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PURPOSE To report the outcomes of two-piece microkeratome-assisted MK for eyes with full-thickness traumatic corneal scars and otherwise functional endothelium following corneal penetrating injury. DESIGN Interventional case series METHODS: : In this single-center study, 41 consecutive eyes with traumatic corneal scars that underwent two-piece microkeratome-assisted mushroom keratoplasty were evaluated. The two-piece mushroom graft consisted of an anterior lamella of 9-mm diameter and a posterior lamella of 6-mm diameter. Outcome measures were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism (RA), endothelial cell density and postoperative complication rates. RESULTS Of the 41 total cases, 38 eyes (93%) reached Snellen vision ≥20/100, 36 (88%) reached ≥20/60, 29 (71%) reached ≥20/40 and 13 (32%) reached ≥20/25 2 years following MK. Excluding eyes with vision-impairing comorbidities, baseline logMAR BSCVA (1.41±0.73) significantly improved annually during the first 2 years (p < 0.001) reaching 0.16±0.13 at year 2 which subsequently remained stable up to 10 years (p = 0.626). RA exceeded 4.5 diopters in 2 cases (5%) after wound revision for high-degree astigmatism in 5 cases. Endothelial cell loss was 35.1% at 1 year with an annual decline of 2.9% over 10 years. Elevation in IOP was observed postoperatively in 7 eyes of which 6 had pre-existing glaucoma. The 10-year cumulative risk for graft rejection and failure was 8.5% and 10% respectively. CONCLUSION Two-piece microkeratome-assisted MK for traumatic corneal scars can allow excellent visual rehabilitation with relatively stable ECL and low rates of immunologic rejection and graft failure.

A 20-year-old male patient presented to our tertiary eye centre with post-traumatic cataract in the right eye, 3 months after penetrating trauma with metal wire while working with electric cables. The corneal laceration had been repaired soon after trauma elsewhere and the patient had some gain of

Biomechanical properties of corneal scar are strongly correlated with many corneal diseases and some types of corneal surgery, however, there is no elasticity information available about corneal scar to date. Here, we proposed an acoustic radiation force optical coherence elastography system to evaluate corneal scar elasticity. Elasticity quantification was first conducted on ex vivo rabbit corneas, and the results validate the efficacy of our system. Then, experiments were performed on an ex vivo human scarred cornea, where the structural features, the elastic wave propagations, and the corresponding Young’s modulus of both the scarred region and the normal region were achieved and based on this, 2D spatial distribution of Young’s modulus of the scarred cornea was depicted. Up to our knowledge, we realized the first elasticity quantification of corneal scar, which may provide a potent tool to promote clinical research on the disorders and surgery of the cornea.

Purpose: analgesic drugs, including nonselective opioids and non-steroidal anti-inflammatory drugs, should be used with great precautions to relieve pain after trauma to the corneal epithelium because of their unfavorable effects on wound healing. Biphalin is a synthetic opioid peptide that has been demonstrated to possess a strong analgesic effect on rodents. The purpose of this study is to investigate the effects of biphalin on human corneal epithelial wound healing. Methods: an immortalized human corneal epithelial cell (HCEC) culture was used to analyze the effects of biphalin on wound healing. The toxicity of biphalin at various concentrations was measured by the MTT assay. The effects of 1 μM and 10 μM biphalin on wound closure, cell migration and proliferation were tested in an in vitro scratch assay of HCECs. Naloxone, a non-selective competitive opioid receptor antagonist, was also used to inhibit the effects of biphalin in all experiments. Results: biphalin did not cause any toxic effect on HCECs at concentrations lower than 100 μM at various incubation time points. Biphalin significantly increased wound healing at 1 μM concentration in an in vitro scratch assay of HCECs (P < 0.05). It also significantly increased migration of HCECs (P < 0.01). There was no significant difference between the biphalin and control groups of HCECs in the Ki67 proliferation assay. Conclusion: biphalin, which is a synthetic opioid peptide, promotes corneal epithelial wound healing by increasing cell migration. This role should be evaluated in further in vivo and clinical studies. / Objet: les analgésiques, dont les morphiniques non-sélectifs et les anti-inflammatoires non stéroïdiens (AINS) devraient être utilisés avec beaucoup de précautions pour traiter la douleur dans les lésions de l’épithélium cornéen du fait de leurs effets indésirables sur la cicatrisation. La Biphaline est un peptide morphinique de synthèse dont on a démontré qu’il possède un effet analgésique puissant chez les rongeurs. Le but de cette étude est d’évaluer les effets de la Biphaline sur les lésions de l’épithélium cornéen humain. Méthodes: une culture de cellules épithéliales immortalisées de cornée humaine (HCEC) a été utilisée pour tester les effets de la Biphaline sur la cicatrisation. La toxicité de la Biphaline a été mesurée à diverses concentrations par essai MTT. L’effet de 1 μM et de 10 μM de Biphaline ont été testées sur la cicatrisation dans un essai in vitro de grattage de HCEC et séparément de migration et de prolifération cellulaire. La Naloxone, un antagoniste compétitif non sélectif des récepteurs morphiniques, fut aussi utilisée pour inhiber les effets de la Biphaline dans toutes les expériences. Résultats: la Biphaline ne produit aucun effet toxique sur les HCEC aux concentrations inférieures à 100 μM aux différents temps d’incubation. La Biphaline augmente significativement la cicatrisation à la concentration de 1 μM dans un test de grattage in vitro d’HCEC (p < 0,05). Elle accroît également significativement la migration des HCEC (p < 0,01). Il n’y a pas de différence significative entre la Biphaline et le groupe témoin de HCEC au test de prolifération Ki67. Conclusion: la Biphaline, un peptide morphinique de synthèse, favorise la cicatrisation de l’épithélium cornéen par l’augmentation de la migration cellulaire. Ce rôle serait à évaluer par des études in vivo et cliniques ultérieures., NA

Aquaporins (AQPs) are a highly conserved group of membrane proteins that play critical roles in water and small solute transport across epithelial and endothelial barriers. The aim of this study was to determine whether AQP5, a well-known water channel protein, also plays a role in corneal epithelial wound healing. AQP5 knockout (AQP5−/−) mice were generated using CRISPR/Cas9. A corneal wound healing model was established using epithelial debridement of corneas. The time to corneal epithelial and nerve regeneration was significantly delayed in the AQP5−/− mice. Reduction in Ki-67–positive cells and nerve growth factor (NGF) expression was confirmed in the AQP5−/− mice during healing. Epithelial and nerve regeneration rates were significantly increased in the AQP5−/− mice after treatment with NGF, which was accompanied by recovered levels of phosphorylated Akt. NGF treatment also improved the recovery of corneal nerve fiber density and sensitivity in the AQP5−/− mice. While the promotion of NGF induced corneal epithelial and nerve regeneration, Akt inhibitor reversed Akt reactivation. A significant impairment of corneal wound healing in the AQP5−/− mice resulted from distinct defects in corneal epithelial cell proliferation and nerve regeneration. These results provide evidence for the involvement of aquaporin in cell proliferation and suggest that AQP5 induction could be a potential therapy for accelerating the resurfacing of corneal defects.

PURPOSE This study aimed to investigate the clinical and histopathological effects of corneal cross-linking (CXL) and matrix-regenerating agent (RGTA) treatments after corneal alkali burn. MATERIALS AND METHODS Twenty-four alkali-burned corneas from 24 rabbits were divided into three groups: control, CXL, and RGTA. All animals were investigated for epithelial healing, opacification, ulceration, and neovascularization at days 1, 7, 14, and 21 after the alkali burn. Corneas were excised and sent for histological examination on day 21. RESULTS One animal each from the CXL and control groups exhibited moderate ulceration, while no ulceration was observed in the RGTA group. No significant difference was observed among the groups in corneal thickness or corneal opacity measurements at the final visit (p = .058 and p = .544, respectively). Both RGTA and CXL treatments were effective in terms of epithelial healing and neovascularization (p = .023 and p = .03, respectively). On histological examination, the CXL and RGTA groups were more effective in treating epithelial loss, stromal edema, corneal vascularization, and leukocytic infiltration than the control group (p .05). In contrast, the stromal staining scores of the CXL and RGTA groups were lower than those of the control group (p

PURPOSE To establish a physiologically relevant ex vivo model of equine corneal epithelial wound healing. METHODS Fourteen equine corneas were randomly assigned to one of two groups: wounded (n = 8) or unwounded (n = 6) controls. In the wounded group, the axial corneal epithelium was removed by applying a 6 mm filter paper disk soaked in 1N-NaOH for 60 s. Corneas were subsequently cultured using an air-liquid interface model. Evaluation of corneal healing was performed daily, and culture medium was collected. Corneas were randomly assigned to undergo processing via histopathology and RNAscope in situ hybridization for interleukin-6 (IL-6) and alpha-smooth muscle actin (αSMA) expression at T24, T48, and T72 h after wounding. Media of the cultured corneas were evaluated for the presence of lactate dehydrogenase (LDH) by a colorimetric assay. RESULTS The ulcerated area of the wounded corneas decreased over time and all corneas healed within 72 h. Histologically, normal corneal architecture was observed including healthy epithelium (in areas other than the ulcerated ones), minimal stromal edema, intact endothelium, and Descemet's membrane. IL-6 expression was increased in wounded corneas compared with unwounded controls. LDH expression was elevated for both wounded and unwounded corneas at T24 but decreased substantially and was not detected at T48 in media from wounded and unwounded corneas, respectively. No αSMA expression was detected from either wounded or unwounded corneas. CONCLUSIONS The equine air-liquid interface, ex vivo, corneal epithelial wound healing model is effective and physiologically relevant. This model can be used in future studies evaluating various corneal therapies.

Corneal injury due to ocular trauma or infection is one of the most challenging vision impairing pathologies. The aim of the work was to study the effect of biodegradable silk fibroin-based scaffolds containing GDNF on the corneal regeneration process. During cultivate the highest keratocytes proliferative activity was registered with scaffolds containing 250 ng/ml and 500 ng/ml GDNF. In mice with an experimental model of epithelial-stromal damage to the cornea, silk fibroin-based scaffolds containing GDNF in various concentrations were used (in groups 1, 2 and 3 silk fibroin-based scaffolds containing GDNF in a concentration of 50 ng/ml, 250 ng/ml and 500 ng/ml, respectively; in group 4 - silk fibroin-based scaffolds without GDNF; in group 5 - a solution of GDNF with concentration of 500 ng/ml; group 6- control). The area of the corneal epithelial defect in groups 2, 3, and 5 was less than in the other groups. The most pronounced positive immunohistochemical reaction with antibodies to Bcl2, Bax, phosphoERK1/2 and phospho-JNK1/2, Ki67, Gap43 was observed in groups 2 and 3. Thus, silk fibroin-based scaffolds with GDNF stimulate the epithelialization process, proliferative activity of epithelial cells and keratocytes, accelerate the formation of the stromal nerve plexus and exhibit anti-apoptotic activity.

Background: This review summarized prophylactic retinectomy technique and its effect on anatomic and functional outcomes in severe open globe injuries (OGIs). Methods: A comprehensive search in PubMed (MEDLINE), Embase, Scopus, and EuropePMC databases was performed up until 8 January 2020. Enrolled studies include case series, studies involving pars plana vitrectomy (PPV) combined with retinectomy in severe penetrating injuries with or without IOFB, perforating injuries, and globe ruptures. Primary outcome was best-corrected visual acuity (BCVA) ⩾20/200 at the end of the study. Secondary outcomes were the rate of proliferative retinopathy (PVR), globe survival rate and retinal reattachment rate. Results: A total of seven studies, involving 275 eyes with severe OGIs, is included in this study. Meta-analysis indicates that final BCVA ⩾20/200 was achieved in 61% (95% CI 49%–73%). Meta-regression analysis showed that improvement was inversely affected by the presence of pre-operative direct macular injury ( p = 0.001) and corneal scar ( p = 0.015). The proportion of pre-operative BCVA Conclusion: Early PPV combined with retinectomy was associated with acceptable visual improvement and anatomical success.

PURPOSE: Bioactive substrates can be used therapeutically to enhance wound healing. Here, we evaluated the effect of an in-situ thermoresponsive hydrogel from decellularized porcine cornea ECM, COMatrix (COrnea Matrix), for application as an ocular surface bandage for corneal epithelial defects. METHODS: COMatrix hydrogel was fabricated from decellularized porcine corneas. The effects of COMatrix hydrogel on attachment and proliferation of human corneal epithelial cells (HCECs) were evaluated in vitro. The effect of COMatrix on the expressions of the inflammatory genes, IL-1β, TNF-α, and IL-6 was assessed by RT-PCR. The in-situ application and also repairing effects of COMatrix hydrogel as an ocular bandage was studied in a murine model of corneal epithelial wound. The eyes were examined by optical coherence tomography (OCT) and slit-lamp microscopy in vivo and by histology and immunofluorescence post-mortem. RESULTS: In vitro, COMatrix hydrogel significantly enhanced the attachment and proliferation of HCECs relative to control. HCECs exposed to COMatrix had less induced expression of TNF-α (P

OBJECTIVE To evaluate the efficacy of bovine amniotic membrane homogenate (BAMH) on wounded ex vivo rabbit corneas. PROCEDURE Eighteen corneas obtained from normal rabbit eyes were wounded equally using a 6 mm trephine and cultured into an air-liquid interface model. Corneas were treated with phosphate-buffered saline (PBS) (n = 6, control group), 0.2% ethylenediaminetetraacetic acid (EDTA; n = 6), or BAMH (n = 6). All treatments were applied topically 6 times/day. Each cornea was macrophotographed daily with and without fluorescein stain to assess epithelialization and haziness. After 7 days, corneal transparency was evaluated, and the tissues prepared for histologic analysis of viability, and total and epithelial thickness. RESULTS The mean epithelialization time was 6.2 ± 0.82 days for the control group, 6.2 ± 0.75 days for the EDTA-treated group, and 5.1 ± 0.40 days for the BAMH-treated group, demonstrating a significant difference between the BAMH and the other groups. The corneas that received EDTA had better transparency compared with the other groups. Histologically, all corneas had adequate morphology and architecture after healing. Analysis of corneal and epithelial thickness revealed no significant difference among groups. CONCLUSION Bovine amniotic membrane homogenate is an effective and promising treatment for stromal and epithelial ulcers.

Purpose How sensory neurons and epithelial cells interact with one another, and whether this association can be considered an indicator of health or disease is yet to be elucidated. Methods Herein, we used the cornea, Confetti mice, a novel image segmentation algorithm for intraepithelial corneal nerves which was compared to and validated against several other analytical platforms, and three mouse models to delineate this paradigm. For aging, eyes were collected from 2 to 52 week-old normal C57BL/6 mice (n ≥ 4/time-point). For wound-healing and limbal stem cell deficiency, 7 week-old mice received a limbal-sparing or limbal-to-limbal epithelial debridement to their right cornea, respectively. Eyes were collected 2–16 weeks post-injury (n=4/group/time-point), corneas procured, immunolabelled with βIII-tubulin, flat-mounted, imaged by scanning confocal microscopy and analyzed for nerve and epithelial-specific parameters. Results Our data indicate that nerve features are dynamic during aging and their curvilinear arrangement align with corneal epithelial migratory tracks. Moderate corneal injury prompted axonal regeneration and recovery of nerve fiber features. Limbal stem cell deficient corneas displayed abnormal nerve morphology, and fibers no longer aligned with corneal epithelial migratory tracks. Mechanistically, we discovered that nerve pattern restoration relies on the number and distribution of stromal-epithelial nerve penetration sites. Conclusions Microstructural changes to innervation may explain corneal complications related to aging and/or disease and facilitate development of new assays for diagnosis and/or classification of ocular and systemic diseases.

The corneal epithelium is continuously exposed to oxygen, light, and environmental substances. Excessive exposure to those stresses is thought to be a risk factor for eye diseases. Photokeratitis is damage to the corneal epithelium resulting in a painful eye condition caused by unprotected exposure to UV rays, usually from sunlight, and is often found in people who spend a long time outdoors. In modern life, human eyes are exposed to artificial light from light-emitting diode (LED) displays of computers and smartphones, and it has been shown that short-wavelength (blue) LED light can damage eyes, especially photoreceptors. However, the effect of blue LED light on the cornea is less understood. In addition, it is important to develop new treatments for preserving human eyesight and eye health from light stress. Here, we used human corneal epithelial cells-transformed (HCE-T) cells as an in-vitro model to investigate the protective effect of NSP-116, an imidazolyl aniline derivative, against the oxidative stress induced by light in the corneal epithelium. Treatment with 10 µM NSP-116 significantly increased the cell viability and reduced the death ratio following UV or blue LED light exposure. Furthermore, NSP-116 treatment decreased light-induced reactive oxygen species production and preserved the mitochondrial membrane potential. Immunoblotting data showed that NSP-116 suppressed the stress response pathway. Finally, NSP-116 treatment prevented corneal epithelial apoptosis induced by blue LED light in an in-vivo mouse model. In conclusion, NSP-116 has a protective effect against oxidative stress and corneal cell death from both UV and blue LED light exposure.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that causes coronavirus disease 2019 (COVID-19) has resulted in a pandemic affecting the most vulnerable in society, triggering a public health crisis and economic collapse around the world. Effective treatments to mitigate this viral infection are needed. Since the eye is a route of virus entrance, we use an in vivo rat model of corneal inflammation as well as human corneal epithelial cells (HCEC) in culture challenged with IFNγ as models of the eye surface to study this issue. We explore ways to block the receptor-binding domain (RBD) of SARS-CoV-2 Spike (S) protein to angiotensin-converting enzyme 2 (ACE2). We found that the lipid mediators, elovanoid (ELV)-N32 or Resolvin D6-isomer (RvD6i) decreased the expression of the ACE2 receptor, furin, and integrins in damaged corneas or IFNγ-stimulated HCEC. There was also a concomitant decrease in the binding of Spike RBD with the lipid treatments. Using RNA-seq analysis, we uncovered that the lipid mediators also attenuated the expression of pro-inflammatoy cytokines participating in hyper-inflammation and senescence programming. Thus, the bioactivity of these lipid mediators will contribute to open therapeutic avenues to counteract virus attachment and entrance to the body.

Sulfur mustard (SM) is a lipid soluble alkylating agent that causes genotoxic injury. The eye is highly sensitive to SM toxicity and exposures exceeding 400 mg min/m3 can elicit irreversible corneal pathophysiologies. Development of medical countermeasures for ocular SM exposure has been hindered by a limited understanding of dose-dependent effects of SM on corneal injury. Here, clinical, histological and ultrastructural analyses were used to characterize the effects of SM dose on corneal injury progression. Corneas were evaluated for up to 20 wk following exposure to saturated SM vapor for 30−150 s, which corresponds to 300−1,500 mg min/m3. In acute studies, a ceiling effect on corneal edema developed at doses associated with full-thickness corneal lesions, implicating endothelial toxicity in corneal swelling. Recurrent edematous lesions (RELs) transiently emerged after 2 wk in a dose-dependent fashion, followed by the development of secondary corneal pathophysiologies such as neovascularization, stromal scarring and endothelial abnormalities. RELs appeared in 96 % of corneas exposed for ≥ 90 s, 52 % of corneas exposed for 60 s and 0 % of corneas exposed for 30 s. While REL latency was variable in corneas exposed for 60 s, REL emergence was synchronized at exposures ≥ 90 s. Corneas did not exhibit more than one REL, suggesting RELs are part of a programmed pathophysiological response to severe alkylating lesions. In post-mortem studies at 12 wk, corneal edema was positively correlated to severity of endothelial pathologies, consistent with previous findings that endothelial toxicity influences long-term outcomes. These results provide novel insight into long-term corneal pathophysiological responses to acute toxicity and identify exposure conditions suitable for therapeutic testing.

Purpose: The aim of this study was to investigate the microRNA (miRNA) expressions of the corneal tissue after an alkaline burn and to compare the efficiency of adipose- and bone marrow-derived mes...

Corneal damage‐induced various wavelength UV (311, 254, 235, 222 and 207 nm) was evaluated in rats. For 207 and 222‐UV‐C, the threshold radiant exposure was between 10 000 and 15 000 mJ cm−2 at 207 nm and between 3500 and 5000 mJ cm−2 at 222 nm. Penetrate depth to the cornea indicated by cyclobutene pyrimidine dimer (CPD) localization immediately after irradiation was dependent on the wavelength. 311 and 254 nm UV penetrate to corneal endothelium, 235 nm UVC to the intermediate part of corneal stroma, 222 and 207 nm UVC only to the most outer layer of corneal epithelium. CPD observed in corneal epithelium irradiated by 222 nm UVC disappeared until 12 h after. The minimum dose to induce corneal damage of short‐wavelength UV‐C was considerably higher than the threshold limit value (TLV®) promulgated by American Conference of Governmental Industrial Hygienists (ACGIH). The property that explains why UV‐C radiation at 207 and 222 nm is extremely less hazardous than longer UV wavelengths is the fact that this radiation only penetrates to the outermost layer of the corneal epithelium. These cells typically peel off within 24 h during the physiological turnover cycle. Hence, short‐wavelength UV‐C might be less hazardous to the cornea than previously considered until today., Comparison of the lowest observed adverse effects level (LOAEL), the no observed adverse effect level (NOAEL) in this study and the threshold limit value (TLV®) regulated by The American Conference of Governmental Industrial Hygienists (ACGIH). Radiant exposure threshold is estimated to be between LOAEL and NOAEL; however, there is a large difference from TLV® at the far UV‐C band, such as 207 nm and 222 nm. Our results suggested that the TLV® of the far UV‐C band may be much higher than previously thought.

Most of the people in the world are affected by glaucoma, which leads to irreversible blindness. Several patient friendly treatments are available, nevertheless medications lack an easy and efficient way of sustained delivery. To make the delivery with enhanced bioavailability, biodegradable and non-biodegradable polymers-based drug carriers are explored. However, ocular drug delivery issues have not been resolved yet due to less adhesiveness, poor penetration ability, pH, and temperature dependent burst releases. Chitosan is found to be effective for ocular drug delivery due to excellent physio-chemical properties in terms of overcoming the existing issues. In this review, we aim to highlight why it has been chosen and the holy grail for ocular drug delivery. Besides, we have comprehensively reviewed recent patents on chitosan as a platform for ocular drug delivery and future perspectives on factors, lacunae and challenges that need to be addressed for better ocular delivery methods for glaucoma management.

Objectives Corneal abrasions are common ophthalmic presentations to emergency departments. Among emergency physicians and ophthalmologists, there are highly variable practice patterns with regard to management of resultant pain and discomfort. The goal of this study was to review and analyze the efficacy and safety of topical pain therapies for corneal abrasions, including topical anesthetics, nonsteroidal anti-inflammatory drugs (NSAIDs), cycloplegics, steroids, pressure patching, and the use of a bandage contact lens (BCL). Methods The review followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. The protocol was established a priori and published on PROSPERO (CRD42020201288). MEDLINE, EMBASE, CENTRAL, and Web of Science were searched until December 31, 2020. Primary studies comparing topical pain therapies to another therapy or control were included. Primary outcomes included percentage of corneal abrasions healed at 24, 48, and 72 hours, as well as pain control at 24 and 48 hours. Secondary outcomes included use of oral analgesia and incidence of complications. Risk of bias was assessed using validated tools. Quality of evidence was assessed using the GRADE methodology. Results Overall, 33 studies (31 randomized controlled trials [RCTs], two cohort studies) comprising 4,167 patients with corneal abrasions were analyzed. Only the data for topical NSAIDs were of adequate evidence from which to draw conclusions; topical NSAIDs demonstrated significantly reduced pain scores at 24 hours (standardized mean differences [SMD] -0.69, 95% CI = -0.98 to -0.41) and 48 hours (SMD = -0.56, 95% CI = -1.02 to -0.10) as well as 53% (95% CI = 34% to 67%) lower oral analgesia use compared to control. Based on available data, topical anesthetics, cycloplegics, patching, and the use of a BCL did not result in any significant difference in pain scores or use of oral analgesia, while no studies examined topical steroids. No interventions resulted in healing delays or significantly higher rates of complications compared to controls. Conclusions There was strong evidence to support that topical NSAIDs reduce pain associated with corneal abrasions in the first 48 hours and the need for oral analgesia. The existing evidence was insufficient to support or refute the use of topical anesthetics, cycloplegics, steroids, or BCL for pain control in corneal abrasions. Pressure patching was ineffective at pain reduction and may increase the risk of complications. Delays in healing or other complications were not significantly different between any intervention or control for simple, uncomplicated corneal abrasions; however, larger RCTs are required to identify any differences in rare complications.

We compared the therapeutic effects of topical 8-oxo-2′-deoxyguanosine (8-oxo-dG) and corticosteroid in a murine ocular alkali burn model. (n = 128) The corneal alkali burn model was established by applying 0.1 N sodium hydroxide (NaOH), followed by treatment with 8-oxo-dG, 0.1% fluorometholone (FML), 1% prednisolone acetate (PDE), or phosphate-buffered saline (PBS) twice daily. One week later, the clinical and histological status of the cornea were assessed. Transcript levels of inflammatory cytokines and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase as well as the levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the cornea, were assayed. The 8-oxo-dG and PDE groups showed marked improvements in corneal integrity and clarity when compared with the PBS group (each p p p

This review is intended to describe the therapeutic approaches for corneal blindness, detailing the steps and elements involved in corneal wound healing. It also presents the limitations of the actual surgical and pharmacological strategies used to restore and maintain corneal transparency in terms of long-term survival and geographic coverage. In addition, we critically review the perspectives of anabolic agents, including vitamin A, hormones, growth factors, and novel promitotic and anti-inflammatory modulators, to assist corneal wound healing. We discuss the studies involving nanotechnology, gene therapy, and tissue reengineering as potential future strategies to work solely or in combination with corneal surgery to prevent or revert corneal blindness.

PURPOSE: To develop a stromal wound healing model and a reliable scar classification score system that correlates photographic evaluation with changes in the structure and organization of the extracellular matrix. MATERIALS AND METHODS: We tested three stromal injury techniques in adult C57BL/6 mice. Technique 1, a lineal partial thickness keratotomy in the horizontal axis. Technique 2, corneal epithelial and stromal debridement using a diamond burr in the horizontal axis, and technique 3, a combination of techniques 1 and 2. To assess intra-observer and inter-observer agreement between two examiners evaluating formed stromal scars, stereo microscopic photographs of anterior segment were scored by two masked examiners at around 1-month. Depending on the severity of opacification and the area of involvement, scars were classified on a scale from 0 to 3 based on a modified Fantes haze scale. Extracellular matrix composition as well as matrix organization, macrophage infiltration and neovascularization were evaluated with immunofluorescence and second harmonic generation (SHG) microscopy. RESULTS: Technique 1 created mild scars, with a score of 0.5 ± 0.43, while techniques 2 (score 2.1 ± 0.45) and 3 (score 2 ± 0.66), created dense scars with a higher score. A significant difference in scar severity score was noted between the 3 techniques (one way ANOVA, p < 0.0001). Masked graders demonstrated excellent agreement (intraclass correlation = 0.927 [95% confidence interval: 0.87–0.96]). The severity of scars noted at stereo microscopy correlated with the severity of changes in extracellular matrix in the stroma as demonstrated by the expression of collagens I, IV and fibronectin and evaluation of matrix hierarchical organization. In contrast to mild scarring, moderate and severe scars had increased expression of CD31 and CD68, markers of vascular endothelial cells and macrophages, respectively. CONCLUSION: Mouse models of stromal scarring using simple surgical techniques are described. Corneal scars can be consistently classified by two observers. Grading of scar severity positively correlates with changes in extracellular matrix composition, disorganization and cell infiltration.

Amniotic membrane (AM) transplantation is often used as a treatment for corneal repair, but AM is prone to dissolving and shedding after surgery; multiple transplants will cause pain and financial burden. In this work, human amniotic membrane was firstly decellularized to obtain an AM extracellular matrix (dAM). This dAM was homogenized and extracted to obtain the dAM extract (simplified as dAME). Different forms of administration for corneal injury were performed as liquid drops (diluted dAME), in situ gels (using temperature-dependent Poloxamer 407 as the matrix), and tablets (poly(vinyl alcohol) as the matrix). The cytocompatibility of dAME was evaluated using corneal epithelial cells, corneal stromal cells and fibroblasts as cell models. The results showed that dAME is biocompatible to all these cells. Cells exhibited normal morphology and growth state at a dAME concentration of up to 160 μg mL−1. In vivo, dAME exhibited increased wound healing efficiency in severe corneal injury, being characterized with a shorter healing time for epithelium and a faster recovery for stromal opacity and thickness, compared with those of the control eyes. Different forms of administration have different effects on corneal repair; among them, in situ gels achieved the best therapeutic efficiency. Their biological mechanism was detected via quantitative real-time polymerase chain reaction (qRT-PCR) technology. It was confirmed that dAME plays important roles in promoting the mRNA expression of leucine-rich and immunoglobulin-like domains 1 (LRIG1) and in inhibiting the mRNA of transforming growth factor-β1 (TGF-β1).

Corneal neovascularization (CNV) is the major cause of blindness after eye injury; however, only several drugs can be applied and the invasive administration ways (i.e., intravitreal injection and subconjunctival injection) are used. Resveratrol is a highly effective anti-VEGF agent against CNV. However, its applications are limited due to its strong hydrophobicity and instability. Here, we developed a resveratrol-loaded ocular lamellar crystalline gel (ROLG) for high inhibition of CNV. ROLGs were composed of resveratrol, glyceryl monooleate (GMO), ethanol, and water, and their lamellar crystalline structures were identified by polarizing light microscopy and small-angle X-ray scattering. High drug loading (4.4 mg/g) of ROLGs was achieved due to the hydrogen bonding between GMO and resveratrol. Resveratrol showed sustained release with 67% accumulative release in 7 h, which was attributed to the slow erosion of gels. Resveratrol in ROLGs had a high corneal permeation 3 times higher than resveratrol in hyaluronic acid suspensions (RHSs). ROLGs were administered to rats only once a day because of their strong retention on the cornea surface. ROLGs were safe due to the very little contact of ethanol in ROLGs to the cornea. CNV post-rat corneal alkaline injury was highly inhibited by ROLGs, resulting from the attenuation of corneal VEGF expression and then corneal healing was improved. The ROLG was a promising ocular medicine for the prevention of CNV.

Introduction The current study was designed to test the potential role of recombinant human MG53 (rhMG53) protein on protecting against alkaline-induced corneal injury in mice. Materials and Methods A round filter paper with 2-mm diameter was soaked in 1 mol/L of NaOH solution. The mouse alkaline injury was generated by placing the filter paper directly on the cornea for 30 seconds and washed with 30-mL saline; 10 µL of rhMG53 solution (20 µg/mL) or saline control was topically administrated on the mouse corneas (twice per day for 10 days). Re-epithelialization was measured by fluorescein staining and imaged by a slit lamp equipped with a digital camera. Clinical neovascularization and opacity scores were measured every day after injury. Ten days after injury, mice were sacrificed and corneas were dissected out for flat mount staining of CD31 for neovascularization. Results MG53 was present in both dog aqueous humor and human tears. mg53-/- corneas were more susceptible to alkaline-induced corneal injury. Topical treatment of rhMG53 improved re-epithelialization, suppressed neovascularization, and fibrosis induced by alkaline injury. Conclusions rhMG53 may be an effective means to treat corneal wounding.

Purpose Neutrophils play a critical role in defending against threats such as microbial infection, yet their activation during innate immune response incites collateral damage to healthy tissues. We have previously shown that corneal injury induces mast cells to express the neutrophil chemoattractant CXCL2. Here we delineate the mechanism of injury-induced, non-IgE-mediated mast cell activation at the ocular surface. Methods Corneal injury was induced by mechanical removal of the epithelium and anterior stroma in mast cell deficient (cKitW-sh) and C57BL/6 mice using Algerbrush II. Corneas were analyzed for frequencies of total CD45+ inflammatory cells, CD11b+Ly6G+ neutrophils, and cKit+FceR1+ mast cells using flow cytometry. Mast cells were stimulated with different inflammatory factors known to increase during corneal injury (IL-33, IL-1β, IL-36γ, IL-6, SDF1α and Substance P) and assessed for the secretion of β-hexosaminidase, tryptase and CXCL2 using ELISA. IL-33 neutralizing antibody (1 mg/ml) was administered locally for mast cell inhibition in vivo. Results Mast cell deficient mice failed to recruit early neutrophils to the injured corneas. IL-33 stimulation upregulated CXCL2 secretion by mast cells. Corneal injury resulted in amplified expression of IL-33 at the cornea and epithelium was identified as its primary source. Topical neutralization of IL-33 at the ocular surface inhibited mast cell activation, limited neutrophil infiltration, and reduced corneal inflammatory haze, normalizing tissue architecture following ocular injury. Conclusions These data implicate IL-33 in mast cell activation and early neutrophil recruitment in non-allergic inflammation, suggesting IL-33 as a potential therapeutic target in inflammatory disorders of the ocular surface.

Purpose To describe a technique for traumatic cataract management for cases in which part of the anterior capsule has been incarcerated into a healed corneal laceration. Methods This is a single-center retrospective chart review of 3 patients with capsular/corneal incarceration after penetrating injury. Each patient underwent primary globe repair, followed by subsequent cataract surgery with intraocular lens (IOL) and iris prosthesis placement. The main outcome measure was corrected distance visual acuity. Results At a mean of 19-month postoperative follow-up (range 12-26 mo), corrected distance visual acuity ranged from 20/25 to 20/80 and all patients had improved vision compared with before cataract surgery. At the final follow-up, all IOLs and iris prostheses were in stable position and no eyes required corneal transplantation. Conclusions Traumatic cataracts may be complicated by incarceration of the anterior capsule into the cornea. Incorporating the posterior aspect of the cornea into the anterior capsulotomy enables cataract removal and IOL placement in a stable capsular bag complex.

Eye burns due to the accidental application of pharmacological or nonpharmacological substances packaged in plastic dropper bottles have been described for more than three decades and continue to occur. These burns can cause potentially serious corneal injuries. We report the case of a patient who mistakenly applied salicylic acid to the right eye after confusing it with an eye lubricant, which caused him a severe corneal burn. Fortunately, after aggressive medical and surgical management (including oxygen therapy and amniotic membrane grafting), the visual results were good. We suggest conducting educational campaigns and taking legislative measures in our country to avoid packaging corrosive substances in this type of dropper bottle to reduce the risk of accidental burns.Las quemaduras oculares por aplicación accidental de sustancias farmacológicas o no farmacológicas envasadas en frascos goteros plásticos, se han descrito desde hace más de tres décadas y siguen ocurriendo. Estas quemaduras pueden causar lesiones potencialmente graves de la córnea. Se presenta el caso de un paciente que se aplicó ácido salicílico en el ojo derecho al confundir el envase con el de un lubricante ocular, lo que le causó una grave quemadura corneal. Afortunadamente, tras un manejo médico y quirúrgico agresivo (incluida oxigenoterapia e injerto de membrana amniótica) los resultados visuales fueron buenos. Se sugiere hacer campañas educativas y adoptar normas en el país para evitar el envase de sustancias corrosivas en este tipo de frascos goteros, con el fin de disminuir el riesgo de quemaduras accidentales.

Purpose: The aim of this study was to design naproxen sodium (NS)-containing, biomimetic, porous poly(lactide-co-glycolide) (PLGA) scaffolds for regeneration of damaged corneal epithelium. Methods:...

Background To report a case of enucleation caused by Streptococcus dysgalactiae endophthalmitis after traumatic corneal laceration. Case presentation A 69-year-old man with history of retinal detachment treated with vitrectomy and subsequent cataract surgery presented with traumatic corneal laceration while cutting grass. Appropriate repair of corneal laceration and intravitreal antibiotics (vancomycin, ceftazidime) injection was performed. S. dysgalactiae which was sensitive to the conventional antibiotics (Ampicillin, Ceftriaxone, Levofloxacin, etc.) detected by aqueous culture. One day following primary closure, the patient developed a complete hypopyon and vitreous membranes. Despite vigorous systemic and intravitreal antibiotics administration with vitrectomy, endophthalmitis was not controlled and patient’s ocular pain was increased. The vitreous culture was also positive for S. dysgalactiae. Finally, total enucleation was performed 9 days after trauma due to fulminant endophthalmitis with severe scleritis. Conclusion Progression of traumatic endophthalmitis associated with S. dysgalactiae can be fulminant. Sufficient warning to patient about enucleation and intensive care is needed in the case of this infection.

Introduction Chemical ocular burns are among the most frequently eye-related injuries, which require immediate and intensive evaluation and care since they may lead to potential complications such as superinfection, corneal perforation, and blindness.Vasconcellea cundinamarcensis, a species from Caricaceae family, contains highly active proteolytic enzymes in its latex that show healing activity in animal models bearing lesions of different etiologies. Methods We evaluate the ocular toxicity of the proteolytic fraction from V. cundinamarcensis (P1G10) by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Hen’s Egg Test-Chorioallantoic Membrane test. The corneal healing property of P1G10 was studied by the ethanol-chemical burn in the rabbit’s eyes. Results P1G10 is safe for ocular administration, except when administrated at 10 μg/mL. P1G10 at 1 μg/mL accelerates the corneal re-epithelization achieving complete wound closure after 72 h of chemical burn. Also, P1G10 modulated the inflammatory response and controlled the arrangement of collagen fibers in the stroma, demonstrating its potential corneal healing properties. Conclusions Our work was the first one to evaluate the ophthalmic application of P1G10. Here we demonstrated that P1G10 is suitable for ocular administration and it has a promising corneal healing activity which may emerge as a new pharmacological tool to the development of a new drug for ocular surface chemical injuries in the future.

PURPOSE Opiorphin is an endogenous inhibitor of enkephalin-degrading enzymes. It has a strong analgesic effect in chemical and mechanical pain models. We aimed to evaluate the tear opiorphin levels in ocular pain caused by corneal foreign bodies and demonstrate whether there is any correlation with pain levels obtained from the Visual Analog Scale (VAS) score and tear opiorphin level. METHODS Thirty-two healthy individuals and 34 individuals diagnosed with corneal foreign bodies were included in this study. Tear opiorphin levels were measured by the ELISA method using a commercially available kit. The difference in tear opiorphin levels between the patient and control groups were evaluated using the Mann-Whitney U test. The correlation between VAS scores and tear opiorphin levels was evaluated using the Spearman rank correlation coefficient. RESULTS The median values of tear opiorphin levels of the patient and control groups were 134 pg/mL (86.86-296.25) and 109.80 pg/mL (66.15-191.49), respectively. The Mann-Whitney U test showed a statistically significant difference in tear opiorphin levels between patient and control groups (P < 0.05). No ocular pain was reported in the control group. The median VAS score of the patient group was 6 points (1-9). No correlation was found between VAS scores and tear opiorphin levels in the patient group. CONCLUSIONS The cornea is the most densely innervated tissue, and the highest opiorphin concentrations have been observed in tear. It is, therefore, expected that the stimulation or damage to the nerve endings in cornea would cause an increase in opiorphin secretion as a pain relief mechanism.

To review the use of clinical corneal sealants for the closure of full thickness corneal wounds.A systematic review was conducted across CENTRAL, Medline, PubMed, Embase, Scopus, mRCT and ICTRP for the keywords of 'cornea', 'full-thickness wound', 'sealant' and their synonyms. Only evidence level 2 of higher as graded by Oxford Centre of Evidence-based Medicine were included for this review.Seven studies were included; three randomized controlled trials investigated ReSure® sealant, 2 OcuSeal®, 1 human fibrin glue vs cyanoacrylate and 1 human fibrin glue as an adjunct to sutures vs sutures alone in penetrating keratoplasty. ReSure® was superior to suture for sealing leaking corneal incisions after cataract surgery despite provocation. ReSure® sealant has not been tested on complex full thickness corneal wounds, perforated ulcers or penetrating keratoplasty. OcuSeal® was also able to seal full thickness cornea wound post-cataract surgery to prevent ingress of Trypan blue dye. Human fibrin glue and cyanoacrylate were similarly effective in treating corneal perforations3 mm of mixed etiologies.There are limited high-level evidence for corneal sealants. The currently available sealants with human data are ReSure®, OcuSeal®, human fibrin glue and cyanoacrylates. While ReSure® and OcuSeal® are effective post-cataract surgery, there are no data for perforations from other etiologies. Post-approval data from ReSure® registry report good tolerability and no apparent safety concerns.

Objectives To evaluate recent in vivo studies on emerging therapies for managing corneal epithelial injuries. Methods The search was conducted on PubMed for articles published between January 2015 and September 2019 and in English language. Results Thirty studies were identified for evaluation, including those on mesenchymal stem cells, amniotic membrane-derived therapies, endogenous peptides and their inhibitors, as well as hydrogel therapies. Intermediate to strong levels of evidence are presented regarding the use of these strategies on chemically injured cornea, including their effects on healing of corneal epithelial defect, anti-inflammatory properties, prevention of corneal neovascularization, as well as restoration of anatomy and functions of the anterior eye, although clinical trials are needed to determine the safety and efficacy of these strategies on humans. Conclusion Recent advances and understanding in various novel therapeutic methods for corneal epithelial chemical injuries should provide potential alternatives to current standard treatment regimens and help reduce risks of complications, hence improve patient outcomes.

OBJECTIVES: The conditioned-medium derived from corneal mesenchymal stromal cells (cMSCs) has been shown to have wound healing and immunomodulatory effects in corneal injury models. Here, the therapeutic effects of lyophilized cMSC conditioned-medium were compared with fresh conditioned-medium. METHODS: The epithelial wound healing effects of fresh and lyophilized cMSC conditioned-medium were compared with conditioned-medium from non-MSC cells (corneal epithelial cells) using scratch assay. To evaluate the anti-inflammatory effects of fresh and lyophilized cMSC conditioned-media, macrophages were stimulated by a Toll-Like Receptor (TLR) ligand followed by treatment with the conditioned-media and measuring the expression of inflammatory genes. In vivo wound healing effects of fresh and lyophilized cMSC conditioned-media were assessed in a murine model of cornea epithelial injury. RESULTS: Both fresh and lyophilized cMSCs-derived conditioned-medium induced significantly faster closure of in vitro epithelial wounds compared to conditioned-medium from non-MSC cells (P

Background The cornea is innervated with a rich supply of sensory nerves that play important roles in ocular surface health. Any injury or pathology of the corneal nerves increases the risk of dry eye disease and infection. This study aims to evaluate the therapeutic potential of topical decorin to improve corneal nerve regeneration in a mouse model of sterile epithelial abrasion injury. Methods Bilateral central corneal epithelial abrasions (2-mm, Alger Brush) were performed on young C57BL/6 J mice to remove the corneal sensory nerves. Decorin, or vehicle, was applied topically, three times per day for 1 week or every 2 h for 6 h. Spectral-domain optical coherence tomography was performed to measure the abrasion area and corneal thickness. Wholemount immunofluorescence staining was used to assess sensory nerve regeneration (β-tubulin III) and immune cell density (CD45, Iba1, CD11c). To investigate the specific role of dendritic cells (DCs), Cx3cr1gfp/gfp mice, which spontaneously lack resident corneal epithelial DCs, were also investigated. The effect of prophylactic topical administration of recombinant human decorin (applied prior to the abrasion) was also investigated. Nerve tracing (NeuronJ software) was performed to compare recovery of basal nerve axons and superficial nerve terminals in the central and peripheral cornea. Results At 6 h after injury, topical decorin application was associated with greater intraepithelial DC recruitment but no change in re-epithelialisation or corneal thickness, compared to the vehicle control. One week after injury, sub-basal nerve plexus and superficial nerve terminal density were significantly higher in the central cornea in the decorin-treated eyes. The density of corneal stromal macrophages in the decorin-treated eyes and their contralateral eyes was significantly lower compared to saline-treated corneas. No significant improvement in corneal nerve regeneration was observed in Cx3cr1gfp/gfp mice treated with decorin. Conclusions Decorin promotes corneal epithelial nerve regeneration after injury. The neuroregenerative effect of topical decorin was associated with a higher corneal DC density during the acute phase, and fewer macrophages at the study endpoint. The corneal neuroregenerative effects of decorin were absent in mice lacking intraepithelial DCs. Together, these findings support a role for decorin in DC-mediated neuroregeneration following corneal abrasion injury.

Purpose: The objective of this study was to describe the short-term results of allogenic transplantation of limbal stem cells expanded on amniotic membrane for the ocular surface reconstruction. Methods: Prospective nonrandomized, nonmasked study in a single ophthalmological center. Ten patients with bilateral total limbal stem cell deficiency (LSCD) were included. Expression and presence of ABCB5 and Δp63α in amniotic membrane-cultured limbal epithelial stem cells were analyzed, in relationship with clinical changes after allogenic transplantation. An objective evaluation was performed to determine corneal transparency and superficial vascularization. Results: In a median follow-up time of 11.6 months, 7 patients (70%) were considered as failure compared with the preoperative status. ABCB5 and Δp63α are expressed in similar amount in the limbal epithelial cells expanded in vitro and transplanted in patients with bilateral LSCD. Conclusions: Transplantation of allogenic epithelial limbal cells expanded in amniotic membrane could be considered in patients with LSCD due to burns or congenital etiologies such as aniridia, but its benefit is limited for patients with immunologic diseases.

Corneal nerve fibers serving sensory, reflex and neurotrophic functions sustains the corneal homeostasis and transparency to warrant the normal visual function. It remains unknown whether corneal epithelium is also reciprocally important for the corneal innervation. Herein, we generated a compound transgenic mouse strain, K14rtTA;tetO-Cre (TC);Shp2flox/flox, in which Shp2 was conditionally knocked out from the K14-positive cells including corneal epithelium (Shp2K14ce-cko) upon doxycycline (dox) administration. Our data revealed that Shp2K14ce-cko resulted in corneal denervation. More specifically, the corneal epithelium thickness and corneal sensitivity reduced dramatically in Shp2K14ce-cko mice. In addition, corneal epithelial debridement wound healing was delayed substantially in the mutant mice. These defects manifested in Shp2K14ce-cko mice resemble the symptoms of human neurotrophic keratopathy. Our In vitro study unveiled that neurite outgrowth of the mouse primary trigeminal ganglion cells (TGCs) was inhibited as co-cultured with mouse corneal epithelial cells (TKE2) transfected by Shp2-, Mek1/2-, or ∆Np63-targeted siRNA but not by Akt1/2-targeted siRNA. Furthermore, ∆Np63 RNA interference down-regulated Ngf expression in TKE2 cells. More interesting, co-transfection experiments revealed that Shp2 tightly monitored ΔNp63 protein level in HEK293 and TKE2 cells. Taken together, our data suggested that Shp2-mediated MAPK pathway regulated ΔNp63, which in turn positively regulated Ngf in epithelium to warrant corneal innervation and epithelial homeostasis

Oxidative stress is a major pathogenesis of some ocular surface diseases. Our previous study demonstrated that epidermal growth factor (EGF)-activated reactive oxygen species (ROS) could protect against human corneal epithelial cell (HCE) injury. In the present study, we aimed to explore the role and mechanisms of oxidative stress and mitochondrial autophagy in HCE cells subjected to scratch injury. CCK-8 assays, EdU assays, Western blot analysis, wound-healing assays, and flow cytometry were conducted to determine cell viability, proliferation, protein expression, cell apoptosis, and intracellular ROS levels, respectively. The results showed that EGF could promote damage repair and inhibit cell apoptosis in scratch injured HCE cells by upregulating ROS (**p < .01, ***p < .001). EGF also induced mitochondrial autophagy and alleviated mitochondrial damage. Interestingly, the combination of the mitochondrial autophagy inhibitor and mitochondrial division inhibitor 1 (MDIVI-1) with EGF could reduce cell proliferation, viability, and the ROS level (*p < .05, **p < .01, ***p < .001). Treatment using the ROS inhibitor N-acetyl- l-cysteine abrogated the increase in mitochondrial membrane potential after EGF treatment. (*p < .05). Taken together, these findings indicated that EGF plays an important role in HCE damage repair and could activate ROS to protect against HCE injury by inducing mitochondrial autophagy via activation of TRPM2.

Purpose Ocular exposure to sulfur mustard (SM) vapor causes acute loss of corneal endothelial cells (CECs). Persistent corneal endothelial pathologies are observed in eyes that do not recover from SM exposure, suggesting that endothelial toxicity contributes to mustard gas keratopathy (MGK). Here, we evaluated the contributions of endothelial loss to acute and chronic corneal injuries in SM-exposed eyes. Methods Rabbit eyes were exposed in vivo to equivalent doses of SM using 9-, 11-, or 14-mm vapor caps. The effects of exposure area on corneal injury progression were longitudinally evaluated over 12 weeks using clinical evaluations. The effects of exposure area on CEC morphology, endothelial and epithelial ultrastructure, and endothelial barrier function were determined from 1 day to 12 weeks. Results SM exposure caused loss of CECs and failure of endothelial barrier integrity at 1 day, independent of exposure cap size. By 3 weeks, eyes exposed with the 14-mm vapor cap exhibited increased corneal permeability, repopulation of the endothelium by cells with fibroblastic morphology, and abnormal deposition of extracellular matrix. Eyes exposed with 9- or 11-mm vapor caps exhibited transient symptoms of injury that fully resolved, with the rate of recovery correlated with cap size. Conclusions The nonlinear correlation between endothelial lesion size and probability of developing MGK suggests that the CEC loss is a determinative factor for emergence of MGK. These studies illustrate the importance of endothelial repair in preventing MGK. Furthermore, they exclude chemical modification of basement membrane as a mechanistic cause of recurrent epithelial erosions in MGK eyes.

Background Patients commonly present to the Emergency Department with a corneal foreign body (FB). There is currently a lack of adequate training for junior doctors in the management of this condition. Our self-made surrogate eye model aims to address this void in our junior doctors’ knowledge. Methods Participants were guided through a hands-on session with a slit-lamp using our eye model, which is made of a hemispherical agar embedded with pencil lead fragments simulating as FBs. Using a 7-point Likert scale, all participants completed a questionnaire both before and after training, for: (1) knowledge in corneal FB removal, (2) confidence in corneal FB removal, and (3) effectiveness of the model. Results Out of 73 participants, 82.2% (60/73) had no prior experience in corneal FBs removal. After the training session, their knowledge improved from a median score of 2 (interquartile range [IQR] 1 to 3) to 5 (IQR 5 to 6), with improvement in confidence levels from 2 (IQR 1 to 2) to 5 (IQR 4 to 6). The effectiveness of our eye model scored a median of 6 (IQR 5 to 7). Conclusions Our surrogate eye model is low-cost, quick and easy to reproduce. After use, our learners expressed greater confidence in managing the removal of corneal FBs and use of slit lamp. With a recent focus in patient safety and quality, teaching this procedure via simulation is a safe way of bridging the gap between traditional didactic teaching and the clinical environment.

Corneal scarring is a major cause of blindness worldwide with few effective therapeutic options. Finding a treatment would be of tremendous public health benefit, but requires a thorough understanding of the complex interactions that underlie this phenomenon. Here, we tested the hypothesis that the large increase in expression of Semaphorin 3A (SEMA3A) in corneal wounds contributes to the development of stromal fibrosis. We first verified this increased expression in vivo, in a cat model of photorefractive keratectomy-induced corneal wounding. We then examined the impact of adding exogenous SEMA3A to cultured corneal fibroblasts, and assessed how this affected the ability of transforming growth factor-beta1 (TGF-β1) to induce their differentiation into myofibroblasts. Finally, we examined how siRNA knockdown of endogenous SEMA3A affected these same phenomena. We found exogenous SEMA3A to significantly potentiate TGF-β1’s profibrotic effects, with only a minimal contribution from cell-intrinsic SEMA3A. Our results suggest a previously unrecognized interaction between SEMA3A and TGF-β1 in the wounded cornea, and a possible contribution of SEMA3A to the regulation of tissue fibrosis and remodeling in this transparent organ.

The cornea, transparent and outermost structure of camera-type eyes, is prone to environmental challenges, but has remarkable wound healing capabilities which enables to preserve vision. The manner in which cell plasticity impacts wound healing remains to be determined. In this study, we report rapid wound closure after zebrafish corneal epithelium abrasion. Furthermore, by investigating the cellular and molecular events taking place during corneal epithelial closure, we show the induction of a bilateral response to a unilateral wound. Our transcriptomic results, together with our TGF-beta receptor inhibition experiments, demonstrate conclusively the crucial role of TGF-beta signaling in corneal wound healing. Finally, our results on Pax6 expression and bilateral wound healing, demonstrate the decisive impact of epithelial cell plasticity on the pace of healing. Altogether, our study describes terminally differentiated cell competencies in the healing of an injured cornea. These findings will enhance the translation of research on cell plasticity to organ regeneration.

A 28-year-old Caucasian male presented with pain, redness, foreign body sensation, reduced vision, and lid swelling after a honey bee collided with his left eye whilst driving an all-terrain vehicl...

Purpose Mesenchymal stromal cells (MSCs) have been shown to enhance tissue repair as a cell-based therapy. In preparation for a phase I clinical study, we evaluated the safety, dosing, and efficacy of bone marrow-derived MSCs after subconjunctival injection in preclinical animal models of mice, rats, and rabbits. Methods Human bone marrow-derived MSCs were expanded to passage 4 and cryopreserved. Viability of MSCs after thawing and injection through small-gauge needles was evaluated by vital dye staining. The in vivo safety of human and rabbit MSCs was studied by subconjunctivally injecting MSCs in rabbits with follow-up to 90 days. The potency of MSCs on accelerating wound healing was evaluated in vitro using a scratch assay and in vivo using 2-mm corneal epithelial debridement wounds in mice. Human MSCs were tracked after subconjunctival injection in rat and rabbit eyes. Results The viability of MSCs after thawing and immediate injection through 27- and 30-gauge needles was 93.1% ± 2.1% and 94.9% ± 1.3%, respectively. Rabbit eyes demonstrated mild self-limiting conjunctival inflammation at the site of injection with human but not rabbit MSCs. In scratch assay, the mean wound healing area was 93.5% ± 12.1% in epithelial cells co-cultured with MSCs compared with 40.8% ± 23.1% in controls. At 24 hours after wounding, all MSC-injected murine eyes had 100% corneal wound closure compared with 79.9% ± 5.5% in controls. Human MSCs were detectable in the subconjunctival area and peripheral cornea at 14 days after injection. Conclusions Subconjunctival administration of MSCs is safe and effective in promoting corneal epithelial wound healing in animal models. Translational relevance These results provide preclinical data to support a phase I clinical study.

Purpose: Given the role of corneal sensory nerves during epithelial wound repair, we sought to examine the relationship between immune cells and polymodal nociceptors following corneal injury. Methods: Young C57BL/6J mice received a 2 mm corneal epithelial injury. One week later, corneal wholemounts were immunostained using β-tubulin-488, TRPV1 (transient receptor potential ion channel subfamily V member-1, a nonselective cation channel) and immune cell (MHC-II, CD45 and CD68) antibodies. The sum length of TRPV1+ and TRPV1- nerve fibers, and their spatial association with immune cells, was quantified in intact and injured corneas. Results: TRPV1+ nerves account for ∼40% of the nerve fiber length in the intact corneal epithelium and ∼80% in the stroma. In the superficial epithelial layers, TRPV1+ nerve terminal length was similar in injured and intact corneas. In intact corneas, the density (sum length) of basal epithelial TRPV1+ and TRPV1- nerve fibers was similar, however, in injured corneas, TRPV1+ nerve density was higher compared to TRPV1- nerves. The degree of physical association between TRPV1+ nerves and intraepithelial CD45+ MHC-II+ CD11c+ cells was similar in intact and injured corneas. Stromal leukocytes co-expressed TRPV1, which was partially localized to CD68+ lysosomes, and this expression pattern was lower in injured corneas. Conclusions: TRPV1+ nerves accounted for a higher proportion of corneal nerves after injury, which may provide insights into the pathophysiology of neuropathic pain following corneal trauma. The close interactions of TRPV1+ nerves with intraepithelial immune cells and expression of TRPV1 by stromal macrophages provide evidence of neuroimmune interactions in the cornea.