Epidemiology, economic and humanistic burdens of Ocular Surface Chemical Injury: A narrative review

Immunological and histopathological changes in alkali burn-induced ocular surface pannus: Implication on success vs. failure of SLET

PURPOSE

This study aimed to investigate the histopathological and immunological characteristics of human alkali burn ocular surface pannus in successful and failed cases of simple limbal epithelial transplantation (SLET).

METHODS

Paraffin embedded pannus sections of limbal stem cell deficiency (LSCD) patients who underwent simple limbal epithelial transplantation were obtained from pathology. Samples included both cases of SLET failure (n = 12) and success (n = 7). Histological features were assessed using Hematoxylin-Eosin and Periodic acid-Schiff staining while infiltrated immune cells were characterised using immunohistochemistry. Data were represented as mean or median with the interquartile range and standard deviation. Multiple comparisons of means by linear mixed effect model with Tukey contrast and Bonferroni method were used.

RESULTS

Conjunctivalization of the cornea that led to fibrous pannus formation was confirmed by the presence of CK19+ and CK3/12- cells. The median percentage of immune cell infiltrates like T-cells (CD3; success (9 %; IQR-9.2) vs. failure (23.5 %; IQR-10.2), (CD5; success (2.2 %; IQR-3) vs. failure (13.4 %; IQR-18.3), B-cells (CD20; success (3.2 %; IQR-3.2) vs. failure (4.1 %; IQR-5.5), antigen presenting cells (co-stimulatory CD40; success (7.8 %; IQR-8.9) vs. failure (16.4 %; IQR-7.1), and plasma cells (CD138; success (1.1 %; IQR-2.1) vs. failure (3.6 %; IQR-3.5) were identified in the pannus.

CONCLUSIONS

This study highlights a significantly higher infiltration of immune cells in the pannus and surrounding ocular tissue in cases of SLET failure compared to successful outcomes. These findings suggest that, strategies to reduce immune infiltration such as immunotherapy, corticosteroids, or amniotic membrane grafting should be considered prior to SLET to improve the success of limbal transplant surgery.

Green propolis extract for the treatment of alkali-induced superficial corneal ulcers: local and systemic analyses

Green propolis, produced by honeybees from the resin of certain plants, has garnered attention for its potential health benefits. Green propolis contains compounds like artepillin C, which exhibits antioxidant, anti-inflammatory, and antimicrobial properties. This study's objective was to examine the effects of green propolis extract containing 21.05% artepillin C, topically administered (5, 10 and 15 mg/mL) in rats with induced superficial corneal ulcers with alkali, applied four times daily, for 96 hours. Rats treated with the green propolis extract exhibited of ulcer reduction more significant reduction after 24 hours of treatment than untreated animals, suggesting a similar healing activity of the commercial drug. After 96 hours of treatment, the rats were euthanized, and the corneas were submitted for histopathological analysis; no statistical difference was detected between rats treated with green propolis and those not treated in terms of polymorphonuclear and neovessel counts in the corneal stroma. In the toxicogenetic analysis, by the micronucleus test, no significant differences were observed in the frequencies of chromosomal damage and the ratio of polychromatic erythrocytes to the total number of erythrocytes between treated and untreated animals, revealing the absence of genotoxicity and cytotoxicity, respectively. The biochemical results did not indicate a hepatotoxic or nephrotoxic effect of the formulations containing green propolis. Like this, the standardized green propolis extract induced corneal epithelialization without toxic effects, rendering it a promising option for treating superficial keratitis.

Outcome of tenonplasty in scleral ischemia secondary to acute ocular surface burn

PURPOSE

To study the outcome of tenonplasty in eyes with perilimbal ischemia in acute ocular surface burns.

METHODS

This was a single-center retrospective study that included all patients presenting between May 2012 and December 2022 with acute ocular surface burn (within 6 weeks from injury) with perilimbal scleral ischemia, without perforation or previous surgical intervention for the same. All these patients underwent single-stage tenonplasty with amniotic membrane transplantation and medical management. Successful outcome was defined as globe preservation at 6 months.

RESULTS

Twenty-three eyes of 20 patients were included in our study. Out of these, alkali was the most common offending agent (10 eyes of 8 patients). The extent of scleral ischemia was <90° in seven eyes, 90°-180° in six eyes, and >180° in 10 eyes. The mean interval between the injury and tenonplasty was 16.5 days. Globe integrity in 20 of the 23 eyes was maintained 6 months post injury. Three eyes that developed hypotony at the end of 6 months had more than 180° of perilimbal scleral ischemia at presentation. The extent of scleral ischemia correlated with the development of phthisis bulbi, but the values were not statistically significant ( P = 0.081).

CONCLUSION

Tenonplasty in the acute stage acts as a globe-salvaging procedure in acute chemical burns with perilimbal scleral ischemia. Extensive scleral ischemia in an acute chemical burn remains a poor prognostic factor for globe integrity in the long term.

Long-lasting comfort ocular surface drug delivery by in situ formation of an adhesive lubricative Janus nanocoating

Topical drug delivery on ocular surface always suffers from frequent administration and low bioavailability due to short drug residence. Despite advances of different adhesive ophthalmic drugs in extending release, cornea and eyelid nonselective adhesion inevitably causes ocular discomfort and even damage. Here, we describe in situ formation of an adhesive lubricative Janus nanocoating (ALJN) to enable long-lasting comfort drug delivery. By iron complexation, an asymmetric ALJN is formed on ocular surface via facile sequential instillation. The adhesive polyphenol inner layer binding with ocular surface enables drug loading and sustained release, while the lubricative zwitterionic polymer outer layer prevents eyelid adhesion to ensure comfort. Following instillation, ALJN retains on ocular surface over 24 hours and reduces blinking frequency to normal level. Moreover, ALJN demonstrates remarkable therapeutic potential in mouse and rabbit models of corneal contusion and alkali burn. This work proposes a comfortable long-lasting topical delivery platform for treating various ocular diseases.

Cultivated autologous limbal epithelial cell (CALEC) transplantation for limbal tem cell deficiency: a phase I/II clinical trial of the first xenobiotic-free, serum-free, antibiotic-free manufacturing protocol developed in the US

We developed a two-stage manufacturing process utilizing cultivated autologous limbal epithelial cells (CALEC), the first xenobiotic-free, serum-free, antibiotic-free protocol developed in the United States, to treat blindness caused by unilateral limbal stem cell deficiency (LSCD) and conducted a single-center, single-arm, phase I/II clinical trial. Primary outcomes were feasibility (meeting release criteria) and safety (ocular infection, corneal perforation, or graft detachment). Participant eligibility included male or female participants age 18 to <90 years old and ability to provide written informed consent with LSCD. Funding was provided by the National Eye Institute of the National Institutes of Health. CALEC grafts met release criteria in 14 (93%) of 15 participants at conclusion of trial. After first stage manufacturing, intracellular adenosine triphosphate levels correlated with colony forming efficiency (r = 0.65, 95% CI [0.04, 0.89]). One bacterial infection occurred unrelated to treatment, with no other primary safety events. The secondary outcome was to investigate efficacy based on improvement in corneal epithelial surface integrity (complete success) or improvement in corneal vascularization and/or participant symptomatology as measured by OSDI and SANDI (partial success). 86%, 93%, and 92% of grafts resulted in complete or partial success at 3, 12, and 18 months, respectively. Our results provide strong support that CALEC transplantation is safe and feasible and further studies are needed to evaluate therapeutic efficacy. Clinicaltrials.gov registration: NCT02592330.

Femtosecond laser-assisted large-diameter lamellar corneal-limbal keratoplasty in ocular chemical burns

Purpose

This study highlights the feasibility of femtosecond laser-assisted large-diameter lamellar corneal-limbal keratoplasty and its efficacy in the treatment of ocular surface failure caused by bilateral ocular chemical injury.

Observations

The series included 3 patients with ocular surface failure caused by bilateral ocular chemical burns. After dissection of the host cornea, a femtosecond laser-assisted large-diameter lamellar corneoscleral button, with varying thickness of 250-400 μm, was sutured to the recipient bed. Postoperatively, patients were maintained on topical corticosteroids drops and systemic immunosuppression. Patients were followed up for a minimum of 16 months. The preoperative best corrected visual acuity was counting fingers, hand motions, and hand motions respectively. Postoperatively, the preoperative best corrected visual acuity reached 20/50, 20/50 and 20/40 at the last follow-up, respectively. A stable ocular surface was achieved in all but one eye, due to the cessation of immunosuppressive drugs. Postoperative anterior segment optical coherence tomography revealed well apposed graft interface in all cases.

Conclusions and importance

Compared with conventional techniques, femtosecond laser is useful to create varying thickness corneoscleral graft to rehabilitate ocular surface and visual acuity in patients with bilateral ocular chemical burns.

Public Awareness of Ocular Chemical Injuries: A Cross-Sectional Study in Lithuania

Background: Ophthalmic emergencies are acute conditions that progress rapidly, posing a significant threat to a patient's vision and requiring urgent intervention to prevent permanent visual impairment. This study aimed to assess the general awareness of ocular chemical burns and the adequacy of the immediate response measures while also seeking to improve the understanding of these injuries and contribute to promoting a healthier society. Methods: A comprehensive literature review was performed, and the most frequently reported questions were incorporated into the original survey. An anonymous questionnaire, available both online and in print, was developed to conduct a cross-sectional study to assess the general knowledge of the causes, symptoms, and appropriate first aid measures to be applied in cases of chemical ocular trauma. Results: Between April and May 2024, 175 individuals completed the questionnaire and were included in the study. More than half (54%) of the tested population demonstrated a poor level of knowledge about chemical ocular injuries, and only 30.9% of the respondents correctly indicated the need for imminent treatment. Twenty percent of the respondents could not identify whether alkalis or acids are more hazardous. Additionally, 5.7% of the respondents falsely considered consultation with an emergency department a priority before thorough irrigation. Most of the respondents (60.6%) incorrectly indicated that the appropriate first aid measures and treatment depend on the substance involved, and 68.1% of the respondents stated that treatment in the emergency department should be delayed, allowing for anamnesis collection and thorough examination. Conclusions: Ocular chemical injuries can substantially impact an individual's quality of life. The present study found that the public knowledge concerning ocular chemical trauma, and the necessary immediate treatment is insufficient. Public education is vital, as delaying prompt and thorough irrigation at the chemical injury site may result in irreversible complications.

Oxidative stress mediates retinal damage after corneal alkali burn through the activation of the cGAS/STING pathway

Retinal damage accounts for irreversible vision loss following ocular alkali burn (OAB), but the underlying mechanisms remain largely unexplored. Herein, using an OAB mouse model, we examined the impact of oxidative stress (OS) in retinal damage and its molecular mechanism. Results revealed that OS in the retina was enhanced soon after alkali injury. Antioxidant therapy with N-acetylcysteine (NAC) preserved the retinal structure, suppressed cell apoptosis and decreased retinal inflammation, confirming the role of OS. Moreover, enhanced OS was linked to mitochondrial dysfunction, mtDNA leakage and initiation of the cytosolic DNA-sensing signaling. The activation of the major DNA sensors cyclic GMP-AMP Synthase (cGas) and cGAS-Stimulator of Interferon Genes (cGAS/STING) pathway was then identified. Notably, inhibiting cGAS/STING signaling with C-176 markedly reduced inflammation and cell apoptosis and ultimately protected the retina against OAB. Overall, our study reveals the vital function of OS in the occurrence of OAB-induced retinal damage and the involvement of cGAS/STING activation. Furthermore, our provides preclinical validation of the use of an antioxidant or a STING inhibitor as a potential therapeutic approach to protect the retina after OAB.

Human embryonic stem cell-derived immunity-and-matrix-regulatory cells on collagen scaffold effectively treat rat corneal alkali burn

Corneal alkali burns (CAB) are a severe form of ocular injury that often leads to significant vision loss, with limited effective treatment options available beyond corneal transplantation. Immunity and matrix-regulatory cells (IMRCs) have emerged as a promising alternative due to their ability to modulate immune responses and support tissue repair. This study investigates the efficacy of IMRCs on collagen scaffolds (IMRCs-col) for treating CAB in a rat model. We developed a novel treatment combining IMRCs with a collagen scaffold to align with the ocular surface structure. In vitro analyses showed that IMRCs-col significantly upregulated the expression of immune regulatory molecules, including IL-1RA and SCF. Additionally, IMRCs-col effectively inhibited the production of pro-inflammatory cytokines (IL-8 and Gro-a/CXCL1) while promoting pro-regenerative cytokines (bFGF, HGF, and PDGF). In an animal model of CAB, IMRCs-col transplantation demonstrated substantial efficacy in restoring corneal opacity and reducing neovascularization. Histological examination revealed reduced inflammation and improved corneal tissue regeneration compared to untreated CAB. Enhanced activation of pathways associated with anti-inflammatory responses and tissue repair was observed at days 3, 7, and 21 post-treatment.

Engineered Mesenchymal Stromal Cell Exosomes-Loaded Microneedles Improve Corneal Healing after Chemical Injury

Corneal alkali burns represent a prevalent ophthalmic emergency with the potential to induce blindness. The main contributing mechanisms include excessive inflammation and delayed wound healing. Existing clinical therapies have limitations, promoting the exploration of alternative methods that offer improved efficacy and reduced side effects. Adipose-derived stem cell-exosome (ADSC-Exo) has the potential to sustain immune homeostasis and facilitate tissue regeneration. Nevertheless, natural ADSC-Exo lacks disease specificity and exhibits limited bioavailability on the ocular surface. In this study, we conjugated antitumor necrosis factor-α antibodies (aT) to the surface of ADSC-Exo using matrix metalloproteinase-cleavable peptide chains to create engineered aT-Exo with synergistic effects. In both in vivo and in vitro assessments, aT-Exo demonstrated superior efficacy in mitigating corneal injuries compared to aT alone, unmodified exosomes, or aT simply mixed with exosomes. The cleavable conjugation of aT-Exo notably enhanced wound healing and alleviated inflammation more effectively. Simultaneously, we developed poly(vinyl alcohol) microneedles (MNs) for precise and sustained exosome delivery. The in vivo results showcased the superior therapeutic efficiency of MNs compared with conventional topical administration and subconjunctival injection. Therefore, the bioactive nanodrugs-loaded MNs treatment presents a promising strategy for addressing ocular surface diseases.

Adaptor protein 14-3-3zeta promotes corneal wound healing via regulating cell homeostasis, a potential novel therapy for corneal injury

Severe corneal injury can lead to blindness even after prompt treatment. 14-3-3zeta, a member of an adaptor protein family, contributes to tissue repair by enhancing cellular viability and inhibiting fibrosis and inflammation in renal disease or arthritis. However, its role in corneal regeneration is less studied. In this study, filter disc of 2-mm diameter soaked in sodium hydroxide with a concentration of 0.5 N was placed at the center of the cornea for 30 s to establish a mouse model of corneal alkali injury. We found that 14-3-3zeta, which is mainly expressed in the epithelial layer, was upregulated following injury. Overexpression of 14-3-3zeta in ocular tissues via adeno-associated virus-mediated subconjunctival delivery promoted corneal wound healing, showing improved corneal structure and transparency. In vitro studies on human corneal epithelial cells showed that 14-3-3zeta was critical for cell proliferation and migration. mRNA-sequencing in conjunction with KEGG analysis and validation experiments revealed that 14-3-3zeta regulated the mRNA levels of ITGB1, PIK3R1, FGF5, PRKAA1 and the phosphorylation level of Akt, suggesting the involvement of the PI3K-Akt pathway in 14-3-3zeta-mediated tissue repair. 14-3-3zeta is a potential novel therapeutic candidate for treating severe corneal injury.

Tamarind seed polysaccharide-metformin insert: Higher ocular retention, slow-release, and efficacy against corneal burn

Metformin (MET) can be an alternative therapeutic strategy for managing ocular burn primarily because of its pleiotropic mechanism. Longer retention on the ocular surface and sustained release are necessary to ensure the efficacy of MET for ocular application. Although the high aqueous solubility of MET is good for formulation and biocompatibility, it makes MET prone to high nasolacrimal drainage. This limits ocular residence and may be a challenge in its application. To address this, polymers approved for ophthalmic application with natural origin were analyzed through in silico methods to determine their ability to bind to mucin and interact with MET. An ocular insert of MET (3 mg/6 mm) was developed using a scalable solvent casting method without using preservatives. The relative composition of the insert was 58 ± 2.06 %w/w MET with approximately 14 %w/w tamarind seed polysaccharide (TSP), and 28 %w/w propylene glycol (PG). Its stability was demonstrated as per the ICH Q1A (R2) guidelines. Compatibility, ocular retention, drug release, and other functional parameters were evaluated. In rabbits, efficacy was demonstrated in the 'corneal alkali burn preclinical model'. TSP showed potential for mucoadhesion and interaction with MET. With adequate stability and sterility, the insert contributed to adequate retention of MET (10-12 h) in vivo and slow release (30 h) in vitro. This resulted in significant efficacy in vivo.

An Assessment of the Ocular Toxicity of Two Major Sources of Environmental Exposure

The effect of airborne exposure on the eye surface is an area in need of exploration, particularly in light of the increasing number of incidents occurring in both civilian and military settings. In this study, in silico methods based on a platform comprising a portfolio of software applications and a technology ecosystem are used to test potential surface ocular toxicity in data presented from Iraqi burn pits and the East Palestine, Ohio, train derailment. The purpose of this analysis is to gain a better understanding of the long-term impact of such an exposure to the ocular surface and the manifestation of surface irritation, including dry eye disease. In silico methods were used to determine ocular irritation to chemical compounds. A list of such chemicals was introduced from a number of publicly available sources for burn pits and train derailment. The results demonstrated high ocular irritation scores for some chemicals present in these exposure events. Such an analysis is designed to provide guidance related to the needed ophthalmologic care and follow-up in individuals who have been in proximity to burn pits or the train derailment and those who will experience future toxic exposure.

Characteristics of ocular injuries associated with mortality in patients admitted with major trauma

BACKGROUND

Few ocular trauma studies have addressed mortality outcomes. We sought to determine characteristics of mortality-related ocular trauma admissions and compared them with non-fatal injuries.

METHODS

A retrospective study was conducted using de-identified data of patients admitted with major trauma from the National Trauma Data Bank (2008-2014). Patients with ocular injury were identified using ICD- 9CM codes. Demographics, intention and mechanism, types of ocular and head injuries, and injury severity were documented. Mortality was determined using post-admission disposition. Statistical analysis using student t-test, chi-square, and odds ratios (OR) calculations were performed with STATA-17 software. Significance was set at P < 0.05.

RESULTS

Of 316,485 patients admitted with ocular trauma, 12,233 (3.86%) were mortality related. Expired patients were older than survivors: mean (SD) of 50.1(25.5) vs. 41.5(22.8) years. White (OR = 1.32; P < 0.001), ≥ 65years old (OR = 2.25; P < 0.001), and male (OR = 1.05; P = 0.029) patients were most likely to expire than their counterparts. Common mechanisms of injury in survivors were falls (25.3%), motor vehicle traffic-occupant, MVTO (21.8%) and struck by/against (18.1%) and for fatal injuries, falls (29.7%), MVTO (21.9%) and firearms (11.5%). Traumatic brain injury (TBI) was documented in 88.2% of mortality-related admissions. Very severe injury severity scores (ISS > 24) (OR = 19.19; P < 0.001) and severe Glasgow Coma Score (GCS < 8) (OR = 19.22; P < 0.001) were most associated with mortality than survival. Firearms were most associated with very severe ISS (OR = 3.73; P < 0.001), severe GCS (OR = 4.68; P < 0.001) and mortality (OR = 5.21; P < 0.001) than other mechanisms. Patients with cut/pierce injuries had the greatest odds of survival (OR = 13.48; P < 0.001). Optic nerve/visual pathways injuries (3.1%) had the highest association with very severe ISS (OR = 2.51; P < 0.001), severe GCS (OR = 3.64; P < 0.001) and mortality (OR = 2.58; P < 0.001) than other ocular injuries. Black patients with very severe ISS (OR = 32.14; P < 0.001) and severe GCS (OR = 31.89; P < 0.001) were more likely to expire than other race/ethnicities with similar injury severity.

CONCLUSIONS

Mortality-related admissions were older, male, and mostly of White race than ocular trauma admissions of survivors. Firearms were the deadliest mechanism. TBI was commonly associated and patients with optic nerve/pathway injuries, very severe ISS and severe GCS had higher mortality rates. Characteristics and demographic variations identified in this study may be useful in developing focused measures aimed at preventing trauma-related deaths.

Animal Models for Limbal Stem Cell Deficiency: A Critical Narrative Literature Review

This literature review will provide a critical narrative overview of the highlights and potential pitfalls of the reported animal models for limbal stem cell deficiency (LSCD) and will identify the neglected aspects of this research area. There exists significant heterogeneity in the literature regarding the methodology used to create the model and the predefined duration after the insult when the model is supposedly fully fit for evaluations and/or for testing various therapeutic interventions. The literature is also replete with examples wherein the implementation of a specific model varies significantly across different studies. For example, the concentration of the chemical, as well as its duration and technique of exposure in a chemically induced LSCD model, has a great impact not only on the validity of the model but also on the severity of the complications. Furthermore, while some models induce a full-blown clinical picture of total LSCD, some are hindered by their ability to yield only partial LSCD. Another aspect to consider is the nature of the damage induced by a specific method. As thermal methods cause more stromal scarring, they may be better suited for assessing the anti-fibrotic properties of a particular treatment. On the other hand, since chemical burns cause more neovascularisation, they provide the opportunity to tap into the potential treatments for anti-neovascularisation. The animal species (i.e., rats, mice, rabbits, etc.) is also a crucial factor in the validity of the model and its potential for clinical translation, with each animal having its unique set of advantages and disadvantages. This review will also elaborate on other overlooked aspects, such as the anaesthetic(s) used during experiments, the gender of the animals, care after LSCD induction, and model validation. The review will conclude by providing future perspectives and suggestions for further developments in this rather important area of research.

Nonlinear fourth-order elastic characterization of the cornea using torsional wave elastography

Measuring the mechanical nonlinear properties of the cornea remains challenging due to the lack of consensus in the methodology and in the models that effectively predict its behaviour. This study proposed developing a procedure to reconstruct nonlinear fourth-order elastic properties of the cornea based on a mathematical model derived from the theory of Hamilton et al. and using the torsional wave elastography (TWE) technique. In order to validate its diagnostic capability of simulated pathological conditions, two different groups were studied, non-treated cornea samples (n=7), and ammonium hydroxide ([Formula: see text]) treated samples (n=7). All the samples were measured in-plane by a torsional wave device by increasing IOP from 5 to 25 mmHg with 5 mmHg steps. The results show a nonlinear variation of the shear wave speed with the IOP, with higher values for higher IOPs. Moreover, the shear wave speed values of the control group were higher than those of the treated group. The study also revealed significant differences between the control and treated groups for the Lamé parameter [Formula: see text] (25.9-6.52 kPa), third-order elastic constant A (215.09-44.85 kPa), and fourth-order elastic constant D (523.5-129.63 kPa), with p-values of 0.010, 0.024, and 0.032, respectively. These findings demonstrate that the proposed procedure can distinguish between healthy and damaged corneas, making it a promising technique for detecting diseases associated with IOP alteration, such as corneal burns, glaucoma, or ocular hypertension.

Types of Descemet Membrane Detachment After Ocular Surface Burns: The Factor Long Been Ignored

PURPOSE

The aim of this study was to explore types of Descemet membrane detachment (DMD) after ocular surface burns by anterior segment optical coherence tomography.

METHODS

This is a pilot, case series, observational study. Patients with DMD after ocular surface burns were enrolled. Ophthalmologic examinations were performed in all patients including slit-lamp photography and anterior segment optical coherence tomography.

RESULTS

Three types of DMDs in 9 eyes of 9 patients with ocular surface burns were identified depending on the detachment components involved with the pre-Descemet layer (PDL). Type A was referred as a taut chord that the PDL and Descemet membrane (DM) detached simultaneously but were remained attached to each other, while type B was identified as a wavy line separated from the stroma by a dark slit that demonstrated the detachment of DM from the PDL and stroma. Type C was defined as the DM detached with or without PDL but they were separated from each other. We found that DM and PDL were detached simultaneously in most condition, with type A in 4 cases, type C in 5 cases, and type B in only 1 case.

CONCLUSIONS

Our study demonstrated 3 types of DMDs after ocular surface burns and revealed that the limbal involvement and retrocorneal exudations may give clues to DMD in the corresponding areas. DMDs may be neglected for long in patients with extensive limbal involvement in early stages and also play an important role in unstable ocular surface condition until the late stages of conjunctivalization after ocular surface burns.

Conjunctival Limbal Autograft Combined with Amnion-Assisted Conjunctival Epithelial Redirection for Unilateral Total Limbal Stem Cell Deficiency after Severe Chemical Burn

(1) Background: To evaluate the efficacy of conjunctival limbal autograft (CLAU) combined with the amnion-assisted conjunctival epithelial redirection (ACER) procedure for patients with unilateral total limbal stem cell deficiency (LSCD) caused by severe chemical burn. (2) Methods: A retrospective interventional case series of unilateral total LSCD after chemical burn who underwent CLAU combined with ACER surgery between September 2021 and July 2023 was collected. Outcome measures included epithelialization of the cornea with donor limbus-derived epithelium, best corrected visual acuity (BCVA), and complications. (3) Results: Nine males and one female were included in this study. The mean age was 40.9 ± 9.63 (range, 26 to 55) years. The average duration between injury and CLAU combined with the ACER procedure was 7.67 ± 3.97 (range, 4 to 18) months. All patients achieved corneal epithelialization and improved BCVA. Postoperative complications occurred in four cases, including delayed corneal epithelial healing in one case, delayed amniotic membrane dissolution and detachment in two cases, and recurrence of symblepharon in one case. No complications were noted in the healthy donor eyes. (4) Conclusions: CLAU combined with ACER is a safe and effective treatment for unilateral total LSCD caused by severe chemical burn. This combined surgery restores visual function for patients with corneal blindness caused by chemical burn, reducing the burden on the families and society.

Enhanced adipose-derived stem cells with IGF-1-modified mRNA promote wound healing following corneal injury

The cornea serves as an important barrier structure to the eyeball and is vulnerable to injuries, which may lead to scarring and blindness if not treated promptly. To explore an effective treatment that could achieve multi-dimensional repair of the injured cornea, the study herein innovatively combined modified mRNA (modRNA) technologies with adipose-derived mesenchymal stem cells (ADSCs) therapy, and applied IGF-1 modRNA (modIGF1)-engineered ADSCs (ADSCmodIGF1) to alkali-burned corneas in mice. The therapeutic results showed that ADSCmodIGF1 treatment could achieve the most extensive recovery of corneal morphology and function when compared not only with simple ADSCs but also IGF-1 protein eyedrops, which was reflected by the healing of corneal epithelium and limbus, the inhibition of corneal stromal fibrosis, angiogenesis and lymphangiogenesis, and also the repair of corneal nerves. In vitro experiments further proved that ADSCmodIGF1 could more significantly promote the activity of trigeminal ganglion cells and maintain the stemness of limbal stem cells than simple ADSCs, which were also essential for reconstructing corneal homeostasis. Through a combinatorial treatment regimen of cell-based therapy with mRNA technology, this study highlighted comprehensive repair in the damaged cornea and showed the outstanding application prospect in the treatment of corneal injury.

Demographic profile and clinical characteristics of patients presenting with acute ocular burns

Purpose

To study and compare the demographic and clinical profile of acute ocular burns (AOB) in children and adults.

Methods

This retrospective case series included 271 children (338 eyes) and 1300 adults (1809 eyes) who presented to two tertiary eye care centers within one month of sustaining AOB. Data regarding demographics, causative agents, severity of injury, visual acuity (VA), and treatment were collected and analyzed.

Results

Males were more commonly affected particularly among adults (81% versus 64%, P < 0.00001). Among children, 79% sustained domestic injuries, whereas 59% of adults had work-place injuries (P < 0.0001). Most cases were due to alkali (38%) and acids (22%). Edible lime (chuna, 32%), superglue (14%), and firecrackers (12%) in children, and chuna (7%), insecticides, lye, superglue (6% each), toilet cleaner (4%) and battery acid (3%) in adults, were the main causative agents. The percentage of cases with Dua grade IV-VI was greater in children (16% versus 9%; P = 0.0001). Amniotic membrane grafting and/or tarsorrhaphy were needed in 36% and 14% of affected eyes in children and adults, respectively (P < 0.00001). The median presenting VA was logMAR 0.5 in children and logMAR 0.3 in adults (P = 0.0001), which improved significantly with treatment in both groups (P < 0.0001), but the final VA in eyes with Dua grade IV-VI burns was poorer in children (logMAR 1.3 versus logMAR 0.8, P = 0.04).

Conclusion

The findings clearly delineate the at-risk groups, causative agents, clinical severity, and treatment outcomes of AOB. Increased awareness and data-driven targeted preventive strategies are needed to reduce the avoidable ocular morbidity in AOB.

Collagen membrane loaded with doxycycline through hydroxypropyl chitosan microspheres for the early reconstruction of alkali-burned cornea

Corneal alkali burn is one of the most devastating ophthalmic emergencies correlated with remarkable morbidity resulting in severe visual impairment. Appropriate intervention in the acute phase determines the eventual outcome for later corneal restoration treatment. Since the epithelium plays an essential role in inhibiting inflammation and promoting tissue repair, sustained anti-matrix metalloproteinases (MMPs) and pro-epithelialization are the prior remedies during the first week. In this study, a drug-loaded collagen membrane (Dox-HCM/Col) that could be sutured to overlay the burned cornea was developed to accelerate the early reconstruction. Doxycycline (Dox), a specific inhibitor of MMPs, was encapsulated in collagen membrane (Col) through hydroxypropyl chitosan microspheres (HCM) to develop Dox-HCM/Col, affording a preferable pro-epithelialization microenvironment and an in-situ controlled release. Results showed that loading HCM into Col prolonged the release time to 7 days, and Dox-HCM/Col could significantly suppress the expression of MMP-9 and -13 in vitro and in vivo. Furthermore, the membrane accelerated the corneal complete re-epithelialization and promoted early reconstruction within the first week. Overall, Dox-HCM/Col was a promising biomaterial membrane for treating alkali-burned cornea in the early stage, and our attempt may provide a clinically feasible method for the ocular surface reconstruction.

TFOS lifestyle: Impact of societal challenges on the ocular surface

Societal factors associated with ocular surface diseases were mapped using a framework to characterize the relationship between the individual, their health and environment. The impact of the COVID-19 pandemic and mitigating factors on ocular surface diseases were considered in a systematic review. Age and sex effects were generally well-characterized for inflammatory, infectious, autoimmune and trauma-related conditions. Sex and gender, through biological, socio-economic, and cultural factors impact the prevalence and severity of disease, access to, and use of, care. Genetic factors, race, smoking and co-morbidities are generally well characterized, with interdependencies with geographical, employment and socioeconomic factors. Living and working conditions include employment, education, water and sanitation, poverty and socioeconomic class. Employment type and hobbies are associated with eye trauma and burns. Regional, global socio-economic, cultural and environmental conditions, include remoteness, geography, seasonality, availability of and access to services. Violence associated with war, acid attacks and domestic violence are associated with traumatic injuries. The impacts of conflict, pandemic and climate are exacerbated by decreased food security, access to health services and workers. Digital technology can impact diseases through physical and mental health effects and access to health information and services. The COVID-19 pandemic and related mitigating strategies are mostly associated with an increased risk of developing new or worsening existing ocular surface diseases. Societal factors impact the type and severity of ocular surface diseases, although there is considerable interdependence between factors. The overlay of the digital environment, natural disasters, conflict and the pandemic have modified access to services in some regions.

Management of limbal stem cell deficiency by amnion-assisted conjunctival epithelial redirection using vacuum-dried amniotic membrane and fibrin glue

PURPOSE

To study the outcome of a modified amnion-assisted conjunctival epithelial redirection (ACER) technique using vacuum-dried amnion (Omnigen) and fibrin glue for managing total limbal stem cell deficiency (LSCD).

METHOD

A retrospective, interventional case series of all patients with total LSCD who underwent limbal stem cell transplant (LSCT) using the modified ACER procedure between 2016 and 2019. The outcome was defined as: (1) success: complete corneal re-epithelialisation without conjunctivalisation; (2) partial success: sub-total corneal re-epithelialisation with partial non-progressive conjunctivalisation sparing the visual axis and (3) failure: conjunctivalisation affecting the visual axis.

RESULTS

Ten patients (six men), with a mean age of 46.2±18.4 years, were included. The mean follow-up was 23.0±13.9 months. Causes of LSCD were chemical eye injury (30%), congenital aniridia-related keratopathy (30%), ocular surface malignancy (20%), Steven-Johnson syndrome (10%) and contact lens overuse (10%). 50% were bilateral. The time from diagnosis to ACER (for acquired causes) was 45.6±44.4 months. 80% of patients achieved a complete/partial success following ACER and 20% of patients required repeat LSCT. Auto-LSCT was associated with a significantly higher chance of success than allo-LSCT (p=0.048). The mean best-corrected-visual-acuity (logMAR) improved significantly from 1.76±0.64 preoperatively to 0.94±0.94 at final follow-up (p=0.009). Omnigen was available off-the-shelf stored at room temperature and its transparency enabled visualisation of the healing epithelium beneath.

CONCLUSION

LSCT using the modified ACER serves as an effective ocular surface reconstruction technique in managing total LSCD and improving vision. Vacuum-dried amnion provides advantages of easy handling, transparency and storage at room temperature.

Epidemiology and etiology of chemical ocular injury: A brief review

Chemical ocular injury is one of the common ophthalmologic emergencies that can cause vision loss and serious complications. Despite all protective measures, it continues to be a serious public health problem, especially in young male patients. Although it is known that injuries occur most frequently in the workplace and in young male patients, there is a variable frequency and distribution in different regions around the world. In addition, with the coronavirus disease 2019 pandemic, there are changing trends in ocular chemical injuries. This review aims to specify an update on the epidemiological and etiological features of ocular chemical injuries.

The role of Tenonplasty in the management of limbal and scleral ischemia due to acute ocular chemical burns

Of the various manifestations of ocular chemical burns (OCBs), ischemia of the limbus and the peri-limbal sclera indicates poor prognosis and in severe cases threaten the integrity of the globe. Tenonplasty is a surgical procedure which involves advancing the Tenon’s capsule over the ischemic areas to provide a vascular supply and to enable migration of the conjunctival epithelium. This review aims to provide an overview of the diagnosis of limbal ischemia and its management with Tenonplasty. A literature review was conducted using the keywords “Tenonplasty,” “Tenon’s capsule,” “ocular chemical injury,” “ocular thermal injury,” “Tenon advancement,” “scleral ischemia,” and “limbal ischemia,” and outcomes were studied from seven selected articles. In addition to clinical evaluation, in vivo imaging techniques such as anterior segment optical coherence tomography angiography can provide an objective method of measuring and monitoring the ischemia and re-perfusion of the peri-limbal vasculature. Tenonplasty can be performed in eyes with acute OCBs with scleral or limbal ischemia by dissecting the Tenon’s layer from the orbit and securing it to the limbus. The indications, mechanism of action, peri-operative considerations, surgical technique, and post-operative care of Tenonplasty are discussed in detail. The average time for post-operative re-epithelization ranges from 1 to 6 months with the formation of a symblepharon being the most common complication. In conclusion, Tenonplasty is a globe-salvaging procedure in cases with severe limbal and scleral ischemia because of OCBs and has good anatomical outcomes priming the globe for subsequent re-constructive and vision-restoring surgeries.

Polystyrene microplastic particles: In vivo and in vitro ocular surface toxicity assessment

Microplastics (MPs) have become a global concern as a key environmental pollutant. MPs are widely found in oceans, rivers, bottled water, plastic-packaged foods, and toiletries. The ocular surface is the exposed mucosal tissue, which comes in contact with MP particles contained in toiletries, tap water, cosmetics, and air. However, the effects of MPs on ocular surface health are still unclear. In this study, the toxic effects of polystyrene MPs (PS-MPs) on the ocular surface in vivo and in vitro were explored. The results demonstrated that 50 nm or 2 μm PS-MPs, following exposure for 48 h appeared in the cytoplasm of two kinds of eye cells in vitro and caused a concentration dependent reduction in cell viability, further causing oxidative stress and cell apoptosis. In addition, after treatment for 2 or 4 weeks, 50 nm and 2 μm PS-MPs were deposited in the conjunctival sac of mice. After 2 and 4 weeks of PS-MP treatment, the number of goblet cells in the lower eyelid conjunctival sac decreased to 65% and 40% of that in the control group, respectively. Moreover, dry eye like ocular surface damage and inflammation of conjunctiva and lacrimal gland in mice were observed. In conclusion, this study revealed that PS-MPs could cause ocular surface dysfunctions in mice, thus providing a new perspective for the toxic effects of MPs on ocular surface.

Clinical outcomes and safety of Diphoterine® irrigation for chemical eye injury: A single-centre experience in the United Kingdom

Purpose:

Diphoterine^® is an amphoteric irrigating solution armed with rapid pH-neutralising action. It serves as an effective first-aid treatment for managing chemical burns, including chemical eye injury (CEI). However, its use is not widely adopted in current clinical practice, primarily attributed to limited clinical evidence. This study aims to highlight the experience in using Diphoterine for managing CEI in a UK tertiary referral centre.

Methods:

This retrospective case series included all patients who presented with CEI and treated with Diphoterine at the James Cook University Hospital, UK, between April 2018 and February 2020.

Results:

Seven patients (10 eyes) were included; the mean age was 28.2 ± 17.0 years (ranged, 3–70 years) and 85.7% were male. All patients presented with an alkaline injury with a mean presenting pH of 8.7 ± 0.7 and a median (±interquartile range [IQR]) corrected-distance visual acuity (CDVA) of 0.10 ± 0.28 logMAR. Based on Roper-Hall classification, 90% and 10% of the eyes were of grade-I and -IV CEI, respectively. All eyes received normal saline/water as the first irrigation fluid and Diphoterine as second irrigation fluid. The mean pH improved slightly after first irrigation (8.4 ± 0.7; p = 0.13) and significantly after second irrigation (7.6 ± 0.4; p = 0.001). The volume of irrigation used was significantly less for Diphoterine (520 ± 193 mL) than for normal saline/water (2700 ± 2451 mL; p = 0.016). At final follow-up (median = 5 days), the median CDVA remained stable at 0.10 ± 0.28 logMAR (p = 0.60). One patient developed near-total limbal stem cell deficiency as a complication of grade-IV injury and was awaiting limbal stem cell transplantation at last follow-up.

Conclusion:

This study represents the first case series in the United Kingdom, reporting the use of Diphoterine in managing CEI. The rapid pH-neutralising action of Diphoterine, with less volume required, makes it an ideal initial treatment for efficiently managing adult and paediatric patients with CEI in clinics.

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

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