Investigation of mechanical strength and structure of corneal graft-host junction.

Dehiscence is a common complication of corneal transplant surgery involving separating the graft from the host eye. The present article aims to investigate fundamental insights into the mechanical and structural aspects of the graft-host junction (GHJ) of a graft that survived in a patient for 13 years after penetrating keratoplasty (PK). Additionally, it adopts the sutur retention strength (SRS) test procedure defined in ISO:7198-2016 and aims to provide a comprehensive test protocol to study the biomechanics of the GHJ in extracted PK buttons. A 9 mm corneal button with GHJ was extracted from a 46-year-old patient who underwent PK 13 years back. The strength of the GHJ was quantified using the SRS test. Corresponding control results were obtained from the SRS tests of a corneoscleral button with no history of any refractive procedure. Birefringence, histological, and scanning electron microscopy (SEM) imaging were used to visualize the microstructural details of the GHJ. The strength of the GHJ was observed to be ten times lower than the native cornea. Histopathological features, such as fragmented Bowman's layer, and fibrosis with a clear demarcation line between host and graft tissue, were observed at the GHJ, suggesting a weak bond across the GHJ. The low strength of the GHJ in PK indicates the high susceptibility of the GHJ towards wound dehiscence.

Model development of aqueous deficient dry eye secondary to periglandular cicatrizing conjunctivitis.

PURPOSE: The current study used various techniques to develop a rabbit animal model of lacrimal gland damage caused by scarring conjunctivitis in the periglandular area. METHODS: Left eyes of New Zealand white rabbits were injected with 0.1ml of 1M NaOH subconjunctivally around superior and inferior lacrimal gland orifices (Group 1, n=4), touched with 1M NaOH for 100 sec to the superior and inferior fornices with conjunctival denuding (Group 2; n=4), and electrocauterization to the ductal opening area (Group 3; n=4). The ocular surface staining, Schirmer, lacrimal gland, and conjunctival changes were observed at baseline, 1, 4, 8, and 12 weeks. The degree of glandular inflammation, conjunctival fibrosis (Masson Trichrome), and goblet cell density (PAS) were also assessed. RESULTS: At 12 weeks, the lacrimal glands of group 2 rabbits with periglandular injection showed severe inflammation with mean four foci/10HPF and a significant mean reduction in the Schirmer values by 7.6mm (P=0.007). Lacrimal glands had diffuse acinar atrophy, loss of myoepithelial cells, and ductular dilatation. The overlying conjunctiva showed fibrosis, goblet cell loss, and corneal vascularization in the inferotemporal quadrant. No lacrimal gland or ocular surface changes were observed in groups 1 and 3 at 12 weeks, except for localized subconjunctival fibrosis. CONCLUSION: Periglandular injection of 0.1ml of 1M NaOH induced extensive lacrimal gland damage with reduced secretion and scarring in the subconjunctival plane compared to direct cauterization or direct NaOH contact to the ductal orifices of rabbit cornea.

Radiological Imaging of the Lacrimal Gland in Sjogren's Syndrome: A Systematic Review and Meta-Analysis.

PURPOSE: To critically appraise the evidence on the ability of the lacrimal gland ultrasonography (USG) or magnetic resonance imaging (MRI) to differentiate between Sjogren's syndrome and non-Sjogren's syndrome/healthy controls. METHODS: A systematic review and meta-analysis (based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines) of online literature search was performed using PubMed, Scopus, and Cochrane databases. Cohort studies comparing the imaging features of the lacrimal glands of Sjogren's syndrome with a control group were included. Quantitative synthesis was performed using the RevMan (Version 5.4.1). RESULTS: Six studies used USG as an imaging technique, and three used MRI for the lacrimal gland imaging. The lacrimal gland affected with Sjogren's syndrome shows glandular heterogeneity on USG and MRI. Heterogeneity on USG had 6.18 times higher odds of the lacrimal gland being involved with Sjogren's syndrome (95% CI, 3.31-11.55). Gland hyperechogenicity cannot reliably differentiate the glandular involvement in Sjogren's syndrome. There is insufficient data for analysis on the gland size, hypoechoic areas, fibrous bands, and increased lacrimal artery resistance in Sjogren's syndrome patients. Of the three MRI-based studies, reduced apparent diffusion coefficient and heterogeneity were the characteristics of Sjogren's syndrome. Clinical parameters such as dry eye symptomatology and Schirmer values had variable associations with USG or MRI parameters. Ultrasonography parameters were no different between dry eye versus no dry eye in Sjogren's syndrome patients, whereas small-sized glands had low Schirmer on MRI-based studies. CONCLUSION: Glandular heterogeneity on USG is significantly associated with lacrimal gland involvement in Sjogren's syndrome patients. However, the role of radiology in predicting lacrimal gland involvement is unclear as the evidence is insufficient and heterogeneous.

Tear Film Dynamics in Visual Display Terminal Users: A Review of Impact on Goblet Cells, Lacrimal and Meibomian Gland Function.

PURPOSE: The prevalence of dry eye disease (DED) is rising among visual display terminal (VDT) users, a trend that correlates with the growing use of digital devices. The prevalence of VDT-associated DED is reported based on dry eye questionnaires; however, VDT's impact on tear film parameters is less understood. METHODS: A review of published literature on both the alterations in tear film observed in VDT users and the impact of various interventions on their tear film. RESULTS: Most studies show reduction in tear stability as well as reduction in the blink rate. The role of lacrimal gland hypofunction in visual display terminal (VDT) users is a subject of ongoing debate. Schirmer test values typically exceed the 10 mm threshold, suggesting normal tear production, and tear osmolarity remains within normal ranges but VDT users consistently present with lower Schirmer values compared to non-VDT users. The effects on Meibomian glands and mucin levels need more research as the numbers studied are small. Very few studies have analysed mucin levels in VDT users with reports of normal or reduced values. Even asymptomatic users can have tear film instability; hence, the diagnostic criteria need to be formulated and validated. Different interventions such as neurostimulation, blink improving apps, eyelid warming devices, moist goggles, and lubricants have been explored in VDT users but without a control arm and in asymptomatic VDT users in most studies. CONCLUSION: The alterations have been observed on aqueous, lipid and mucin components of the tear film, although the extent of the impact is variable across studies. There is urgent need of well-designed studies for studying the tear film changes and management options for the upcoming lifestyle epidemic in VDT users.

Maackia amurensis seed lectin (MASL) and soluble human podoplanin (shPDPN) sequence analysis and effects on human oral squamous cell carcinoma (OSCC) cell migration and viability.

Maackia amurensis lectins serve as research and botanical agents that bind to sialic residues on proteins. For example, M. amurensis seed lectin (MASL) targets the sialic acid modified podoplanin (PDPN) receptor to suppress arthritic chondrocyte inflammation, and inhibit tumor cell growth and motility. However, M. amurensis lectin nomenclature and composition are not clearly defined. Here, we sought to definitively characterize MASL and its effects on tumor cell behavior. We utilized SDS-PAGE and LC-MS/MS to find that M. amurensis lectins can be divided into two groups. MASL is a member of one group which is composed of subunits that form dimers, evidently mediated by a cysteine residue in the carboxy region of the protein. In contrast to MASL, members of the other group do not dimerize under nonreducing conditions. These data also indicate that MASL is composed of 4 isoforms with an identical amino acid sequence, but unique glycosylation sites. We also produced a novel recombinant soluble human PDPN receptor (shPDPN) with 17 threonine residues glycosylated with sialic acid moieties with potential to act as a ligand trap that inhibits OSCC cell growth and motility. In addition, we report here that MASL targets PDPN with very strong binding kinetics in the nanomolar range. Moreover, we confirm that MASL can inhibit the growth and motility of human oral squamous cell carcinoma (OSCC) cells that express the PDPN receptor. Taken together, these data characterize M. amurensis lectins into two major groups based on their intrinsic properties, clarify the composition of MASL and its subunit isoform sequence and glycosylation sites, define sialic acid modifications on the PDPN receptor and its ability to act as a ligand trap, quantitate MASL binding to PDPN with KD in the nanomolar range, and verify the ability of MASL to serve as a potential anticancer agent.

Role of Mesenchymal Stem Cell-Derived Conditioned Medium in Modulating the Benzalkonium Chloride-Induced Cytotoxic Effects in Cultured Corneal Epithelial Cells In Vitro.

PURPOSE: Benzalkonium chloride (BAK) is a common preservative in ophthalmic formulations that causes cytotoxic damage to the corneal epithelial cells. This study aims to explore the role of mesenchymal stem cell (MSC)-derived conditioned medium in modulating the BAK-induced cytotoxic effects in cultured human corneal epithelial cells (HCECs) as a cell-free therapeutic agent. METHODS: The in vitro cultured HCECs derived from a HCE cell line were treated with BAK (0.001% and 0.005%, diluted in DMEM/F12, v/v) for 15 min, washed with 1xPBS, and allowed to recover for 24 h in human bone marrow MSC-derived conditioned medium (MSC-CM: undiluted (100%) and diluted (50%, v/v)). On the other hand, HCECs were co-incubated with BAK (0.005%, v/v) and MSC-CM (100% and 50%, v/v) for 24 h. The HCEC-derived conditioned medium (HCE-CM) was used as an optimal control for MSC-CM, whereas HCECs cultured in DMEM/F12 were used as a control. The DMEM/F12 was used as the base medium for the culture of HCECs and preparation of HCE- and MSC-CM. The role of MSC-CM in modulating the metabolic activity, cell death, epithelial repair, and proliferation, in BAK-treated HCECs was evaluated using MTT assay, Propidium iodide staining, scratch assay, and Ki-67 staining, respectively. RESULTS: Compared to the control, recovery of BAK-treated (0.001% and 0.005%, for 15 min) HCECs in MSC-CM showed significantly reduced cell death with enhanced metabolic activity, epithelial repair, and proliferation. However, in comparison with HCE-CM, the beneficial effects of MSC-CM were predominantly observed at lower BAK concentration (0.001%, for 15 min). Whereas the co-incubation of BAK (0.005%) and MSC-CM for a longer duration (24 h) was marginally beneficial. CONCLUSIONS: Our results suggest that the MSC-CM is effective in modulating the BAK-induced cell death, retardation of metabolic activity and proliferation in cultured HCECs, particularly at lower concentration (0.001%) and shorter exposure (15 min) of BAK.

Neutrophil-driven and interleukin-36γ-associated ocular surface inflammation in chronic Stevens-Johnson syndrome.

PURPOSE: This study aims to elucidate the tear proteome and understand the underlying molecular mechanisms involved in the ocular complications following Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). METHODS: Mass spectrometry (MS) was performed to quantify the tear fluid proteins from chronic SJS/TEN patients (n = 22 eyes) and age- and gender-matched controls (n = 22 eyes). The candidate proteins were validated using ELISA (n = 80 eyes) in tear samples and immunohistochemistry (IHC; n = 12) in eyelid margin specimens. These proteins were compared for significant differences based on age, gender, disease duration, and ocular severity. RESULTS: A total of 1692 tear fluid proteins were identified, of which 470 were significantly differentially regulated in chronic SJS/TEN. The top 10 significantly upregulated proteins were neutrophil secretions including neutrophil elastase (p < .0001), defensin (p < .0001), and matrix metalloproteinase 8 (p < .0001). The presence of neutrophils was confirmed by the upregulation of IL-8 (p < .001) in tears, a key cytokine known for recruiting neutrophils. Additionally, positive expression of myeloperoxidase was observed in the keratinized eyelid margins of SJS/TEN to validate the presence of neutrophils. Among 41 unique proteins identified by MS, IL-36γ (p < .01) was expressed in three SJS/TEN patients and was confirmed in SJS/TEN tears and eyelid margins by ELISA and IHC, respectively. IL-36γ was specifically expressed in the superficial layers of eyelid margin keratinized conjunctiva. The majority of the significantly downregulated proteins were lacrimal gland secretions such as lacritin (p < .0001) and opiorphin (p < .002). Neutrophil elastase (p < .02) was significantly elevated in patients with severe eyelid margin keratinization. CONCLUSION: Our observations indicate a clear correlation between eyelid margin keratinization and the expression of IL-36γ, potentially mediated by neutrophils recruited via IL-8. Future experimental studies are needed to test the role of therapies targeting IL-8 and/or IL-36γ in reducing eyelid margin keratinization and its associated ocular complications in SJS/TEN.

Bone marrow mesenchymal stem cell-derived extracellular vesicles promote corneal epithelial repair and suppress apoptosis via modulation of Caspase-3 in vitro.

Corneal injuries are the major cause of blindness and visual impairment. Available treatments are limited by their efficacy and side effects. Mesenchymal stem cell-derived extracellular vesicles are presumed as functional equivalents and potential candidates for cell-free therapy. This study reports isolation and characterization of extracellular vesicles from human bone marrow mesenchymal stem cells and evaluates their role in mediating epithelial repair and apoptosis in cultured corneal epithelial cells through scratch assay, PCR, immunofluorescence, and flow cytometry in vitro. The isolated extracellular vesicles were spherical, < 150 nm in diameter, and characterized as CD9+, CD63+, CD81+, TSG101+, and Calnexin-. Further, these vesicles promoted corneal epithelial repair by enhancing proliferation and suppressed apoptosis by regulating the expression of BAD, P53, BCL-2, and cleaved CASPASE-3. Thus, our results suggest that BM-MSC-EVs might have the potential to be used for the treatment of injury-induced corneal epithelial defects. Clinical translation of this work would require further investigations.

Clinical profile and management of ocular superglue injuries: Case series and review of literature.

PURPOSE: To describe the clinical profile and management of patients with ocular superglue injury (OSI). METHODS: This retrospective study included all patients with OSI who presented at a tertiary eye care institute between 2016 and 2020. Data regarding demographics, clinical profile, and management were collected. RESULTS: A total of 66 eyes of 58 patients (24 children, 34 adults) with a median age of 22.5 years [interquartile range (IQR): 11.3-31] were included. All cases sustained accidental injuries, with domestic injury at home being the most common location of injury among children (79%) and adults (53%) ( P = 0.39). The median visual acuity at presentation was worse in children [0.3 logMAR (IQR: 0.2-0.4)] as compared to adults [0.1 logMAR (IQR: 0.1-0.3)] ( P = 0.03)]. The most common clinical sign at presentation was conjunctival congestion in 77% of eyes (51/66) followed by polymerized glue stuck to the eyelashes and eyelids in 52% of eyes (34/66). The median duration from the time of injury to presentation was 2 hours in both groups. All eyes resolved with medical management. Examination under anesthesia was required in three children (13%) to evaluate the extent of OSI. None of the patients had long-term ocular complications. CONCLUSION: Improper and careless handling of superglue in the domestic setting may cause accidental ocular injuries that require immediate medical attention. OSI represents less severe ocular injuries that respond to medical therapy alone and is not associated with long-term visual morbidity. Modifications in the packaging of superglue containers and awareness about their deleterious effects could prevent these injuries.

Revisiting rabbit models for keratoconus: A long-term study on collagenase-induced disease progression.

Keratoconus (KC) is a degenerative disorder resulting from the degradation of the stromal collagen fibril network in the cornea, leading to its thinning and conical deformation. Various studies have established animal models of KC by using the collagenase type II enzyme to gain a better understanding of the pathogenesis, however, long-term monitoring or follow-up of the models have not been reported so far. This study evaluates the long-term stability of collagenase type II-induced KC in a rabbit model. Six New Zealand rabbits were divided into 4 study groups with 3 eyes per group. The groups were control (group 1), 0.5% proparacaine + 5 min collagenase treatment on day 0 and day 30 (group 2), 0.5% proparacaine + 10 min collagenase treatment on day 0 (group 3) and, mechanical debridement + 2 min collagenase treatment on day 0 (group 4). Inflammation was observed in group 4 till week 10. Significant decrease in the central corneal thickness was observed in group 3 by week 4 (p < 0.001) however, the thickness was regained in the subsequent follow-ups in all the groups. Keratography results showed no changes in Km values but an increased astigmatic power in all groups. Scanning electron microscopy images revealed thinner collagen fibrils arranged in a mesh-like pattern above the uniform layer of the collagen lamellae in the central part of the treated corneas. Similarly, histological staining revealed loosely packed stromal fibrils in the anterior portion of the cornea which corroborates with the immunofluorescent staining results. This study revealed the remodeling of the corneal structure by eight weeks of collagenase treatment. Consequently, the possibility of creating a rabbit keratoconus model induced by collagenase may warrant further consideration.

Intraoperative collagen imaging of sutured cornea: A way towards managing post-penetrating keratoplasty astigmatism.

The birefringent nature of the human cornea plays an important role in comprehending its structural behavior in both diseased and surgical conditions. During corneal transplantation, irregular astigmatism is a common post-surgical complication that depends on the characteristics of suturing. Four human cadaver corneas are subjected to an in-vitro model of a typical full-thickness penetrating keratoplasty (PK) procedure using 16 simple interrupted 10-0 vicyrl sutures. The birefringence of these four corneas is analyzed using digital photoelasticity and compared with the control cornea (without PK). It is found that the sutures and their mutual interaction influence the morphology of the peripheral birefringence of the cornea. The findings of the present investigation are pertinent to intraoperative suture management during PK. Results suggest conserving the typical diamond-shaped morphology of peripheral birefringence would ensure uniform distribution of sutures. Therefore, birefringence imaging could be useful in suture management to ensure proper apposition of the graft-host junction, thus minimizing the risk of irregular astigmatism.

Direct Immunofluorescence Findings and Factors Affecting Conjunctival Biopsy Positivity in Ocular Mucous Membrane Pemphigoid.

PURPOSE: The aim of this study was to describe the direct immunofluorescence (DIF) findings and factors affecting conjunctival biopsy positivity in patients clinically diagnosed with ocular mucous membrane pemphigoid (OMMP). METHODS: This retrospective observational case series included patients with clinical OMMP who underwent conjunctival biopsy for DIF in at least 1 eye between 2018 and 2021 in an institutional setting. The primary outcome measures were association of age and chronic ocular complications with biopsy positivity. RESULTS: Of 61 patients, DIF positivity was seen in 33 (54.1%) clinically suspected cases of OMMP. Of 39 patients who underwent bilateral biopsy, 23 (59%) were positive, of which 12 (52%) were positive in both eyes while 11 (48%) were positive in 1 eye. Of 22 patients who underwent unilateral biopsy, 10 (45%) were positive. Of the 100 biopsied eyes, 45 (45%) were DIF positive. Among the immunoreactants studied, linear deposition of C3 was seen in all 45 positive eyes (100%). Increasing age was significantly associated with higher likelihood of biopsy negativity ( P = 0.032), whereas a greater Sotozono chronic ocular complication score, indicative of disease severity, was associated with low likelihood of biopsy positivity ( P = 0.0042) and lower overall expression of immunoreactants on DIF ( P = 0.0007). CONCLUSIONS: Older patients and patients with more severe ocular surface disease sequelae are likely to have negative DIF results. To optimize the chances of confirming the diagnosis of OMMP by DIF, both eyes should be biopsied early in the disease course. If 1 eye is being biopsied, the less affected eye must be chosen.

Ocular surface pseudoepitheliomatous hyperplasia secondary to allergic eye disease: clinical features and management.

PURPOSE: To study the clinical characteristics and treatment outcomes of ocular surface pseudoepitheliomatous hyperplasia (PEH) associated with chronic vernal keratoconjunctivitis (VKC). METHODS: This retrospective study includes 39 eyes of 32 patients with VKC induced PEH who presented from 2016-2022. A database search was conducted for diagnosis of PEH, and data on clinical features, imaging characteristics, and treatment were analyzed. RESULTS: Of the 32 patients, 11 (34%) were children and adolescents, 21 (66%) were adults. PEH was common in males (72%) and ocular surface squamous neoplasia (OSSN) was the commonest referral diagnosis (43.7%). Mean age at presentation was 26.62 ± 10.18 (range: 6-52) years. While history of VKC was present in 21 patients, 11 were diagnosed with VKC at the time of diagnosis of PEH. The mean base/largest diameter was 5.2 ± 1.67 mm. Anterior segment optical coherence tomography (AS-OCT) showed irregular hyper-reflective epithelium, epithelial dipping, and sub-epithelial hyper-reflective lesion with shadowing in all lesions. Of the 31 eyes that received medical therapy, 21 (67%) and 10 (32%) eyes showed complete and partial resolution respectively with median time to resolution of 3(IQR:2-4) months. Eight eyes that underwent surgical excision showed complete resolution and one developed partial limbal stem cell deficiency. CONCLUSION: Ocular surface PEH is a manifestation of chronic VKC which closely mimics OSSN. Detailed history-taking, examination for signs of allergy, and AS-OCT imaging can distinguish it from OSSN. It responds well to medical therapy and should be considered first-line therapy before planning any surgical intervention.

Impact of Symblepharon Management With Ocular Surface Reconstruction on Scleral Lens Fitting in Eyes With Chronic Cicatrizing Conjunctivitis and Keratopathy.

PURPOSE: The aim of this study was to describe the importance of symblepharon release with ocular surface reconstruction (OSR) for optimal fitting of scleral contact lenses (SCLs) in eyes with chronic cicatrizing conjunctivitis (CCC) and keratopathy. METHODS: This retrospective study included 32 eyes with CCC and keratopathy with symblepharon which underwent symblepharon release with OSR and were fitted with SCLs. The primary outcome measure was the improvement in best-corrected visual acuity with SCL wear. RESULTS: A total of 32 eyes of 29 patients (66% men) with a median age of 30.5 years were included. The common causes of CCC were Stevens-Johnson syndrome (66%) and ocular burns (16%). The most common location of symblepharon was superior (59%) with limbal involvement in most eyes (94%). Symblepharon release was combined with mucous membrane grafting (63%), amniotic membrane grafting (31%), or conjunctival autografting (6%). The median interval between symblepharon release with OSR and SCL trial was 15 weeks [interquartile range (IQR): 6-24]. The median best-corrected visual acuity improved from logMAR 1.5 (IQR: 1.2-1.8) to logMAR 1.2 (IQR: 0.6-1.4) with SCLs after symblepharon release with OSR (P < 0.001). The median diameter of the SCL used was 15 mm (IQR: 15-16), with a median base curve of 7.9 mm (IQR: 7.9-8). Symblepharon recurrence was noted in 70% of eyes that underwent amniotic membrane grafting; no recurrence was seen with mucous membrane grafting or conjunctival autografting. CONCLUSIONS: In eyes with CCC with keratopathy and symblepharon, visual rehabilitation is possible with SCLs after symblepharon release with OSR without having to resort to a penetrating corneal procedure.

Successful use of conjunctival flaps to prolong survival of type I keratoprosthesis in severe bilateral chemical burns: two case reports.

INTRODUCTION: This report describes the use of conjunctival flaps to enable the survival of type I keratoprosthesis (KPro) in two cases of bilateral severe total limbal stem cell deficiency (LSCD) following chemical burns. PRESENTATION OF CASE: Two patients had a history of bilateral chemical injury with lime. On examination, the presenting vision was light perception to hand motions and both cases had conjunctivalized ocular surfaces with symblepharon. A modified technique of type I keratoprosthesis was used, where the conjunctivalized corneal pannus was dissected and lifted off as an inferior fornix-based conjunctival flap. This was followed by a standard surgical technique of type I KPro. The flap was then secured over the device and optical opening was made two weeks later. Both the patients had stable ocular surfaces with visual acuity of 20/20 at 2-7 years of follow-up. DISCUSSION: In patients with total LSCD with adnexal involvement, type I KPro has unsatisfactory long-term survival because of the risk of repeated epithelial breakdowns and stromal ulceration. With the innovative approach described in this report, type I KPro can be successfully used for sustainable visual improvement in the presence of severe ocular surface disease and symblepharon. CONCLUSION: Conjunctival flaps can be used along with type I KPros to improve long-term survival and give sustainable visual outcomes in cases of bilateral corneal blindness due to advanced ocular surface damage.

Development and validation of a reliable rabbit model of limbal stem cell deficiency by mechanical debridement using an ophthalmic burr.

A simple and reproducible method is necessary to generate reliable animal models of limbal stem cell deficiency (LSCD) for assessing the safety and efficacy of new therapeutic modalities. This study aimed to develop and validate a rabbit model of LSCD through mechanical injury. The corneal and limbal epithelium of New Zealand White rabbits (n = 18) were mechanically debrided using an ophthalmic burr (Algerbrush II) with a 1.0-mm rotating head after 360° conjunctival peritomy. The debrided eyes were serially evaluated for changes in corneal opacity, neo-vascularization, epithelial defect and corneal thickness using clinical photography, slit lamp imaging, fluorescein staining, and anterior segment optical coherence tomography scanning (AS-OCT). Following this, an assessment of histopathology and phenotypic marker expression of the excised corneas was conducted. The experimental eyes were grouped as mild (n = 4), moderate (n = 10), and severe (n = 4) based on the grade of LSCD. The moderate group exhibited abnormal epithelium, cellular infiltration in the stroma, and vascularization in the central, peripheral, and limbal regions of the cornea. The severe group demonstrated central epithelial edema, peripheral epithelial thinning with sparse goblet cell population, extensive cellular infiltration in the stroma, and dense vascularization in the limbal region of the cornea. A significant decrease in the expression of K12 and p63 (p < 0.0001) was observed, indicating the loss of corneal epithelium and limbal epithelial stem cells in the LSCD cornea. This study demonstrates that the Alger brush-induced mechanical debridement model provides a reliable model of LSCD with comprehensive clinic-pathological features and that is well suited for evaluating novel therapeutic and regenerative approaches.

Morphologic variants of Meibomian glands: age-wise distribution and differences between upper and lower eyelids.

Purpose: To evaluate the distribution of various Meibomian gland morphologies across different age groups in healthy individuals. Methods: The infrared meibographic morphologies of the Meibomian glands from the upper and lower eyelids of 236 healthy individuals (472 eyes; mean age 38.4 ± 17.5 years; 80 female participants: 156 male participants) were evaluated for their prevalence and differences across six decades of life, from 10 to 80 years. A linear mixed-effects modeling test was performed for statistical analysis. Results: Of 14,452 glands, 8,830 (61%) glands were located in the upper eyelid. No significant differences in frequency were noted between different age groups for distorted, tortuous, hooked, overlapping, abnormal gap, fluffy areas, dropout (except for 51-60 vs. 10-20 years, P = 0.023), and thick and thin morphologies. Short glands were significantly more common in individuals aged over 30 years (P = 0.015), whereas moderately short and severely short glands were more common in the upper eyelids of individuals older than 50 years compared to those aged 10-20 years (P = 0.035). The frequency of distorted, hooked, tortuous, overlapping, and tadpole-shaped Meibomian glands was significantly higher in the upper eyelids than in the lower eyelids for all age groups. Dropout glands were more common in the lower eyelids of individuals younger than 50 years, but no difference was observed in the upper and lower eyelids of individuals over 50 years. Dropout (P = 0.006) and severely short glands (0.026) of the lower eyelid were associated with low non-invasive tear break-up time (NIBUT) values. Conclusion: Various morphologic characteristics of the Meibomian glands that are considered abnormal can be present in healthy individuals, and only moderate to severely short glands display an increase in abnormal morphologic characteristics of the Meibomian glands with age.

Human cornea-derived extracellular matrix hydrogel for prevention of post-traumatic corneal scarring: A translational approach.

Corneal scarring and opacification are a significant cause of blindness affecting millions worldwide. The current standard of care for corneal blindness is corneal transplantation, which suffers from several drawbacks. One alternative approach that has shown promise is the use of xenogeneic corneal extracellular matrix (ECM), but its clinical applicability is challenging due to safety concerns. This study reports the innovative use of human cornea-derived ECM to prevent post-traumatic corneal scarring. About 30 - 40% of corneas donated to the eye banks do not meet the standards defined for clinical use and are generally discarded, although they are completely screened for their safety. In this study, human cornea-derived decellularized ECM hydrogel was prepared from the non-transplantation grade human cadaveric corneas obtained from an accredited eye-bank. The prepared hydrogel was screened for its efficacy against corneal opacification following an injury in an animal model. Our in vivo study revealed that, the control collagen-treated group developed corneal opacification, while the prophylactic application of human cornea-derived hydrogel effectively prevented corneal scarring and opacification. The human hydrogel-treated corneas were indistinguishable from healthy corneas and comparable to those treated with the xenogeneic bovine corneal hydrogel. We also demonstrated that the application of the hydrogel retained the biological milieu including cell behavior, protein components, optical properties, curvature, and nerve regeneration by remodeling the corneal wound after injury. The hydrogel application is also sutureless, resulting in faster corneal healing. We envision that this human cornea-derived ECM-based hydrogel has potential clinical application in preventing scarring from corneal wounding. STATEMENT OF SIGNIFICANCE: There are significant challenges surrounding corneal regeneration after injury due to extensive scarring. Although there is substantial research on corneal regeneration, much of it uses synthetic materials with chemical cross-linking methods or xenogeneic tissue-based material devices which have to undergo exhaustive safety analysis before clinical trials. Herein, we demonstrate the potential application of a human corneal extracellular matrix hydrogel without any additional materials for scarless corneal tissue regeneration, and a method to reduce the wasting of donated allogenic corneal tissue from eye banks. We found no difference in efficacy between the usage of human tissues compared to xenogeneic sources. This may help ease clinical translation and can be used topically without sutures as an outpatient procedure.