dysgenesis had higher haze grades (P = 0.012) and more severe vascularization (P = 0.003 for density; P = 0.008 for extent), while the angle closure range was related to haze grade (P = 0.013) and vascularization extent (P = 0.003).

CONCLUSIONS

This classification method based on UBM and slit-lamp photography findings in the eyes of CCO infants and toddlers can truly reflect the degree of abnormality of the ocular surface and anterior segment and is correlated with the severity of ocular surface anomalies. This method might provide meaningful guidance for surgical procedure design and prognostic determinations for keratoplasty in CCO eyes.

Clinical Factors Impacting Outcomes From Failed Trabeculectomy Leading to Glaucoma Drainage Device Implantation and Subsequent Penetrating Keratoplasty

PRCIS

We evaluated the factors that impacted time from glaucoma drainage implant (GDI) surgery to penetrating keratoplasty (PK) in eyes with previously clear corneas (ie, GDI-first sequence), and that specifically underwent a trabeculectomy before GDI surgery for intraocular pressure (IOP) control.

PURPOSE

To describe through an event-triggered data collection method the clinical course and the long-term outcomes of 2 procedures that are commonly performed sequentially in complex clinical situations: GDI surgery and PK. The study investigates the clinical factors associated with the progression to PK and determines the GDI success rate and graft survival.

METHODS

A single, tertiary-care center retrospective interventional cases series including patients with a sequential history of trabeculectomy, GDI surgery, and PK from 1999 to 2009. Outcome measures included IOP, visual acuity, graft failure, GDI failure, and time from GDI to PK.

RESULTS

Of the eyes, 56% had primary open angle glaucoma. The time from the last trabeculectomy to GDI was 66.5 ± 66.7 months. Of the eyes, 84% received a Baerveldt GDI. Time from GDI to PK was 36.4 ± 28.4 months. IOP at the time of PK was between 5 mm Hg and 21 mm Hg in 90% of eyes. At the last follow-up, 48% of grafts were clear. At 5 years post-PK, 33% of corneal grafts remained clear, whereas 81% of tubes remained functional.

CONCLUSIONS

Nearly half of the corneal grafts are clear at the last long-term follow-up. Graft failure occurs at a higher rate than tube failure suggesting that IOP control is only one and possibly not the most important factor in graft survival in eyes with prior glaucoma surgery.

Outcomes of Corneal Transplant in Childhood Glaucoma

PRCIS

Childhood glaucoma produces alterations in the postnatal development and function of various ocular structures, including the cornea. Childhood glaucoma patients present lower corneal transplant survival rates. Our series shows outcomes of corneal transplant in childhood glaucoma with survival rates of 29% at 2 years.

OBJECTIVE

To investigate the surgical outcome of different types of keratoplasty in eyes with childhood glaucoma.

PATIENTS AND METHODS

A retrospective review was made of the medical records from 17 eyes of 15 patients who were diagnosed with childhood glaucoma and received a corneal transplantation between January 2010 and July 2020. Patient demographics, intraocular pressure, previous ocular surgery, comorbidities, corneal transplant surgery, and follow-up outcome were collected. The primary efficacy endpoint was graft survival (in months) until failure, the latter being considered as irreversible loss of corneal transparency. Secondary efficacy points were the need for an increase in topical hypotensive therapy and the need for additional surgery.

RESULTS

Seventeen eyes of 15 patients were included, 11 eyes (10 patients) with primary congenital glaucoma and 6 with other types of childhood glaucoma. Corneal transplantation was performed at the mean age of 23.76 ± 14.86 years. At the time of the transplantation, the number of topical medications was 1.35 ± 1.27, intraocular pressure was 15.00 ± 8.34 mm Hg, and patients had received up to 7 glaucoma surgeries. Descemet stripping automated endothelial keratoplasty was performed in 13 eyes (76%) and penetrating keratoplasty in 4 (24%). After surgery, 7 (41%) eyes required increased topical treatment and 2 (12%) glaucoma surgery. Twelve eyes (71%) developed graft failure at 24 months, the mean time of survival being 13.88 ± 8.25 months.

CONCLUSIONS

Management of corneal decompensation in childhood glaucoma poses a challenge. In this series of childhood glaucoma with corneal transplantations, the survival rate was 29% at 24 months.

A novel technique of penetrating keratoplasty to prevent intraocular contents extrusion for infectious keratitis

PURPOSE

To evaluate the safety and the effectiveness of our novel penetrating keratoplasty for infectious keratitis.

METHODS

Retrospective, noncomparative, interventional case series of patients with infectious keratitis who received the novel penetrating keratoplasty technique were analyzed. A prepared plastic sheet was located between the diseased cornea and iris-lens diaphragm. After the diseased lesions were removed, the graft was positioned on the plastic sheet and sutured to the recipient bed. The plastic sheet was pulled out from the anterior chamber before the all interrupted sutures were placed. The intra- and post-operative complications, the outcome of the graft and the number of corneal endothelial cells were analyzed.

RESULTS

A total of 82 eyes of 82 patients was included. The mean follow-up period was 29 ± 16 months (range from 13 to 45 months). No intraocular content extrusion, simultaneous cataract extraction and suprachoroidal hemorrhage occurred. Direct contact between the infectious cornea and the graft was successfully avoided. Greater than expected endothelial cell reduction or complications were not found.

CONCLUSIONS

This modified technique effectively prevents the extrusion of intraocular contents while avoiding the direct contact with donor endothelium during the procedure. The occurrence rate of complications such as endothelial cell loss is not higher than the conventional methods.

An Overview of Corneal Transplantation in the Past Decade

The cornea is a transparent avascular structure located in the front of the eye that refracts light entering the eyes and also serves as a barrier between the outside world and the internal contents of the eye. Like every other body part, the cornea may suffer insult from trauma, infection, and inflammation. In the case of trauma, a prior infection that left a scar, or conditions such as keratoconus that warrant the removal of all or part of the cornea (keratoplasty), it is important to use healthy donor corneal tissues and cells that can replace the damaged cornea. The types of cornea transplant techniques employed currently include: penetrating keratoplasty, endothelial keratoplasty (EK), and artificial cornea transplant. Postoperative failure acutely or after years can result after a cornea transplant and may require a repeat transplant. This minireview briefly examines the various types of corneal transplant methodologies, indications, contraindications, presurgical protocols, sources of cornea transplant material, wound healing after surgery complications, co-morbidities, and the effect of COVID-19 in corneal transplant surgery.

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.

Determinants of Glaucoma Therapy Escalation After Descemet-Stripping Automated Endothelial Keratoplasty To Treat Pseudophakic Bullous Keratopathy: A Nested Case-Control Study

Purpose:

To study the determinants of glaucoma therapy escalation (GTE) after Descemet-stripping automated endothelial keratoplasty (DSAEK) for pseudophakic bullous keratopathy in an eye-care hospital in Saudi Arabia.

Methods:

This nested case-control study evaluated patients who required medical or surgical treatment for controlling glaucoma after DSAEK (defined as GTE; GTE group). A group of patients who did not require any intervention post-DSAEK served as controls (control group). Data were collected on preoperative, intraoperative, and postoperative parameters for DSAEK. Variables were compared between groups to evaluate risk factors for GTE and graft failure.

Results:

The study sample comprised 117 eyes (40 in the GTE group and 77 in the control group). Glaucoma was present in 20 (17.1%) of the eyes before DSAEK. The median duration of follow-up was 27 months [Interquartile range (IQR): 24; 42]. Intraoperative complications occurred in 4 eyes, and 2 eyes had a decentered donor button. Graft failure causing vision impairment and GTE at the final follow-up were noted in 19 (16.2%) and 40 (34.2%) eyes, respectively. Glaucoma prior to DSAEK was significantly associated with GTE [odds ratio (OR) = 6.4; 95% confidence interval (CI) 2.4; 18.3; P = 0.0004]. A history of penetrating keratoplasty (PK) was significantly associated with GTE after DSAEK [OR = 6.2 (95% CI 1.5; 24.7) P = 0.008]. At the last visit, GTE and graft failure were positively associated (OR = 27.2, P < 0.005).

Conclusion:

Escalation of glaucoma therapy was warranted in one in 3 eyes that had undergone DSAEK. GTE and graft failure are interrelated complications. Patients with glaucoma and PK have a higher risk of GTE post-DSAEK.

Selective laser trabeculoplasty for steroid-induced ocular hypertension following endothelial keratoplasty

Purpose: To examine the safety and efficacy of selective laser trabeculoplasty (SLT) in patients responding to topical steroids with elevated intraocular pressure following endothelial keratoplasty.Methods: Patients that underwent Descemet Membrane Endothelial Keratoplasty (DMEK) or Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) were offered SLT as first-line therapy if they presented with steroid response and met inclusion criteria. Patient demographics, best-corrected visual acuity (BCVA), steroid and glaucoma regimens were recorded before and after SLT.Results: Twelve eyes of 8 patients were recruited to the study. All patients demonstrated a reduction in IOP and only one patient remained on anti-glaucoma drops after SLT. The mean (±SD) reduction in IOP following SLT was 8.8 (±4.9) mmHg (p < 0.0001). BCVA remained stable and no adverse events following treatment were observed.Conclusions: SLT may be a safe and effective treatment option that reduces topical antihypertensive burden while allowing continuance of corticosteroids in steroid-responsive eyes at high risk of rejection following endothelial keratoplasty. Larger randomized studies are needed to compare SLT efficacy with topical medication in this patient group and to review any impact on graft survival and glaucoma progression.

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.

Effects of femtosecond laser-assisted trephination on donor tissue in liquid interface as compared to applanated interface

Purpose

To evaluate the effects of femtosecond laser‐assisted keratoplasty using a liquid patient interface (L‐PI) as opposed to an applanated interface (A‐PI) on graft quality and functionality markers.

Methods

Pressure measurements during femtosecond laser‐assisted trephination were performed using two groups of 10 porcine eyes. Trephination was performed either in an L‐PI or in an A‐PI setting. Pressure sensor needles placed intravitreally continuously recorded intraocular pressure during trephination. Twenty paired human donor eyes were used to test the morphological quality of donor tissue after trephination in L‐PI and A‐PI settings. Optical coherence tomography (OCT) scans were performed before and after trephination. Images were processed using ImageJ and pixel².

Results

During trephination, pressure measurements with an L‐PI were significantly lower than with an A‐PI (p = 0.0121). Mean pressure during trephination was 78.1 mmHg ± 37.6 mmHg with L‐PI and 188.6 mmHg ± 17.7 mmHg with A‐PI. Trephination in A‐PI produced a significantly larger increase (p < 0.00001) in donor pachymetry than trephination in L‐PI. Significantly lower areas of Descemet folds were achieved in L‐PI trephination than in A‐PI trephination (p < 0.01). There was no significant difference in circularity between A‐PI and L‐PI (p = 0.27). Total time required for trephination was comparable between L‐PI and A‐PI (p = 0.45). Time taken to reach working vacuum was achieved significantly more quickly in L‐PI (p < 0.05).

Conclusion

Femtosecond laser‐assisted L‐PI keratoplasty appears to be a promising method to decrease stress to donor and recipient tissue during femtosecond laser‐assisted trephination. Results showed favourable donor tissue morphology markers after L‐PI trephination.

Intraocular Pressure Measurement after Penetrating Keratoplasty

Assessing the intraocular pressure is a difficult but crucial task in the follow-up of patients that have undergone penetrating keratoplasty. Early recognition of elevated intraocular pressure and/or glaucoma and establishment of the appropriate treatment is essential to ensure the best possible visual outcome for patients dealing with this feared complication. Although Goldmann applanation tonometry is still the gold standard for measuring the intraocular pressure, its limitations in postkeratoplasty eyes, due to postoperative modified corneal morphology, have led to the search for more suitable alternatives. This review is the result of a comprehensive literature search in the MEDLINE database that aims to present glaucoma in the context of perforating keratoplasty, the corneal properties with impact on ocular pressure measurement, and the results achieved with the most important tonometers that have been studied in this pathology. Goldmann applanation tonometry remains the reference for intraocular pressure assessment even in corneas after penetrating keratoplasty. However, some promising alternatives have emerged, the most important of which are the Pascal dynamic contour tonometry, the Tono-Pen XL, the ocular response analyzer, and the iCare. All have advantages and disadvantages but have proved to be appropriate alternatives, especially in cases in which Goldmann applanation tonometry cannot be used.

Fourier-Domain Optical Coherence Tomographic Assessment of Changes in the Schlemm's Canal of Nonglaucomatous Subjects After Keratoplasty

Purpose: This study aimed to evaluate the impact of keratoplasty on the in vivo anatomical structures in the Schlemm's canal (SC) of nonglaucomatous subjects using Fourier-domain optical coherence tomography (FD-OCT). Methods: Sixty-six nonglaucomatous eyes that underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), or triple surgery were enrolled in this prospective, comparative, observational study. The SC imaging was performed using FD-OCT before and after surgery in both the nasal and temporal quadrants. Patient demographics, SC parameters [e.g., cross-sectional area (CSA), meridional diameter of SC (MSC), sagittal diameter of SC (SSC), and circumference (CCF)], and the correlations between the variation of SC parameters and intraocular pressure (IOP) were analyzed. Results: The mean age of all subjects was 40.27 ± 18.97 years. Among all cases, the nasal, temporal, and mean MSC significantly decreased on the first day after surgery and then increased at 1 week (p = 0.04, 0.017, and 0.01, respectively). Temporal CSA (tCSA), temporal MSC (tMSC), and temporal circumference (tCCF) after PK (p = 0.017, 0.020, and 0.018, respectively) and nasal MSC (nMSC) after DALK (p = 0.025) decreased significantly on the first day after surgery. The shift in mean IOP was significantly correlated with the changes in tMSC (r = 0.341, p = 0.003) and CCF (r = 0.207, p = 0.048). Conclusion: SC had significant in vivo morphological changes in the early period after keratoplasty in nonglaucomatous eyes, accompanied with elevation of IOP. Early intervention might be necessary to prevent secondary glaucoma early after keratoplasty.

Long-term corticosteroid-induced chronic glaucoma model produced by intracameral injection of dexamethasone-loaded PLGA microspheres

PURPOSE

To evaluate a new chronic glaucoma model produced by intracameral injection of dexamethasone-loaded poly lactic-co-glycolic acid microspheres (Dex-PLGA-Ms) over six months.

METHODS

Healthy rats received two injections (at baseline and Week 4) of Dex-PLGA-Ms into the anterior chamber of the right eye. Clinical signs and intraocular pressure (IOP) were weekly recorded. The structure of the retina and optic nerve was in vivo evaluated using optical coherence tomography (OCT) every two weeks and functionally using dark- and light-adapted electroretinography at 0-12-24 weeks. Histological studies were also performed.

RESULTS

IOP progressively increased up to hypertension (23.22 ± 3.63 mmHg) in both eyes but did so later in left eyes. OCT quantified a decrease in full-thickness retina posterior pole (R), retinal-nerve-fiber layer (RNFL), and ganglion-cell layer (GCL) thickness up to 24 weeks. Right eyes showed higher neuroretinal thickness loss up to week 8. RNFL experienced the highest percentage thickness loss at the inferior-superior axis, while in GCL the inner sectors of the horizontal axis (Nasal-Temporal) suffered the greatest decrease in thickness. Retinal ganglion cell, photoreceptor, and intermediate cell functionality decreased over time. Increased deposition of collagen IV was also found in zonular fibers and the ciliary body.

CONCLUSIONS

This work shows the usefulness of drug delivery systems, not to treat pathology but to induce it. Only two injections of Dex-PLGA-Ms in the anterior chamber of rat eyes were enough to progressively create ocular hypertension and subsequent functional and structural neuroretinal degeneration, at least over 6 months.

Descemet-stripping automated endothelial keratoplasty with intrascleral haptic-fixated intraocular lens in a sequential vs simultaneous approach

PURPOSE

To compare the outcomes of Descemet-stripping automated endothelial keratoplasty (DSAEK) with intrascleral haptic-fixated intraocular lens (IOL) in a sequential and simultaneous approach.

SETTING

Tertiary eyecare center.

DESIGN

Prospective randomized comparative study.

METHODS

Patients with aphakic or complicated pseudophakic bullous keratopathy visiting a tertiary eyecare center were included in the study. A total of 40 patients were randomized into 2 groups of 20 each. Group 1 had subjects who underwent scleral-fixated IOL (SF IOL) implantation by intrascleral haptic fixation technique, followed by DSAEK (sequential procedure) with an interval of at least 3 months. Group 2 (simultaneous) had subjects who underwent DSAEK with SF IOL as a combined procedure. Graft survival, endothelial cell loss (ECL), corrected distance visual acuity (CDVA), and need for any intervention such as rebubbling were evaluated for both the groups at the end of 6 months.

RESULTS

At 6 months, the sequential group had significantly better CDVA of 0.62 ± 0.17 logMAR compared with 0.87 ± 0.19 logMAR in the simultaneous group (P = .002). Group 1 had significantly better overall cumulative graft survival (100% vs 60%, P = .002), significantly lower ECL (P = .006), lesser mean central corneal thickness (P = .03), and significantly thinner donor lenticule (P = .009). Rebubbling rate was significantly higher in Group 2 (P = .025). The mean hyperopic shift was significantly more in Group 2 (P = .02).

CONCLUSION

The sequential procedure of SF IOL followed by DSAEK has better visual outcomes and graft survival when compared with simultaneous procedure in cases of aphakic or complicated pseudophakic bullous keratopathy.

Challenges in the complex management of post-keratoplasty glaucoma

Glaucoma is a serious complication after corneal transplantation and itself a common cause for graft failure and leading cause of vision loss post-keratoplasty due to corneal endothelial decompensation. Endothelial keratoplasty procedures like Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) may be superior to penetrating keratoplasty (PK) regarding the incidence of elevated intraocular pressure (IOP) and development of glaucoma. There are indications that regardless of the method of keratoplasty, some corneal diseases like pseudophakic bullous keratopathy, corneal perforation, and graft rejection have a higher risk for developing post-keratoplasty glaucoma than keratoconus and corneal dystrophies and likewise respond less to IOP lowering therapy. In this review, the pathophysiology of post-keratoplasty glaucoma, the diagnostic tools with focus on different devices, and their limitations with regard to measuring IOP and the treatment modalities are presented.

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.

Outcomes of Gel Stent Implantation for Glaucoma in Patients With Previous Corneal Graft Surgery: A Case Series

PURPOSE

To report a series of 5 cases with successful placement of a minimally invasive glaucoma surgery (MIGS) device for glaucoma refractory to medical management in patients with previous corneal grafts.

METHODS

This is a retrospective analysis of all cases with a Xen45 Gel Stent (Allergan plc, Dublin, Ireland) for ocular hypertension and glaucoma refractory to medical treatment after corneal graft surgery between 2016 and 2019 at the Rothschild Foundation, Paris. We did the imaging studies and studied the intraocular pressure (IOP) and the endothelial cell count preimplantation and postimplantation with a MIGS device.

RESULTS

Five cases were included in this study, demonstrating a well-tolerated, highly effective, and sustained method for controlling the IOP, which was refractory to previous treatment. An average IOP reduction of 70.5% was noted with a needling rate of 20%, and no adverse events were noted except 1 IOP spike day 7 post-op with no long-term effects.

CONCLUSIONS

Glaucoma after graft surgery is a well-known and devastating complication, and as numbers of graft surgery performed increases, so will the incidence of glaucoma. MIGS devices such as the Xen45 Gel Stent (Allergan plc) should become a part of our accepted armory to treat raised IOP refractory to medical treatment without delay.

Iatrogenic corneal diseases or conditions

Any prescribed or self-administered therapy carries inherent risks of secondary adverse events. While the volume of treatments being administered through healthcare systems has been increasing, scientific advancements in our understanding of the mechanisms of pharmaceutical side effects and complications from procedures now allow us to reduce the risk of non-intentional damage to ocular health. This review summarizes the most common and leading causes of iatrogenic visual impairment, corneal diseases, and conditions that present in a general ophthalmologic practice, including a comprehensive analysis of their pathophysiology and recommendations for management and prophylaxis.Iatrogenic corneal diseases and conditions can arise from topical drugs, contact lens use, eye surgeries and procedures, systemic drugs, non-ophthalmological events, and cosmetic procedures. Topical and systemic drugs may disturb tear film homeostasis or result in ocular surface deposits. The use of ill-fitted contact lenses can trigger eye discomfort and poor hygiene conditions that can predispose to severe infections. Procedures to the eye may result in a variety of anatomical and functional complications that ophthalmologists should be aware of how to avoid or at least be prepared to manage if they occur. Even non-ophthalmological events such as non-invasive ventilation, radiation therapies and, immune-based conditions, or cosmetic procedures such as eyelash growth and fillers, can result in unwanted damage to the ocular surface.

Comparative observation of the efficacy of simplified Descemet stripping endothelial keratoplasty and penetrating keratoplasty in treating bullous keratopathy

The aim of the present study was to compare the clinical efficacy between simplified Descemet stripping endothelial keratoplasty (DSEK) and penetrating keratoplasty (PKP) in the treatment of patients with bullous keratopathy (BK). A cohort of 65 patients (65 eyes) with BK recruited between December 2002 and June 2018 was divided into two groups according to the treatment they received: The simplified DSEK group (n=38) and the PKP group (n=27). The best-corrected visual acuity (BCVA) during the follow-up at 1, 3, 6 and 12 months and postoperative complications were all recorded. Furthermore, the graft survival rate after 1 year was recorded. The mean BCVA in the simplified DSEK group was significantly better than that in the PKP group after 1, 3, 6 and 12 months (P<0.05). Furthermore, the 1-year graft survival rate in the simplified DSEK group (91.2%) was significantly higher than that in the PKP group (70.4%; P=0.039). A total of 13 eyes (34.21%) in the simplified DSEK group and 11 eyes (40.74%) in the PKP group were diagnosed with glaucoma; there was no significant difference between the rate of glaucoma diagnosis between the two groups (P=0.591). Graft rejection was observed in 5 eyes (13.16%) of the simplified DSEK group and 8 eyes (29.63%) of the PKP group and the rate of graft rejection did not differ significantly between the groups (P=0.279). Graft infection occurred in 1 eye (2.63%) in the simplified DSEK group and 6 eyes (22.22%) in the PKP group. Simplified DSEK achieved better visual acuity and longer graft survival rates than PKP. The incidence of postoperative secondary glaucoma, graft rejection and graft infection after simplified DSEK was lower than that in the PKP group, but only the incidence of graft infection was significantly different.

Surgery for glaucoma in modern corneal graft procedures

Glaucoma is a common cause of vision loss after corneal transplantion and is considered a major risk factor for graft failure. Glaucoma may be present before corneal transplant surgery, or increased intraocular pressure may develop after keratoplasty in up to one-third of patients. Pre-existing glaucoma should be controlled before keratoplasty, either medically or surgically. For postkeratoplasty increase in intraocular pressure; identifying the risk factors allows appropiate follow-up and management. Patients undergoing anterior lamellar keratoplasty may take advantage of reduced rates of postkeratoplasty glaucoma. Glaucoma also complicates eyes with endothelial keratoplasties, mostly related to management of intraocular pressure spikes derived from anterior chamber air bubbles. Nevertheless, the severity is less, and the intraocular pressure is more easily controlled when compared with penetrating keratoplasty. Adequate management of glaucoma that develops before or after keratoplasty may save eyes from irreversible damage to the optic nerve and increase graft survival.

Predicting factors of ocular hypertension following keratoplasty: Indications versus the procedure

PURPOSE

To assess the incidence of ocular hypertension (OHTN) following penetrating keratoplasty (PKP) versus deep anterior lamellar keratoplasty (DALK) corneal transplant surgeries, and to assess the impact of indication for transplantation versus surgery type on OHTN development.

METHODS

A retrospective study of 76 eyes of 76 patients who underwent PKP or DALK between 1 January 2009 and 1 September 2014. Data included: preoperative intraocular pressure (IOP), indication and type of surgery, post-surgical IOP at 1 to 5, 14 to 21 days, 3, 6 months, 1 year and at the last follow up. Primary outcome was post-operative OHTN (defined as IOP >21 mm Hg).

RESULTS

A total of 13 patients (17.1%) developed OHTN of whom 9 (20.45%) underwent PKP and 4 (12.5%) DALK (p = 0.33). OHTN occurred after an average of 16.46 ± 8.47 months (0.1-58 months). Twenty-one keratoconus patients (39.62%) underwent PKP and 32 (60.37%) underwent DALK. Patients with indications other than keratoconus all underwent PKP. Keratoconus patients were less likely to develop OHTN (9.43% vs 34.78%, p = 0.02). Among patients developing OHTN, mean age of the non-keratoconus group was significantly higher (63.25±16.7 vs 33 ± 10, p = 0.01). No significant difference in OHTN among keratoconus patients undergoing DALK versus PKP (12.5% vs 4.76%, respectively, p = 0.35) was found. PKP was associated with less OHTN in keratoconus eyes (4.76% vs 34.78%, p = 0.02).

CONCLUSION

Patients who underwent keratoplasty due to keratoconus are at a lower risk to develop OHTN than those who underwent surgery for other indications.

Clinical Outcomes of Micropulse Transscleral Cyclophotocoagulation in Patients with a History of Keratoplasty

Purpose

To examine the surgical outcomes and graft conditions in patients receiving micropulse transscleral cyclophotocoagulation (MP-TSCPC) to treat post-keratoplasty ocular hypertension.

Methods

This retrospective observational study included 30 eyes of 28 consecutive glaucoma patients with a history of penetrating keratoplasty (PKP) or Descemet's stripping automated endothelial keratoplasty (DSAEK) who underwent MP-TSCPC at the University of California, San Francisco from 09/2015 to 08/2018. Using the Wilcoxon signed-rank test, we compared preoperative and postoperative intraocular pressure (IOP), number of glaucoma medications, visual acuity, and central corneal thickness at 1, 3, 6, and 12 months. Postoperative complications, additional surgeries, and graft failures were also recorded at these follow-up times. Linear regression model was used to study whether PKP vs. DSAEK affects the effectiveness of MP-TSCPC.

Results

Thirty eyes from 28 patients were followed for 12 months. IOP was significantly decreased from preop at all follow-up points (P < 0.001). There was no significant change in the number of glaucoma drops, visual acuity, or CCT. At 12 months, 21 of the 30 eyes met the definition of success, and only one underwent repeat PKP due to graft rejection. The type of corneal transplant was not a significant factor for IOP reduction at the last follow-up.

Conclusions

MP-TSCPC achieved desirable IOP control and success rates for postkeratoplasty patients while resulting in minimal complications and graft failure. It appears to be a safe and effective procedure in patients who received corneal transplant with one-year follow-up.

Extracellular Vesicles Secreted by Corneal Epithelial Cells Promote Myofibroblast Differentiation

The corneal epithelium mediates the initial response to injury of the ocular surface and secretes a number of profibrotic factors that promote corneal scar development within the stroma. Previous studies have shown that corneal epithelial cells also secrete small extracellular vesicles (EVs) in response to corneal wounding. In this paper, we hypothesized that EVs released from corneal epithelial cells in vitro contain protein cargo that promotes myofibroblast differentiation, the key cell responsible for scar development. We focused on the interplay between corneal epithelial-derived EVs and the stroma to determine if the corneal fibroblast phenotype, contraction, proliferation, or migration were promoted following vesicle uptake by corneal fibroblasts. Our results showed an increase in myofibroblast differentiation based on α-smooth muscle actin expression and elevated contractility following EV treatment compared to controls. Furthermore, we characterized the contents of epithelial cell-derived EVs using proteomic analysis and identified the presence of provisional matrix proteins, fibronectin and thrombospondin-1, as the dominant encapsulated protein cargo secreted by corneal epithelial cells in vitro. Proteins associated with the regulation of protein translation were also abundant in EVs. This paper reveals a novel role and function of EVs secreted by the corneal epithelium that may contribute to corneal scarring.

Case Series of Brittle Cornea Syndrome

Purpose

This case series demonstrate diagnostic features, treatment options, and challenges for Brittle Cornea Syndrome. Observations. Three cases presented with bluish sclera and extremely thin cornea. Genetic workup was performed and confirmed the diagnosis of Brittle Cornea Syndrome, a rare autosomal recessive disorder characterized by corneal thinning and blue sclera. Case 1 was a 4-year-old boy who developed cataract and glaucoma after undergoing right tectonic penetrating keratoplasty (PK) secondary to a spontaneous corneal rupture. Glaucoma was controlled medically. Later, the kid underwent right transcorneal lensectomy and vitrectomy with synechiolysis. After 6 weeks, he sustained graft dehiscence that was repaired using onlay patch graft. Case 2 was a 7-year-old boy who underwent PK in the right eye, then a pericardial patch graft in the left eye following spontaneous corneal rupture. Glaucoma in both eyes was controlled medically. Case 3 was the 2-year-old sister of the 2^nd case. She had a pachymetry of 238 μm OD and 254 μm OD and 254 

Conclusions

Long-term follow-up of children diagnosed with Brittle Cornea Syndrome is paramount to minimize the morbidity of corneal rupture and late-onset extraocular conditions.

Glaucoma After Corneal Trauma or Surgery-A Rapid, Inflammatory, IOP-Independent Pathway

To review clinical aspects and cellular and molecular steps in the development of long-term glaucoma after corneal surgery or acute trauma—especially the pivotal role of tumor necrosis factor alpha (TNF-α), the rapidity of the secondary damage to the retinal ganglion cells, and the clinical promise of early antiinflammatory intervention.

Approaches toward enhancing survival probability following deep anterior lamellar keratoplasty

The greatest advantage of deep anterior lamellar keratoplasty over full-thickness corneal transplantation is the elimination of graft failure caused by endothelial rejection. Despite this advantage, a deep anterior lamellar keratoplasty graft can fail because of several factors, such as complications related to the donor-recipient interface, graft epithelial abnormalities, graft vascularization, stromal graft rejection, and recurrence of herpetic keratitis. Increased deep anterior lamellar keratoplasty graft survival is mainly built upon optimization of the ocular surface to provide a hospitable environment for the graft. Any predisposing factors for graft epithelial abnormalities, corneal neovascularization, and preexisting vernal keratoconjunctivitis should be identified and treated preoperatively. Prompt recognition and appropriate treatment of interface-related complications and stromal graft rejection usually result in good anatomic outcomes, with no detrimental effects on vision.

Comparison of Short-term Outcomes of Aurolab Aqueous Drainage Implant with Ahmed Glaucoma Valve in Post-Penetrating Keratoplasty Glaucoma: A Retrospective Follow-up Study at a Tertiary Care Center

PURPOSE

Comparison of short-term outcomes of the Aurolab aqueous drainage implant (AADI) with the Ahmed glaucoma valve (AGV) in post-penetrating keratoplasty glaucoma (PPKG).

DESIGN

Retrospective study design.

PARTICIPANTS

We analyzed the data of patients who underwent glaucoma drainage device (GDD) implantation for PPKG between the time period of 2008 to 2017. A total of 57 eyes of 55 patients were included.

METHODS

Parameters including age, sex, corneal graft clarity, duration between the keratoplasty and glaucoma surgery, visual acuity (VA), intraocular pressure (IOP), the number of antiglaucoma drugs (topical and oral) before surgery, and type of GDD were studied. The patients were divided into 2 groups: group I, patients undergoing AADI implantation; and group II, patients undergoing AGV implantation. Patients with at least 6 months follow-up were included. The postoperative VA and IOP were analyzed on day 1 and at 1 week, 4 weeks, 6 weeks, 3 months, and 6 months. The success of GDD was defined as complete success (IOP > 5 mmHg or <21 mmHg without topical antiglaucoma drug) or qualified success (IOP > 5 mmHg or <21 mmHg with up to 2 topical antiglaucoma drugs). Failure was defined as IOP < 5 mmHg or >21 mmHg with or without antiglaucoma medication; IOP < 21 mmHg with 3 or more topical medications or use of systemic medications irrespective of the IOP; loss of perception of light; and/or need for further glaucoma surgery.

RESULTS

Nineteen eyes in group I (mean age = 40.16±16.36 years) and 38 eyes in group II (mean age = 56.61±19.35 years) were studied. The mean baseline IOP in group I and group II was not significantly different (28.63±11.21 vs. 30±14.61 mmHg, P = 0.72). Mean postoperative IOP at 6 months was not significantly different in the 2 groups (12.11±4.86 mmHg vs. 14.95±6.35 mmHg, P = 0.2). There was statistically significant fall in IOP at each visit compared to preoperative IOP in both the groups (P = 0.001), but there was no significant difference between the 2 groups at any time point (P > 0.05). At 6 months overall success rate was 84.21% in both groups (P = 1.00), though the complete success was slightly higher in group II, which was nonsignificant (31.58% vs. 39.47%, P = 0.56). There was no significant difference between baseline and final VA in either group.

CONCLUSIONS

Both AADI and AGV are equally effective in controlling IOP in post-penetrating glaucoma. The AADI, being a cost-effective implant, may be more suitable for developing countries.

Risk of Glaucoma Surgery After Corneal Transplant Surgery in Medicare Patients

PURPOSE

Glaucoma is a well-documented complication of corneal transplants, contributing significantly to ultimate visual loss. Reported incidence of glaucoma following corneal transplants is highly variable, and definitions of posttransplant glaucoma are inconsistent. Here we use glaucoma surgery as a more rigid and specific endpoint to compare rates following different corneal transplant surgeries.

DESIGN

Retrospective cohort study.

METHODS

A 5% random sample of Medicare beneficiaries from 2010-2013 was obtained and patients were identified with Current Procedural Terminology (CPT) codes for penetrating keratoplasty (PK), endothelial keratoplasty (EK), anterior lamellar keratoplasty (ALK), and keratoprosthesis (KPro). Rates of glaucoma surgery within the same year following the abovementioned corneal transplants were analyzed. Subgroup analyses included patients who carried preexisting glaucoma diagnoses prior to corneal transplant surgery.

RESULTS

There were 3098 patients who underwent corneal transplants during the study period, including 1919 EK, 1012 PK, 46 ALK, 32 KPro, and 89 both PK and EK. Rates of glaucoma surgery ranged from 6.1% to 9.4% in the corneal transplant groups, without statistically significant differences among groups. However, 10.0% of patients with preexisting glaucoma required glaucoma surgery following any transplant surgery, compared with 5.3% of patients without preexisting glaucoma. This included 12.4% of PK patients with preexisting glaucoma compared with 2.8% of PK patients without preexisting glaucoma (P < .01).

CONCLUSIONS

Despite literature suggesting that more angle-altering cornea surgeries confer higher risk, we found no statistically significant differences among various transplant groups. Patients with preexisting glaucoma, however, had higher risk of glaucoma surgery within the same year following corneal transplant surgery, which was especially pronounced in the PK group. These patients require special care when considering long-term effects of corneal transplants.

Angiogenesis and lymphangiogenesis in corneal transplantation-A review

Corneal transplantation has been proven effective for returning the gift of sight to those affected by corneal disorders such as opacity, injury, and infections that are a leading cause of blindness. Immune privilege plays an important role in the success of corneal transplantation procedures; however, immune rejection reactions do occur, and they, in conjunction with a shortage of corneal donor tissue, continue to pose major challenges. Corneal immune privilege is important to the success of corneal transplantation and closely related to the avascular nature of the cornea. Corneal avascularity may be disrupted by the processes of angiogenesis and lymphangiogenesis, and for this reason, these phenomena have been a focus of research in recent years. Through this research, therapies addressing certain rejection reactions related to angiogenesis have been developed and implemented. Corneal donor tissue shortages also have been addressed by the development of new materials to replace the human donor cornea. These advancements, along with other improvements in the corneal transplantation procedure, have contributed to an improved success rate for corneal transplantation. We summarize recent developments and improvements in corneal transplantation, including the current understanding of angiogenesis mechanisms, the anti-angiogenic and anti-lymphangiogenic factors identified to date, and the new materials being used. Additionally, we discuss future directions for research in corneal transplantation.

Incidence and risk factors for post-penetrating keratoplasty glaucoma: A systematic review and meta-analysis

Objectives

To establish the incidence and risk factors for post penetrating keratoplasty glaucoma (PKKG).

Methods

Studies published between 1947 and 2016 regarding penetrating keratoplasty (PK) were identified using an electronic search and reviewed. For search purpose, PKKG was defined as ocular hypertension (> 21mmHg) after PK. The incidence and risk factors of PKKG were extracted for all studies. Pooled incidence, odd ratios (ORs) and 95% confidence intervals (CIs) were calculated.

Results

Thirty studies reporting on 27146 patients were included in the analysis of the incidence and risk factors for PKKG. Exact PKKG definitions used in the literature could be classified in to three subgroups: I, ocular hypertension (> 21mmHg) after PK; II, I plus > 4 weeks medical treatment required; III, II plus treatment escalation among patients with preexisting glaucoma. Overall (Definition I) pooled incidence in all studies was 21.5% (95% CI 17.8%, 25.7%). The incidence varied according to different definitions. The highest incidence value was found when only studies using Goldmann tonometer were included (22.5%), while the lowest incidence was found when a strict definition was used and steroid-induced PPKG was excluded (12.1%). The incidence was higher in patients with preexisting glaucoma, bullous keratopathy (BK), aphakia, pseudophakia, failed graft, and surgical indication of trauma. A triple procedure (combined PK with extra capsular cataract extraction and intraocular lens implantation) was not identified as being associated with the increased risk for PKKG.

Conclusions

The overall pooled incidence of PKKG was 21.5%, but it varied according to the criteria used to define the presence of PPKG. Strong risk factors for PKKG included preexisting glaucoma and aphakia, while modest predictors included pseudophakia, regrafting, and preoperative diagnosis like BK and trauma. There may not be sufficient evidence to identify a significant association between a triple procedure and PKKG.

Innovative approaches to glaucoma management of Boston keratoprosthesis type 1

Glaucoma remains a prevalent disorder and visual limiting factor after Boston keratoprosthesis type 1 implantation. Patients with glaucoma have worse initial and late visual acuity outcomes after otherwise successful keratoprosthesis implantation. Management of glaucoma in the setting of a keratoprosthesis is challenging because of relatively rapid progression and an inability to accurately measure intraocular pressure (IOP). In addition, there are no standard guidelines for glaucoma surveillance and monitoring after keratoprosthesis surgery. This report provides a review of the current literature and offers innovative strategies that will overcome the challenges in managing glaucoma in the setting of a Boston keratoprosthesis type 1 implant. The topics that will be discussed in this section include alternative methods for IOP measurement, rationales and surgical techniques for a pars plana tube placement for glaucoma drainage device, effective medical and laser treatment, the risk for IOP elevations after YAG laser, and practical guides to glaucoma surveillance and monitoring.