9†Supply of non-clinical ocular tissue from a tissue and eye services research tissue bank.

INTRODUCTION: NHS Blood and Transplant Tissue and Eye Services (TES) is a human multi-tissue, tissue bank supplying tissue for transplant to surgeons throughout the UK. In addition, TES provides a service to scientists, clinicians and tissue bankers by providing a range of non-clinical tissue for research, training and education purposes. A large proportion of the non-clinical tissues supplied is ocular tissue ranging from whole eyes, to corneas, conjunctiva, lens and posterior segments remaining after the cornea is excised. The TES Research Tissue Bank (RTB) is based within the TES Tissue Bank in Speke, Liverpool and is staffed by two full-time staff. Non-clinical tissue is retrieved by Tissue and Organ Donation teams across United Kingdom. The RTB works very closely with two eye banks within TES, the David Lucas Eye Bank in Liverpool and the Filton Eye Bank in Bristol. Non-clinical ocular tissues are primarily consented by TES National Referral Centre Nurses. METHODS AND RESULTS: The RTB receives tissue via two pathways. The first pathway is tissue specifically consented and retrieved for non-clinical use and the second pathway is tissue that becomes available when tissue is found to be unsuitable for clinical use. The majority of the tissue that the RTB receives from the eye banks comes via the second pathway. In 2021, the RTB issued more than 1000 samples of non-clinical ocular tissue. The majority of the tissue, ~64% was issued for research purposes (including research into glaucoma, COVID-19, paediatrics and transplant research), ~31% was issued for clinical training purposes (DMEK and DSAEK preparation, especially after COVID-19 cessation of transplant operations, training for new eye bank staff) and ~5% was issued for in-house and validation purposes. One of the findings was that corneas are still suitable for training purposes up to 6-months after removal from the eye.In 2021, the RTB received 43 applications for ocular projects from new customers and supplied to 36 different projects, meeting 95% of all orders placed this year. DISCUSSION: The RTB works to a partial cost-recovery system and in 2021 became self-sufficient. The supply of non-clinical tissue is crucial for advancement in patient care and has contributed to several peer-reviewed publications.

3†Emergency salvage of time expired clinical corneas during the COVID-19 pandemic.

INTRODUCTION: Corneas for clinical use can be stored for a maximum of 28 days in organ culture medium after death. At the beginning of the COVID-19 pandemic in 2020 it became apparent that; a rare situation was arising in that clinical operations were being cancelled and that there would be a surplus of "clinical grade" corneas. Consequently, when the corneas reached the end of the storage period, if the tissue had appropriate consent, they were transferred to the Research Tissue Bank (RTB). However, University research had also stopped due to the pandemic and there was a situation where the RTB had good quality tissue without any users. Rather than discarding the tissue, a decision was made to store the tissue for future use by cryopreservation. MATERIALS AND METHODS: An established protocol for cryopreserving heart valves was adapted. Individual corneas were placed into wax histology cassettes then inside a Hemofreeze heart valve cryopreservation bag with 100 ml cryopreservation medium (10% Dimethyl sulphoxide)). They were frozen in a controlled rate freezer (Planer, UK) to below -150oC and stored in vapour phase over liquid nitrogen (VPLN) below -190oC. To assess morphology, six corneas were cut in half, one half was processed for histology whilst the other half was cryopreserved, stored for 1 week then thawed and processed for histology. The stains used were Haematoxylin and Eosin (H&E) and Miller's with Elastic Van Gieson (EVG). RESULTS: Comparative histological examination indicated that there were no visible, major, detrimental changes in morphology in the cryopreserved group as compared to the controls. Subsequently, a further, 144 corneas were cryopreserved. Samples were assessed for handling properties by eye bank technicians and ophthalmologists. The eye bank technicians felt that the corneas may be suitable for training purposes such a DSAEK or DMEK. The ophthalmologists said that they had no preference between the fresh or cryopreserved corneas, and both would be equally suitable for training purposes. CONCLUSION: Time expired, organ-cultured corneas, can be successfully cryopreserved using an established protocol by adapting the storage container and conditions. These corneas are suitable for training purposes and may prevent discard of corneas in future.

Virtual keratoconus monitoring clinic in a tertiary university hospital in the United Kingdom.

Purpose: To describe a new pathway for virtual keratoconus (KC) monitoring in the corneal department of a tertiary referral center in the UK during the coronavirus disease 2019 (COVID-19) pandemic. Methods: A virtual outpatient clinic to monitor KC patients (KC PHOTO clinic) was created. All patients from the KC database in our department were included. At each hospital visit, patients' visual acuity and tomography (Pentacam; Oculus, Wetzlar, Germany) were collected by a health-care assistant and an ophthalmic technician, respectively. The results were virtually reviewed by a corneal optometrist to identify stability or progression of KC and discussed with a consultant if needed. Those with progression were contacted by telephone and listed for corneal crosslinking (CXL). Results: From July 2020 until May 2021, 802 patients were invited to attend the virtual KC outpatient clinic. Of them, 536 patients (66.8%) attended and 266 (33.2%) did not attend. After corneal tomography analysis, 351 (65.5%) were stable, 121 (22.6%) showed no definite evidence of progression, and 64 (11.9%) showed progression. Forty-one (64%) patients with progressive KC were listed for CXL and the remaining 23 patients deferred treatment after the pandemic. By converting a face-to-face clinic to a virtual clinic, we were able to increase our capacity by nearly 500 appointments per year. Conclusion: In pandemic times, hospitals have developed novel methods of delivering safe patient care. KC PHOTO is a safe, effective, and innovative method of monitoring KC patients and diagnosing progression. In addition, virtual clinics can increase the clinic capacity tremendously and reduce the need of face-to-face appointments, which is beneficial in pandemic conditions.

Corneal confocal microscopy identifies corneal nerve fibre loss and increased dendritic cells in patients with long COVID.

BACKGROUND/AIMS: Long COVID is characterised by a range of potentially debilitating symptoms which develop in at least 10% of people who have recovered from acute SARS-CoV-2 infection. This study has quantified corneal sub-basal nerve plexus morphology and dendritic cell (DC) density in patients with and without long COVID. METHODS: Forty subjects who had recovered from COVID-19 and 30 control participants were included in this cross-sectional comparative study undertaken at a university hospital. All patients underwent assessment with the National Institute for Health and Care Excellence (NICE) long COVID, Douleur Neuropathique 4 (DN4) and Fibromyalgia questionnaires, and corneal confocal microscopy (CCM) to quantify corneal nerve fibre density (CNFD), corneal nerve branch density (CNBD), corneal nerve fibre length (CNFL), and total, mature and immature DC density. RESULTS: The mean time after the diagnosis of COVID-19 was 3.7±1.5 months. Patients with neurological symptoms 4 weeks after acute COVID-19 had a lower CNFD (p=0.032), CNBD (p=0.020), and CNFL (p=0.012), and increased DC density (p=0.046) compared with controls, while patients without neurological symptoms had comparable corneal nerve parameters, but increased DC density (p=0.003). There were significant correlations between the total score on the NICE long COVID questionnaire at 4 and 12 weeks with CNFD (ρ=-0.436; p=0.005, ρ=-0.387; p=0.038, respectively) and CNFL (ρ=-0.404; p=0.010, ρ=-0.412; p=0.026, respectively). CONCLUSION: Corneal confocal microscopy identifies corneal small nerve fibre loss and increased DCs in patients with long COVID, especially those with neurological symptoms. CCM could be used to objectively identify patients with long COVID.

Establishing a Virtual Corneal Clinic: A Real-Time Teleophthalmology Approach.

PURPOSE: Keratoplasty patients require regular and timely follow-ups. During this COVID-19 pandemic which restricted global travel, we developed a novel real-time, hybrid teleophthalmology approach to comanage international keratoplasty patients between Singapore and Indonesia. METHODS: A retrospective consecutive observational study of 72 corneal patients (63 were postkeratoplasty) who attended a virtual corneal clinic (VCC) between June 2020 and April 2021 at JEC Eye Hospitals (JEC) in Jakarta, Indonesia. ZOOM Meeting software (Zoom Video Communication Inc, San Jose, CA) was used to simultaneously connect the Singapore corneal specialist at Eye & Cornea Surgeons (ECS), Singapore, using a real-time approach. Clinical examinations included full panels of video-linked corneal, glaucoma, and retinal imaging and investigations performed before real-time video-linked slit-lamp examination, with immediate clinical decision making between corneal specialists and patients. RESULTS: VCC enabled effective real-time clinical evaluation and collaborative clinical decisions, with full patient interaction, with the aim of maintenance of graft clarity, visual function, and management of comorbidities-a) topical and systemic medications were adjusted in 79.2% of patients; b) further referrals to glaucoma, retinal, and oculoplastic subspecialists were made in 16.6% of cases; c) additional adjunctive surgical procedures were performed at JEC in 6.9% cases; and d) government permission was obtained for 4 patients (5.6%) to fly to Singapore for urgent corneal surgery. CONCLUSIONS: The virtual corneal clinic is a novel real-time hybrid teleophthalmology approach which is effective in the comanagement of international keratoplasty patients and represents the advances in ophthalmic telemedicine.

In vitro infection of human ocular tissues by SARS-CoV-2 lineage A isolates.

BACKGROUND: The purpose of this study was: [1] to evaluate the infectivity of two SARS-CoV-2 lineage A variants on human ocular tissues in vitro, and [2] to evaluate the stability of SARS-CoV-2 lineage A variants in corneal preservation medium. METHODS: Primary cultures of donor corneal, conjunctival, and limbal epithelium were inoculated with two lineage A, GISAID clade S isolates of SARS-CoV-2 (Hong Kong/VM20001061/2020, USA-WA1/2020), to evaluate the susceptibility of the ocular tissue to infection. Flat-mounted Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK) grafts were inoculated with SARS-CoV-2 to evaluate the susceptibility of the endothelium to infection. All inoculated samples were immunostained for SARS-CoV-2 nucleocapsid (N)-protein expression to confirm positive infection. SARS-CoV-2 Hong Kong was then inoculated into cornea preservation media (Life4°C, Numedis, Inc.). Inoculated media was stored at 4oC for 14 days and assayed over time for changes in infectious viral titers. RESULTS: Corneal, conjunctival, and limbal epithelial cells all demonstrated susceptibility to infection by SARS-CoV-2 lineage A variants. Conjunctiva demonstrated the highest infection rate (78% of samples infected [14/18]); however, infection rates did not differ statistically between cell types and viral isolates. After inoculation, 40% (4/10) of DSAEK grafts had active infection in the endothelium. SARS-CoV-2 lineage A demonstrated < 1 log decline in viral titers out to 14 days in corneal preservation media. CONCLUSIONS: SARS-CoV-2 lineage A variants can infect corneal, limbal, and conjunctival epithelium, as well as corneal endothelium. There was no statistical difference in infectivity between different lineage A variants. SARS-CoV-2 lineage A can survive and remain infectious in corneal preservation media out to 14 days in cold storage.

Class-Aware Attention Network for infectious keratitis diagnosis using corneal photographs.

Infectious keratitis is one of the common ophthalmic diseases and also one of the main blinding eye diseases in China, hence rapid and accurate diagnosis and treatment for infectious keratitis are urgent to prevent the progression of the disease and limit the degree of corneal injury. Unfortunately, the traditional manual diagnosis accuracy is usually unsatisfactory due to the indistinguishable visual features. In this paper, we propose a novel end-to-end fully convolutional network, named Class-Aware Attention Network (CAA-Net), for automatically diagnosing infectious keratitis (normal, viral keratitis, fungal keratitis, and bacterial keratitis) using corneal photographs. In CAA-Net, a class-aware classification module is first trained to learn class-related discriminative features using separate branches for each class. Then, the learned class-aware discriminative features are fed into the main branch and fused with other feature maps using two attention strategies to assist the final multi-class classification performance. For the experiments, we have built a new corneal photograph dataset with 1886 images from 519 patients and conducted comprehensive experiments to verify the effectiveness of our proposed method. The code is available at https://github.com/SWF-hao/CAA-Net_Pytorch.

Corneal manifestations and treatment among patients with COVID-19-associated rhino-orbito-cerebral mucormycosis.

Purpose: TO report the corneal manifestations in patients with COVID-19-associated rhino-orbito-cerebral mucormycosis (ROCM). Methods: This study was a retrospective, observational, and record-based analysis of patients of ROCM with corneal involvement. Results: A total of 220 patients were diagnosed with ROCM over a period of 3 months. Thirty-two patients had developed corneal manifestations. The mean age at diagnosis was 52.84 ± 12.8 years. The associated risk factors were systemic mucormycosis, uncontrolled diabetes, recent COVID-19 infection, and injudicious use of systemic steroids. Twenty-nine patients were known diabetics, 32 had recent COVID-19 infection, and 13 gave a history of injudicious use of steroids. The right eye (RE) was affected in nine patients, the left eye (LE) in 20 patients, and both eyes in three patients. Nine patients had a round-oval corneal ulcer. One patient each had a perforated corneal ulcer with uveal prolapse, sealed perforated corneal ulcer, spontaneously healed limbal perforation, diffuse corneal haze with hyphemia, panophthalmitis, diffuse corneal stromal abscess, limbal ischemia, anterior uveitis with posterior synechiae, inferior corneal facet, and filamentary keratitis. Three patients each had a corneal melt and inferior conjunctival xerosis with chemosis. Orbital exenteration was performed in six patients. Five patients with corneal ulcers healed. Topical eye drops of amphotericin (0.5 mg/ml) cycloplegic, antiglaucoma medications, and lubricant eye drops were started along with systemic antifungals. Conclusion: Central corneal ulcer was the most common manifestation of mucormycosis. A concentration as low as 0.5 mg/ml of amphotericin eye drops was effective in the treatment.

20†Factors influencing the discard of clinical tissue and NHSBT methods to maintain a low discard rate.

INTRODUCTION: NHS Blood and Transplant Tissue and Eye Services (TES) is a human multi-tissue, tissue bank supplying tissue for transplant to surgeons throughout the UK. NHSBT has two Eye Banks. These are NHSBT Filton, based in Bristol and NHSBT David Lucas Eye Bank, which is based in Speke Liverpool. MATERIALS AND METHODS: NHSBT monitors our monthly discard rates with the aim to review for any patterns. Due to the NHSBT Eye Banks using a computer system called PULSE we can categorise all our discard for further analysis. Focusing on key areas such as Contamination, Corneal Assessment failure such as Low Endothelial Cell count, Medical deferrals and blood sample quality. RESULTS: 2019- NHSBT Procured 5705 Eyes and Issued 4725. This is a discard rate of 19%2020- NHSBT Procured 3725 Eyes and Issued 2676. This is a discard rate of 28%2021- NHSBT Procured 4394 Eyes and Issued 3555. This is a discard rate of 19%Based on the EEBA Statistical report of Eye Banking Activity in Europe for 2019- 42663 Eyes/Corneas in situ were procured and 25254 Corneas supplied for transplant. This is a discard rate of 41%.Based on the EEBA Statistical report of Eye Banking Activity in for 2020- 33460 Eyes/Corneas in situ were procured and 21212 Corneas supplied for transplant. This is a discard rate of 37%. DISCUSSION: Based on this data, NHSBT discard rate is below the European Average. Key factors which contribute to this low discard rate. Independent Clean rooms for excision and assessment operating to a Grade A Level. A centralised National Referral Centre and 4 dedicated Retrieval Teams ensure retrievals are within 24 hours of Death, and excision occur within 24 hours of enucleation. A dedicated Admin and Clinical Nursing Team performing the medical release ensures the Tissue is released promptly after Microbiological Testing (Day 10) for Assessment. During 2020 due to COVID all routine operations were cancelled suddenly. This resulted in an Increase of discard due to time expiry. REFERENCES: EEBA Statistical report of Eye Banking Activity in Europe for 2019 and 2020.

18†A porcine cornea and lamellar tissue model to investigate effects of storage conditions on corneal preservation.

BACKGROUND: Globally, more than 12 million people are awaiting corneal transplantation and cornea donor reduction has been observed since the outbreak of the COVID-19 pandemic, negatively influencing the availability of human corneas for research purposes as well. Therefore, the exploitation of ex vivo animal models in this field is of great value.The present study aimed at the development of a novel experimental model of porcine cornea ex vivo and lamellar tissue preparation to investigate the effects of storage conditions on corneal preservation. METHODS: Twelve fresh porcine eye bulbs were disinfected by immersion in 10 mL of 5% povidone-iodine under orbital mixing for 5 minutes at room temperature. The corneoscleral rims were dissected, and stored in Tissue-C (Alchimia S.r.l., n=6) at 31°C and in Eusol-C (Alchimia S.r.l., n=6) at 4°C up to 14 days.The evaluation of Endothelial Cell Density (ECD) and endothelial mortality was performed using vital dye Trypan Blue staining (TB-S, Alchimia S.r.l.). Digital 1X pictures of TB-stained corneal endothelium were acquired and percentage of stained area was quantified using FIJI ImageJ software. ECD and endothelial mortality were determined at 0, 3, 7 and 14 days.Medium turbidity detected by naked eye was considered as proof of tissue contamination.Additionally, non-vital staining of the endothelium with Alizarin Red (AR) was performed and the endothelial morphology was investigated at Day 14 in both whole corneas and dissected endothelial lamellae. RESULTS: The contamination rate of porcine corneas corresponded to <10% and 0% in Tissue-C and Eusol-C after 14 days, respectively.Porcine corneas stored in Tissue-C and Eusol-C showed <10% and <20% mortality in Tissue-C and Eusol-C respectively at the end of storage.Preliminary ECD determination (range 3700-4100 cells/mm2) at Day 0 aligned with data present in the literature (Meltendorf et al., Graefe's Arch Clin Exp Ophthalmol, 2007).Whole cornea and dissected lamellae stained with TB and AR showed comparable endothelial morphology after incubation in Tissue-C and Eusol-C for 14 days. The lamellar tissue allowed endothelium morphology analysis at higher magnification compared to whole cornea. CONCLUSION: The presented ex vivo porcine model allows evaluation of the performance and safety of storage conditions. Future perspectives of this method will be the extension of the porcine corneas storage up to 28 days.

4†New strategies in the barcelona eye bank to minimize the impact of the COVID-19 pandemic.

Since the start of the pandemic, the tissue donation in Catalonia (Spain) has decreased drastically. At the beginning of the lockdown (from March to May 2020) there was a drop of around 70% in donation of corneas and of approximately 90% in donation of placentas. Despite the fast updating of standard operating procedures, we had big difficulties in different points. For instance, in the availability of the transplant coordinator for the donor detection and evaluation, in obtaining the necessary PPE (personal protective equipment), or in the resources available in the quality control laboratories for screening. This, added to the collapse that hospitals suffered due to the large number of patients hospitalized each day, made donation levels slowly rebound.In order to provide solutions to all patients, we tried to adapt quickly to these emerging changes.In the case of corneas, we found a scenario that we had never had before. Although the cornea transplant plummeted at the beginning of the confinement (decreased by 60% compared to 2019), we run out of corneas -even for emergency situations- at the end of March.This situation led us to develop a new type of therapeutic solution in our Eye Bank. The cryopreserved cornea for tectonic purposes is a tissue that is kept frozen at -196°C and can be preserved for up to 5 years. Therefore, it is a tissue that allows us to respond to possible emergencies in subsequent similar situations.Regarding amniotic membrane for ocular care indications, the strategy was completely different. For this kind of tissue, we carried out an adaptation of our processing with two different purposes. On the one hand, to make sure that we could inactivate the SARS-CoV-2 virus, if it was there. On the other hand, to increase the donation of placentas. For this, changes in the transport medium and in the antibiotic cocktail were performed. In addition, an irradiation step was added to the final product.Little by little, it seems that the donations of corneas and placentas have been recovering. However, it is necessary to think about future contingency strategies in case a stop in donation is repeated.

Analysis of SARS-CoV-2 in Corneal Tissue of Deceased Asymptomatic Novel Coronavirus Disease 2019 Donors.

PURPOSE: The aim of this study was to analyze the presence of the SARS-CoV-2 virus in the corneal tissue of asymptomatic deceased novel coronavirus disease 2019 (COVID-19) patients. METHODS: This was a cross-sectional study performed at a tertiary eye hospital. All corneas of the deceased asymptomatic donors who tested positive for SARS-CoV-2 on a nasopharyngeal swab at the time of corneal tissue harvesting were included in the study. Histopathological examination and immunohistochemistry were performed. mRNA in situ hybridization for SARS-CoV-2 was performed in all specimens that showed positive immunostaining. The main outcome measure was the presence of SARS-CoV-2 virus in the corneal tissues. RESULTS: Twenty-two corneal tissues of 11 donors were analyzed. The mean age was 72.2 ± 14.2 years. On histological examination, no signs of inflammation or any other abnormalities were detected in the cornea and adjacent bulbar conjunctiva. Immunohistochemistry revealed faint to moderate cytoplasmic staining in the basal layer of the corneal epithelium in 8 specimens from 5 patients. None of the specimens with positive immunostaining showed the presence of SARS-CoV-2 mRNA. CONCLUSIONS: In line with previous studies , our study also reflects the absence of SARS-CoV-2 viral mRNA in corneal tissues of clinically asymptomatic deceased COVID-19 donors, thereby indicating a probable low risk of transmission of the SARS-CoV-2 virus through the transplantation of corneas from donors who tested positive for, but were asymptomatic for COVID-19. In addition, further studies on the subject should include histopathological examination because of the false positive and negative rates of molecular tests.

Corneal Cellular and Neuroinflammatory Changes After SARS-CoV-2 Infection.

PURPOSE: The purpose of this study was to evaluate corneal cellular and ultrastructural changes and to quantify the neuroinflammatory process in patients after mild severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS: Thirty patients after SARS-CoV-2 infection and 41 age-matched controls were examined. All subjects underwent in vivo confocal microscopy of the corneal cell layers and subbasal nerve fibers with the Heidelberg Retina Tomograph II. Semiautomated analysis of basal epithelial, anterior and posterior stromal keratocyte, and endothelial cell density was performed. Dendritic cell (DC) density and area were also calculated, and subbasal nerve plexus morphology was analyzed. RESULTS: The posterior stromal keratocyte density was significantly lower in patients after SARS-CoV-2 infection ( P = 0.0006). DC density in the central cornea was significantly higher in patients after SARS-CoV-2 infection ( P = 0.0004). There was a significant difference in the DC area between the 2 groups ( P < 0.0001). Significantly altered subbasal nerve fiber morphology was detected in patients after SARS-CoV-2 infection compared with healthy volunteers ( P < 0.05). CONCLUSIONS: Corneal cellular and ultrastructural changes demonstrated in this study suggest neuroinflammatory consequences of COVID-19 in the cornea in the absence of ophthalmoscopic alterations.

Presence of SARS-CoV-2 RNA in human corneal tissues donated in Italy during the COVID-19 pandemic.

OBJECTIVE: To analyse corneal tissues from asymptomatic donors with a postmortem nasopharyngeal swab tested positive for the presence of SARS-CoV-2 RNA, and therefore, understand the role that corneal transplantation may have in viral transmission. METHODS AND ANALYSIS: Between March 2020 and October 2021, 101 corneas (out of 8154 collected in Italy) from 51 donors (out of a total of 4155 Italian donors) positive for SARS-CoV-2 after postmortem nasopharyngeal swab tests were analysed for the presence of SARS-CoV-2 RNA through real-time RT-PCR. When available, the corneal tissue storage media were also assessed. Corneas and/or storage media with confirmed presence of SARS-CoV-2 RNA were further investigated by isolating SARS-CoV-2 virions, which were used to infect VeroE6 target cells. RESULTS: Only N=4 corneas and/or storage media out of 101 showed presence of SARS-CoV-2 RNA. No VeroE6 cell infection was detected with viral isolates, thus suggesting no presence of SARS-CoV-2 virions in corneal specimens and storage media. CONCLUSIONS: The presence of SARS-CoV-2 in cornea specimens would seem to be more likely due to prolonged detection of RNA rather than to active viral replication, with very low risk of infectivity and transmission through keratoplasty.

Impact of the COVID-19 Pandemic on Corneal Transplantation and Cornea Procurement.

OBJECTIVES: In this study, we aimed to analyze the effects of the COVID-19 pandemic in its first year on corneal transplant outcomes performed at a tertiary eye care center in Turkey. MATERIALS AND METHODS: Clinical records of patients who underwent corneal transplant between March 2020 and February 2021 (group A) at the Baskent University Faculty of Medicine, Department of Ophthalmology, were analyzed retrospectively. Patient demographics, indications for transplant, type of transplant procedure (lamellar vs penetrating), follow-up duration, and postoperative complications were recorded. The same data were collected for cornea transplant patients who were seen the previous year, between March 2019 and February 2020 (group B). Data from the 2 groups were compared. In related samples, the Wilcoxon signed rank test was used for statistical analysis, and a P value < .05 was considered statistically significant. RESULTS: Six corneal transplants were performed between March 2020 and February 2021 (group A), and 48 corneal transplantations were performed in the previous year (group B). There was an 80% decline in total corneal transplant numbers when compared with the previous year, and lamellar surgeries were not performed at all during the first year of the pandemic. Indications during the pandemic were mainly urgent and limited to tectonic or therapeutic causes. Postoperative follow-up regimens were impaired, and the complication rate was significantly higher during the pandemic period compared with the previous year (67% in group A vs 16% in group B) (P < .001). CONCLUSIONS: There was a steep decline in transplants in 2020, the first year of the pandemic. The prominent increase in complication rates can be attributed to the late diagnosis of corneal rejections due to impaired postoperative follow-up regimens.

Impact of the COVID-19 pandemic on the trends in corneal donor mortality data from Eye Bank records in India.

Purpose: To describe the causes and trends of corneal donor mortality from eye bank data in India during the coronavirus disease 2019 (COVID-19) pandemic. Methods: This retrospective eye bank-based study included 13,529 donors who donated their cornea between January 2018 and December 2021. Donors in whom the cause of mortality was documented were included as cases. The data were collected from the eye bank records. Results: Overall, 13,529 corneal donors were included in the study. Most of the donors were males (69.71%). The mean age of the donors was 51.55 ± 20.54 years, whereas the median age was 51 (inter-quartile range: 35-68) years. The mean age of males (49.3 ± 19.47 years) was lesser than the mean age of females (56.72 ± 21.94 years) at the time of donation. The most common age group at the time of donation was during the sixth decade of life with 2,139 (15.81%) donors. The mean age of the donors decreased by a decade from 54.95 ± 20.51 years in 2018 to 44.35 ± 18.88 years in 2021. The most common cause of donor mortality was cardio-respiratory arrest in 5,190 (38.36%) donors and trauma in 3,469 (25.64%) donors, followed by suicide in 2,790 (20.62%) donors. The trend of cardio-respiratory arrest decreased from 53.01% to 9.5% (p = <0.00001), whereas the trends of trauma increased from 21.93% to 36% (p = <0.00001) and suicide increased from 12.71% to 36.41% (p = <0.00001) between 2018 and 2021. Conclusion: Corneal donors are more commonly males in their sixth decade of life. The most common cause of donor mortality was related to cardio-respiratory arrest with a concerning rising trend in suicide cases over the years seen significantly during the pandemic.

An Experimental Model of Neuro-Immune Interactions in the Eye: Corneal Sensory Nerves and Resident Dendritic Cells.

The cornea is an avascular connective tissue that is crucial, not only as the primary barrier of the eye but also as a proper transparent refractive structure. Corneal transparency is necessary for vision and is the result of several factors, including its highly organized structure, the physiology of its few cellular components, the lack of myelinated nerves (although it is extremely innervated), the tightly controlled hydration state, and the absence of blood and lymphatic vessels in healthy conditions, among others. The avascular, immune-privileged tissue of the cornea is an ideal model to study the interactions between its well-characterized and dense sensory nerves (easily accessible for both focal electrophysiological recording and morphological studies) and the low number of resident immune cell types, distinguished from those cells migrating from blood vessels. This paper presents an overview of the corneal structure and innervation, the resident dendritic cell (DC) subpopulations present in the cornea, their distribution in relation to corneal nerves, and their role in ocular inflammatory diseases. A mouse model in which sensory axons are constitutively labeled with tdTomato and DCs with green fluorescent protein (GFP) allows further analysis of the neuro-immune crosstalk under inflammatory and steady-state conditions of the eye.

1 year posterior corneal changes after Bowman Layer Transplant for keratoconus.

INTRODUCTION: To report the posterior corneal changes after Bowman Layer Transplant for keratoconus in a tertiary hospital in the UK. METHODS: 5 eyes of 5 patients receiving Bowman Layer Transplant for advanced keratoconus in Royal Gwent Hospital (Newport, UK) were included. Pre and postoperative posterior corneal astigmatism, posterior Kmean, and back surface elevation were analysed. RESULTS: No significant changes were seen in the posterior corneal astigmatism, posterior Kmean, or back surface elevation between the pre- and postoperative period. CONCLUSION: This results would support the idea that the corneal changes seen after Bowman Layer Transplant are mainly in the anterior corneal surface.

Role of Neutrophils on the Ocular Surface.

The ocular surface is a gateway that contacts the outside and receives stimulation from the outside. The corneal innate immune system is composed of many types of cells, including epithelial cells, fibroblasts, natural killer cells, macrophages, neutrophils, dendritic cells, mast cells, basophils, eosinophils, mucin, and lysozyme. Neutrophil infiltration and degranulation occur on the ocular surface. Degranulation, neutrophil extracellular traps formation, called NETosis, and autophagy in neutrophils are involved in the pathogenesis of ocular surface diseases. It is necessary to understand the role of neutrophils on the ocular surface. Furthermore, there is a need for research on therapeutic agents targeting neutrophils and neutrophil extracellular trap formation for ocular surface diseases.