Developing a model for 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 0.1 ml of 1M NaOH subconjunctivally around superior and inferior lacrimal gland orifices (Group 1, n = 4), touched with 1M NaOH for 100 s 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 I, 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 1 rabbits with periglandular injection showed severe inflammation with mean four foci/10HPF and a significant mean reduction in the Schirmer values by 7.6 mm (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 2 and 3 at 12 weeks, except for localized subconjunctival fibrosis. CONCLUSION: Periglandular injection of 0.1 ml 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 the rabbit lacrimal gland.

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.

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.

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.

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.

Investigation of microstructural failure in the human cornea through fracture tests.

Fracture toughness of the human cornea is one of the critical parameters in suture-involved corneal surgeries and the development of bioengineered mimetics of the human cornea. The present article systematically studied the fracture characteristics of the human cornea to evaluate its resistance to tear in the opening (Mode-I) and trouser tear mode (Mode-III). Tear experiments reveal the dependency of the fracture behavior on the notch size and its location created in the corneal specimens. The findings indicate lamellar tear and collagen fiber pull-out as a failure mechanism in trouser tear and opening mode tests, respectively. Experimental results have shown a localized variation of tear behavior in trouser tear mode and indicated an increasing resistance to tear from the corneal center to the periphery. This article demonstrated the complications of evaluating fracture toughness in opening mode and showed that the limbus was weaker than the cornea and sclera against tearing. The overall outcomes of the present study help in designing experiments to understand the toughness of the diseased tissues, understanding the effect of the suturing location and donor placement, and creating numerical models to study parameters affecting corneal replacement surgery.

Simple oral mucosal epithelial transplantation (SOMET) for ocular surface reconstruction in Stevens-Johnson Syndrome: A case report.

INTRODUCTION: We report the clinical outcome of a novel surgical technique called simple oral mucosal epithelial transplantation (SOMET) for the treatment of limbal stem cell deficiency (LSCD) in a patient with Stevens-Johnson Syndrome (SJS). PRESENTATION OF CASE: An eighteen-year-old girl was diagnosed as having chronic bilateral ocular sequelae of SJS. She initially underwent mucous membrane grafting (MMG) in both eyes for lid margin keratinization. Over the course of the next decade, the ocular surface cicatrization worsened in her left eye, leading to progressive symblepharon formation with total corneal conjunctivalization. She then underwent ocular surface reconstruction using bulbar MMG and SOMET. Following SOMET, the ocular surface epithelialized within 3 weeks and remained stable throughout the follow-up period. At one-year postoperatively, the visual acuity had improved from light perception to 20/250 unaided, and to 20/100 with scleral contact lens correction in the left eye. DISCUSSION: Simple limbal epithelial transplantation (SLET) has been a boon for the treatment of unilateral LSCD. Allogeneic SLET and kerato-limbal allografts can be useful for patients with bilateral disease, however this exposes the patients to the risks of long-term systemic immunosuppression. SOMET combines the benefits of cultivated oral mucosal epithelial transplantation (COMET) and SLET, and is an autologous and single-staged surgical alternative for patients with bilateral LSCD. CONCLUSION: This case demonstrates that SOMET is a viable surgical option in cases with bilateral LSCD, eliminating the need for an allogeneic limbal graft, systemic immunosuppression, or laboratory cell culture.

Human Lacrimal Gland Derived Mesenchymal Stem Cells - Isolation, Propagation, and Characterization.

Purpose: The existing treatment options for dry eye disease (DED) due to lacrimal gland (LG) dysfunction are mainly palliative. Mesenchymal stem cells (MSCs) based therapies and 3D-LG organoids have been explored as a curative option for LG regeneration in animal models. Human LG epithelial cultures are previously established and, here, we aim to isolate and characterize the spindle-shaped cells obtained from primary human LG cultures in order to unveil its MSC property. Methods: Normal human lacrimal glands were obtained from individuals undergoing LG debulking surgery. The conditions for human LG-MSC culture were standardized to obtain pure population of LG-MSCs at passage 3. Population doubling time (PDT), expression of phenotypic markers, tri-lineage differentiation, colony forming potential, and gene expression analysis were carried out to assess the phenotypic and genotypic characteristics compared to bone marrow-MSCs (BM-MSCs). Results: Our data show that these spindle-shaped cells exhibit similar phenotypic expression, colony-forming ability, and trilineage differentiation like BM-MSCs. Moreover, the gene expression also did not show any significant difference, except for increased IL1-ß in LG-MSCs. The LG-MSCs do not express any lacrimal epithelial markers unlike LG tissue. Conclusions: This study reveals the first-time evidence for the presence of MSC population within the human LGs, and these cells might play a role in maintaining healthy microenvironment within normal LG and repair in diseased LGs.

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.

Vortex Keratopathy as a Presenting Feature of Ocular Mucous Membrane Pemphigoid.

PURPOSE: The aim of this study was to describe the presenting feature of vortex keratopathy in 3 patients with biopsy-proven ocular mucous membrane pemphigoid (OMMP). METHODS: The first patient was a 52-year-old woman with chronic redness and foreign body sensation for 3 years who presented with unilateral vortex keratopathy. Seven months later, in the same eye, she developed conjunctival signs suggestive of OMMP. The second patient was a 33-year-old woman with similar chronic symptoms that were exacerbated by pterygium surgery. Clinical examination revealed vortex keratopathy in the right eye with subtle conjunctival signs suggestive of OMMP. The third patient was a 70-year-old woman with complaints of repeated episodes of redness and foreign body sensation for 18 months who presented with vortex keratopathy in the right eye and conjunctival signs suggestive of OMMP in the same eye. To confirm the clinical diagnosis, bilateral conjunctival biopsy was performed in all patients. RESULTS: OMMP was diagnosed based on conjunctival signs and confirmed on direct immunofluorescence positivity, demonstrating antibodies characteristic and diagnostic of OMMP in the basement membrane zone. A unique feature that preceded or coexisted with the conjunctival signs was unilateral vortex keratopathy seen in all 3 patients, independent of the stage of the disease at which they presented. CONCLUSIONS: Vortex keratopathy can be a presenting feature in patients with OMMP. A complete ocular surface examination, especially checking the medial canthus for keratin and the inferior fornix for foreshortening, is necessary. Conjunctival biopsy should be performed in all cases to confirm the clinical diagnosis wherever required.

Cicatricial Entropion in Chronic Cicatrizing Conjunctivitis: Potential Pathophysiologic Mechanisms and Long-Term Outcomes of a Modified Technique.

PURPOSE: The purpose of this study was to assess the long-term outcomes of severe cicatricial entropion repair with mucous membrane grafting in patients with chronic cicatrizing conjunctivitis and report histopathological changes in the eyelid margin area. METHODS: Prospective interventional study included 19 patients with severe cicatricial entropion with trichiasis (N = 20 eyelids; 19 upper and 1 lower eyelid) who underwent anterior lamellar recession (with back cuts) and mucous membrane grafting cover for bare anterior tarsus, lid margin, and 2 mm of marginal tarsus, and had a minimum 6 months of follow-up. The anterior lamella and metaplastic eyelid margins were sent for routine Haematoxylin and Eosin and special staining with Masson trichrome stain. RESULTS: The etiologies were chronic Stevens-Johnson syndrome (N = 6), chemical injury (N = 11), and drug-induced pseudopemphigoid (N = 2). Five eyes had undergone entropion correction in the past, and 9 had electroepilation for trichiasis. Entropion was well corrected (without residual trichiasis) in 85% of eyelids with primary surgery. The etiology-wise success rates were 100% for Stevens-Johnson syndrome, 72.7% for chemical injury, and 100% for drug-induced pseudopemphigoid. Three eyelids with failure belonged to chemical injury, and trichiasis in these eyes could be managed with subsequent interventions except in 1 case. All eyelids had no entropion at a mean follow-up of 10.8 months (range, 6-18). Histopathological evaluation of anterior lamella (N = 10) and eyelid margins revealed significant fibrosis in subepithelial, perimysium (muscle of Riolan), and perifollicular areas. CONCLUSION: Anterior lamellar recession combined with mucous membrane grafting achieves good cicatricial entropion correction except in eyes with chemical injury. The eyelid margins in these eyes have persistent inflammation, and fibrosis involving lash follicles.

Expansion and characterization of human limbus-derived stromal/mesenchymal stem cells in xeno-free medium for therapeutic applications.

BACKGROUND: Mesenchymal stem cells (MSCs) have been proven to prevent and clear corneal scarring and limbal stem cell deficiency. However, using animal-derived serum in a culture medium raises the ethical and regulatory bar. This study aims to expand and characterize human limbus-derived stromal/mesenchymal stem cells (hLMSCs) for the first time in vitro in the xeno-free medium. METHODS: Limbal tissue was obtained from therapeutic grade corneoscleral rims and subjected to explant culture till tertiary passage in media with and without serum (STEM MACS XF; SM), to obtain pure hLMSCs. Population doubling time, cell proliferation, expression of phenotypic markers, tri-lineage differentiation, colony-forming potential and gene expression analysis were carried out to assess the retention of phenotypic and genotypic characteristics of hLMSCs. RESULTS: The serum-free medium supported the growth of hLMSCs, retaining similar morphology but a significantly lower doubling time of 23 h (*p < 0.01) compared to the control medium. FACS analysis demonstrated ≥ 90% hLMSCs were positive for CD90+, CD73+, CD105+, and ≤ 6% were positive for CD45-, CD34- and HLA-DR-. Immunofluorescence analysis confirmed similar expression of Pax6+, COL IV+, ABCG2+, ABCB5+, VIM+, CD90+, CD105+, CD73+, HLA-DR- and CD45-, αSMA- in both the media. Tri-lineage differentiation potential and gene expression of hLMSCs were retained similarly to that of the control medium. CONCLUSION: The findings of this study demonstrate successful isolation, characterization and culture optimization of hLMSCs for the first time in vitro in a serum-free environment. This will help in the future pre-clinical and clinical applications of MSCs in translational research.

Keratoprosthesis in dry eye disease.

Bilateral corneal blindness with severe dry eye disease (DED), total limbal stem cell deficiency with underlying corneal stromal scarring and vascularization, combined with adnexal complications secondary to chronic cicatrizing conjunctivitis is a highly complex situation to treat. In such eyes, procedures such as penetrating keratoplasty alone or combined with limbal stem cell transplantation are doomed to fail. In these eyes, keratoprosthesis (Kpro) or an artificial cornea is the most viable option, eliminating corneal blindness even in eyes with autoimmune disorders such as Stevens-Johnson syndrome, ocular mucous membrane pemphigoid, Sjogren's syndrome, and nonautoimmune disorders such as chemical/thermal ocular burns, all of which are complex pathologies. Performing a Kpro in these eyes also eliminates the need for systemic immunosuppression and may provide relatively early visual recovery. In such eyes, the donor cornea around the central cylinder of the Kpro needs to be covered with a second layer of protection to avoid desiccation and progressive stromal melt of the underlying cornea, which is a common complication in eyes with severe DED. In this review, we will focus on Kpro designs that have been developed to survive in eyes with the hostile environment of severe DED. Their outcomes in such eyes will be discussed.

A review on drug-induced dry eye disease.

Dry eye disease encompasses a broad range of etiologies and disease subtypes which have similar clinical manifestations. Medications can cause dry eye disease or symptoms of dryness as a side effect by either interfering with the lacrimal gland or meibomian gland function, or both, and by other mechanisms that affect the ocular surface homeostasis. This is important to know and recognize as eliminating the offending medication can reverse the symptoms and, in many cases, prevent further deterioration of the ocular surface inflammation. This review focuses on drugs like systemic isotretinoin and taxanes, which cause meibomian gland dysfunction; immune checkpoint inhibitors that cause lacrimal gland dysfunction; gliptins and topical antiglaucoma medications that cause cicatrizing conjunctivitis; and epidermal growth factor receptor inhibitors, fibroblast growth factor receptor inhibitors, and belantamab mafodotin, which cause mucosal epitheliopathy. Many of these medications, particularly the newer anticancer agents, have only recently been introduced for clinical use, and knowledge and awareness of their ocular side effects are still evolving. This review aims to update ophthalmologists on the drug-induced causes of dry eye disease or symptoms of dryness, which is avoidable by discontinuation of the incriminating agent or can be mitigated by reducing the dose or frequency of usage.

Management of cataract in dry eye disease: Preferred practice pattern guidelines.

Cataract surgery is one of the most commonly performed ophthalmic surgeries in the world. Dry eye disease (DED) is found to coexist in most patients with cataracts due to the overlapping age groups of both these conditions. Preoperative evaluation for DED is important to improve outcomes. A pre-existing DED affecting the tear film is likely to affect biometry. Moreover, special intraoperative considerations are needed in eyes with DED to reduce complications and improve postoperative outcomes. Dry eye disease (DED) is known to occur following an uneventful cataract surgery or a pre-existing DED is likely to worsen following cataract surgery as well. In these situations, despite a good visual outcome, patient dissatisfaction is common owing to the distressing DED symptoms. This review aims to summarize the preoperative, intraoperative, and postoperative considerations when performing cataract surgery in the presence of a coexisting DED.

Dry eye disease and risk factors for corneal complications in chronic ocular graft-versus-host disease.

Purpose: The current study was carried out to evaluate the clinical features and management outcomes of dry eye disease (DED) in chronic ocular GvHD following allogenic hematopoietic stem cell transplantation (HSCT). Methods: A retrospective review of consecutive patients diagnosed with chronic ocular GvHD between 2011 and 2020 was performed at a tertiary eye care network. Multi-variate regression analysis was carried out for identifying risk factors associated with progressive disease. Results: A total of 34 patients (68 eyes) with a median age of 33 years [inter-quartile range (IQR) 23-40.5] were studied. The most common indication for HSCT was acute lymphocytic leukemia (26%). Ocular GvHD developed at a median of 2 years (IQR 1-5.5 years) after HSCT. Aqueous tear deficiency was present in 71% of the eyes, of which 84% had a Schirmer value of <5 mm. The median visual acuity at presentation and that after a median follow-up of 6.9 months were comparable at 0.1 log minimum angle of resolution (logMAR) (P = 0.97). Topical immunosuppression was required in 88% of cases, and with this, improvement in corneal (53%, P = 0.003) and conjunctival staining scores (45%, P = 0.43) was noted. A progressive disease was present in 32% with persistent epithelial defects being the most common complication. Grade 2 conjunctival hyperemia [odds ratio (OR): 2.6; P = 0.01] and Schirmer's value <5 mm (OR: 2.7; P = 0.03) were found to be associated with progressive disease. Conclusion: Aqueous deficient DED is the most common ocular manifestation of chronic ocular GvHD, and the risk of the disease progression is greater in eyes with conjunctival hyperemia and severe aqueous deficiency. Awareness among ophthalmologists of this entity is essential for its timely detection and optimal management.

Pre-Clinical Evaluation of Efficacy and Safety of Human Limbus-Derived Stromal/Mesenchymal Stem Cells with and without Alginate Encapsulation for Future Clinical Applications.

Corneal opacification or scarring is one of the leading causes of blindness worldwide. Human limbus-derived stromal/mesenchymal stem cells (hLMSCs) have the potential of clearing corneal scarring. In the current preclinical studies, we aimed to determine their ability to heal the scarred corneas, in a murine model of corneal scar, and examined their ocular and systemic toxicity after topical administration to rabbit eyes. The hLMSCs were derived from human donor corneas and were cultivated in a clean room facility in compliance with the current good manufacturing practices (cGMP). Before the administration, the hLMSCs were analyzed for their characteristic properties including immunostaining, and were further subjected to sterility and stability analysis. The corneas (right eye) of C57BL/6 mice (n = 56) were stripped of their central epithelium and superficial anterior stroma using a rotary burr (Alger Brush® II). Few mice were left untreated (n = 8), while few (n = 24) were treated immediately with hLMSCs after debridement (prophylaxis group). The rest (n = 24, scar group) were allowed to develop corneal scarring for 2 weeks and then treated with hLMSCs. In both groups, the treatment modalities included encapsulated (En+) and non-encapsulated (En-) hLMSCs and sham (vehicle) treatment. The follow-up (4 weeks) after the treatment or debridement included clinical photography, fluorescein staining, and optical coherence tomography at regular intervals. All the images and scans were analyzed using ImageJ software to assess the changes in corneal haze, scar area, and the reflectivity ratio of the epithelium to the stroma. The scar area and the scar intensity were found to be decreased in the groups that received hLMSCs. The reflectivity of the stroma was found to be normalized to the baseline levels before the debridement in the eyes that were treated with hLMSCs, relative to the untreated. In the safety study, the central corneas of the left eye of 18 New Zealand rabbits were scraped with a needle and then treated with En+ hLMSCs, En- hLMSCs, and the sham (n = 6 each). Rabbits were then followed up for 4 weeks, during which blood and tear samples were collected at regular intervals. These rabbits were then assessed for changes in the quantities of inflammatory markers (TNF-α, IL-6, and IgE) in the sera and tears, changes in the ocular surface observations such as intraocular pressure (IOP), and the hematological and clinical chemistry parameters. Four weeks later, the rabbits were euthanized and examined histopathologically. No significant changes in conjunctival congestion, corneal clarity, or IOP were noticed during the ophthalmic examination. The level of inflammatory molecules (TNF-α and IL-6 TNF-α) and the hematological parameters were similar in all groups without any significant changes. Histological examination of the internal organs and ocular tissues did not reveal any abnormalities. The results of these studies summarize that the En+ and En- hLMSCs are not harmful to the recipient and potentially restore the transparency of debrided or scarred corneas, indicating that hLMSCs can be assessed for clinical use in humans.

Safety and Efficacy of Contact Lenses in Eyes After Simple Limbal Epithelial Transplantation.

PURPOSE: The aim of this study was to evaluate the safety and efficacy of contact lenses (CLs) in eyes after simple limbal epithelial transplantation (SLET) for limbal stem cell deficiency (LSCD). METHODS: This retrospective study included 61 eyes with partial or total LSCD which underwent SLET and were fitted with corneal or scleral rigid gas-permeable CLs. The primary outcome measure was best-corrected visual acuity (BCVA) with CLs. RESULTS: The median age at presentation was 22 years. The most common cause of LSCD was chemical injury [47/61 eyes (77%)]. Twenty-seven eyes (44%) were fitted with corneal rigid gas-permeable lenses, while 34 eyes (56%) were prescribed scleral lenses. The median duration of interval between SLET and CL trial was 10 months (interquartile range: 4-17). The median preoperative BCVA was logarithm of minimal angle of resolution (logMAR) 1.8. This improved to logMAR 1 ( P < 0.001) after SLET and to logMAR 0.6 ( P < 0.001) with CLs. Eyes with chemical injury (logMAR 1 vs. 0.6, P = 0.0001), grade 1 (logMAR 0.8 vs. 0.4, P < 0.0001), and grade 2 (logMAR 0.9 vs. 0.6, P = 0.004) corneal scarring had better improvement in BCVA with CLs. No complications were noted until the last follow-up visit. CONCLUSIONS: CLs, both corneal and scleral lenses, provide significant visual improvement in eyes after SLET with residual corneal scarring. These can be safely prescribed in such eyes without any adverse effects. This option can be considered before offering keratoplasty in these eyes.