Clinical outcome of repeat penetrating keratoplasty

Feature developments in artificial corneal devices: a review

Corneal disease ranks as the fifth leading cause of global blindness, affecting more than 10 million individuals. Donor corneal transplantation, keratoplasty, remains the mainstay of addressing loss of corneal clarity. Historically, full-thickness penetrating keratoplasty (PK) has been one of the most successful and widely performed transplant procedures, although predominantly available in developed countries. The landscape for corneal transplantation has changed dramatically over the last two decades with the emergence of partial-thickness transplantation techniques and corneal cross-linking, which provide less invasive means of treating diseases like Fuchs' dystrophy and keratoconus, respectively. Currently, PK is often performed in eyes with complex problems and at high risk of graft failure. In fact, repeat grafting has become the second most common indication for PK. Furthermore, a significant shortage of donor corneas persists, with half of the global population lacking access to tissues. This shortage is particularly pronounced in developing countries, which lack the necessary infrastructure to support corneal transplantation despite bearing the highest burden of corneal blindness. Artificial corneal devices, known as keratoprostheses, have been posited as a remedy for various constraints of conventional keratoplasty and have demonstrated promising outcomes, particularly in high-risk cases. Synthetic devices are not subject to the risk of allograft rejection or endothelial failure. In resource-limited areas, keratoprostheses could potentially replace donor keratoplasty by eliminating the costly eye banking system to access, preserve and distribute the short-lived fresh donor tissues. Herein, we report the design, surgical technique, indications and early outcomes of clinical-stage fully synthetic keratoprostheses currently undergoing trials globally.

Ten-year outcomes of repeat keratoplasty for optical indications

Aim

To analyze the clinical outcomes of repeat keratoplasties following a failed primary optical keratoplasty in an Asian population.

Methods

In this prospective cohort study, clinical data of consecutive patients who had repeat keratoplasty at Singapore National Eye Centre from 2007 to 2020 were recorded from our ongoing Singapore Corneal Transplant Registry.

Results

A total of 284 first regrafts (181 Descemet stripping automated endothelial keratoplasty (EK), 63 penetrating keratoplasty (PK), 21 Descemet membrane endothelial keratoplasty, and 19 deep anterior lamellar keratoplasty (DALK)) were analyzed. Graft rejection (38.4%) and late endothelial failure (15.8%) were the main causes of initial graft failure. PK/EK and EK/EK had better one-year postoperative best corrected visual acuity compared to PK/PK (p = 0.006 and p < 0.001 respectively). Kaplan-Meier 10-year cumulative regraft survival probabilities were 69.2% for PK/EK, 52.8% for EK/EK, and 43.1% for PK/PK. Regraft survival was 100% for DALK/PK, DALK/DALK, and DALK/EK at three to 5 years. Log-rank test showed higher survival of PK/EK compared to PK/PK (p = 0.002) and EK/PK (p = 0.009), and of EK/EK compared to PK/PK (p = 0.003) and EK/PK (p = 0.005). High-risk regrafts had significantly lower 10-year survival probabilities compared to non-high-risk regrafts (p = 0.045). Cox multiple regression analysis showed male gender (p = 0.023), PK regraft (p = 0.003), regraft rejection (p = 0.003), and initial graft indications of pseudophakic bullous keratopathy (p = 0.005) and aphakic bullous keratopathy (p = 0.004) to be risk factors for regraft failure, while longer time to regraft was associated with decreased risk of failure (p = 0.013).

Conclusion

Performing EK for failed optical PK or EK significantly improved regraft survival compared to repeat PK. Regrafts performed for failed initial DALK grafts did well regardless of type.

Prognostic Significance of Biointegration at the Optic-Cornea Joint in Keratoprosthesis Implantation

PURPOSE

The purpose of this study was to characterize the morphological and immunological aspects of biointegration at the optic-cornea joint of a second-generation synthetic corneal device.

METHODS

The initial prototype, single-piece optic-skirt configuration, is constructed from compact and flexible perfluoroalkoxy alkane with porous expanded polytetrafluoroethylene (ePTFE) overlying the skirt to allow skirt-cornea biointegration. The second-generation version was modified to add ePTFE around the optic wall to allow optic-cornea biointegration. Initial and amended second-generation devices were implanted into healthy rabbit eyes. Clinical examination, anterior segment optical coherence tomography, light microscopy, and immunofluorescence studies were performed to assess structural integrity and determine molecular signatures indicative of inflammation and tissue remodeling between the 2 prototypes.

RESULTS

Recipient eyes with both device versions showed no epithelial defects or tissue retraction at 3 months postoperatively. Optical coherence tomography images demonstrated no appreciable perioptic space with either prototype. Histopathology of the initial device demonstrated lack of stromal adhesion at the optic-cornea joint with epithelium filling the perioptic space. Second-generation devices demonstrated full sealing of the recipient stroma along the optic stem. Although the routine histopathology did not demonstrate inflammatory cells in the recipient cornea with either device, immunohistochemistry stains demonstrated quiescent phenotype of stromal and epithelial cells only in the second-generation devices.

CONCLUSIONS

Biointegration between the synthetic corneal device and recipient tissue at the optic-cornea joint seems to avert inflammation and may help prevent sterile tissue lysis and prolong retention.

Outcomes of Pre-Descemet Endothelial Keratoplasty for Failed Therapeutic Penetrating Keratoplasty

PURPOSE

The aim of this study was to analyze the outcomes of pre-Descemet endothelial keratoplasty (PDEK) for failed therapeutic penetrating keratoplasty.

METHODS

This was a retrospective, interventional study that involved 12 eyes of 12 patients with failed therapeutic penetrating keratoplasty that underwent PDEK. All cases had a minimum follow-up of 12 months. The main outcome measures were best-corrected visual acuity, graft clarity, endothelial cell density loss, and graft survival. Corneal clarity was graded on a scale from 0 to 4, where grade 4 denoted an absolutely clear cornea and grade 0 denoted a totally opaque cornea. Three cases underwent PDEK, 6 cases PDEK with phacoemulsification, and 3 cases underwent PDEK with pupilloplasty.

RESULTS

The mean follow-up period for all cases was 18.5 ± 4.9 months. The mean preoperative and postoperative best-corrected visual acuity (in Snellen decimal equivalent) was 0.02 ± 0.01 and 0.54 ± 0.17, respectively, at the last follow-up. Postoperatively, corneal clarity grade 4 was present in 9 eyes, grade 3 in 2 eyes, and grade 2 in 1 eye. Mild subepithelial haze was noted in 2 eyes. The percentage of endothelial cell density loss was 28.2% ± 10.6%. No correlation was observed between the postoperative graft clarity and preoperative specular count (r = -0.021, P = 0.512). Rebubbling was performed for 1 eye that developed partial graft detachment in the first postoperative week. One patient had an episode of rejection that was managed with systemic and topical steroids.

CONCLUSIONS

In patients with failed therapeutic penetrating keratoplasty, PDEK can be a useful alternative for visual rehabilitation as it demonstrates favorable visual outcomes with a good graft survival rate.

Repeat corneal transplantation in Southern China: Indications, surgical technique, outcomes, and risk factors for repeat keratoplasty failure

PURPOSE

To report the indications, surgical techniques, and outcomes of repeat keratoplasty and evaluate the risk factors for graft failure in the Chinese population.

METHODS

The medical records of 216 patients (243 cases) who underwent at least two keratoplasties at a leading eye hospital in southern China between 2011 and 2020 were retrospectively reviewed. Indications and surgical procedures for repeat corneal transplantation were analyzed. Kaplan-Meier survival analysis was used to determine the graft survival rate after repeat keratoplasty. A multivariable survival model was used to assess the risk factors.

RESULTS

Repeated keratoplasties increased continuously from 2011 to 2020 (P = 0.002). The most common primary indication was infectious keratitis (38.7%), and the most common reason for repeat keratoplasty was graft rejection (30.04%). Regraft techniques included penetrating keratoplasty (PK) in 165 cases (67.9%), deep lamellar keratoplasty (DALK) in 52 cases (21.40%), and endothelial keratoplasty (EK) in 26 cases (10.7%). Median survival was 5.3, 6.8, and 6.4 years for PK, DALK, and EK, respectively. The 5-year survival rate was 53.5%, 66.6%, and 69.8% for PK, DALK, and EK, respectively. The median LogMAR visual acuity was 1.4 for PK, 0.75 for DALK, and 1.2 for EK at the end of the follow-up. Multivariate analysis revealed that graft rejection is a risk factor for repeat keratoplasty failure (P = 0.002).

CONCLUSIONS

DALK and EK may provide better outcomes than PK in treating graft failure. Preventing and treating postoperative graft rejection may be key to improving regraft survival. These findings will aid in the management of failed corneal grafts.

Descemet Membrane Endothelial Keratoplasty for Penetrating Keratoplasty

Background

Descemet membrane endothelial keratoplasty (DMEK) has been utilized more frequently during recent years to treat penetrating keratoplasty (PKP) graft failures. The perioperative evaluation technique of anterior segment optical coherence tomography (AS-OCT) is increasingly significant. Our goal is to discuss DMEK surgical and clinical for subsequent PKP graft failure, along with significant surgical modifications and adjustments in accordance with preoperative assessment utilizing AS-OCT.

Materials and Methods

Patients' records who performed DMEK for PKP failure were retrospectively reviewed. Demographic information, PKP graft size determined by postoperative problems, corneal donor endothelial cell density (ECD), AS-OCT, central pachymetry, visual acuity (VA) evaluated in Snellen units, intraoperative surgical procedure modifications, and postoperative ECD were all included in the data collection.

Results

The observation was conducted with 16 patients with 16 eyes, nine males and seven females. The observation period is 18 months. DMEK was performed at an average age of 63. Preoperative AS-OCT was performed on all patients, and based on cases, surgical plans were created. Before processing DMEK, the mean VA is 0.04, and central pachymetry is 685 m. They improved considerably to 0.3 (P value = 0.001) and 542 m (P value = 0.008) at the most recent follow-up. About 93.75% of the grafts were adhered to after the procedure. Late decompensation caused a 6.25% graft failure rate. Graft detachment rates and cases requiring rebubble rates were respectively 18.75%.

Conclusion

In DMEK for failed PKP, a good case-specific preoperative assessment by AS-OCT is essential. As a result, it relies on developing a surgical strategy that can improve surgical outcomes, lower the risk of complications, and quicken visual recovery.

Management and prevention of corneal graft rejection

The management of an episode of corneal graft rejection (CGR) is primarily by corticosteroids. Immunomodulators are useful for long-term immunosuppression and in dealing with cases of high-risk (HR) corneal grafts. The classical signs of CGR following penetrating keratoplasty (PKP) include rejection line, anterior chamber (AC) reaction, and graft edema. However, these signs may be absent or subtle in cases of endothelial keratoplasty (EK). Prevention of an episode of graft rejection is of utmost importance as it can reduce the need for donor cornea significantly. In our previous article (IJO_2866_22), we had discussed about the immunopathogenesis of CGR. In this review article, we aim to discuss the various clinical aspects and management of CGR.

Twelve-Month Clinical and Histopathological Performance of a Novel Synthetic Cornea Device in Rabbit Model

Purpose

To report the biological stability and postoperative outcomes of a second-generation, single-piece, flexible synthetic cornea in a rabbit model.

Methods

Device materials and design were amended to enhance biointegration. Optic skirt design devices were made from compact perfluoroalkoxy alkane with porous expanded polytetrafluoroethylene ingrowth surface overlying the skirt and optic wall. Sixteen devices were implanted into intrastromal pocket in rabbit eyes. Rabbits were randomly assigned to 6- and 12-month follow-up cohorts (n = 8 in each) postoperatively. Monthly examinations and optical coherence tomography assessed cornea-device integration, iridocorneal angle, optic nerve, and retina.

Results

There were no intraoperative complications. All devices were in situ at exit, with clear optics. No retroprosthetic membrane, glaucoma, cataract formation, or retinal detachment was observed. Two rabbits in the 6-month group had mild, focal anterior lamella thinning without retraction adjacent to the optic near tight sutures. Three postoperative complications occurred in the 12-month group. One rabbit diagnosed with endophthalmitis was euthanized on day 228. Mild sterile focal retraction of anterior lamella occurred in two rabbits, which were terminated on days 225 and 315. Light microscopic examination of enucleated globes demonstrated fibroplasia with new collagen deposition into the porous scaffold without significant inflammation, encapsulation, or granuloma formation.

Conclusions

Clinical evaluations, imaging, and histopathological findings indicate favorable outcomes of this synthetic corneal device in a rabbit model. Early feasibility studies in humans are being planned.

Translational Relevance

Favorable 12-month results of the device in rabbits demonstrate vision-restoring potential in corneally blind individuals at high risk of failure with donor keratoplasty.

Etiology-Specific Comparison of the Long-Term Clinical Outcome of Repeat Deep Anterior Lamellar Keratoplasty for Optical Indications

PURPOSE

The aim of this study was to evaluate the etiology-specific clinical outcomes and complications of repeat deep anterior lamellar keratoplasty (DALK) after failed DALK.

METHODS

This retrospective case study included 32 eyes of 27 patients who underwent repeat DALK of 450 cases of DALK performed for optical indications between 1997 and 2013. The patients were divided into 4 etiology-specific subgroups (the corneal dystrophy, ocular surface disease, stromal scar, and others) or those with or without limbal stem cell deficiency (LSCD). The clinical outcomes evaluated were graft survival, best-corrected visual acuity, endothelial cell density, and complications.

RESULTS

The mean postoperative follow-up duration was 69.6 ± 54.8 months. The 1-, 3-, and 5-year overall graft survival rate were 76.7%, 57.5%, and 38.8% respectively. The graft survival rate was the highest in the corneal dystrophy group ( P = 0.0014) and was significantly ( P = 0.0010) higher in eyes without LSCD than in eyes with LSCD. There were no significant differences in the graft survival rates between the previous and current DALK groups. The postoperative best-corrected visual acuity of all subjects improved significantly. The postoperative endothelial cell density did not decrease after repeat DALK. There were no significant differences in the incidence of complications between patients with and without LSCD, except the incidence of persistent epithelial defects.

CONCLUSIONS

Repeat DALK had favorable outcomes in all etiology-specific groups, whereas eyes with LSCD required careful assessment of the ocular surface to avoid graft failure due to persistent epithelial defects.

Bowman Layer Transplantation for Treating Keratoconus-Preliminary Findings

(1) Background: Mid-stromal isolated Bowman layer transplantation aims to reduce and stabilize corneal ectasia in patients with advanced, progressive keratoconus. The purpose of this review is to evaluate the effectiveness and safety of this new surgical technique. (2) Methods: Following the PRISMA statement and checklist, we searched Medline, the Cochrane Controlled Trials Register, and Embase and used a broad systematic search strategy according to the Cochrane Collaboration. (3) Results: Eight studies with a total number of 120 eyes of 106 patients met our inclusion criteria. One month after Bowman layer transplantation, patients with keratoconus showed a significant decrease in the measured simulated keratometry (-4.74 D [95% CI -6.79 to -2.69]) and the maximum keratometry (-7.41 D [95% CI -9.64 to -5.19]), which remained significant one year postoperatively (-2.91 D [95% CI -5.29 to -0.53] and -5.80 D [-8.49 to -3.12]). Intra- and postoperative complications were observed in 3% and 9% of the patients, respectively. An estimated success rate of 75% to 85% was achieved by experienced surgeons at 5 to 8 years postoperatively. (4) Conclusions: Bowman layer transplantation may be an effective and safe treatment option in patients with advanced, progressive keratoconus. Additional multicenter prospective interventional studies are needed to confirm these preliminary findings.

Management and Treatment Outcomes of High-Risk Corneal Transplantations

Corneal transplantation is the most effective treatment for corneal blindness. Standard planned keratoplasties have a high success rate. Conditions such as active inflammation at the time of surgery, the presence of ocular surface disease, previous graft disease, or neovascularization make them more susceptible to rejection. These are so-called high-risk corneal transplantations. In our study, we selected 52 patients with a higher risk of graft rejection. A total of 78 procedures were performed. The main indications for the first keratoplasty were infections (59.6%) and traumas (21.2%). Visual acuity (VA) significantly improved from 2.05 logMAR on the day of keratoplasty to 1.66 logMAR in the latest examination (p = 0.003). An analysis of the graft survival showed a 1-year survival of 54% and a 5-year survival of 19.8% of grafts. The mean observation time without complications after the first, second, and third surgery was 23, 13, and 14 months, respectively. The best results were noted among patients with infectious indications for keratoplasty (p = 0.001). Among them, those with bacterial infection had the best visual outcomes (p = 0.047).

Review of Corneal Graft Registries

PURPOSE

Corneal graft registries are organized systems that collect and analyze outcome data (such as long-term graft survival and visual outcomes) after keratoplasty procedures. The aim of this review was to identify existing corneal graft registries and to describe their characteristics.

METHODS

A search of the PubMed database was performed on June 1, 2021, for articles pertaining to corneal graft registries.

RESULTS

The PubMed literature search yielded 958 publications, of which 116 met all the inclusion and exclusion criteria. Among these articles, 15 corneal graft registries were identified, including 6 regional registries, 8 national registries, and 1 multinational registry. This article provides an overview of their characteristics and discusses the main advantages and pitfalls of clinical registries.

CONCLUSIONS

Clinical registry data are increasingly recognized as a valuable tool to monitor corneal transplant outcomes to improve health care services and optimize resource management.

[Descemet membrane endothelial keratoplasty (DMEK) for graft failure after penetrating keratoplasty and in vascularized high-risk eyes]

BACKGROUND

Descemet membrane endothelial keratoplasty (DMEK) is considered the gold standard for the treatment of corneal endothelial dysfunction and generally leads to good postoperative results. Recently, studies have also analyzed the outcome of DMEK in so-called high-risk eyes.

MATERIAL AND METHODS

The relevant literature and own data on DMEK for graft failure after penetrating keratoplasty and in vascularized high-risk eyes are presented and discussed.

RESULTS

A DMEK for the treatment of transplant failure after penetrating keratoplasty can be considered for eyes without stromal scars and without high astigmatism. A retrospective analysis of 52 patients with failed penetrating grafts showed that DMEK leads to a significant increase in visual acuity, albeit to a lesser extent than after primary DMEK. Rejection and transplant failure rates seem to be similar those seen after penetrating re-keratoplasty and are thus higher than after primary DMEK. A DMEK might also be a feasible option for eyes with corneal neovascularization and stromal edema without stromal scars. A retrospective analysis of 24 eyes with at least 2 vascularized corneal quadrants demonstrated that DMEK leads to a significant improvement in visual acuity and regression of corneal neovascularization. The rejection rate in this cohort was 4.2% and is therefore slightly higher than after low-risk DMEK in eyes without corneal neovascularization but still much better compared to penetrating keratoplasty.

CONCLUSION

Indications for DMEK are expanding and it can be a therapeutic option for transplant failure after penetrating keratoplasty with acceptable outcomes. Furthermore, DMEK seems to be a good option for the treatment of endothelial dysfunction in vascularized high-risk eyes without stromal scars.

Management of Post-DALK Recipient Posterior Stromal Scarring: A Novel Approach

AIM

Management of recipient posterior stromal scarring following deep anterior lamellar keratoplasty (DALK) by a novel approach.

METHODS

A side port knife bent at the tip is used to make a linear incision in the host posterior stroma. Plane between host posterior stroma and DALK tissue is separated using a reverse sinskey hook and multiple radial incisions are made using microvitroretinal scissors. The recipient posterior stromal wedges are removed using 20G vitrector with a cut rate of 800 cuts/min. A Descemet stripping endothelial keratoplasty lenticule is inserted into the anterior chamber and apposed to the posterior surface of DALK tissue using air tamponade.

RESULT

This technique was used in 10 patients who showed clearing of the scarring after the surgery with good apposition of the donor graft to the previous DALK tissue. Conclusion: This is a sutureless, relatively simple, inexpensive, and effective novel surgical technique that avoids complications of open sky procedure and can be replicated in any ophthalmologic operation theatre setup.

Applications of augmented reality in ophthalmology [Invited]

Throughout the last decade, augmented reality (AR) head-mounted displays (HMDs) have gradually become a substantial part of modern life, with increasing applications ranging from gaming and driver assistance to medical training. Owing to the tremendous progress in miniaturized displays, cameras, and sensors, HMDs are now used for the diagnosis, treatment, and follow-up of several eye diseases. In this review, we discuss the current state-of-the-art as well as potential uses of AR in ophthalmology. This review includes the following topics: (i) underlying optical technologies, displays and trackers, holography, and adaptive optics; (ii) accommodation, 3D vision, and related problems such as presbyopia, amblyopia, strabismus, and refractive errors; (iii) AR technologies in lens and corneal disorders, in particular cataract and keratoconus; (iv) AR technologies in retinal disorders including age-related macular degeneration (AMD), glaucoma, color blindness, and vision simulators developed for other types of low-vision patients.

Long-term outcome of descemet membrane endothelial keratoplasty (DMEK) following failed penetrating keratoplasty (PK)

PURPOSE

To assess the long-term outcome of Descemet membrane endothelial keratoplasty (DMEK) following failed penetrating keratoplasty (PK).

METHODS

Retrospective review of 1840 consecutive DMEK surgeries from the prospective Cologne DMEK database performed between 07/2011 and 08/2017 at the Department of Ophthalmology, University of Cologne.

RESULTS

Fifty-two eyes received a DMEK surgery after failed PK. Main indications for initial PK were Fuchs endothelial corneal dystrophy (23.1%), keratoconus and herpetic keratitis (each 15.4%). Best-corrected visual acuity (BCVA) at 3, 6 and 12 months was 0.72 ± 0.39 (n = 33), 0.56 ± 0.36 (n = 32) and 0.38 ± 0.28 (n = 23), respectively. Two- and 3-year BCVA was 0.37 ± 0.21 (n = 21) and 0.32 ± 0.18 (n = 10). Mean improvement in visual outcome in logMAR lines was +4.3 ± 3.4 at 6 months, +5.0 ± 3.6 at 12 months, +6.0 ± 2.3 at 24 months and +5.4 ± 2.7 at 36 months, respectively. 59.6% received at least one rebubbling and 40.4% did not necessitate a rebubbling. Endothelial cell density (ECD)-decrease at 6 months was 36% (n = 17), 37% at 12 months (n = 17), 40% at 2 years (n = 8) and 32% at 3 years (n = 2). 34.6% of transplants needed a regraft.

CONCLUSION

Descemet membrane endothelial keratoplasty (DMEK) is a feasible treatment option after failed PK having a relatively good long-term outcome.

High-risk Corneal Transplantation: Recent Developments and Future Possibilities

Human corneal transplantation (keratoplasty) is typically considered to have superior short- and long-term outcomes and lower requirement for immunosuppression compared to solid organ transplants because of the inherent immune privilege and tolerogenic mechanisms associated with the anterior segment of the eye. However, in a substantial proportion of corneal transplants, the rates of acute rejection and/or graft failure are comparable to or greater than those of the commonly transplanted solid organs. Critically, while registry data and observational studies have helped to identify factors that are associated with increased risk of corneal transplant failure, the extent to which these risk factors operate through enhancing immune-mediated rejection is less clear. In this overview, we summarize a range of important recent clinical and basic insights related to high-risk corneal transplantation, the factors associated with graft failure, and the immunological basis of corneal allograft rejection. We highlight critical research areas from which continued progress is likely to drive improvements in the long-term survival of high-risk corneal transplants. These include further development and clinical testing of predictive risk scores and assays; greater use of multicenter clinical trials to optimize immunosuppressive therapy in high-risk recipients and robust clinical translation of novel, mechanistically-targeted immunomodulatory and regenerative therapies that are emerging from basic science laboratories. We also emphasize the relative lack of knowledge regarding transplant outcomes for infection-related corneal diseases that are common in the developing world and the potential for greater cross-pollination and synergy between corneal and solid organ transplant research communities.

Repeat keratoplasty in failed Descemet stripping automated endothelial keratoplasty

Purpose:

To evaluate the clinical factors associated with repeat Descemet stripping automated endothelial keratoplasty (DSAEK) or penetrating keratoplasty (PKP) in cases of failed DSAEK.

Methods:

Retrospective observational study of cases with failed DSAEK admitted to our center for a repeat keratoplasty over 5 years (January 2013–Decemeber 2017) was undertaken. Demographic and perioperative details of all cases and type of repeat keratoplasty were recorded. Logistic regression analysis was performed to analyze the factors affecting the type of repeat keratoplasty.

Results:

A total of 94 eyes with failed DSAEK were evaluated. Repeat DSAEK was performed in 66% and PKP in 34% of cases. Significantly increased odds for requiring PKP were observed in association with stromal scarring [odds ratio (OR) = 2.9, P = 0.018)], trainee surgeons (OR = 4.05, P = 0.008), intraoperative complications (OR = 4.58, P = 0.003), scleral fixated intraocular lens or anterior chamber intraocular lens in situ (OR = 33.8, P < 0.001), secondary glaucoma (OR = 3.02, P = 0.015), peripheral anterior synechiae (OR = 8.6, P < 0.001), preoperative corneal thickness (OR = 1.01, P < 0001), time to primary surgery (OR = 1.03, P = 0.03), post-DSAEK host thickness (OR = 1.01, P < 0.001), and time interval from graft failure to regraft (OR = 1.18, P < 0.001). All eyes with congenital hereditary endothelial dystrophy, bee-sting-induced corneal decompensation, Axenfeld-Rieger syndrome, and multiple failed grafts underwent secondary PKP. All cases (nine eyes) that required surgical intervention for secondary glaucoma underwent secondary PKP (P < 0.001).

Conclusion:

Repeat DSAEK is feasible in up to two-third of cases of failed DSAEK. A PKP is required in one-third of cases, and various preoperative, intraoperative and postoperative factors are associated with unsuitability for repeat DSAEK.

Differential Survival of Penetrating and Lamellar Transplants in Management of Failed Corneal Grafts

Importance

An increasing proportion of corneal transplant procedures are undertaken for replacement of a failed previous graft. The proportion of lamellar transplant procedures has significantly increased. There are limited large-scale reports on regraft procedures that may help guide surgeons and patients in their choice of surgery.

Objective

To examine the corneal transplant replacement survival rates for the 3 main indications and types of regraft surgery.

Design, Setting, and Participants

This national transplant registry study examined surgery and follow-up data on all corneal transplants performed in the United Kingdom from April 1, 1999, through March 31, 2016.

Main Outcomes and Measures

Actuarial regraft 5-year survival rates were compared for the 3 main indications and types of graft: penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty for keratoconus, PK and endothelial keratoplasty (EK) for Fuchs endothelial dystrophy (FED), and pseudophakic bullous keratopathy (PBK).

Results

A total of 9925 regrafts were analyzed during the 17-year study period. Penetrating keratoplasty represented 7261 cases (73.2%) in the cohort. Endothelial keratoplasty increased by 1361.5%, from 12 (2.6%; 95% CI, 1.3%-4.5%) of all 467 regrafts during 2005-2006 to 292 (38.0%; 95% CI, 34.6%-41.6%) of 768 during 2015-2016. The median time to first regraft for all graft types was 28 months (interquartile range, 10-64 months). When examining all graft types performed for all indications, stratification of 5-year survival was found for successive grafts, with a difference in survival of 25 270 (72.5%; 95% CI, 71.7%-73.2%) from the first graft to 4224 (53.4%; 95% CI, 51.4%-55.4%) from the second graft and 1088 (37.3%; 95% CI, 33.4%-41.3%) from the second to third graft. For first regrafts in keratoconus and PBK, survival after lamellar and PK procedures was similar. For FED, there was a higher regraft survival after PK (375 [70.8%]; 95% CI, 64.6%-76.1%) compared with EK (303 [54.7%]; 95% CI, 45.8%-62.8%) (P < .001). For FED and PBK, there was no difference in first regraft survival identified between EK followed by PK vs PK followed by PK or EK followed by EK vs PK followed by EK.

Conclusions and Relevance

In this large registry-based analysis of corneal regraft survival, regraft survival was found to vary with indication for first graft surgery and for FED with type of regraft procedure performed. For FED and PBK, the permutation of graft and subsequent first regraft procedure were not associated with any survival benefit for the first regraft. These reported outcomes may assist decision-making in management of a failed corneal transplant.

Outcome and Histopathology of Secondary Penetrating Keratoplasty Graft Failure Managed by Descemet Membrane Endothelial Keratoplasty

PURPOSE

To describe the clinical outcome and histopathology of Descemet membrane endothelial keratoplasty (DMEK) performed for secondary graft failure after penetrating keratoplasty (PK).

METHODS

A total of 11 eyes from 10 patients who underwent DMEK for secondary PK graft failure at a tertiary referral center were included in this retrospective study. Best-corrected visual acuity, endothelial cell density, and central pachymetry were evaluated before and at regular time intervals up to 36 months after DMEK and complications were recorded; 1 post mortem cornea was available for light microscopy.

RESULTS

At their last follow-up visit (on average, 16 months after DMEK), 7 of 11 transplanted corneas were clear. In the 7 eyes with clear grafts, 5 had a best-corrected visual acuity of ≥20/25 (≥0.8), central pachymetry averaged 535 (±70) μm, and endothelial cell density averaged 1045 (±500) cells/mm. Of the 11 eyes, 4 required rebubbling in the early postoperative phase; 1 eye was left with a small (<1/3) detachment. Light microscopy of the pathology specimen showed complete attachment of the DMEK graft onto the preexisting PK posterior stroma, with interface scarring over DMEK graft folds and underneath the graft area that had initially been detached.

CONCLUSIONS

DMEK may be a viable option to manage secondary PK graft failure with acceptable outcomes in many cases. Rebubbling for graft detachment may be anticipated, especially because of preexisting glaucoma conditions (severe decompensation, hypotony, and tubes from glaucoma-draining devices). Graft reattachment may occur through interface scarring.

Endothelial keratoplasty versus repeat penetrating keratoplasty after failed penetrating keratoplasty: A systematic review and meta-analysis

Objective

This study sought to compare graft survival, graft rejection and the visual acuity outcome of endothelial keratoplasty (EK) with repeat penetrating keratoplasty (PK) after failed PK.

Methods

A systematic literature search with subsequent screening of the identified articles was conducted to obtain potentially eligible randomized clinical trials (RCTs) and comparative cohort studies. To assess the methodological quality of the included studies, the Jadad Scale or Newcastle-Ottawa Scale (NOS) was used based on the study design. To calculate the pooled odds ratios (ORs) for graft survival, graft rejection and the visual acuity outcome with 95% confidential intervals (CIs), a fixed- or random-effects model was applied based on the heterogeneity across studies.

Results

Four comparative cohort studies (n = 649 eyes) comparing the outcome of EK with repeat PK after failed PK were included in this review. These studies were considered high quality, with NOS scores ranging from 6 to 9. The EK group showed a significantly lower risk of graft rejection than the repeat PK group [0.43 (95% CI: 0.23–0.80, P = 0.007)]. In addition, no significant differences were observed in a comparison of graft survival and visual acuity (P values ranged from 0.81 to 0.97 using the Der-Simonian and Laird random-effects model).

Conclusions

As an alternative to repeat PK, EK after failed PK allows for potential reduction of the risk of graft rejection; however, it does not appear to confer a significant advantage in graft survival or visual acuity.

Deep Anterior Lamellar Keratoplasty After Descemet Stripping Automated Endothelial Keratoplasty

PURPOSE

To report the indications and long-term outcomes of deep anterior lamellar keratoplasty (DALK) performed after Descemet stripping automated endothelial keratoplasty (DSAEK) in cases of visually significant stromal opacities.

DESIGN

Retrospective, interventional, consecutive case series.

METHODS

Setting: Private hospital.

STUDY POPULATION

Thirteen eyes that underwent DALK after DSAEK at our institution. Indications for DALK after DSAEK included both stromal opacities persisting after DSAEK and stromal opacities occurring secondarily in post-DSAEK corneas. DALK was always performed in a standardized fashion including exchange of a disc of full-thickness recipient cornea (up to the DSAEK stromal surface),7.0 mm in diameter, with a donor lamella obtained by microkeratome-assisted dissection, punched to 7.0 mm and sutured into place with a double running 10-0 nylon suture.

MAIN OUTCOME MEASURES

Best spectacle-corrected visual acuity (BSCVA), manifest refraction, and endothelial cell density (ECD).

RESULTS

Mean follow-up was 26 ± 18 months (range = 6-60 months). Indications for DSAEK were full-thickness graft failure (n = 8), DSAEK graft failure (n = 3), and pseudophakic bullous keratopathy (n = 2). Indications for subsequent DALK were persisting stromal opacity (n = 9) and stromal opacities newly occurred after DSAEK as a result of HSV keratitis (n = 2) or interface infection (n = 2). After complete suture removal, mean BSCVA was 20/28 (0.14 ± 0.8 logMAR) in eyes without ocular comorbidities affecting visual acuity (n = 7), while refractive astigmatism was within 4 diopter (D) in all but 1 eye (average = 3.2 ± 1.4 D). No intraoperative complications were recorded.

CONCLUSIONS

Performing DALK on DSAEK eliminates the need for open-sky surgery, achieving visual results comparable to those of penetrating keratoplasty, while sparing a healthy endothelial graft.

Descemet membrane endothelial keratoplasty for graft failure following penetrating keratoplasty

PURPOSE

Descemet membrane endothelial keratoplasty (DMEK) is superior to penetrating keratoplasty (PK) in terms of visual rehabilitation, intraoperative safety and risk of rejection. Therefore, it seems reasonable to perform DMEK in eyes with endothelial failure following PK. We herein report our first clinical results.

METHODS

Nineteen eyes with endothelial graft failure following PK were treated with DMEK. The majority of these eyes (12) had limited visual potential. The major indication for DMEK was pain relief in patients with bullous keratopathy. Visual acuity (VA), central corneal thickness (CCT), rate of graft dislocations, graft survival, graft rejections and other complications were extracted from the medical records.

RESULTS

Although comorbidities limiting VA were present in 12 of the 19 eyes, VA increased from 0.05 to 0.1 (median) in 16 eyes. CCT decreased substantially (range 63-363 μm). Rebubbling was necessary in five eyes with incomplete graft adherence. There were two immunologic graft reactions and three graft failures. No major complications like endophthalmitis or expulsive bleeding occurred.

CONCLUSIONS

DMEK is feasible to treat endothelial graft failure following PK. This is even true for eyes with limited visual potential.

Outcomes of Repeat Keratoplasty for Failed Therapeutic Keratoplasty

PURPOSE

To analyze clinical outcomes of repeat optical penetrating (PK) or endothelial keratoplasty (EK) after failed therapeutic keratoplasty (TPK).

DESIGN

Retrospective consecutive, comparative, interventional case series.

METHODS

setting: LV Prasad Eye Institute, Hyderabad, India.

STUDY POPULATION

Patients aged >18 years who underwent a repeat PK or EK following a failed TPK with a follow-up of at least 1 year were included. Patients with culture-negative ulcers, viral etiology, coexistent ocular surface disease, and multiple grafts were excluded from the study.

INTERVENTION

PK or EK for failed TPK.

MAIN OUTCOME MEASURE

Corrected distance visual acuity at 1 year follow-up. secondary outcome measure: Graft clarity.

RESULTS

One hundred twelve eyes (67 PK, 45 EK) were included in the study. The PK group had a significantly higher number of cases with high-risk features prior to regraft. Improvement in visual acuity in each of the types of grafts was statistically significant (P < .01), but there was no difference between the 2 groups at 1 year postoperatively. A statistically significant proportion of grafts regained graft clarity after regrafting in the PK group (P < .01) but not in the EK group (P = .205) at 1 year postoperatively. Endothelial rejection rates were higher in the PK group. Subgroup analysis showed that eyes that had PK or EK for failed TPK conducted for Aspergillus keratitis showed better outcomes in terms of graft clarity. Kaplan-Maier (KM) survival analysis for graft clarity showed cumulative survival of 50% at 5 years. The survival using the KM curve was not statistically different between the 2 groups (P = .33).

CONCLUSION

This study shows that visual rehabilitation with relatively good functional outcomes can be achieved by performing repeat PK or EK in patients after failed TPK.

Three-dimensional ray-tracing model for the study of advanced refractive errors in keratoconus

We propose a numerical three-dimensional (3D) ray-tracing model for the analysis of advanced corneal refractive errors. The 3D modeling was based on measured corneal elevation data by means of Scheimpflug photography. A mathematical description of the measured corneal surfaces from a keratoconus (KC) patient was used for the 3D ray tracing, based on Snell's law of refraction. A model of a commercial intraocular lens (IOL) was included in the analysis. By modifying the posterior IOL surface, it was shown that the imaging quality could be significantly improved. The RMS values were reduced by approximately 50% close to the retina, both for on- and off-axis geometries. The 3D ray-tracing model can constitute a basis for simulation of customized IOLs that are able to correct the advanced, irregular refractive errors in KC.

Corneal surgery in keratoconus: which type, which technique, which outcomes?

Keratoconus is a disease characterized by progressive thinning, bulging, and distortion of the cornea. Advanced cases usually present with loss of vision due to high irregular astigmatism. A majority of these cases require surgical intervention. This review provides an update on the current treatment modalities of corneal surgery available for the management of advanced corneal ectasias.

Predictors of visual outcomes following Boston type 1 keratoprosthesis implantation

PURPOSE

To identify predictors of visual outcomes following Boston type 1 Keratoprosthesis (KPro) implantation.

DESIGN

Retrospective chart review.

METHODS

Data regarding preoperative clinical and demographic characteristics and postoperative course were collected.

PATIENTS

Fifty-nine eyes of 59 adult patients who underwent KPro implantation between January 2006 and March 2012 at a single tertiary care center.

MAIN OUTCOME MEASURES

Preoperative factors associated with all-cause and glaucoma-related loss of visual acuity from the best postoperative visual acuity noted.

RESULTS

Fifty-two of 59 eyes (88%) achieved improved vision post implantation, with 7 eyes failing to gain vision as a result of pre-existing glaucoma (n = 4) or retino-choroidal disease (n = 3). Twenty-one eyes (21/52, 40%) maintained their best-ever visual acuity at last visit (mean follow-up period was 37.8 months). The likelihood of maintaining best-ever vision was 71% at 1 year, 59% at 2 years, and 48% at 3 years. Primary KPro implantation was associated with a higher likelihood of losing best-ever vision as compared to KPro implantation as a repeat corneal procedure (hazard ratio [HR] = 3.06; P = 006). The main reasons for postimplantation vision loss was glaucoma (12/31, 39%), and the risk of glaucomatous visual acuity loss was 15% at 2 years and 27% at 3 years. Prior trabeculectomy was associated with a higher rate of vision loss from glaucoma (HR = 3.25, P = .04).

CONCLUSION

Glaucoma is the primary reason for loss of visual acuity after KPro implantation. Conditions necessitating primary KPro surgery are associated with more frequent all-cause vision loss. Prospective trials are necessary to better determine which clinical features best predict KPro success.

Matching for Human Leukocyte Antigens (HLA) in corneal transplantation - to do or not to do

As many patients with severe corneal disease are not even considered as candidates for a human graft due to their high risk of rejection, it is essential to find ways to reduce the chance of rejection. One of the options is proper matching of the cornea donor and recipient for the Human Leukocyte Antigens (HLA), a subject of much debate. Currently, patients receiving their first corneal allograft are hardly ever matched for HLA and even patients undergoing a regraft usually do not receive an HLA-matched graft. While anterior and posterior lamellar grafts are not immune to rejection, they are usually performed in low risk, non-vascularized cases. These are the cases in which the immune privilege due to the avascular status and active immune inhibition is still intact. Once broken due to infection, sensitization or trauma, rejection will occur. There is enough data to show that when proper DNA-based typing techniques are being used, even low risk perforating corneal transplantations benefit from matching for HLA Class I, and high risk cases from HLA Class I and probably Class II matching. Combining HLA class I and class II matching, or using the HLAMatchmaker could further improve the effect of HLA matching. However, new techniques could be applied to reduce the chance of rejection. Options are the local or systemic use of biologics, or gene therapy, aiming at preventing or suppressing immune responses. The goal of all these approaches should be to prevent a first rejection, as secondary grafts are usually at higher risk of complications including rejections than first grafts.

Review of 103 Swedish Healthcare Quality Registries

BACKGROUND AND OBJECTIVES

In the past two decades, an increasing number of nationwide, Swedish Healthcare Quality Registries (QRs) focusing on specific disorders have been initiated, mostly by physicians. Here, we describe the purpose, organization, variables, coverage and completeness of 103 Swedish QRs.

METHODS

From March to September 2013, we examined the 2012 applications of 103 QRs to the Swedish Association of Local Authorities and Regions (SALAR) and also studied the annual reports from the same QRs. After initial data abstraction, the coordinator of each QR was contacted at least twice between June and October 2013 and asked to confirm the accuracy of the data retrieved from the applications and reports.

RESULTS

About 60% of the QRs covered ≥80% of their target population (completeness). Data recorded in Swedish QRs include aspects of disease management (diagnosis, clinical characteristics, treatment and lead times). In addition, some QRs retrieve data on self-reported quality of life (EQ5D, SF-36 and disease-specific measures), lifestyle (smoking) and general health status (World Health Organization performance status, body mass index and blood pressure).

CONCLUSION

Detailed clinical data available in Swedish QRs complement information from government-administered registries and provide an important source not only for assessment and development of quality of care but also for research.

Corneal inflammation after miniature keratoprosthesis implantation

PURPOSE

To compare corneal inflammation after syngeneic and allogeneic penetrating keratoplasty (PK) with miniature Keratoprosthesis (m-KPro) implantation in mice.

METHODS

BALB/C (syngeneic) or C57BL/6 (allogeneic) corneas were transplanted onto BALB/C host beds as part of PK or m-KPro implantation. Corneal inflammation was assessed by determining the frequencies of CD45(+) leukocytes, CD4(+) T cells, CD11b(+) cells, and Gr-1(+) granulocytes/monocytes by flow cytometry at 2, 4, and 8 weeks post transplantation. In addition, expression levels of the proinflammatory cytokines TNF-α and IL-1β were analyzed using real-time qPCR at 8 weeks post transplantation.

RESULTS

Cell frequencies in the syngeneic (syn) and allogeneic (allo) m-KPro groups were higher compared with the syngeneic and allogeneic PK groups, respectively, at all time points. However, after week 4, frequencies of all analyzed immune cells were higher in the alloPK group as compared with synKPro group. At 8 weeks, the expression of TNF-α was higher in synKPro, alloPK, and alloKPro groups compared with the naïve and synPK groups. The expression of IL-1β was significantly higher in both KPro groups as compared with PK groups.

CONCLUSIONS

Although the m-KPro device augments the inflammatory response in the cornea after its implantation, allogenicity (of the carrier tissue) is also a significant contributor to corneal inflammation. These data suggest that using syngeneic or decellularized corneal tissue as a Boston-KPro carrier could reduce the postoperative inflammation response.

Ocular manifestations of graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation (HSCT) has evolved over the past two decades to become the standard of care for hematologic and lymphoid malignancies. Major ocular complications after allogeneic HSCT have been increasing in number and severity. Graft-versus-host disease (GVHD) remains a major cause of ocular morbidity after allogeneic HSCT. The main objective of this review is to elucidate the ocular complications in patients developing GVHD following HSCT. Ocular complications secondary to GVHD are common and include dry eye syndrome, acquisition of ocular allergy from donors with allergic disorders. Eyelid changes may occur in GVHD leading to scleroderma-like changes. Patients may develop poliosis, madarosis, vitiligo, lagophthalmos, and entropion. The cornea may show filamentary keratitis, superficial punctate keratitis, corneal ulcers, and peripheral corneal melting which may lead to perforation in severe cases. Scleritis may also occur which can be anterior or posterior. Keratoconjunctivis sicca appears to be the most common presentation of GVHD. The lacrimal glands may be involved with mononuclear cell infiltration of both the major and accessory lacrimal glands and decrease in tear production. Severe dry eye syndrome in patients with GVHD may develop conjunctival scarring, keratinization, and cicatrization of the conjunctiva. Therapy of GVHD includes systemic immunosuppression and local therapy. Surgical treatment in refractory cases includes surgical intervention to improve the manifestation of GVHD of the eye. This may include tarsorrhapy, prose lenses, punctal occlusions and corneal transplantation.