Emergency corneal grafting in the UK: a 6-year analysis of the UK Transplant Registry

Patch endothelial keratoplasty for corneal perforations secondary to ocular surface disease: case series

BACKGROUND

Corneal perforation is an ophthalmic emergency. The conventional management of corneal perforation can be associated with severe complications especially in patients with ocular surface disease. Endothelial keratoplasty has been suggested as an alternative surgical technique for the management of corneal perforations. We present a case series of nine patients with corneal perforation and ocular surface disease managed with secondary patch endothelial keratoplasty.

METHODS

This is a retrospective case series of nine patch endothelial keratoplasties performed between 2016 and 2022 at a quaternary eye hospital in Australia. The surgical technique is similar to conventional endothelial keratoplasty except descemetorhexis was not performed.

RESULTS

A total of 9 cases were treated during the review period. Eight of the nine cases had an improvement in visual acuity. One case failed to achieve corneal tectonic objective.

CONCLUSION

Patch endothelial keratoplasty is a safe secondary procedure for the management of corneal perforations in patients with ocular surface disease.

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.

Topical antibiotics for treating bacterial keratitis: a network meta‐analysis

This is a protocol for a Cochrane Review (prototype). The objectives are as follows:

To compare the effectiveness and safety of topical antibiotics for treating BK and to rank different interventions through a systematic review and NMA.

Corneal cross-linking guards against infectious keratitis: an experimental model

BACKGROUND

PACK-CXL (photo-activated chromophore for keratitis-corneal cross-linking) is an alternative option in treatment of corneal infections. It inhibits corneal melting by increasing the stromal resistance, besides the microbicidal effect of photo-activated riboflavin.

METHODS

Corneal infection with Pseudomonas aeruginosa and Staph aureus bacteria was induced in 20 eyes of 10 rabbits after 6 weeks of corneal cross-linking in half of the eyes, while the other acted as control group. Clinical and corneal histopathological examination was done to evaluate the extent of inflammation, ulceration, organism penetration, and depth of corneal stromal affection.

RESULTS

The control eyes developed severe inflammation compared to the cross-linked eyes. Corneal melting occurred in 6 eyes in the control versus none in cross-linked group. Histopathological examination showed that the inflammation was confined to the superficial part of the stroma with localization of the inflammation in the cross-linked eyes in contrast to the control eyes that showed deep infiltration.

CONCLUSION

PACK-CXL provides infection localization through increasing the corneal rigidity and resistance to enzymatic digestion, even in the absence of the riboflavin microbicidal role. So, early PACK-CXL is worth to be considered in the IK treatment algorithm.

Case series of staged lamellar corneal grafting with thin manual Descemet's stripping endothelial keratoplasty, followed by manual deep anterior lamellar keratoplasty, as an alternative to penetrating keratoplasty

The purpose of this report is to present the outcomes of Descemet's stripping endothelial keratoplasty (DSEK), followed by deep anterior lamellar keratoplasty (DALK), as an alternative to penetrating keratoplasty (PKP) for different indications. Patients in this retrospective case series underwent manual DSEK, followed by manual DALK, for tectonic and/or visual reasons. It includes three cases that underwent DSEK followed by DALK as an alternative to PKP for the following conditions: failed PKP and stromal scarring, aphakic bullous keratopathy and herpetic stromal scarring, and herpetic corneal perforation. All cases had successful anatomical repair with visual improvement. Many corneal conditions involving endothelium and stroma have been traditionally managed with PKP. However, in certain settings with high risk of complications, this might not be an appropriate option. Therefore, for these cases, we propose management with DSEK followed by DALK as an alternative approach in a 'closed anterior chamber' fashion, which can reduce the risk of significant, sometimes irreversible, complications.

Combined Photoactivated Chromophore for Infectious Keratitis-Corneal Collagen Cross-Linking (PACK-CXL) and Therapeutic Penetrating Keratoplasty for Resistant Bacterial Keratitis

Purpose

Methods

Results

Conclusion

Evaluation of Host Defense Peptide (CaD23)-Antibiotic Interaction and Mechanism of Action: Insights From Experimental and Molecular Dynamics Simulations Studies

Background/Aim: Host defense peptides (HDPs) have the potential to provide a novel solution to antimicrobial resistance (AMR) in view of their unique and broad-spectrum antimicrobial activities. We had recently developed a novel hybrid HDP based on LL-37 and human beta-defensin-2, named CaD23, which was shown to exhibit good in vivo antimicrobial efficacy against Staphylococcus aureus in a bacterial keratitis murine model. This study aimed to examine the potential CaD23-antibiotic synergism and the secondary structure and underlying mechanism of action of CaD23. Methods: Peptide-antibiotic interaction was evaluated against S. aureus, methicillin-resistant S. aureus (MRSA), and Pseudomonas aeruginosa using established checkerboard and time-kill assays. Fractional inhibitory concentration index (FICI) was calculated and interpreted as synergistic (FIC<0.5), additive (FIC between 0.5-1.0), indifferent (FIC between >1.0 and ≤4), or antagonistic (FIC>4). SYTOX green uptake assay was performed to determine the membrane-permeabilising action of CaD23. Molecular dynamics (MD) simulations were performed to evaluate the interaction of CaD23 with bacterial and mammalian mimetic membranes. Circular dichroism (CD) spectroscopy was also performed to examine the secondary structures of CaD23. Results: CaD23-amikacin and CaD23-levofloxacin combination treatment exhibited a strong additive effect against S. aureus SH1000 (FICI = 0.60-0.69) and MRSA43300 (FICI = 0.56-0.60) but an indifferent effect against P. aeruginosa (FIC = 1.03-1.15). CaD23 (at 25 μg/ml; 2xMIC) completely killed S. aureus within 30 min. When used at sub-MIC concentration (3.1 μg/ml; 0.25xMIC), it was able to expedite the antimicrobial action of amikacin against S. aureus by 50%. The rapid antimicrobial action of CaD23 was attributed to the underlying membrane-permeabilising mechanism of action, evidenced by the SYTOX green uptake assay and MD simulations studies. MD simulations revealed that cationicity, alpha-helicity, amphiphilicity and hydrophobicity (related to the Trp residue at C-terminal) play important roles in the antimicrobial action of CaD23. The secondary structures of CaD23 observed in MD simulations were validated by CD spectroscopy. Conclusion: CaD23 is a novel alpha-helical, membrane-active synthetic HDP that can enhance and expedite the antimicrobial action of antibiotics against Gram-positive bacteria when used in combination. MD simulations serves as a powerful tool in revealing the peptide secondary structure, dissecting the mechanism of action, and guiding the design and optimisation of HDPs.

Photodynamic Therapy for Infectious Keratitis

Infectious keratitis is a sight-threatening microbial infection. The prevalence of antimicrobial resistance in cases of infectious keratitis has increased the demand for fortified compounded antimicrobial drops. Even with proper medical management, severe cases of infectious keratitis can further evolve into corneal perforation, requiring surgical intervention in the form of keratoplasty to control the infectious process. Due to the invasive nature of the procedure and the shortage of available donor tissue around the world, alternative treatments are needed for the management of progressive infectious keratitis. In ophthalmology, photodynamic therapy (PDT) has been used for numerous applications. PDT with Rose Bengal as a photosensitizer combined with green light optical irradiation (RB-PDAT) is a novel treatment with dual purpose: to arrest the infection from progressing and strengthen the collagen of the cornea. RB-PDAT may be considered as an adjunct therapy in severe cases of infectious keratitis to minimize the need for a therapeutic keratoplasty.

Amniotic membrane transplantation for infectious keratitis: a systematic review and meta-analysis

Infectious keratitis (IK) is the 5th leading cause of blindness globally. Broad-spectrum topical antimicrobial treatment is the current mainstay of treatment for IK, though adjuvant treatment or surgeries are often required in refractory cases of IK. This systematic review aimed to examine the effectiveness and safety of adjuvant amniotic membrane transplantation (AMT) for treating IK. Electronic databases, including MEDLINE, EMBASE and Cochrane Central, were searched for relevant articles. All clinical studies, including randomized controlled trials (RCTs), non-randomized controlled studies and case series (n > 5), were included. Primary outcome measure was time to complete corneal healing and secondary outcome measures included corrected-distance-visual-acuity (CDVA), uncorrected-distance-visual-acuity (UDVA), corneal vascularization and adverse events. A total of twenty-eight studies (including four RCTs) with 861 eyes were included. When compared to standard antimicrobial treatment alone, adjuvant AMT resulted in shorter mean time to complete corneal healing (− 4.08 days; 95% CI − 6.27 to − 1.88; p < 0.001) and better UDVA (− 0.26 logMAR; − 0.50 to − 0.02; p = 0.04) at 1 month follow-up in moderate-to-severe bacterial and fungal keratitis, with no significant difference in the risk of adverse events (risk ratio 0.80; 0.46–1.38; p = 0.42). One RCT demonstrated that adjuvant AMT resulted in better CDVA and less corneal vascularization at 6 months follow-up (both p < 0.001). None of the RCTs examined the use of adjuvant AMT in herpetic or Acanthamoeba keratitis, though the benefit was supported by a number of case series. In conclusion, AMT serves as a useful adjuvant therapy in improving corneal healing and visual outcome in bacterial and fungal keratitis (low-quality evidence). Further adequately powered, high-quality RCTs are required to ascertain its therapeutic potential, particularly for herpetic and Acanthamoeba keratitis. Future standardization of the core outcome set in IK-related trials would be invaluable.

Mini-Descemet Stripping-Automated Endothelial Keratoplasty for Macro Corneal Perforations

PURPOSE

We present a technique that preserves good vision in paracentral macroperforations and avoids challenges of tectonic lamellar or penetrating keratoplasty in eyes with poor visual potential.

METHOD

A wet laboratory was implemented for mini-Descemet stripping endothelial keratoplasty to seal macroperforations ab interno. This included a suture support technique designed to prevent graft herniation. We also present 3 cases who were treated successfully with this technique.

RESULTS

The laboratory test confirmed that mini-Descemet stripping endothelial keratoplasty can successfully seal macroperforations without the need of large incisions. The minidisc is introduced through the perforation, and a double mattress suture prevents graft herniation. The technique allowed us to preserve 20/15 unaided vision in a case with paracentral macroperforation. It also restored eye globe integrity and achieved long-term stability in 2 cases with limbal stem-cell deficiency.

CONCLUSIONS

Mini-Descemet stripping-automated endothelial keratoplasty technique can be an alternative approach to avoid poor visual outcomes of tectonic keratoplasty in paracentral perforations. It also offers host tissue preservation in eyes with high risk of rejection for tectonic grafts.

Indications, surgical procedures and outcomes of keratoplasty at a Tertiary University-based hospital: a review of 10 years' experience

OBJECTIVE

To investigate keratoplasty outcomes in a university-based hospital.

METHODS

Medical records of all patients undergoing keratoplasty at King Abdulaziz University Hospital, Riyadh, Saudi Arabia, between January 1, 2006, and December 31, 2015, with a minimum follow-up period of three months were reviewed retrospectively. Indications, surgical procedures, complications and outcomes of all surgeries were collected and analyzed.

MAIN OUTCOME MEASURES

Graft survival and visual acuity.

RESULTS

Data were available for 488 grafts in the study period, including 313 optical penetrating keratoplasty (PKP), 42 therapeutic/tectonic PKPs, 72 deep anterior lamellar keratoplasty, 58 Descemet's stripping automated endothelial keratoplasty and 3 Descemet's membrane endothelial keratoplasty. A total of 389 (79.7%) grafts survived, whereas 99 (20.3%) grafts failed. The projected 1-year, 3-year and 5-year cumulative survival rates for the entire study group were 85.8%, 74.9% and 71.1%, respectively. Corneal ectasia was the commonest surgical indication accounting for 48% of the cases. The best long-term survival rates were observed in the stromal dystrophy and corneal ectasia groups. The worst survival rates were noticed in the congenital corneal opacities group. Vision improved in in 57.5% of grafted eyes, remained the same in 39.8% and deteriorated in 2.7%. Postoperative complications occurred in 36% of the grafts with rejection being the most common, and its mere occurrence increased the risk of graft failure by 20-fold.

CONCLUSION

The outcome of grafting in a university-based hospital can be excellent in low-risk grafts and fair to low in high-risk grafts. Our results are relatively comparable to nationally and internationally reported outcomes.

Tectonic Keratoplasty in Patients with Non-traumatic, Non-infectious Corneal Perforations

Introduction:

The study aims to report clinical results of tectonic keratoplasty for non-traumatic, non-infectious corneal perforations.

Materials and Methods:

The medical records of 12 patients who underwent tectonic penetrating keratoplasty between October 2014 and August 2018 at Ege University Ophthalmology Department were retrospectively reviewed.

Results:

The mean age of the patients was 52.92±30.34 (range, 2-82) years. The causes of corneal perforation were dry eye (neurotrophic keratopathy (n=4), limbal stem cell deficiency (n=2), exposure keratopathy (n=2) and graft versus host disease (n=1)) in 9 patients. In the remaining 3 patients, the etiology of perforation was not determined. The mean Visual Acuity (VA) was 2.98±0.39 (range, 1.8-3.1) LogMAR before the surgery. Despite conservative treatment, tectonic penetrating keratoplasty had to be performed in all patients in order to manage the perforation. Mean time in between initial examination and surgery was 10.75±12.04 (1-41) days. In 2 patients, allogenic limbal stem cell transplantation; in one patient, lateral tarsorrhaphy and in one patient symblepharon release with amniotic membrane transplantation were performed additional to tectonic keratoplasty. Mean follow-up time was 57.88±55.47 (4-141) weeks. Grafts were clear in 6 eyes and opaque in 5 eyes. The main causes of graft failure among opaque grafts were ocular surface disease (3), allograft rejection (1) and glaucoma-related endothelial failure (1). Phthisis bulbi was detected in one patient with congenital glaucoma due to vitreous loss at the time of perforation. The mean final VA in patients who had clear grafts was 1.83±1.03 (range, 0.8-3.1) LogMAR.

Conclusion:

To prevent serious complications in non-traumatic, non-infectious corneal perforations, providing anatomic integrity immediately is a must. If conservative treatment is inadequate or the perforation area is extensive, tectonic penetrating keratoplasty is indicated. Besides, it is important to manage the etiological risk factors in order to obtain successful clinical follow up.

Endothelial Safety and Efficacy of Ex Vivo Collagen Cross-linking of Human Corneal Transplants

PURPOSE

To assess endothelial safety and efficacy of ex vivo corneal collagen cross-linking (CXL) in human corneal transplants stored in 2 different culture media.

DESIGN

Fellow-eye controlled laboratory study of ex vivo human donor corneas.

METHODS

Three sets of paired human donor corneas, 5 pairs each, were stored in organ culture medium before deswelling either at 31 C or at room temperature. One eye of each pair was cross-linked by 0.1% riboflavin in hydroxylpropyl methylcellulose (HPMC) instillation for 10 minutes followed by 10 minutes of ultraviolet-A (9 mW/cm²) irradiation while contralateral eyes served as controls. In Set 1, endothelial cell densities were determined. In Set 2, paired samples were assigned to the 2 deswelling media and CXL efficacy was assessed comparing to untreated controls using collagenase-A-assisted enzymatic digestion. In Set 3, biomechanical testing was performed in the eye pairs (treated vs control) by stress/strain measurements.

RESULTS

There was no difference in endothelial cell counts between CXL samples and controls (P = .21). No statistically significant difference in digestion dynamics was found between tissues stored in the 2 different culture media. Complete enzymatic digestion was slowed down by 3 hours in the cross-linked samples (P = .036). Stress needed for a 12% strain was increased by 34% in the treatment group compared to control (P = .04).

CONCLUSIONS

Ex vivo CXL of human donor tissue is an effective and safe procedure with no difference regarding efficacy between 2 commercially available deswelling media. Biochemical and biomechanical resistance were significantly increased after CXL. Patients requiring keratoplasty owing to corneal melting might benefit from the strengthening effect of preoperative CXL of donor tissue.

A 27-Year Report from the Central Eye Bank of Iran

Purpose

To report the 27-year statistical data from the Central Eye Bank of Iran (CEBI) and its activity.

Methods

All CEBI records regarding procured eyes, tissue utilizations, corneal transplants per capita, and indications for keratoplasty from 1991 to 2017 were analyzed.

Results

In total, 115,743 whole eyes were donated during the 27-year period. Out of the 114,169 eyes donated between 1994 and 2017, 95,314 eyes were distributed for transplantation, and 95,057 corneas were actually transplanted. The mean annual rate of corneal transplants per capita was 55.10 - 6 ± 27.10 - 6 . Although penetrating keratoplasty (PKP, 70%) was the most common technique of corneal transplantation during the study period, it exhibited a decreasing trend between 2006 and 2017 (P = 0.048). It was in contrast to Descemet stripping automated endothelial keratoplasty (DSAEK) that demonstrated an increasing trend during the same period (P < 0.001). Keratoconus (KCN, 39.70%) was the most leading indication for keratoplasty over the last three decades followed by bullous keratopathy (BK, 18.5%), corneal scar and opacities (15.7%), and graft failure (GF, 7.5%), with an increasing trend for BK, GF, and KCN. A majority of scleral tissues (83.7%) were utilized for orbital implant protection.

Conclusion

An increasing trend in the number of procured eyes was observed over the past 27 years in Iran. The most leading indications for corneal transplantation were KCN and BK. While PKP was the most common keratoplasty technique, DSAEK showed an increasing trend over the last 12 years.

Effectiveness of adjuvant photoactivated chromophore corneal collagen cross-linking versus standard antimicrobial treatment for infectious keratitis: a systematic review protocol

OBJECTIVE

The objective of this review is to systematically examine the effectiveness of adjuvant photoactivated chromophore for keratitis - corneal collagen cross-linking (PACK-CXL) versus standard antimicrobial treatment alone for corneal healing in patients with infectious keratitis.

INTRODUCTION

Infectious keratitis is a major cause for corneal blindness globally. Broad-spectrum antimicrobial therapy is currently the standard treatment, but there is a growing need for alternative or adjuvant antimicrobial treatment, due to the emerging antimicrobial resistance, long treatment duration and cost of treatment. Photoactivated chromophore for keratitis - corneal collagen cross-linking has been increasingly used as an adjuvant treatment for infectious keratitis but high-quality evidence is limited.

INCLUSION CRITERIA

This review will consider studies that include patients with infectious keratitis, encompassing bacterial, fungal, acanthamoeba, viral, mixed or culture-negative presumed infectious keratitis cases. Patients who have a previous history of infectious keratitis before the study or those that had less than seven days' follow-up from the start of the treatment will be excluded.

METHODS

The electronic databases to be searched will include MEDLINE, Embase and Cochrane Central Register of Controlled Trials. Only English articles will be included. Titles, abstracts and full text of the relevant studies will be assessed by two independent reviewers. The extracted data will include specific details about the study, including authors and study title, year of publication, sample size, populations, and study methods. A meta-analysis will be performed for the included randomized controlled trials when there are sufficient similarities in the reporting of outcome measures.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42019131290.

Photoactivated chromophore for infectious keratitis - Corneal cross-linking (PACK-CXL): A systematic review and meta-analysis

PURPOSE

To examine the efficacy of adjuvant photoactivated chromophore for infectious keratitis-corneal cross-linking (PACK-CXL) for the treatment of infectious keratitis (IK).

METHODS

Electronic databases, including MEDLINE, EMBASE and Cochrane Central, were searched for articles related to PACK-CXL. All clinical studies, including randomized controlled trials (RCTs), non-randomized controlled studies, case series and case reports, were included. A meta-analysis was further performed when there were sufficient similarities in the included RCTs. Primary outcome measure was time to complete corneal healing and secondary outcome measures included size of epithelial defect and infiltrate, corrected-distance-visual-acuity (CDVA), and adverse events.

RESULTS

Forty-six eligible studies (including four RCTs) with 435 patients were included. When compared to standard antimicrobial treatment (SAT) alone, adjuvant PACK-CXL resulted in shorter mean time to complete corneal healing (-7.44 days; 95% CI, -10.71 to -4.16) and quicker resolution of the infiltrate at 7 days (-5.49 mm²; 95% CI, -7.44 to -3.54) and at 14-30 days (-5.27 mm²; 95% CI, -9.12 to -1.41). There was no significant difference in the size of epithelial defect, CDVA and risk of adverse events. Evidence on the use of PACK-CXL in acanthamoeba and mixed IK was insufficient.

CONCLUSIONS

Our study demonstrates that adjuvant PACK-CXL expedites the healing of IK when compared to SAT alone (low-quality evidence). Further adequately powered, high-quality RCTs are required to fully ascertain the therapeutic effect of PACK-CXL.

Long-term outcomes of riboflavin photodynamic antimicrobial therapy as a treatment for infectious keratitis

Purpose

To report the long-term outcomes of three patients with infectious keratitis treated with riboflavin photodynamic antimicrobial therapy (PDAT).

Observations

Case series reporting three patients with infectious keratitis unresponsive to standard medical treatment who underwent riboflavin photodynamic antimicrobial therapy (PDAT) as an adjunct therapy. One male and two female patients were treated, the median age of presentation was 58 years (range, 29-79 years). The organisms isolated and treated were Pseudomonas aeruginosa, Mycobacterium chenolae, and Curvularia spp. Different risk factors to develop corneal infection ulcers were identified, including corneal abrasion in a contact lens user, history of penetrating keratoplasty with chronic use of topical corticosteroids, and organic trauma. The median follow-up was 47 months (range 37-54 months), and there were no complications secondary to riboflavin PDAT treatment. Two cases underwent optical penetrating keratoplasty after infection was resolved and ocular surface was quiet for at least 3 years.

Conclusions and importance

Riboflavin PDAT can be used as an adjunct treatment in infectious keratitis to strengthen the corneal collagen fibers, delay keratolysis, and allow more time for antimicrobials to work and this way prevent a corneal perforation.

Total Penetrating Keratoplasty: Indications, Therapeutic Approach, and Long-Term Follow-Up

Purpose

Evaluation of the indications, anatomical and functional results, and complications of total penetrating keratoplasty (TPK) in disorders involving whole cornea.

Materials and Methods

We analyzed outcomes of the surgical treatment of 47 eyes of 46 patients that underwent TPK. Indications were infectious keratitis, autoimmune disease, injury of the eyeball (mainly chemical burns), and other combined disorders. The surgical technique involved dissection of affected tissues with a margin of 1.0 mm. The size of the corneal graft ranged from 10.0 to 14.0 mm. We analyzed indications, outcomes, and complications of surgery.

Results

Final restoration of the ocular integrity and maintenance of the globe were achieved in 27 eyes (57%). More than one surgery was necessary in a total of 29 eyes (62%). The frequency of retransplantations did not vary significantly between the groups with different causes of corneal melting/perforation (63% of eyes with infection, 66% of eyes after trauma and 70% of eyes of patients with autoimmune disorders). Surgical treatment failed in 20 eyes (43%). Evisceration was necessary in 13 eyes (28%), phthisis occurred in 7 cases (15%).

Conclusion

TPK should be considered as a last line treatment in huge corneal destruction to restore integrity of the eye globe.