Corneal graft survival and visual outcome. A multicenter Study. Corneal Transplant Follow-up Study Collaborators

Risk factors for corneal graft rejection after penetrating keratoplasty for keratoconus

PURPOSE

To evaluate the association between donor-related factors and the risk of rejection in patients undergoing penetrating keratoplasty (PKP) for keratoconus.

METHODS

A retrospective review was performed of keratoconus patients with no corneal neovascularization who underwent PKP from November 2014 to December 2016 and completed at least two years of follow-up. Preoperative, donor, operative, and postoperative data were collected and analyzed to identify factors leading to corneal graft rejection.

RESULTS

A total of 201 eyes (of 201 patients) that underwent PKP for keratoconus were included. Of these, 22.9% (95% CI 17.6-29.2%) had an episode of graft rejection. The overall graft survival rate was 98.5%. Receipts with a history of corneal transplant in the fellow eye (IRR 1.69, 95% CI 1.01, 2.80; p = 0.044) and those with postoperative stromal neovascularization (IRR 2.51, 95% CI 1.49, 4.21; p = 0.001) had a significantly higher incidence of rejection than those without these features. In univariate analysis, death-to-surgery time and death-to-excision time (DET) showed a weak association with graft rejection (p 0.05 and 0.08 respectively); However, in the multivariable analysis, this significance was lost. Grafts with a death-to-excision time (DET) greater than 8 h had a 0.53X lower risk of rejection compared with grafts with DET within 8 h or less (p = 0.05). Rejection was higher in patients receiving grafts with a preservation time within 7 days or less compared with preservation time greater than 7 days (30.6% vs. 21.2%, respectively, p = 0.291).

CONCLUSION

In the multivariable analysis, none of the donor-related factors were significantly associated with graft rejection; however, short death-to-surgery time may be associated with rejection after PKP. Recipients with a history of PKP in the fellow eye and those who developed corneal neovascularization were also at increased risk of developing rejection after keratoplasty.

Topical tacrolimus for high-risk corneal transplantation: a randomized, clinical trial

BACKGROUND

The prevalence of rejection is 10-30% in penetrating keratoplasty (PKP) case, and the rate is higher in cases of high-risk patients. Although using topical corticosteroids is a standard method for management the rejection of post-PKP patients, it may not be sufficiently potent in high-risk patients. Topical administration of tacrolimus (TAC) may be effective in suppression rejection after corneal transplantation. This study aimed to investigate the efficacy and safety of topical TAC in high-risk PKP patients in Japan.

METHODS

This study was a single centre, single-blinded, randomized controlled trial. Patients with a history of PKP, graft rejection, atopic dermatitis, or deep corneal neovascularisation who underwent PKP were enrolled. They were randomly assigned to receive 0.1% TAC ophthalmic suspension or artificial tear (AT) up to week 52 after surgery. All participants received 0.1% betamethasone up to week 13 after surgery then they received 0.1% fluorometholone up to week 52. The incidence of immunological rejection during the observation period was the main outcome measure in this study.

RESULTS

Thirty patients were enrolled in this study, and 12 eyes in the TAC group and 13 eyes in the AT group completed the study, respectively. Five out of 30 patients discontinued participation after providing informed consent. No serious adverse effects were developed in patients who received 0.1% TAC ophthalmic suspension. No rejection episodes occurred in the TAC group, while one eye in the AT group had rejection. Graft clarity, best spectacle-corrected visual acuity, intraocular pressure, and corneal endothelial cell density were not significantly different between the TAC and AT groups.

CONCLUSION

Our results demonstrated that good tolerability of 0.1% TAC ophthalmic suspension. However, we failed to demonstrate its efficacy in preventing immunological rejection in high-risk patients undergoing PKP.

TRIAL REGISTRATION

This study was first registered in the University Hospital Medical Information Network (UMIN000029669, Date of registration: November 1, 2017). With the enforcement of the Clinical Trial Act in Japan, the study re-registered in the Japan Registry of Clinical Trials (jRCTs031180342, Date of registration: March 18, 2019).

Long-Term Outcome After Bilateral Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Corneal Dystrophy

PURPOSE

The aim of this study was to assess the long-term clinical outcome, complications, and graft survival of bilateral Descemet membrane endothelial keratoplasty (DMEK) in patients with Fuchs endothelial corneal dystrophy.

METHODS

This was a retrospective cohort study of 181 patients (362 eyes) with sequential bilateral DMEK for Fuchs endothelial corneal dystrophy. Clinical outcomes were assessed up to 5 years postoperatively. Outcome measures were best-corrected visual acuity, pachymetry, endothelial cell density, graft survival, and complication rates.

RESULTS

Contralateral DMEK was performed on average 15 ± 11 months (range: 2-60 months) after the first eye. From 1 until 5 years after DMEK, best-corrected visual acuity, pachymetry, endothelial cell density, and graft survival did not differ between the first and second eyes (all P > 0.05). Graft detachment occurred in 67 eyes (19% [18% first eyes, 19% second eyes], 6% bilateral), graft rejection in 9 eyes (3% [3% first eyes, 2% second eyes], 1% bilateral), glaucoma in 25 eyes (7% [8% first eyes, 6% second eyes], 2% bilateral), and graft failure in 22 eyes (6% [4% first eye, 8% second eye], 2% bilateral). All differences were not significant (all P > 0.05). Five-year graft survival rates were comparable for first and second eyes (0.95 and 0.92, respectively; P = 0.15).

CONCLUSIONS

Clinical outcomes after bilateral DMEK are similar in both eyes and sustainable in the longer term. Within the first 5 years, the same complication may rarely occur in the contralateral eye.

3D printing sequentially strengthening high-strength natural polymer hydrogel bilayer scaffold for cornea regeneration

3D printing of high-strength natural polymer biodegradable hydrogel scaffolds simultaneously resembling the biomechanics of corneal tissue and facilitating tissue regeneration remains a huge challenge due to the inherent brittleness of natural polymer hydrogels and the demanding requirements of printing. Herein, concentrated aqueous solutions of gelatin and carbohydrazide-modified alginate (Gel/Alg-CDH) are blended to form a natural polymer hydrogel ink, where the hydrazides in Alg-CDH are found to form strong hydrogen bonds with the gelatin. The hydrogen-bonding-strengthened Gel/Alg-CDH hydrogel demonstrates an appropriate thickened viscosity and shear thinning for extrusion printing. The strong hydrogen bonds contribute to remarkably increased mechanical properties of Gel/Alg-CDH hydrogel with a maximum elongation of over 400%. In addition, sequentially Ca2+-physical crosslinking and then moderately chemical crosslinking significantly enhance the mechanical properties of Gel/Alg-CDH hydrogels that ultimately exhibit an intriguing J-shaped stress-strain curve (tensile strength of 1.068 MPa and the toughness of 677.6 kJ/m2). The dually crosslinked Gel-Alg-CDH-Ca2+-EDC hydrogels demonstrate a high transparency, physiological swelling stability and rapid enzymatic degradability, as well as suturability. The growth factor and drug-loaded biomimetic bilayer hydrogel scaffold are customized via a multi-nozzle printing system. This bioactive bilayer hydrogel scaffold considerably promotes regeneration of corneal epithelium and stroma and inhibits cornea scarring in rabbit cornea keratoplasty.

Pediatric corneal transplantation: techniques, challenges, and outcomes

Pediatric corneal transplant is a highly demanding and technically challenging procedure for the cornea surgeon in today's era. These cases pose unique challenges in clinical and surgical management. The indications of pediatric corneal transplant can be therapeutic, tectonic, optical, and cosmetic. Pediatric patients undergoing corneal transplants are at a high risk of graft infection, failure, rejection, dehiscence, and amblyopia due to young age, robust immune system, increased incidence of trauma, and compliance issues. The other factors contributing to graft failure can be allograft rejection, secondary glaucoma, corneal vascularization, multiple surgeries, vitreous prolapse, and lack of treatment compliance. A successful corneal transplant in children depends on meticulous preoperative evaluation, uneventful surgery, the expertise of a corneal surgeon, and regular and timely postoperative follow-up. Therapeutic and optical penetrating keratoplasty are the most commonly performed transplants in children. However, with the advancements in surgical technique and management protocol, the current focus has shifted toward lamellar keratoplasty. Lamellar keratoplasty offers early visual recovery and potentially fewer complications. Visual rehabilitation through corneal transplant in otherwise blind eyes can be a boon for the children. Recently, keratoprostheses have been promising in children with multiple graft failures. The current review gives insights into epidemiology, etiology, indications, clinical characteristics, investigations, management options, recent advances, and the future of pediatric corneal transplants. As surgical techniques continue to grow and comprehension of pediatric corneal transplants is improving, we can safeguard these eyes with the best possible anatomical and functional outcomes.

Keratoplasty Registries: Lessons Learned

ABSTRACT

Clinical registries have been developed for decades in the field of ophthalmology, and they are especially well-suited to the study of keratoplasty practices. A comprehensive donor/recipient registry system can provide insight into donor, recipient, and surgical factors associated with immediate and long-term outcomes and adverse reactions. Furthermore, linkage with demographic databases can elucidate relationships with social determinants of health and potentially shape public policy. The vast sample size and multicenter nature of registries enable researchers to conduct sophisticated multivariate or multilayered analyses. In this review, we aim to emphasize the importance of registry data for keratoplasty practice and 1) summarize the structure of current keratoplasty registries; 2) examine the features and scientific contributions of the registries from Australia, the United Kingdom, Singapore, the Netherlands, Sweden, Eye Bank Association of America, and European Cornea and Cell Transplant registries; 3) compare registry-based studies with large single-site clinical studies; 4) compare registry-based studies with randomized control studies; and 5) make recommendations for future development of keratoplasty registries. Keratoplasty registries have increased our knowledge of corneal transplant practices and their outcomes. Future keratoplasty registry-based studies may be further strengthened by record linkage, data sharing, and international collaboration.

Penetrating Keratoplasty: Indications and Graft Survival by Geographic Region

Corneal transplantation, or penetrating keratoplasty (PK), is the most common form of solid-organ transplantation performed worldwide. Here, we evaluated the indications for PK and rates of transplant survival around the world by geographic region. We conducted a literature search of PubMed, MEDLINE, and Google Scholar databases and identified 155 relevant studies from 41 countries published between 1987 and 2021. The most common indications for PK were keratoconus in Europe, Africa, the Middle East, Australia, New Zealand, and Central and South America, bullous keratopathy in North America, and corneal scarring in Asia. The overall global mean graft survival rates at 1-, 2-, 3-, 5-, and 10-years were 88.6%, 81.2%, 78.9%, 72.8%, and 61.2%, respectively. Through this systematic analysis of PK by region, we hope to bring a new perspective to the corneal transplantation literature and to potentially highlight global differences and unmet needs in patient care.

Development of a Nomogram to Predict Graft Survival After Penetrating Keratoplasty

PURPOSE

To develop a nomogram to predict the 3- and 5-year likelihood of graft survival after penetrating keratoplasty (PK) based on preoperative assessment and intraoperative plan.

DESIGN

Retrospective clinical case-control study.

METHODS

Data from 1,029 consecutive PKs in 903 eyes of 835 patients performed at a single tertiary center from May 2007 to September 2018 were extracted from electronic medical records and evaluated for corneal graft failure, defined as irreversible and visually significant graft edema, haze, or scarring. Thirty-seven variables were assessed by multivariable Cox models. A nomogram to predict the probability of graft survival was created.

RESULTS

Mean recipient age was 57.1 ± 22.0 years and mean follow-up was 4.22 ± 3.05 years. Overall, 37.4% of grafts failed during follow-up. Eleven variables were significantly associated with graft failure, including active microbial infection at the time of PK (hazard ratio [HR] = 5.10, 95% confidence interval [CI] 3.53-7.37), intraocular silicone oil at the conclusion of the PK (HR = 4.28, 95% CI 2.38-7.71), history of systemic autoimmune disease (HR = 2.83, 95% CI 1.63-4.90), 4 quadrants of corneal neovascularization (HR = 2.76, 95% CI 1.56-4.86), any prior anterior segment surgery (HR = 2.41, 95% CI 1.55-3.75), and lens status as anterior chamber intraocular lens at the conclusion of surgery (HR = 2.35, 95% CI 1.30-4.26). The nomogram exhibited a concordance index of 0.76 (95% CI 0.74-0.78); internal calibration plots depicted strong correlation between prediction and observation of graft survival.

CONCLUSIONS

PK graft prognosis may be predicted relatively accurately based on 11 variables. Although established from retrospective data, this nomogram would be valuable for data-driven patient counseling prior to corneal transplantation.

Random Survival Forests Analysis of Intraoperative Complications as Predictors of Descemet Stripping Automated Endothelial Keratoplasty Graft Failure in the Cornea Preservation Time Study

Importance

A new analytic method can evaluate factors of interest associated with graft failure after Descemet stripping automated endothelial keratoplasty (DSAEK) or more generally in any ophthalmic surgical setting with a time-to-event outcome.

Objective

To reanalyze types of intraoperative complications associated with DSAEK graft failure in the Cornea Preservation Time Study using random survival forests.

Design, Setting, and Participants

This cohort study, initially conceived in April 2019, used a prediction model to conduct a post hoc secondary analysis of data collected in a multicenter, double-masked, randomized clinical trial. Forty US clinical sites with 70 surgeons participated, with donor corneas provided by 23 US eye banks. The study included 1090 participants, representing 1330 eyes, undergoing DSAEK for Fuchs dystrophy (1255 eyes [94.4%]) or pseudophakic or aphakic corneal edema (75 eyes [5.6%]). Enrollment occurred between April 16, 2012, and February 20, 2014, and follow-up ended June 5, 2017. Statistical analysis was performed from July 10, 2019, to May 29, 2020.

Intervention

Descemet stripping automated endothelial keratoplasty with random assignment of a donor cornea with preservation time of 7 days or less or 8 to 14 days.

Main Outcomes and Measures

Ranked variable importance for intraoperative complications among 50 donor, recipient, and eye bank variables and restricted mean survival time through 47 months (1434 days) after DSAEK were examined. Random survival forests, a nonparametric method (with less restrictive model assumptions) that is far more flexible in its ability to model nonlinear effects and interactions, was used to analyze the data.

Results

This study included 1090 participants (663 women [60.8%]; median age, 70 years [range, 42-90 years]), representing 1330 eyes. Random survival forests ranked a DSAEK intraoperative complication as the third most predictive factor of graft failure, after surgeon and eye bank, in the final model with 5 predictors. In the first 47 months after DSAEK, the estimated mean difference in restricted mean survival time for grafts that experienced a DSAEK intraoperative complication vs those that did not was -227 days (99% CI, -352 to -70 days) based on the final RSF model.

Conclusions and Relevance

These findings, while post hoc, support the hypothesis that random survival forests allow for an improved analytic approach for identifying factors predictive of graft failure and for obtaining adjusted graft survival estimates. Random survival forests offer the opportunity to guide the development of future population-based cohort ophthalmic surgical studies, establishing definitive factors for procedural success.

Survival of penetrating keratoplasty: a claims-based longitudinal analysis

OBJECTIVES

To report real-world long-term survival of primary penetrating keratoplasty (PK) in the United States and analyze risk factors associated with failure.

DESIGN

Retrospective longitudinal cohort study using a large commercial insurance database.

PARTICIPANTS

Ten million patients enrolled in the database from 2011 to 2017 were identified using Current Procedural Terminology codes for PK.

METHODS

Kaplan-Meier survival analysis was performed to determine failure rate and risk factors impacting graft outcomes.

RESULTS

Five hundred and ninety-six primary PKs were identified. The 3-year survival was 78% (confidence interval [CI]: 73%-82%), 5-year survival was 76% (CI: 70%-80%), and 7-year survival was 73% (CI: 66%-79%).

CONCLUSION

This study demonstrated a significantly lower 5-year success rate for primary PK performed for all causes than previously published case series in the United States.

Initial High-Dose Prophylaxis and Extended Taper for Mushroom Keratoplasty in Vascularized Herpetic Scars

PURPOSE

To report the outcomes of initial high-dose and extended taper of antiviral and steroid prophylaxis for the treatment of eyes with high-risk vascularized herpetic corneal scars that underwent 2-piece mushroom keratoplasty (MK).

DESIGN

Prospective interventional case series.

METHODS

In this single-center study, 52 consecutive eyes with vascularized (≥2 quadrants) herpetic corneal scars underwent 2-piece microkeratome-assisted MK. Initial high-dose and extended taper of combined oral and topical antiviral and steroid prophylaxis was administered. Outcome measures were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism (RA), endothelial cell density, immunologic rejection, herpetic recurrence, and graft failure rates.

RESULTS

Excluding patients with vision-impairing comorbidities, baseline BSCVA (1.73 ± 0.67 logMAR) significantly improved annually during the first 2 years (P < .001, P = .016), reaching 0.17 ± 0.18 logMAR at year 2, and remaining stable up to 10 years (P = .662). At 2 years, 86% of eyes saw ≥20/40, 55% saw ≥20/25, and 18% saw ≥20/20 Snellen BSCVA. RA exceeded 4.5 diopters in 7% of cases after wound revision for high-degree astigmatism in 7 cases. Endothelial cell loss was 40.9% at 1 year with an annual decline of 3.1% over 10 years. The 10-year cumulative risk for immunologic rejection, herpetic recurrence, and graft failure was 9.7%, 7.8%, and 7.6%, respectively.

CONCLUSIONS

Initial high dose and extended taper of antiviral and steroid prophylaxis for MK in high-risk, vascularized herpetic corneal scars achieves clinical outcomes that remain stable for up to 10 years after surgery with minimal risk of immunologic rejection, herpetic recurrence and graft failure.

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.

Graft-size selection and anisometropia reduction in penetrating keratoplasty (PKP)

PURPOSE

To compare the amount of myopia induced by same-size donor-to-host penetrating keratoplasty with that of the amount of myopia induced by over-sized donor-to-host penetrating keratoplasty.

SETTING

Tertiary referral academic center.

DESIGN

Retrospective cohort study.

METHODS

Charts from patients who underwent penetrating keratoplasty by the same technique at Bascom Palmer Eye Institute between Nov 1, 2002, and January 1, 2006, were reviewed. The patients underwent optical penetrating keratoplasty using 12 interrupted 10-0 nylon sutures and a 12-bite continuous 10-0 nylon suture by a single surgeon (R.K.F.). The surgical technique used would be considered standard of care at most institutions. The Institutional Review Board, University of Miami Human Subjects Research Office, approved the study protocol. The donor graft was over-sized by 0.25mm in eyes when the intended final refractive target was greater than -1.00 diopters spherical equivalent (SE). The same-size donor graft was used when the intended final refractive target was less than -1.00 diopters SE. The selection of donor graft size was entirely based upon clinical parameters, meaning that the intended final refractive target was determined per each patient's fellow eye refraction, with the intention of reducing anisometropia. All patients received postoperative refraction and corneal topography. These measurements were performed at 6-8 weeks when the initial removal of sutures commenced, then at 6 months, then after completion of selective suture removal, then again at 12 months.

RESULTS

At 12 months, the over-sized group resulted in -1.35 diopters (SD = 2.25) SE of refraction, and the same-size group resulted in -0.14 diopters (SD = 2.42) SE. This approached statistical significance (p = 0.052) in comparison to -1.00 diopters spherical equivalent.

CONCLUSIONS

Using a donor graft that is over-sized by 0.25mm results in refraction of -1.00 diopters SE or more of myopia. Using a same-size donor-graft results in refraction of less than -1.00 diopters SE. Therefore, careful graft-size selection can result in a more favorable clinical outcome-namely, reduction in anisometropia-in patients undergoing penetrating keratoplasty.

Corneal endothelial cell dysfunction: etiologies and management

A transparent cornea is essential for the formation of a clear image on the retina. The human cornea is arranged into well-organized layers, and each layer plays a significant role in maintaining the transparency and viability of the tissue. The endothelium has both barrier and pump functions, which are important for the maintenance of corneal clarity. Many etiologies, including Fuchs’ endothelial corneal dystrophy, surgical trauma, and congenital hereditary endothelial dystrophy, lead to endothelial cell dysfunction. The main treatment for corneal decompensation is replacement of the abnormal corneal layers with normal donor tissue. Nowadays, the trend is to perform selective endothelial keratoplasty, including Descemet stripping automated endothelial keratoplasty and Descemet’s membrane endothelial keratoplasty, to manage corneal endothelial dysfunction. This selective approach has several advantages over penetrating keratoplasty, including rapid recovery of visual acuity, less likelihood of graft rejection, and better patient satisfaction. However, the global limitation in the supply of donor corneas is becoming an increasing challenge, necessitating alternatives to reduce this demand. Consequently, in vitro expansion of human corneal endothelial cells is evolving as a sustainable choice. This method is intended to prepare corneal endothelial cells in vitro that can be transferred to the eye. Herein, we describe the etiologies and manifestations of human corneal endothelial cell dysfunction. We also summarize the available options for as well as recent developments in the management of corneal endothelial dysfunction.

Systemic Immunosuppression in High-Risk Penetrating Keratoplasty: A Systematic Review

Cornea transplantation has a high success rate and typically only requires topical immunomodulation. However, in high-risk cases, systemic immunosuppression can be used. We conducted a systematic review on the efficacy and side effects of systemic immunosuppression for high-risk cornea transplantation. The study population was 18 years old or older with a high-risk transplant (two or more clock hours of cornea vascularization or a previous failed graft or a graft needed because of herpes simplex keratitis). A comprehensive search strategy was performed with the help of an information specialist and content experts from ophthalmology. All study designs were accepted for assessment. Level 1 and level 2 screening was performed by two reviewers followed by data abstraction. Forest plots were created whenever possible to synthesize treatment effects. Quality assessment was done with a Downs and Blacks score. From 1,150 articles, 29 were ultimately used for data abstraction. The odds ratios (ORs) for clear graft survival in cyclosporine and controls were 2.43 (95% CI: 1.00 - 5.88) and 3.64 (95% CI: 1.48 - 8.91) for rejection free episodes. Mycophenolate mofetil (MMF) significantly improved the rejection free graft survival rates at 1 year (OR: 4.05, 95% CI: 1.83 - 8.96). The overall results suggested that both systemic cyclosporine and MMF improved 1-year rejection free graft survival in high-risk keratoplasty. Cyclosporine also significantly improved clear graft survival rates at 1 year; however, there were insufficient data to analyze the same in the MMF group. Higher quality studies are needed to understand this issue better.

Efficacy and safety of systemic tacrolimus in high-risk penetrating keratoplasty after graft failure with systemic cyclosporine

PURPOSE

The aim of this study was to investigate the efficacy and safety of systemic tacrolimus for the treatment of eyes that developed graft failure despite treatment with cyclosporine (CsA).

METHODS

Ten eyes of 10 patients who underwent high-risk penetrating keratoplasty (PKP) and developed graft failure despite treatment with systemic CsA were included in this study. The patients underwent PKP and were treated with systemic tacrolimus according to the standardized protocol.

RESULTS

Treatment with tacrolimus was continued for 18.1 ± 13.9 months. The median duration of corneal graft clarity was 34.5 months. Graft rejection occurred in 2 of 10 eyes during a mean follow-up period of 48.9 ± 22.9 months. Kaplan-Meier survival plots showed significantly fewer graft rejection episodes (P = 0.033) and longer graft survival (P = 0.042) after treatment with tacrolimus compared those with CsA. Tacrolimus was discontinued in 2 patients; 1 had renal dysfunction and the other had muscle pain and fatigue. These side effects subsided after discontinuation of tacrolimus.

CONCLUSIONS

Treatment with systemic tacrolimus is possibly safe and effective in reducing graft rejection and prolonging graft survival in patients with high-risk PKP after graft failure with systemic CsA.

Long-term resolution of immunological graft rejection after a dexamethasone intravitreal implant

PURPOSE

To present the results of the injection of an intravitreal implant of dexamethasone 0.7 mg (DEX 0.7 mg) in 4 patients with an immunologic graft rejection after penetrating keratoplasty.

METHODS

Two of the patients received DEX 0.7 mg because inflammation and corneal edema not related to endothelial cell loss persisted despite the administration of topical prednisolone acetate, subconjunctival betamethasone, and systemic methylprednisolone. The other 2 cases received DEX 0.7 mg at the time rejection was diagnosed.

RESULTS

At 1 and 6 months after implantation, all rejection episodes resolved with improvement in uncorrected and best-corrected visual acuity, restoration of graft transparency, reduction of central corneal thickness, and no significant increase in intraocular pressure.

CONCLUSIONS

In 4 eyes with an immunologic graft rejection after penetrating keratoplasty, the dexamethasone 0.7 mg intravitreal implant was an effective treatment option, even in cases refractory to standard topical and systemic therapy.

A preliminary descriptive analysis of Corneal Transplant Registry of National Eye Bank in India

PURPOSE

To describe and analyze the Corneal Transplant Registry of National Eye Bank and also evaluate graft outcomes in India.

METHODS

All patients who underwent corneal transplant at our center within six months of setting up of Corneal Transplant Registry and installation of database at National Eye Bank were included in the study. The established database was analyzed for utilization, donor and recipient details and graft outcomes. Outcome was assessed at the end of one year follow up. The influence of various donor and recipient factors affecting outcome were evaluated. Visual outcome was analyzed in terms of shift in visual handicap category. Statistical tests like analysis of variance, Kruskal-Wallis test and Chi square tests were applied for determination of clinical significance wherever required.

RESULTS

326 corneas were received from 168 donors; of these, 234 (71.7%) were utilized for transplantation. Out of 177 patients with adequate (one year) follow up (75.6% patients), optical corneal replacement was performed in106 patients and therapeutic keratoplasty in71. 78% (82/106) patients in the optical group retained clear grafts at the end of follow up. 59.7% (49 of 82) of patients who attained clear grafts belonged to visual disability category 3 or worse pre-operatively. 59.1% of these achieved BCVA of ≥6/60 at the end of follow up; thus shifting up their visual handicap category. Primary graft failure was found to be associated with full thickness keratoplasty and not with lamellar procedures (p<0.05) and occurred in 4.2% patients (5) with optical corneal replacement whereas 7.5% patients (8) developed secondary graft failure. Age of donor (p=0.54), death enucleation time (p>0.05), cause of donor death (p=0.15), type of surgical procedures (p=0.538) and indication for surgery did not have any significant effect on outcome. 76% patients who underwent therapeutic graft achieved elimination of corneal infection.

CONCLUSIONS

The development of corneal graft registry established an effective means to evaluate our corneal transplantation services. Outcomes of sight restoring corneal transplants performed were comparable to results of graft registries from developed nations.

Prognostic factors for corneal graft recovery after severe corneal graft rejection following penetrating keratoplasty

Background

To investigate the outcome and prognostic factors for corneal graft recovery after severe corneal graft rejection following penetrating keratoplasty (PKP) treated with topical and systemic steroids.

Methods

Fifty-eight eyes in 58 patients with severe corneal graft rejection following PKP were treated with topical and systemic steroids. Factors affecting the reversibility and maintenance of graft transparency were analyzed.

Results

Graft transparency was restored in 37 of 58 eyes (63.8%). Clarity of the graft was maintained in 25 of 37 eyes after transparency was restored, while corneal decompensation developed at a mean of 6.0 ± 4.3 months in the remainder. The interval between rejection and treatment with systemic steroids was shorter in cases that recovered graft transparency (OR, 0.88, 95% CI. 0.80–0.97, P = 0.0093). Corneal decompensation after the recovery of corneal transparency tend to occur in cases of regraft (OR, 0.09, 95% CI. 0.01–0.54, P = 0.0091).

Conclusions

Severe corneal graft rejection after PKP was reversible in approximately two-thirds of the cases, with graft transparency being maintained in two-thirds of them when treated with both topical and systemic steroids. Early treatment confers a benefit in terms of the recovery of graft transparency.

Blepharoptosis repair outcomes from trainee versus experienced staff as the primary surgeon

PURPOSE

To compare outcomes of conjunctival Müllerectomy with or without tarsectomy versus external levator advancement for correction of upper blepharoptosis when performed by trainee versus staff surgeons.

DESIGN

Retrospective, nonrandomized, interventional, consecutive case series.

METHODS

Charts of patients undergoing conjunctival Müllerectomy with or without tarsectomy and external levator advancement blepharoptosis repair from January 2006 through December 2009 were reviewed. Main outcome measures included age, gender, preoperative and postoperative use of artificial tears, preoperative and postoperative marginal reflex distance, surgical complications, surgeon (trainee or staff surgeon), and anesthesia time. The Student t test was used for statistical analysis.

RESULTS

A total of 170 patients underwent 248 surgeries (154 conjunctival Müllerectomies with or without tarsectomy and 94 external levator advancements). There were 108 female and 62 male patients. Mean patient age was 62 years (range, 3 to 94 years). Forty-one (24%) patients (26 conjunctival Müllerectomies with or without tarsectomy and 15 external levator advancements) underwent concurrent eyelid surgery, such as blepharoplasty. Trainees performed surgery on a total of 88 (35%) eyelids in 60 patients (35%). There was no significant difference in the percentage of cases undergoing concomitant surgery between trainee and staff surgeons (P = .18). The mean postoperative marginal reflex distance difference was 0.53 and 0.59 for trainee and staff surgeons, respectively. Mean overall anesthesia time was 26.8 minutes and 30.3 minutes for trainee and staff surgeons, respectively. Complications, including increase in dry eye or irritative symptoms and reoperation, occurred in 8 (13%) of 60 patients undergoing surgery by a trainee surgeon and in 22 (20%) of 110 patients undergoing surgery by staff surgeon. There was no significant difference in eyelid symmetry (P = .55), mean anesthesia time (P = .14), complication rate (P = .26), or reoperation rate (P = .17) when surgery was performed by a trainee versus a staff surgeon.

CONCLUSIONS

There is no significant difference in mean postoperative marginal reflex distance, mean anesthesia time, complication rate, or reoperation rate between either conjunctival Müllerectomy with or without tarsectomy or external levator advancement blepharoptosis repair performed by trainee versus staff surgeons.

Vascular Endothelial Growth Factor Receptor 1 morpholino increases graft survival in a murine penetrating keratoplasty model

PURPOSE

This study sought to determine whether a Vascular Endothelial Growth Factor Receptor 1 (VEGFR1)-specific morpholino (MO) could decrease neovascularization, thereby enhancing murine cornea transplant survival, and if this effect is synergistic with steroid therapy.

METHODS

Graft survival, corneal neovascularization, and corneal lymphangiogenesis were compared among the VEGFR1_MO, STD MO and PBS groups following subconjunctival injection in mice that underwent normal risk penetrating keratoplasty (NR PK) and high-risk penetrating keratoplasty (HR PK). Graft survival, corneal neovascularization, and corneal lymphangiogenesis in groups treated with both VEGFR1_MO and steroid therapy were also analyzed in HR PK.

RESULTS

In NR PK, the VEGFR1_MO decreased angiogenesis, lymphangiogenesis, and increased graft survival compared with the PBS group (P = 0.055, P = 0.003, P = 0.043, respectively). In HR PK, VEGFR1_MO decreased angiogenesis, lymphangiogenesis, and increased graft survival compared with the STD MO (P = 0.000, P = 0.000, P = 0.029, respectively) and PBS groups (P = 0.004, P = 0.002, P = 0.024). In HR PK, when the VEGFR1_MO was combined with steroid therapy, a significant increase in graft survival was seen compared with steroid treatment alone (P = 0.045). The 2-month graft survival rate for HR PK was 27% in the combination group compared with 0% in the triamcinolone only group.

CONCLUSIONS

VEGFR1_MO decreased angiogenesis and lymphangiogenesis, resulting in increased graft survival in both NR PK and HR PK. This beneficial effect is synergistically enhanced with steroid treatment in HR PK.

Systemic cyclosporin treatment for high-risk corneal transplantation

The success rate for uncomplicated penetrating keratoplasty is very high. However, in high risk patients there is a significantly increased risk for immunologic graft failure and the success rate is relatively poor. Oral cyclosporin A treatment has dramatically decreased the rejection rate in solid organ transplantation. Its oral use in ophthalmology has so far been relatively limited and topical use restricted by poor penetration of the drug into ocular tissues. The favorable results of oral cyclosporin treatment to prevent corneal graft failure in high-risk patients is demonstrated in this study. High-risk corneal transplant patients were selected from the general population scheduled to undergo corneal transplantation. Twenty-two of 277 patients who were operated during a four-year period were regarded as high-risk keratoplasty patients. Systemic cyclosporin A treatment (5mg/kg/day) was given prophylactically to 14 of these patients who were considered to be at high-risk for keratoplasty rejection (CsA group). In addition the patients received a low dose of corticosteroids. Eight similar patients receiving high dose corticosteroids served as a control group (control group). In the CsA group graft survival was 78.6% compared with 37.5% in the control group at 1.5 years. The grafts of patients receiving CsA had a significantly better survival rate (p.o5) than those in control at one and 1.5 years. On the follow-up to four years graft survival in patients treated with CsA was, however, decreasing to 35.7%. The low graft survival in both high-risk groups is in great contrast to graft survival in all patients operated during the same period (93.1%). Systemic cyclosporin treatment when received at the time of the operation is effective in reducing failure from irreversible rejection in high-risk keratoplasty, but for maximal effect, a six-month period of treatment is too short. Subjective side effects were frequent but still acceptable. Blood tests did not reveal any pathological hepatic or renal laboratory values caused by system CsA administration. Careful and frequent follow-ups of the patients are however needed.

Endothelial keratoplasty: a revolution in evolution

Endothelial keratoplasty (EK) is continually evolving both in surgical technique and clinical outcomes. Descemet's stripping endothelial keratoplasty (DSEK) has replaced penetrating keratoplasty (PK) as the treatment of choice for corneal endothelial dysfunction. It is safe and predictable and offers early visual rehabilitation. Newer iterations include Descemet's membrane endothelial keratoplasty, Descemet's membrane automated endothelial keratoplasty, and other hybrid techniques. Early data on these newer EK techniques suggests that they provide significantly better visual outcomes compared to DSEK. Initial 5-year survival data indicates that EK is at least comparable to PK, and more widespread survival data is anticipated. Further work is needed to simultaneously optimize visual outcomes, refractive predictability, and endothelial cell survival, as well as surgical techniques of donor preparation and insertion.

A case of interface keratitis following anterior lamellar keratoplasty

Anterior lamellar keratoplasty (ALK) is indicated in patients with anterior corneal opacities. Benefits over penetrating keratoplasty include quicker visual rehabilitation, less postoperative astigmatism, and preservation of the host endothelium, thus minimizing the chances of graft rejection. A rare complication of lamellar corneal surgery is infectious interface keratitis between the donor and host tissue. We report a case of infectious interface keratitis following automated ALK successfully treated medically and by removal of the ALK disk, eventually having a deep anterior lamellar keratoplasty with good visual recovery.

Efficacy and safety of long-term corticosteroid eye drops after penetrating keratoplasty: a prospective, randomized, clinical trial

PURPOSE

Endothelial rejection remains a major cause of graft failure after penetrating keratoplasty (PKP). Topical corticosteroids are the gold standard for preventing rejection; however, protocols for corticosteroid treatment have been diverse. The aim of the present study was to examine the efficacy and safety of long-term use of corticosteroid eye drops after PKP in a randomized, clinical trial.

DESIGN

Randomized, nonblinded, clinical trial.

PARTICIPANTS

We enrolled 42 patients (21 males and 21 females) with a mean age of 65.3 years who underwent PKP and maintained graft clarity for >1 year with topical steroid eye drops.

INTERVENTION

Patients were randomly assigned to 1 of 2 groups: Administration of 0.1% fluorometholone 3 times a day (steroid group) or discontinuation of steroid eye drops (no steroid group). All patients were followed for 12 months.

MAIN OUTCOME MEASURES

Proportion of eyes without endothelial rejection and the proportion of eyes with clear grafts and the incidence of local or systemic side effects.

RESULTS

Of the initial 42 patients, 4 in the steroid group and 6 in the no steroid group did not complete the trial. Of the patients who completed the trial, 1 patient in the steroid group and 6 in the no steroid group developed endothelial rejection at an average of 5.2±4.5 (mean ± standard deviation) months after study enrollment. The difference in the incidence of rejection between groups was found to be significant by both chi-square (P = 0.027) and Kaplan-Meier analyses (log-rank test, P = 0.032). No difference was observed between the 2 groups in visual acuity, intraocular pressure, epithelial damage, tear-film break-up time, cataract progression, infection, or incidence of systemic side effects.

CONCLUSIONS

Prolonged use of 0.1% fluorometholone was beneficial for the prevention of rejection after PKP. Because no adverse consequences were noted, we recommend continuing use of the low-dose corticosteroids, even in non-high-risk cases.

Survival of mushroom keratoplasty performed in corneas with postinfectious vascularized scars

PURPOSE

To report the visual outcomes and graft survival rates of mushroom keratoplasty for the treatment of postinfectious corneal scars.

DESIGN

Prospective, noncomparative, interventional case series.

METHODS

A microkeratome-assisted mushroom-shaped keratoplasty was performed in 31 eyes of 31 patients with a central vascularized full-thickness leukoma, resulting from infectious keratitis of various origin (herpes simplex virus, n = 16; bacteria, n = 10; Acanthamoeba, n = 5), with healthy endothelium. The donor graft consisted of a large anterior stromal lamella (9.0 mm in diameter and ± 250 μm in thickness) and a small posterior button (5 to 6 mm in diameter). Visual acuity, refraction, and endothelial cell density were evaluated before surgery, as well as at 12, 24, and 36 months after surgery, and the postoperative graft survival rate was evaluated.

RESULTS

Three years after surgery, in 26 (83.8%) of 31 patients, best spectacle-corrected visual acuity was 20/40 or better with a refractive astigmatism of 4.5 diopters or less. The endothelial cell count at the last follow-up examination averaged 1584 ± 381 cells/mm(2), with an average cell loss of 40.7% from the preoperative value. The survival rate at 3 years was 90.3%, improving to 96.7% when excluding nonimmunologic causes for graft failure.

CONCLUSIONS

Similarly to penetrating keratoplasty, microkeratome-assisted mushroom keratoplasty restores vision in eyes with postinfectious, full-thickness, central corneal scars. For these vascularized corneas at high risk for immunologic rejection, mushroom keratoplasty combines the visual and refractive advantages of large penetrating keratoplasty grafts with the high survival rate of small penetrating keratoplasty grafts.

Treatments for corneal neovascularization: a review

Corneal neovascularization (CNV) may be a physiological response to various stimuli, but a chronic and persistent upregulation of neoangiogenesis can result in pathological CNV. Pathological blood vessels are immature and lack structural integrity, predisposing the cornea to lipid exudation, inflammation, and scarring. CNV can therefore become a potentially blinding condition. In this review, we frame CNV in an epidemiological perspective, consider risk factors for CNV, provide an overview of CNV pathogenesis, and consider the impact of CNV on corneal transplantation. We consider treatments that are of largely historical interest, before reviewing contemporary medical and surgical treatments. Within medical treatments, we report on steroids, nonsteroidal anti-inflammatory agents, antivascular endothelial growth factor agents, and cyclosporine. Within surgical treatments, we report on the use of lasers, photodynamic therapy, superficial keratectomy, and diathermy/cautery-based treatments.

Factors influencing outcomes of the treatment of allograft corneal rejection

PURPOSE

To identify patient characteristics influencing treatment outcomes of allograft corneal rejection.

DESIGN

Retrospective case file review.

METHODS

Files containing details of first episode of corneal allograft rejections in patients who underwent penetrating keratoplasty at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia from 1991 to 2006 were reviewed. Cases were divided into 2 groups based on the response to treatment for graft rejection: treatment responders and failures. Main parameters evaluated were demographic characteristics, preoperative clinical profile, donor characteristics, surgical technique, presentation, and treatment of rejection episode.

RESULTS

A total of 235 cases of graft rejection were identified, of which 195 cases (83%) were successfully treated and 40 (17%) failed to respond. Age (P = .08) and gender (P = .61) were comparable in both groups. On univariate analysis, primary diagnosis of keratoconus (P = .04) and phakic lens status at the time of surgery (P = .02) were more common in treatment responders whereas aphakic bullous keratopathy (P ≤ .01), history of glaucoma (P < .01), aphakia (P < .01), and previous grafts (P < .01) were more common among treatment failures. Multivariate analysis revealed that preoperative corneal neovascularization (adjusted odds ratio [aOR] 3.6, 95% CI: 1.3-9.7, P = .01), a larger (>9 mm) donor size (aOR 5.7, 95% CI: 1.3-24.9, P = .02), and corneal edema at presentation (aOR 4.7, 95% CI: 1.7-13.2, P < .01), were independently associated with failure of treatment of graft rejection.

CONCLUSIONS

Treatment failure in cases of corneal allograft rejection is more likely to occur among patients with corneal neovascularization, large donor graft buttons, and corneal edema at presentation.

Mushroom keratoplasty in pediatric patients

OBJECTIVE

To report the outcome of mushroom keratoplasty for the treatment of full thickness corneal disease in pediatric patients with healthy endothelium.

METHODS

A retrospective analysis of pediatric patients who underwent mushroom keratoplasty. The medical records of pediatric patients suffering from full thickness corneal stromal disease with normal endothelium who underwent mushroom keratoplasty at our Institution were included. A two-piece donor graft consisting of a large anterior stromal lamella (9.0 mm in diameter and ±250 μm in thickness) and a small posterior lamella (5-6.5 mm in diameter) including deep stroma and endothelium, prepared with the aid of a microkeratome had been transplanted in all cases. Ophthalmic examination including slit lamp examination, best corrected visual acuity, and corneal topography was performed preoperatively and at each postoperative visit on all patients. The endothelial cells were assessed by specular microscopy in these patients.

RESULTS

Six eyes of six patients (five males and one female) were included. The mean age was 9.3 years (range 5-15 years). Average follow-up was 17.8 months (range 9-48 months). There were no early or late complications recorded. All corneas were clear at the last follow up visit. Preoperative best corrected visual acuity (BCVA) was worse than 20/70 in all six eyes. Postoperatively, four eyes achieved BCVA of 20/40 or better. Endothelial cell loss (n eyes = 3 averaged 24% (range 19-31%). The mean endothelial cell loss was 24% (range 19-31%) among these patients.

CONCLUSIONS

Microkeratome assisted mushroom keratoplasty is a viable surgical option for pediatric eyes with full thickness corneal stromal disease and healthy endothelium. Mushroom keratoplasty combines the refractive advantage of a large penetrating keratoplasty with the survival advantage of a small penetrating keratoplasty. Furthermore, mushroom keratoplasty exhibits the mechanical advantage of a shaped keratoplasty.

Postkeratoplasty corneal wavefront analysis of selective suture removal

PURPOSE

To analyze the corneal wavefront higher order aberrations (HOAs) after penetrating keratoplasty and selective suture removal.

METHODS

All patients undergoing penetrating keratoplasty by the same surgeon (R.K.F.) using identical suturing technique were retrospectively identified. Corneal HOAs were calculated at the week 6, week 10, 6-month, and final postoperative visits and compared with simulated corneal astigmatism, surface regularity index, surface asymmetry index, and best-corrected visual acuity.

RESULTS

Ninety-two eyes were identified. Total corneal HOAs declined from the week 6 visit to the final visit (week 6: 0.65, final: 0.50, P = 0.041). Final visit linear regression demonstrated correlations of surface asymmetry index and surface regularity index with total corneal HOAs (R = 0.51 and R = 0.45, respectively). No relationship for simulated corneal astigmatism or vision was found with total corneal HOAs (R = 0.003 and 0.30, respectively).

CONCLUSIONS

Total corneal HOAs are increased in the early postkeratoplasty course, possibly representing the optical consequences of surface irregularity. Because simulated keratometry provides no information in regard to corneal HOAs, measuring HOAs may be indicated in select cases. Total corneal HOAs perhaps provide a clinical representation of irregular astigmatism. The visual significance of these total corneal HOAs was not evident.

The influence of donor and recipient factors in allograft rejection of the human cornea

The health of the corneal endothelium is essential in maintaining the clarity of the transplanted human cornea. Immune-mediated endothelial rejection is a complex series of events, which may culminate in the decompensation of the donor button. It is the commonest instigator of failure in penetrating corneal transplantation.

METHODS

This retrospective case note review of 203 penetrating keratoplasties with adequate follow-up data during a 5-year study period from 1 January 2000 to 31 December 2003 at Manchester Royal Eye Hospital, were used for analysis.

RESULTS

Forty-three of the 203 donor grafts underwent at least one single episode of immune-mediated endothelial rejection, an incidence of 21% over a 5-year follow-up. Recipient's age was inversely associated with the risk of rejection. The average age for the cohort of 58.7 years and average age for rejecting patients of 47.6 years were strongly significantly different (P=0.009). Rejection in keratoconic patients accounted for 30% of cases. Death to enucleation time (P=0.03) was also associated with an increased risk of rejection.

CONCLUSION

Although penetrating keratoplasty is an effective long-term treatment option for improving visual function, the endothelial rejection rate in our study was 21% over a mean follow-up of over 5 years. Host vascularisation, regrafts, younger recipient age group, and donor factors were found to be significantly associated with a risk of rejection. Rejection in keratoconic recipients was more common than expected.

The effect of donor age on corneal transplantation outcome results of the cornea donor study

OBJECTIVE

To determine whether graft survival over a 5-year follow-up period using corneal tissue from donors older than 65 is similar to graft survival using corneas from younger donors.

DESIGN

Multicenter prospective, double-masked, controlled clinical trial.

PARTICIPANTS

One thousand ninety subjects undergoing corneal transplantation for a moderate-risk condition (principally Fuchs' dystrophy or pseudophakic corneal edema); 11 subjects with ineligible diagnoses were not included.

METHODS

Forty-three participating eye banks provided corneas from donors in the age range of 12 to 75 with endothelial cell densities of 2300 to 3300 cells/mm(2), using a random approach without respect to recipient factors. The 105 participating surgeons at 80 sites were masked to information about the donor cornea including donor age. Surgery and postoperative care were performed according to the surgeons' usual routines. Subjects were observed for 5 years.

MAIN OUTCOME MEASURES

Graft failure, defined as a regraft or a cloudy cornea that was sufficiently opaque as to compromise vision for a minimum of 3 consecutive months.

RESULTS

The 5-year cumulative probability of graft survival was 86% in both the <66.0 donor age group and the >/=66.0 donor age group (difference = 0%, upper limit of 1-sided 95% confidence interval = 4%). In a statistical model with donor age as a continuous variable, there was no significant relationship between donor age and outcome (P = 0.11). Three graft failures were due to primary donor failure, 8 to uncorrectable refractive error, 48 to graft rejection, 46 to endothelial decompensation (23 of which had a prior, resolved episode of probable or definite graft rejection), and 30 to other causes. Distributions of the causes of graft failure did not differ between donor age groups.

CONCLUSIONS

Five-year graft survivals for cornea transplants at moderate risk for failure are similar using corneas from donors >/= 66.0 years and donors < 66.0. Surgeons and patients now have evidence that corneas comparable in quality to those used in this study from donors through age 75 are suitable for transplantation.

Contrast sensitivity in deep anterior lamellar keratoplasty versus penetrating keratoplasty

PURPOSE

To compare the measurements of contrast sensitivity at a distance in patients submitted to penetrating keratoplasty versus patients submitted to deep anterior lamellar keratoplasty for keratoconus treatment.

METHODS

Contrast sensitivity of 15 subjects submitted to penetrating keratoplasty and 15 subjects submitted to deep anterior lamellar keratoplasty have been analyzed through the Functional Acuity Contrast Test (F.A.C.T) 301.

RESULTS

There was no statistically significant difference between the measurements for penetrating keratoplasty and deep anterior lamellar keratoplasty.

CONCLUSION

Contrast sensitivity was similar among the subjects submitted to penetrating keratoplasty and to deep anterior lamellar keratoplasty for keratoconus treatment.

Microkeratome-assisted Posterior Lamellar Keratoplasty in Pseudophakic and Aphakic Corneal Edema

PURPOSE

To evaluate the outcome of microkeratome-assisted posterior lamellar keratoplasty for replacing diseased endothelium in pseudophakic and aphakic corneal edema.

METHODS

Microkeratome-assisted posterior lamellar keratoplasty was performed on 10 eyes with pseudophakic or aphakic corneal edema. A nasal hinged 130- to 250-microm-thick flap was created with an automated microkeratome. The underlying 7.0-mm trephined button of deep stroma and endothelium was substituted with the same size donor button prepared by removing a same-sized flap and trephination of the remaining donor bed. The donor lenticule was fixated without sutures in position; the retracted flap was repositioned and sutured to the peripheral recipient tissue. The viscoelastic content of the anterior chamber was replaced by air to hold the graft in position.

RESULTS

All surgeries were uneventful except for one case of donor button posterior dislocation forming a secondary anterior chamber, which was corrected through donor button exchange 1 month postoperatively. All uncomplicated cases had stable refraction and corneal topography as early as 1 month after surgery, which was maintained in follow-up examinations. In two eyes, corneal astigmatism > 5.00 diopters was recorded. One case of prolonged re-epithelialization and two cases of epithelial interface ingrowth occurred.

CONCLUSIONS

Microkeratome-assisted posterior lamellar keratoplasty is an alternative to conventional penetrating keratoplasty for patients with diseased corneal endothelium, significantly reducing the time of visual rehabilitation. Determination of the relative advantages of this technique over penetrating keratoplasty and other recent alternative endothelial graft procedures relies on controlled prospective studies.

Risk factors for endothelial cell loss post-keratoplasty

PURPOSE

Transplant survival following penetrating keratoplasty is determined to a large extent by the course of endothelial cell density loss. Different influencing factors such as organ culture conditions, surgical trauma, exchange between donor and recipient cells, cell ageing and immune reactions can contribute to endothelial cell loss. The aim of this study was to determine the rate of endothelial cell loss in our patients and to detect dependencies on donor-and recipient-related factors.

METHODS

Using non-contact specular microscopy, endothelial cell counts were obtained every 6 months from 293 consecutive patients who underwent keratoplasty in our institution between 1996 and 2000. Follow-up time was 36 months.

RESULTS

In comparison with the density of donor endothelial cells, the mean endothelial cell loss of patients was 28.8% after 6 months, 39.8% after 12 months and 49% after 24 months. Donor age and initial cell density did not have a significant influence on the course of endothelial cell loss. The lowest rate of endothelial cell loss was associated with patients diagnosed with keratoconus. Conversely, those with preoperative glaucoma had a significantly increased rate of endothelial cell loss (p < 0.05).

CONCLUSIONS

This study shows that preoperative glaucoma is a major risk factor for increased endothelial cell loss following keratoplasty.

Comparative cohort study of the outcomes of deep lamellar keratoplasty and penetrating keratoplasty for keratoconus

AIM

To compare the outcomes and complications of deep lamellar keratoplasty (DLK) and penetrating keratoplasty (PK) for keratoconus.

METHODS

A cohort of 20 consecutive PKs, for keratoconus, was compared with 20 consecutive DLKs, for keratoconus. The PKs were performed between June 2000 and July 2001, the DLKs between October 2001 and October 2002. Surgery was performed by one surgeon. Best-corrected visual acuities (BCVA), refraction and complications were recorded at the time of surgery, 6 and 12 months postoperatively. chi(2)-tests were used to compare visual acuity outcomes and independent t-tests in the analysis of astigmatism.

RESULTS

Groups were comparable for age, sex, and ethnicity. All PKs were uncomplicated. Two of the DLK group had microperforations of Descemet's membrane. There was no significant difference in the proportion of patients achieving 6/9 or better between the PK and DLK groups (85 vs 78%, P=0.54). PK patients were, however, more likely than the DLKs to achieve 6/6 at 1 year; 70% (14/20) of PKs compared to 22% of (4/18) DLKs (P=0.04). Astigmatism was significantly higher in the PKs compared to the DLKs (P=0.022). There were two cases of graft rejection in the PK group, while none in the DLKs.

CONCLUSIONS

This study confirms good visual results from both PK and DLK in keratoconus with similarly high percentages reaching 6/9 BCVA. DLK appears to cause less astigmatism and also has the advantage of no endothelial graft rejection. The apparent cost, however, is a reduction in the likelihood of achieving 6/6 BCVA.

[Satisfaction with penetrating keratoplasty. Results of a questionnaire census]

BACKGROUND

Penetrating keratoplasty (PKP) is commonly referred to as the most successful transplantation procedure in medicine. This appraisal, however, is currently poorly supported by evidence. The aim of our study was to collect data on patient satisfaction with PKP as well as to analyze factors predisposing to dissatisfaction.

PATIENTS AND METHODS

In the years 1988-2002 a total of 3,219 PKPs were performed on 2,981 patients. These patients were sent a questionnaire. The items pertained to subjective assessment of visual quality as compared to the situation before PKP and about regretting the PKP.

RESULTS

The questionnaire was answered by 1,142 patients (59% of the traceable persons). The mean follow-up was 3.3+/-2.9 years. Indications for PKP were Fuchs' endothelial dystrophy (26%), keratoconus (23%), bullous keratopathy (15%), and further indications (36%). For these groups, best corrected visual acuity improved by more than two lines in 51, 80, 42, and 50%, respectively. The percentage of subjective improvement of vision was 73, 78, 47, and 63%. The percentage of regretting the PKP was 12, 4, 27, and 10%, respectively. All differences were highly statistically significant. Significant influencing factors on regretting the PKP were (inversely sorted for relevance): repeat graft failure, bullous keratopathy, contact lens wear, paresthesia, removal of running sutures, and patient age.

CONCLUSIONS

General satisfaction with PKP is high. An important exception is bullous keratopathy, most likely due to accompanying morbidity (e.g., cystoid macular edema).

Tacrolimus immunosuppression in high-risk corneal grafts

BACKGROUND

Unlike the immune privilege enjoyed by low-risk corneal grafts, high-risk corneal grafts experience rejection rates comparable to liver and kidney transplants. Systemic immunosuppression reduces the risk of rejection in high-risk corneal grafts.

METHODS

Systemic tacrolimus, a specific T cell inhibitor, was used at a mean daily dose of 2.5 mg to immunosuppress 43 patients undergoing high-risk corneal transplantation. Immunosuppression was continued for a period of 18-24 months after the high-risk corneal graft.

RESULTS

During a mean follow-up period of 33.7 months, clarity of the graft was maintained in 65% of patients. Eight patients experienced rejection episodes while on tacrolimus, and this led to graft failure in five patients.

CONCLUSION

Tacrolimus is relatively safe and effective in reducing rejection and prolonging graft survival in patients with high-risk keratoplasty compared with other series where similar immunosuppression was not used.