ObjectivesTo assess to which extent the COVID-19 pandemic affected corneal transplantation by virtue of donor selection algorithms in different European countries.DesignSurvey.Setting110 eye banks in 26 European countries.Participants64 eye banks covering 95% of European corneal transplantation activity.InterventionsA questionnaire listing the number of corneas procured and distributed from February to May 2018–2020 was circulated to eye banks.Main outcome measuresThe primary outcome was the number of corneal procurements. Additional outcomes were national algorithms for donor selection, classified according to their stringency (donors with COVID-19 history, suspected for COVID-19, asymptomatic, PCR testing) and the pandemic severity in each country. We calculated Spearman’s correlation coefficient to determine, two by two, the relationship between the 3-month decline in eye banking activity (procurement), the stringency of donor selection algorithm and the grading of pandemic severity (cases and deaths). A partial correlation was run to determine the relationship between decline and stringency while controlling for pandemic severity.ResultsProcurements decreased by 38%, 68% and 41%, respectively, in March, April and May 2020 compared with the mean of the previous 2 years, while grafts decreased, respectively, by 28%, 68% and 56% corresponding to 3866 untreated patients in 3 months. Significant disparities between countries and the decrease in activity correlated with stringency in donor selection independent of pandemic severity.ConclusionsOur data demonstrate significant differences between countries regarding donor screening algorithms based on precautionary principles and, consequently, a decrease in the donor pool, already constrained by a long list of contraindications. Fundamental studies are needed to determine the risk of SARS-CoV-2 transmission by corneal transplantation and guide evidence-based recommendations for donor selection to justify their substantial medical and economic impact.

Background The risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) transmission through corneal graft is an ongoing debate and leads to strict restrictions in corneas procurement, leading to a major decrease in eye banking activity. The aims of this study are to specifically assess the capacity of human cornea to be infected by SARS-CoV-2 and promote its replication ex vivo, and to evaluate the real-life risk of corneal contamination by detecting SARS-CoV-2 RNA in corneas retrieved in donors diagnosed with Coronavirus Disease 2019 (COVID-19) and nonaffected donors. Methods and findings To assess the capacity of human cornea to be infected by SARS-CoV-2, the expression pattern of SARS-CoV-2 receptor angiotensin-converting enzyme 2 (ACE-2) and activators TMPRSS2 and Cathepsins B and L in ocular surface tissues from nonaffected donors was explored by immunohistochemistry (n = 10 corneas, 78 ± 11 years, 40% female) and qPCR (n = 5 corneas, 80 ± 12 years, 40% female). Additionally, 5 freshly excised corneas (80 ± 12 years, 40% female) were infected ex vivo with highly concentrated SARS-CoV-2 solution (106 median tissue culture infectious dose (TCID50)/mL). Viral RNA was extracted from tissues and culture media and quantified by reverse transcription quantitative PCR (RT-qPCR) (viral RNA copies) 30 minutes (H0) and 24 hours (H24) after infection. To assess the risk of corneal contamination by SARS-CoV-2, viral RNA was tested by RT-qPCR (Ct value) in both corneas and organ culture media from 14 donors diagnosed with COVID-19 (74 ± 10 years, 29% female) and 26 healthy donors (79 ± 13 years, 57% female), and in organ culture media only from 133 consecutive nonaffected donors from 2 eye banks (73 ± 13 years, 29% female). The expression of receptor and activators was variable among samples at both protein and mRNA level. Based on immunohistochemistry findings, ACE-2 was localized mainly in the most superficial epithelial cells of peripheral cornea, limbus, and conjunctiva, whereas TMPRSS2 was mostly expressed in all layers of bulbar conjunctiva. A significant increase in total and positive strands of IP4 RNA sequence (RdRp viral gene) was observed from 30 minutes to 24 hours postinfection in central cornea (1.1 × 108 [95% CI: 6.4 × 107 to 2.4 × 108] to 3.0 × 109 [1.4 × 109 to 5.3 × 109], p = 0.0039 and 2.2 × 107 [1.4 × 107 to 3.6 × 107] to 5.1 × 107 [2.9 × 107 to 7.5 × 107], p = 0.0117, respectively) and in corneoscleral rim (4.5 × 109 [2.7 × 109 to 9.6 × 109] to 3.9 × 1010 [2.6 × 1010 to 4.4 × 1010], p = 0.0039 and 3.1 × 108 [1.2 × 108 to 5.3 × 108] to 7.8 × 108 [3.9 × 108 to 9.9 × 108], p = 0.0391, respectively). Viral RNA copies in ex vivo corneas were highly variable from one donor to another. Finally, viral RNA was detected in 3 out of 28 corneas (11%) from donors diagnosed with COVID-19. All samples from the 159 nonaffected donors were negative for SARS-CoV-2 RNA. The main limitation of this study relates to the limited sample size, due to limited access to donors diagnosed with COVID-19 and concomitant decrease in the procurement corneas from nonaffected donors. Conclusions In this study, we observed the expression of SARS-CoV-2 receptors and activators at the human ocular surface and a variable increase in viral RNA copies 24 hours after experimental infection of freshly excised human corneas. We also found viral RNA only in a very limited percentage of donors with positive nasopharyngeal PCR. The low rate of positivity in donors diagnosed with COVID-19 calls into question the utility of donor selection algorithms. Trial registration Agence de la Biomédecine, PFS-20-011 https://www.agence-biomedecine.fr/.

Background/aimRejection is the main cause of graft failure after penetrating keratoplasty (PK). Its prevention by repeated instillation of steroid eye-drops has not evolved in decades. Poor adherence and discontinuous nature of eye-drop treatment may explain some PK failures. In a rabbit model, we previously demonstrated that a subconjunctival dexamethasone implant was well tolerated and prevented rejection efficiently in the first 5–6 weeks. This clinical trial investigates its tolerance and safety after PK.MethodsSingle-centre, phase II non-randomised tolerance and safety pilot study (NCT02834260). Designed to analyse the risk of elevated intraocular pressure (IOP), discomfort and resorption time. Fourteen patients with a low rejection risk indication of PK were enrolled between January 2017 and August 2018. The implant was injected in the 12 o’clock position, 5 mm from the limbus, at the end of PK. A steroid eye-drop treatment was planned when implant resorption was complete. Patients were monitored regularly for 12 months: IOP (main outcome measure at 1 month), discomfort and redness scores, implant status, rejection episode and central corneal thickness by optical coherence tomography. An independent data safety monitoring committee verified safety aspects.ResultsNo increase in IOP or other adverse event related to the implant was observed. Average resorption time was 6 weeks. The switch to steroid eye-drops was uneventful. One patient, included despite preoperative corneal neovascularisation (unintended protocol deviation) experienced a rejection.ConclusionsThis is the first proof of concept that dropless immunosuppression is possible after low rejection risk PK.Trial registration numberNCT02834260.

Objectives Corneal transplantation is the most common transplant worldwide and its success critically depends on the management of corneal graft rejection through topical steroid therapy during the first 12 months after surgery. There is currently no published data on adherence after keratoplasty. This pilot study aims to explore the adherence to topical steroid after penetrating keratoplasty using a smart electronic device. Methods Thirty patients undergoing penetrating keratoplasty were included to evaluate the adherence to topical dexamethasone medication for 12 months after surgery. Patients received the usual post-transplantation treatment (topical dexamethasone) and follow-up after surgery (day 15, months 1, 2, 3, 4, 5, 6, 9, and 12). Adherence to treatment was monitored using the KaliJAR device (Kali Care, Santa Clara, CA, USA), which recorded the number of single-dose units (SDU) discarded. At control visits, data recorded by the device were compared to the manually count of SDU. Adherence ratio and individual adherence curve were explored for all patients. Results Data from 27 patients showed a high agreement between adherence ratio calculated based on the device data and obtained from manual counting of the discarded SDU (intraclass coefficient correlation of 0.87 [95% CI: 0.738–0.938]). Mean adherence to the treatment over the 12-month study period was 95.2 ± 4%. Conclusions Adherence to topical dexamethasone for 12 months after corneal transplantation was high. The connected device was able to record accurately the discarded SDU. This approach would be a particular interest in the early identification and personalized follow-up of poorly adherent patients.

PurposeOur patented corneal bioreactor (BR) improves the long‐term survival of human corneas ex vivo by restoring intraocular pressure and renewal of storage medium.AimTo use the BR to test the efficacy of eye drops containing devitalized ground amniotic membrane of umbilical cord extract (AMUCE) to treat deep stromal ulcerations. AMUCE contains high level of proteoglycans, collagen and physiological growth factors.MethodsOnly pairs of human corneas (with ECD > 800 cells/mm2) were used to obtain best possible controls. They were first stored for 2 weeks into the BR filled with CorneaMax (Eurobio, France), with 21 mmHg in the endothelial chamber to allow regeneration of a normal epithelium. Then, an 8.0 mm diameter calibrated epithelial ulcer was made with a spatula and a 6 mm diameter × 100 µm in depth was made with Excimer laser in the stroma. Using a specific BR lid allowing sterile handling, each cornea was treated topically 4 times daily either by the AMUCE eye drops (TBF, France) or by the vehicle (0.9% NaCl). Closure of the ulceration was monitored daily using fluorescein staining quantified by image analysis (FIJI) of macro‐zoom microscopy. After wound healing corneas were fixed for histology (HES) and immunolabeling of epithelial markers.ResultsThree pairs were used. Epithelium wound healing was obtained at D3, D9, D10 with AMUCE and D3, D9, D19 with the vehicle. Histology performed in ulcerations centre showed 3‐6 epithelial layers with AMUCE and 1‐4 with the vehicle. At D21, significant epithelial detachment was observed only for 2 corneas treated with the vehicle. For one pair, immunolabelling for E‐cadherin and Cytokeratin K3/K12 showed better epithelial differentiation with AMUCE than with vehicle. No evidence of stromal regeneration was observed in the 6 corneas.ConclusionsAMUCE has potential for a faster and lasting epithelium regeneration (stratification and maturation). Nevertheless, it has no impact on stromal regeneration in this model.

The use of ultrafast laser pulses for eye anterior segment surgery has seen a tremendous growth of interest as the technique has revolutionized the field, from the treatment of myopia, hyperopia, and presbyopia in the cornea to laser-assisted cataract surgery of the crystalline lens. For the latter, a comprehensive understanding of the laser–tissue interaction has yet to be achieved, mainly because of the challenge of observing the interaction zone in situ with sufficient spatial and temporal resolution in the complex and multi-layered tissue of the crystalline lens. We report here on the dedicated characterization results of the laser–tissue interaction zone in the ex vivo porcine lens using three different methods: in situ and real-time microscopy, wide-field optical imaging, and phase-contrast microscopy of the histological cross sections. These complementary approaches together revealed new physical and biological consequences of laser irradiation: a low-energy interaction regime (pulse energy below ~1 µJ) with very limited cavitation effects and a stronger photo-disruption regime (pulse energy above 1 µJ) with a long cavitation duration from seconds to minutes, resulting in elongated spots. These advances in the understanding of the ultrafast laser’s interactions with the lens are of the utmost importance for the preparation of the next-generation treatments that will be applied to the lens.

PurposePenetrating keratoplasty (PK) remains the first technic of corneal transplantation worldwide and rejection a common cause of graft failure. Its prevention has been based for decades on repeated instillation of steroid eye drops (dexamethasone, prednisolone, rimexolone). Nevertheless, the overall survival of corneal transplants, all indications combined, is lower than that of some organ transplants. Both compliance and the discontinuous nature of the eye drops may be involved. The improvement of immunosuppression could avoid numerous graft failures. In a rabbit model of PK, we previously demonstrated that a subconjunctival dexamethasone implant (Ozurdex) was well tolerated and prevented rejection as efficiently as steroid eye drops trice daily during the first 5‐6 weeks. We then designed a clinical trial to first investigate the tolerance and safety of subconjunctival Ozurdex after PK.MethodsSingle centre, phase II non‐randomized tolerance and safety pilot study on 14 patients (NCT02834260). Designed to analyze the risk of increased intraocular pressure (IOP, primary endpoint at month 1), possible discomfort, resorption time, and collect initial efficacy data. The implant was injected at the 12 o'clock position, 5 mm from the limbus, at the end of PK, in order to deliver dexamethasone immediately. A steroid eye drop relay was planned at the time of complete resorption of the implant. Patients were monitored at regular intervals during 12 months: IOP, discomfort and redness scores, implant status, rejection episode, endothelial cell density, and central corneal thickness by OCT. An independent adverse event committee gave its opinion after the first patient, then at regular intervals.ResultsNo increase in IOP, no adverse event related to the implant was observed. The average duration of resorption was 6 weeks. The therapeutic relay with dexamethasone eye drops was uneventful.ConclusionsHis is the first proof of concept that dropless immunosuppression is possible after penetrating keratoplasty. Ozurdex, chosen here because it was the only ophthalmological steroid implant marketed in France, obviously resorbs too quickly, but this work paves the way for the use of other implants that release a steroid or another immunosuppressive agent in the very long term.

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