Corneal Donation: Current Guidelines and Future Direction

Trends in Corneal Donation From 2013 to 2022 in Aotearoa-New Zealand: Impact of Donor Age, Gender, Ethnicity, and COVID-19

PURPOSE

To evaluate corneal donation demographics in New Zealand (NZ) and explore changes over time.

METHODS

Data were collected from all donated corneas processed by the New Zealand National Eye Bank over a 10-year period from January 2013 until December 2022. Demographic data including age, self-identified ethnicity, and gender were collected, along with location and cause of death. National death data for the corresponding period were collected online from Statistics New Zealand.

RESULTS

A total of 1842 donors were processed; 1414 (76.8%) were sourced from Aotearoa-New Zealand and the remainder from Australia/United States. There was a small but statistically significant median age difference between NZ donors (68 years, interquartile range 55-76) and overseas donors [66 years (interquartile range) 51-70]. Most (n = 1151 81.4%) of NZ donors died in hospital settings, with the most common cause of death being cerebrovascular (n = 444 31.4%). Individuals were less likely to donate their cornea if they were female, [incidence rate ratio (IRR) 0.746, P < 0.001] older age (IRR 0.968, P < 0.001), or if they were of Māori (IRR 0.178, P < 0.001) or Pasifika ethnicity (IRR 0.125, P < 0.001). There was also a statistically significant decrease in donation rates over time (IRR 0.945, P < 0.001).

CONCLUSIONS

There remains a profound gap between the demand for corneal transplantation and corneal tissue donation, which is worsening with time. Donor age, gender, and ethnicity seem to influence corneal donation rates. These demographic differences may be ameliorated by increased education, cultural safety, further research into those willing to donate, and the establishment of an organ/tissue donation registry.

Jordanian nursing students' knowledge and attitudes of corneal donation

A high success rate of corneal transplants is evident. However, there is still a lack of corneal grafts available to meet demand, largely because donors are reluctant to donate. Given their critical role in future healthcare teaching and advocacy. There has not been much research on Jordanian nursing students' perspectives on corneal donation, so it's critical to identify and eliminate any obstacles. This study aims to evaluate the knowledge and attitudes of Jordanian nursing students concerning corneal donation. A cross-sectional, descriptive design was used to recruit (n = 440) nursing students from four Jordanian universities. A self-reported questionnaire was used to obtain data on knowledge and attitudes regarding corneal donation. The average age of senior nursing students was (M = 23.07, SD = 3.63) years. Varying levels of understanding were revealed amongst university students toward corneal donation items. Generally, good attitude of nursing students toward corneal donation (M = 34.1, SD = 8.1). Weak positive relationship was found between total knowledge scores and age (r = 0.141, p = 0.003) while there is no significant relationship between age and total attitude score (r = 0.031, p = 0.552). Age was found to be a significant predictor (B = 0.01, Beta = 0.12, t = 2.07, p = 0.04). Also, the educational level of fathers is a significant positive predictor (Beta = 0.128, p = 0.008) for the total attitude scores among nursing students. Limited awareness of corneal donation, highlighting the need for focused educational interventions to improve their comprehension.

Quality assurance in corneal transplants: Donor cornea assessment and oversight

The cornea is the most frequently transplanted human tissue, and corneal transplantation represents the most successful allogeneic transplant worldwide. In order to obtain good surgical outcome and visual rehabilitation and to ensure the safety of the recipient, accurate screening of donors and donor tissues is necessary throughout the process. This mitigates the risks of transmission to the recipient, including infectious diseases and environmental contaminants, and ensures high optical and functional quality of the tissues. The process can be divided into 3 stages: (1) donor evaluation and selection before tissue harvest performed by the retrieval team, (2) tissue analysis during the storage phase conducted by the eye bank technicians after the retrieval, and, (3) tissue quality checks undertaken by the surgeons in the operating room before transplantation. Although process improvements over the years have greatly enhanced safety, quality, and outcome of the corneal transplants, a lack of standardization between centers during certain phases of the process still remains, and may impact on the quality and number of transplanted corneas. Here we detail the donor screening process for the retrieval teams, eye bank operators. and ophthalmic surgeons and examine the limitations associated with each of these stages.

Development of Anterior Segment Focused Biologic Therapies to Regenerate Corneal Tissue for the Treatment of Disease: Drug Development Experience

On February 24-27, 2021, the Association for Ocular Pharmacology and Therapeutics (AOPT) held its 15th biennial scientific meeting online. The meeting was organized by Dr. Sanjoy Bhattacharya of the University of Miami in conjunction with the board of trustees of the AOPT. The 3-day conference was attended by academic scientists, clinicians, and industry and regulatory professionals. The theme of the meeting was Restoring Vision through Regeneration and it was sponsored, in part, by the National Institutes of Health, Bright Focus, Regeneron, and Santen (USA). During the 3 days of the meeting, presentations from several sessions explored different aspects of regenerative medicine in ophthalmology, including optic nerve regeneration, drugs and devices in glaucoma, retinal neuroprotection and plasticity, visual perception, and degeneration of trabecular meshwork. This article summarizes the proceedings of the session on corneal regenerative medicine research and discusses emerging concepts in drug development for corneal epithelial and endothelial regeneration. Since the meeting in 2021, several of these concepts have advanced to clinical-stage therapies, but so far as of 2023, none has been approved by regional regulatory authorities in the United States. One form of corneal endothelial cell therapy has been approved in Japan and only for bullous keratopathy. Ongoing work is proceeding in the United States and other countries. Clinical Registration No: National Clinical Trials 04894110, 04812667; Japan Registry for Clinical Trials a031210199.

Allogenic Lenticular Implantation for Correction of Refractive Error and Ectasia: Narrative Review

INTRODUCTION

Intrastromal lenticule implantation is a promising treatment option for corneal pathologies, from refractive error to ectasia. In this narrative review, we intend to feature up-to-date literature supporting the use of lenticular tissue, a compelling method that can be customized for a variety of applications, providing an additional source of donor tissue for treating corneal diseases.

METHODS

We searched databases PubMed, Mendeley, and Scopus last accessed 10 May 2023, for literature on stromal lenticules and narrowed based on relevance. Review articles, animal studies, ex vivo studies, and book chapters were excluded, while assessable and relevant articles published in English were included.

RESULTS

Storage methods from using fresh lenticules to dehydration have proven successful, with cryopreservation maintaining structure and cellular viability for up to 10 years. Successful use of lenticules for treatment of numerous pathologies including corneal ectasias, hyperopia, and presbyopia with additional insight into the treatment of corneal ulcers and perforations are highlighted in this narrative review.

CONCLUSION

Lenticular implantation is an innovative and advantageous treatment for various ocular pathologies, offering increased bioavailability, flexibility, and customization for patients. They can treat previously untreatable diseases and serve as a replacement for synthetic implants, with promising outcomes worldwide. Lenticular implantation has the potential to become a leading approach in ophthalmologic surgery. Further studies should aim to provide evidentiary support for a standardization of lenticule banking.

Corneal blindness and eye banking: Current strategies and best practices

Corneal blindness (CB) is one of the leading causes of blindness in India and globally, affecting around 8 million population worldwide. Many of these corneal blind patients may be visually rehabilitated by corneal transplantation (CT). Eye banking plays a crucial role in facilitating CT and ocular research. Many countries have adopted regulatory frameworks, quality assurance programs, and technological advancements to enhance the efficacy and safety of CT. Various infrastructural and organizational frameworks of eye banks (EBs) in India, according to the Eye Bank Association of India (EBAI), aid in establishing guidelines and standards for EB practices. Initiatives such as the National Programme for Control of Blindness (NPCB) have significantly contributed to eye donation rates and improved access to donor corneas. This review article discusses the established eye banking networks in countries such as India, the United States (USA), and Europe, where dedicated EB organizations work collaboratively to ensure efficient procurement, processing, and distribution of corneal tissue. It also highlights specific strategies employed in India and global countries to address EBs' challenges. These challenges include the shortage of donor corneas, improving donor screening and tissue processing techniques, ensuring timely distribution of corneal tissue, and maintaining high-quality standards. Interestingly, the comparative analysis between India and other developed countries highlights the similarities and differences in eye banking strategies. By understanding the strategies employed by different regions, EBs can learn from each other's experiences and work toward achieving optimal outcomes in CT and ocular research worldwide. It underscores the importance of knowledge sharing and collaborative efforts in addressing common challenges and implementing best practices in eye banking.

Herpes simplex virus dissemination with necrotizing hepatitis following Descemet membrane endothelial keratoplasty

BACKGROUND

Corneal transplants are the most common type of transplant and increasing in frequency. Donor cornea tissues are a rare source of herpes simplex virus (HSV) transmission and not routinely tested for presence of HSV. Donor graft-to-recipient transmission typically causes graft failure and anterior uveitis, and extra-ocular HSV disease has not been previously reported. We present a case of HSV transmission from donor cornea tissue that nearly cost the corneal transplant recipient his life.

CASE REPORT

An elderly immunocompetent man developed an acute illness 10 days after having donor corneal tissue implanted in a Descemet membrane endothelial keratoplasty (DMEK). He was found to have HSV necrotizing hepatitis per liver biopsy, trilineage cytopenia, rhabdomyolysis, acute kidney failure, altered mental status, early-stage hemophagocytic lymphohistiocytosis (HLH), and donor corneal tissue implant infection resulting in graft failure and anterior uveitis. HSV DNA was detected in cerebral spinal fluid, peripheral blood, explanted donor corneal tissue, and anterior chamber fluid (220 million HSV DNA copies per mL). HSV-1 seroconversion denoted a primary HSV infection, and the patient had no other risk factor for HSV acquisition. Early recognition of HSV dissemination prompting treatment with intravenous acyclovir, as well as a short course of HLH-directed therapy, resolved the systemic illness. Vision was restored to near normal by replacement of the infected corneal graft with new donor DMEK tissue in conjunction with intravitreal foscarnet treatment.

CONCLUSION

Awareness of the potential risk of donor cornea tissue transmitting HSV and leading to life-threatening HSV disease is paramount to early diagnosis and treatment. The role of donor cornea tissue in HSV transmission and disease merits additional attention and investigation.

Transcriptional Profiling Provides New Insights into Organ Culture-Induced Changes in Human Donor Corneas

Corneal transplantation is one of the most common forms of tissue transplantation worldwide. Donor corneal tissue used in transplantation is provided by eye banks, which store the tissue in culture medium after procurement. To date, the effects of cell culture on human corneal tissue have not been fully elucidated. Using the 3' RNA sequencing method for massive analysis of cDNA ends (MACE), we show that cultivation of corneal tissue leads to significant changes in a variety of molecular processes in human corneal tissue that go well beyond aspects of previously known culture effects. Functionally grouped network analysis revealed nine major groups of biological processes that were affected by corneal organ culture, among them keratinization, hypoxia, and angiogenesis, with genes from each group being affected by culture time. A cell type deconvolution analysis revealed significant modulations of the corneal immune cell profile in a time dependent manner. The results suggest that current culture conditions should be further refined and that prolonged cultivation may be detrimental. Recently, we showed that MACE enables transcriptional profiling of formalin-fixed and paraffin-embedded (FFPE) conjunctival tissue with high accuracy even after more than 10 years of storage. Here we demonstrate that MACE provides comparable results for native and FFPE corneal tissue, confirming that the technology is suitable for transcriptome analysis of a wide range of archived diseased corneal samples stored in histological archives. Finally, our data underscore the feasibility of bioinformatics cell-type enrichment analysis in bulk RNA-seq data to profile immune cell composition in fixed and archived corneal tissue samples, for which RNA-seq analysis of individual cells is often not possible.

A Review of Corneal Transplantation: An Insight on the Overall Global Post-COVID-19 Impact

The coronavirus disease 2019 (COVID-19) pandemic made us reframe a lot of the strategies followed in medical practice and ophthalmological services and procedures were also not spared, including corneal transplantation or keratoplasty, the most routine procedure performed worldwide. The prevalence of viral presence in the ocular tissue necessitates a focus on the handling of donor ocular tissue and the functioning of eye banks, ensuring it doesn't risk the patient and the doctor's safety. Restrictions in the movement of people during the pandemic limited the number of donations, causing a shortage of tissues, with a large number of people already waitlisted for tissue needs. The lesson from the COVID-19 pandemic directs us to look for long-term corneal storage techniques taking into consideration the tissue viability time and the possibility of post-pandemic shortages. Although there is not a significant number of reports, the cases of corneal graft rejection post-vaccination against COVID-19 are highlighted and thus should form a part of the lookout while evaluating the possible cause of rejection of grafts. This article summarises the overall impact of the pandemic on corneal transplantation and the possible future of storage techniques, which need to evolve and be adapted.

Review of Presbyopia Treatment with Corneal Inlays and New Developments

Presbyopia may represent the largest segment of refractive errors that is without an established and effective refractive surgery treatment. Corneal Inlays are materials (synthetic or allogenic) implanted in the stroma of patients’ corneas to improve presbyopia. These inlays, introduced into the United States in 2015 via the small-aperture corneal inlay (KAMRA^TM, SightLife Surgical/CorneaGen, Seattle, Washington, United States), were met with an initial wave of enthusiasm. Subsequent models like the shape-changing corneal inlay (RAINDROP^TM, Revision Optics, Lake Forest, California, United States) offered excellent results for patients, but longer-term research raised questions about patient safety. At the time of this article, no synthetic corneal inlays are available in the United States for the correction of presbyopia. Other options for presbyopia correction include allograft corneal inlays, trifocal synthetic corneal inlays, pharmacologic therapies, scleral incisions or additive techniques and PresbyLASIK. Presently, allograft inlays consist of corneal lenticules removed from patients undergoing Small Incision Lenticule Extraction (SMILE). We will review corneal inlays and other alternative procedures that may provide effective and predictable treatments for patients with presbyopia.

Impact of the COVID-19 Pandemic on Corneal Transplantation: A Report From the Italian Association of Eye Banks

Purpose

To analyze the impact of COVID-19 on Italian corneal transplantation from March-2020 to February 2021 compared to the same timeframe of the 2 previous years, in order to identify potential consequences of a global pandemic on corneal procurement and transplantation services during this time.

Methods

This national, multicentric, retrospective cohort study evaluated data collected from 12 (100%) Italian eye banks from March 2020 to February 2021 (Group A). The number of tissues collected, distributed and discarded were compared with the same time-frame of the 2 previous years: 2019 and 2018 (group B and C, respectively). The different type of transplants performed were reported. Data were analyzed using a non-parametric Friedman test.

Results

Corneal procurement and the percentage of distributed tissues reduced in 2020 by more than 30 and 15%, respectively, compared to the 2 previous years. During the pandemic corneal transplant surgery showed only a modest drop: the number of the penetrating keratoplasties (PKs) and the anterior lamellar keratoplasties (ALKs) decreased by about 30 and 20% in comparison with groups B and C, respectively; between the Endothelial Keratoplasties (EKs), the Descemet membrane endothelial keratoplasty (DMEK) increased slightly from March 2020 to February 2021.

Conclusions

Italy was one of the first countries most affected by the outbreak of COVID-19, and the Italian government adopted severe measures to limit viral transmission. The pandemic generated several implications in corneal transplant activity during the first lockdown. Then an efficacious reaction with constant, vigorous work led to a resumption of transplant surgery to a near-normal standard. The increase of EKs, despite the pandemic, is a sign that the advance in corneal transplantation has gone ahead and it continues to evolve.

Knowledge and Attitudes toward Cornea Donation among Different Social Groups in Poland

BACKGROUND

Limited access to corneal tissue for transplantation remains a challenge in many parts of the world. To date, little attention has been paid to the problem of the cornea donor shortage in Poland, where the number of waiting patients exceeds the number of transplants performed three-fold. The aim of this study was to assess the knowledge and willingness towards participating in corneal donation among different social groups in Poland.

METHODS

This prospective, cross-sectional study was conducted among health professionals, medical students, clerics, teachers, journalists, employees and patients of the District Railway Hospital in Katowice. Online and paper questionnaires were used to collect socio-demographic data and information regarding awareness of, knowledge about and attitudes toward corneal donation. For health professionals and medical students, the questionnaires contained additional questions concerning knowledge and solutions for expanding the donor pool. Descriptive analysis and associations were evaluated using the chi² test.

RESULTS

In the survey, 1026 participants took part, including 370 (36.06%, group 1) health professionals and 656 (63.94%, group 2) participants from a non-medical field. A total of 330 (89.18%) from group 1 and 528 (80.49%) respondents from group 2 expressed willingness to donate their corneas. The main reason for refusal of donation in both groups was a lack of knowledge concerning eye donation (7.8%). A social campaign (64.6%) was the most frequently chosen solution for increasing the number of potential donors by health professionals and medical students. In the group of doctors, not knowing how to report a potential donor was chosen as the greatest source of difficulty in donor reporting (40%).

CONCLUSIONS

In the present study, the willingness to donate one's eyes was substantial in both groups. Social campaigns and improving knowledge concerning the donor reporting process among health professionals might be beneficial in expanding the donor pool.