Corneal Pannus Research Articles

Corneal epithelial cell markers in congenital aniridia

Congenital aniridia is a rare panocular disease in which almost all structures of the eye are affected. The observed corneal abnormalities are called aniridia‐associated keratopathy (AAK). AAK is characterized by progressive limbal stem cell deficiency (LSCD), epithelial thinning and erosions, corneal ulceration, vascularization, inflammation and pannus formation. Although in some aspects AAK resembles other types of LSCD, through its specific genetic origin, alterations in corneal epithelial cell gene expression differ from other types of corneal diseases. Primary limbal epithelial cells of aniridia subjects lack expression of KRT3 and KRT12 mRNA and protein, and DSG1, ADH7, FABP5, CRABP2, SPINK7 and ALDH1A1 mRNA expression is decreased in these cells. However, miRNA 138‐5p expression is upregulated. This epithelial behaviour can also be mimicked using an siRNA based aniridia primary limbal epithelial cell model.

Specific corneal epithelial cell markers in congenital aniridia

Congenital aniridia is a rare panocular disease in which almost all structures of the eye are affected. The observed corneal abnormalities are called aniridia‐associated keratopathy (AAK). AAK is characterized by progressive limbal stem cell deficiency (LSCD), epithelial thinning and erosions, corneal ulceration, vascularization, inflammation and pannus formation. Although in some aspects AAK resembles other types of LSCD, through its specific genetic origin, alterations in corneal epithelial cell gene expression differ from other types of corneal diseases. Primary limbal epithelial cells of aniridia subjects lack expression of KRT3 and KRT12 mRNA and protein, and DSG1, ADH7, FABP5, CRABP2, SPINK7 and ALDH1A1 mRNA expression is decreased in these cells. However, miRNA 138‐5p expression is upregulated. This epithelial behaviour can also be mimicked using an siRNA based aniridia primary limbal epithelial cell model.

Secondary Data Analysis of Inflammation-Related mRNAs in Conjunctival Impression Cytology Samples of Aniridia Patients.

Aniridia is a rare corneal disease that is often associated with aniridia-associated keratopathy (AAK). In AAK, the conjunctival tissue crosses the limbal border, forming a corneal pannus that extends into the corneal center. With increasing AAK severity, corneal pannus formation, vascularization, and ocular surface inflammation increase. The purpose of this study was to investigate inflammation-related mRNA expression in conjunctival epithelial cells in AAK and its relationship with AAK severity. Using impression cytology, bulbar conjunctival cells were sampled from 20 subjects with congenital aniridia and 20 age-matched and sex-matched healthy control subjects. RNA was extracted, and mRNA analyses were performed using microarray, which was evaluated for inflammatory markers. In the analyzed aniridia subjects, 70 deregulated mRNAs encoding proinflammatory or antiinflammatory cytokines or factors associated with chronic inflammation, including increased IL-1, IL-8, and MIP3A/CCL20 mRNA. The most downregulated mRNA was TIMP3, and the most upregulated mRNA was Protein c-Fos.Of the 70 mRNAs, 14 inflammation-related genes were altered only in the mild AAK forms, whereas only 2 mRNAs were altered only in the severe AAK forms (TLR4 and PPARG). The expression of numerous proinflammatory and antiinflammatory cytokines is deregulated at the ocular surface of aniridia subjects with mild AAK. Thus, early antiinflammatory treatment may prevent or slow down corneal scarring and pannus formation in aniridia subjects.

It Is All About the Angle: A Clinical and Optical Coherence Tomography Comparison of Corneal Ocular Surface Squamous Neoplasia and Corneal Pannus.

The aim of this study was to compare clinical characteristics and high-resolution optical coherence tomography (HR-OCT) findings between corneal ocular surface squamous neoplasia (OSSN) and corneal pannus. Retrospective study of 9 individuals, 3 with lesions histologically confirmed to be OSSN, 3 with lesions histologically confirmed to be pannus, 1 with lesions histologically confirmed to be OSSN followed by pannus, and 2 with long-standing, nonchanging lesions clinically diagnosed as pannus. All individuals presented to the Miami Veterans Affairs Medical Center eye clinic or Bascom Palmer Eye Institute between 2015 and 2023. Clinical characteristics and HR-OCT findings were evaluated and compared. Mean age of the population was 72.8 ± 5.1 years, 100% self-identified as male, 100% as White, and 11.1% as Hispanic. Clinically, all lesions appeared as whitish, opalescent, variably vascularized opacities extending from the limbus. None of the OSSN cases had vessels that extended to the border, whereas 4 cases of pannus (67%) had at least 1 vessel that reached the border. On HR-OCT, epithelial hyperreflectivity was observed in all cases of OSSN and pannus. Epithelial thickening was observed in all cases of OSSN, but in none of the cases of pannus. An important distinction between the 2 groups was the transition between normal and abnormal epithelium. All cases of OSSN had a vertical transition, whereas all cases of pannus had an angled transition. Corneal OSSN and corneal pannus can both present with clinical findings of an opalescent lesion and may have overlapping findings on HR-OCT. Although both entities may show epithelial hyperreflectivity on HR-OCT, OSSN demonstrates an abrupt transition at a vertical, 90 degrees angle perpendicular to the Bowman layer, whereas pannus appears as an angled transition around 45 degrees. Therefore, the angle of transition between normal and abnormal epithelium can be useful in distinguishing between the 2 entities.

Clinical profile of ocular morbidities associated with systemic lupus erythematosus

: Systemic lupus erythematosus (SLE) is an autoimmune disorder involving multiple organs. Ocular involvement occurs in both the active and chronic phases. We have conducted a study to illustrate the ocular inflammations associated with SLE leading to visual morbidity. : This prospective, descriptive, hospital-based study was conducted on 75 patients with SLE over 1 year diagnosed by the physician based on the Systemic Lupus Collaborating Clinics (SLICC) criteria. These patients underwent complete ocular examination. Ancillary investigations were done for patients with clinically suspected ocular pathology.: 69% patients had ocular involvement and keratoconjunctivitis sicca (76%) was the most common.42% patients had multiple ocular tissue pathologies. Corneal involvement was noted in 7 patients (14%), comprising of punctate corneal erosions (10%), pannus (2%) and peripheral corneal ulcer (2%), all during the active phase of the disease. 30% patients had episcleritis, diffuse pattern (73%) being the most common and also the presenting sign of SLE in 9% of patients. Retinopathy was seen in 9 patients (18%), vasculitis in 12% being the most common posterior segment association with SLE. The most common cause of defective vision in these patients was steroid induced or complicated cataract (24%). 42% of patients had associated SLE nephropathy.: Simultaneous and multiple forms of ocular inflammation can occur at any stage of SLE, which could compromise the quality of life of the individual. The onset of uveitis is indicative of active status of the disease. A complete ophthalmic evaluation is an important part of management during the active stage and remission.

Ophthalmic Manifestation in Neurofibromatosis Type 2

Neurofibromatosis type 2 (NF2) is a genetically determined tumor-predisposing syndrome. Ocular manifestations include cataracts, epiretinal membranes, retinal hamartomas, optic disk gliomas, and optic nerve sheath meningiomas. Moreover, optic disk edema, optical atrophy, motility disorders, pupil and lid dysfunction, and neurotrophic keratitis can be observed as indirect signs. An observational study was conducted with the aim to collect clinical data and describe the most frequent NF2 ocular manifestations. Fourteen patients affected by NF2, according to the Manchester criteria, were enrolled. All patients underwent complete ophthalmologic and orthoptic evaluation and a spectral domain optical coherence tomography. Ocular manifestations were present in all patients. The slit lamp evaluation of the anterior segment highlighted cataracts in five patients, keratitis in two patients, corneal leukoma in two patients, and corneal pannus in one patient. Fundus oculi and OCT evaluation identified epiretinal membranes in four patients, vitreoretinal tufts in three patients, optic nerve edema in one patient, and retinal hamartoma in one patient. Moreover, the orthoptic evaluation identified different types of ocular motility disorders in seven patients. This is a descriptive study of a rare disease with poor previous literature. Clinical data are shown, emphasizing the role of NF2-specific ophthalmological and orthoptic findings to help establish an early diagnosis.

Scleral Contact Lens for Steven-Johnson Syndrome

Background: Steven-Johnson syndrome is one of life-threatening skin abnormality. SJS complication involve multiorgan disfunction such as mucosa, ocular, respiration, and digestive tract. Around 30- 50% of SJS patient experience chronic ocular sequel, which concludes progressive symblepharon, margo palpebral keratinization, trichiasis, entropion, corneal pannus, dry eye syndrome, and persistent epithelial cornea defect. Scleral contact lenses has beneficial in managing SJS patient, on both acute and chronic phases. Methods: A 36-year-old female patient with SJS, presented for eye examination due to unpleasant sensation on both of their eyes and unsatisfactory quality of her vision. She presented high myopia, margo palpebral keratinization with trichiasis and distichiasis, symblepharon and hyperemic conjunctiva, wide corneal scar, and ocular neovascularization. A diagnostic trial set was used in the fitting process, and she was assessed according to standardized fitting methodology. Visual acuity, corneal topography, biometry, and ocular aberrations were evaluated. The follow-up period was 12 months. Results: The best corrected visual acuity was 20/60 with correction lens S – 1.00 D for the left eye (LE) and 20/25 cannot be corrected with correction lens for the right eye (RE). After corneal contact lens fitting, visual acuity was improved to 20/20 and 20/25 for the RE and LE, respectively. The patient wore these contact lenses an average 8 hours a day. The patient’s dry eye complaint was significantly decrease with more comfortable ocular sensation Conclusion: The present case report describes how the patient had scleral contact lens fitted successfully for management of SJS ocular complication. They provided optimal visual quality and restore the patient’s comfort.

Adverse Reactions from Topical Ophthalmic Anesthetic Abuse.

To assess the adverse drug reactions (ADR) of tetracaine among patients referred to an eye emergency department in the southeast of Iran. In this case series study, we assessed 31 eyes of 24 patients who were referred due to adverse effects of ocular anesthetics during2017-2020. We collected the data, including age, sex, job, how the medicine was obtained, symptoms, examination results, and ADR. Of 24 patients, 22 (91.7%) were male. The mean (standard deviation) age of the patients was 32.6 (1.9) years. Twenty-two patients obtained the medicines without a prescription and a general practitioner prescribed the medicine to two patients. In the first interview, the most common symptoms were: photophobia, reduced vision, ocular pain, and redness. The main signs of persistent epithelial defect, patchy or diffuse corneal stromal infiltration, ring infiltration, and Descemet's folds were noticed in the examinations. Finally, 51.6% (n =16) of the eyes had decreased vision, 45.2% (n =14) had corneal opacity, 16.1% (n = 5) had elevated intraocular pressure that needed long-term anti-glaucoma therapy, and 6.5% (n = 2) had corneal pannus. Corneal perforation and phthisis bulbi were the final results in one eye. ADR related to the use of ophthalmic topical anesthetics could cause sight-threatening severe morbidities. It seems that some general practitioners are not careful regarding the prescription of these kinds of medicine. Moreover, the over-the-counter availability of tetracaine eye drops should be managed.

Assessing the Prevalence of Trachoma: Lessons from Community Screening with Laboratory Testing in Australia’s Torres Strait Islands

ABSTRACT Purpose We undertook a screening program between 2016 and 2019 to determine if trachoma was endemic in the Torres Strait Islands of Queensland, Australia. Methods Eleven screening surveys assessing trachoma prevalence were undertaken in seven communities using the World Health Organization (WHO) simplified grading tool. Additionally, an ophthalmologist performed a detailed clinical assessment including examination for Herbert’s pits and corneal pannus and, where clinically indicated, collection of conjunctival specimens to investigate the presence of Chlamydia trachomatis nucleic acid. Results Prevalence of trachomatous inflammation—follicular (TF) in children aged 5–9 years for the aggregated first survey across all communities was 6% (17/284). No child had trachomatous inflammation—intense, trachomatous scarring, corneal pannus, or Herbert’s pits. Of the 66 times any child was tested for C. trachomatis by polymerase chain reaction (PCR), the result was negative. No cicatricial trachoma was identified amongst the adults (n = 186) who were opportunistically offered examination. Conclusion Whilst TF was present, the lack of intense inflammatory thickening in any child examined, the lack of end-stage trachomatous disease, and the lack of ocular C. trachomatis detection by PCR indicate trachoma is not endemic in the Torres Strait Islands, and no ongoing public health intervention is required. These findings add to a growing body of evidence suggesting that use of the WHO simplified grading tool alone in the peri-elimination setting may overestimate the community burden of trachoma.

The Traditional Uses, Phytochemistry, Pharmacokinetics, Pharmacology, Toxicity, and Applications of Corydalis saxicola Bunting: A Review.

Background: Corydalis saxicola Bunting (CSB) is a perennial herb belonging to genus Corydalis (Papaveraceae), called “Yan-huang-lian” in the Chinese folk. Traditionally, it is used to treat acute conjunctivitis, corneal pannus, acute abdominal pain, hemorrhoidal bleeding, haematochezia, swelling, hepatitis, cirrhosis and liver cancer based on traditional Chinese medicine (TCM) concepts. Purpose: This review aims to summarize and analyze the pharmacokinetics, pharmacological and toxicological properties of CSB and its extracts; to highlight the relevance of modern pharmacology to traditional pharmacology; also to assess its therapeutic potential. Methods: CSB related literatures were searched and screened from databases including PubMed, Web of Science and CNKI. The selected literatures provided reliable source identification evidences. Results: In traditional medicine concepts, CSB has the effects of clearing away heat and detoxification, eliminating dampness, relieving pain, and stopping bleeding. Its modern pharmacology includes hepatoprotective, anticancer, anti-inflammatory, analgesic, antibacterial, anti-oxidative effects. Further, some pharmacological effects support its traditional uses. The CSB total alkaloids (CSBTA) are the main constituents isolated from this plant, and they exert the major of the pharmacological effects. Toxicological studies have shown that the toxicity of CSBTA is mild and reversible in rodents and beagle dogs. Conclusion: Although the present study summarizes the botany, phytochemistry, pharmacokinetics, pharmacology, toxicity, and applications of this plant, it is still necessary to systemically evaluate the chemistry, safety and parameters related to drug metabolism of the extracts or compounds from this plant before or in clinical trials in the future. Meanwhile, cancers and inflammatory-related diseases may be new research directions of this ethnomedicine.

Clinical and genetic aspects of a child with monilethrix and visual rehabilitation

Monilethrix is a rare genodermatosis, presented to us with predominant ocular manifestations. The affected proband was typically characterized by severe photophobia, defective vision, and hypotrichosis with brittle and stubby hair. Here, we report a rare case of a 9-year-old male child who has been affected by monilethrix with severe ocular complications including blepharitis, madarosis, and corneal pannus with lamellar cataract. The child has undergone cataract surgery and visual rehabilitation was provided with low-vision devices.

Surgical Management of Unilateral Partial Limbal Stem Cell Deficiency: Conjunctival Autografts versus Simple Limbal Epithelial Transplantation.

PurposeTo evaluate the clinical outcomes of conjunctival autograft (CAG) versus simple limbal epithelial transplant (SLET) for management of unilateral partial limbal stem cell deficiency (LSCD).MethodsThis retrospective, comparative, interventional case series evaluated 30 eyes of 30 patients with unilateral partial LSCD. After corneal pannus dissection, 17 patients underwent CAG where graft was harvested from the ipsilateral or contralateral eye, while 13 patients underwent SLET where limbal biopsy was harvested from the contralateral eye. The primary outcome measure was anatomical success in the form of restoration of a completely epithelised, stable, and avascular corneal surface at last follow-up.ResultsBoth groups were comparable in terms of age at time of surgery, preoperative best-corrected visual acuity, median duration since injury, number of clock hours of limbus involved, and number of previous surgeries performed. The most common etiology for LSCD was chemical burns in both groups. The median duration of post-operative follow-up was 5.6 months [interquartile range [(IQR): 3.6–15.1] in the CAG group versus 6.2 months (IQR: 4.5–12.2) in the SLET group (p=0.75)]. The anatomical success rates were 86.5 ± 8.9% in the CAG group and 28.3 ± 13.7% in the SLET group at final follow-up visit (p = 0.025). Most failures in both groups occurred within the first 8 months after surgery.ConclusionFor eyes with unilateral partial LSCD secondary to chemical burns, CAG is a safe and effective method for restoring the corneal epithelium. Limbal transplantation may not be necessary for the treatment of partial LSCD.

On the issue of the treatment of trachomatous pannus

Pannous inflammation of the cornea, as one of the earliest and most dangerous complications of trachoma, in its severity, course and significance for the patient's vision is not always in one way or another correlated with the strength or duration of the trachomatous process in the mucus of the eye. If in some cases the pannus disappears soon and without a trace, so to speak, by itself or solely under the influence of appropriate treatment of the conjunctiva of the arches and eyelids alone, then in other cases, most often encountered in the practice of an eye doctor, despite the most vigorous therapy of trachoma, the pannus not only does not show a tendency to reverse development, but, gradually or by leaps, from the initial, lighter degrees (pannus incipiens, R. levis) to more severe and persistent forms (R. crassus, R. sarcomatosus), often ulcerating at the same time and ending in cicatricial degeneration of the cornea (p membranaceus), leads the trachomaticus to complete inactivity for his entire subsequent existence. And since, in heavily overworked areas, an eye doctor has to deal with the most severe forms of this disease and its most diverse complications, of which corneal pannus accounts for more than a third of all of them, and the consequences, it is natural that the question of not mediocre treatment of pannus becomes urgent and requires practical measures of a special nature.

Efficacy of Topical Tacrolimus 0.05% Suspension in Steroid-Resistant and Steroid-Dependent Vernal Keratoconjunctivitis

Objective: The purpose of this study was to investigate the safety and effectiveness of topical tacrolimus 0.05% suspension in the management of prolonged steroid-dependent and -resistant vernal keratoconjunctivitis (VKC). Materials and methods: The present interventional prospective case series were conducted on the research units suffering from refractory VKC between 2017, April and 2020, December. Despite routine drug treatment, consisting of topical steroids (steroid-resistant group), all subjects exhibited active symptomatic illness or were dependent on topical steroids (steroid-dependent group). After discontinuation of all medications for at least 1 week, the patients received eye drop (topical tacrolimus 0.05%) minimally for six months. Objective and subjective signs and symptoms were examined for alterations after one week, and one and six months of treatment. Analyses were continued for probable systemic and ocular adverse effects. Results: The study included 28 eyes of 14 participants (including 4 females and 10 males), with the mean age of 22 ± 8 years (between 11 and 38 years), and the mean VKC duration of 12 ± 6 years (between 5 and 23 years), as well as follow up period of 10±2 months (between 6 and 12 months). The results showed an improvement (P<0.001) in the symptoms such as mucus discharge, foreign body sensation, photosensitivity, redness, burning and itching. The initial sign was conjunctival hyperemia, which improved one week after treatment. Other objective signs including, conjunctival and limbal papillary hypertrophy, corneal pannus and corneal punctate epithelial erosions improved at least one month after treatment. No changes were observed in corneal opacity during follow-up (p> 0.05). There were no systemic or ocular adverse effects. Conclusion: This is the first time that tacrolimus suspension drops 0.05%, are used in these cases. Topical tacrolimus 0.05% was shown to be an effectiveness and safe agent to treat the refractory VKC. This drug is recommended to be prescribed prior to the appearance of side effects such as corneal opacity, irreversible deficiency in limbal stem cell, and steroid side effects. Keywords: Vernal keratoconjunctivitis, Tacrolimus eye drop, Refractory

Conjunctival Scarring, Corneal Pannus, and Herbert's Pits in Adolescent Children in Trachoma-endemic Populations of the Solomon Islands and Vanuatu.

BackgroundIn the Solomon Islands and Vanuatu, the sign trachomatous inflammation—follicular (TF) is common, but ocular infection with Chlamydia trachomatis is not. It is therefore debatable whether azithromycin mass drug administration (MDA), the recommended antibiotic treatment strategy for trachoma’s elimination as a public health problem, is necessary in this setting. We set out to estimate what proportion of adolescents were at risk of progression of trachomatous scarring.MethodsA cross-sectional survey was undertaken of all children aged 10–14 years resident in communities identified as high-TF clusters during previous population-based mapping. Graders examined children for clinical evidence of trachomatous scarring, pannus, and Herbert’s pits (HPs) or limbal follicles in both eyes. A dried blood spot was collected from each child and tested for antibodies to C. trachomatis.ResultsA total of 492 children in 24 villages of the Solomon Islands and Vanuatu were examined. In total, 35/492 (7%) of children had limbal signs (pannus and/or HPs) plus any conjunctival scarring. And 9/492 (2%) had limbal signs and moderate or severe conjunctival scarring; 22% of children were anti-Pgp3 seropositive.ConclusionsFew adolescents here are at risk of future complications from trachoma, supporting the conclusion that further antibiotic MDA is not currently required for trachoma elimination purposes in these settings.

Limbal Stem Cell Deficiency After Glaucoma Surgery.

To characterize the clinical presentation of limbal stem cell deficiency (LSCD) associated with glaucoma surgeries. This is a retrospective cross-sectional study of patients with LSCD and glaucoma who presented to the Stein Eye Institute at the University of California, Los Angeles, between 2009 and 2018. Patients who underwent trabeculectomy and/or aqueous shunt surgery were included. The severity of LSCD was staged using global consensus guidelines and a clinical scoring system, and basal epithelial cell density was measured by in vivo confocal microscopy. Anatomic locations of glaucoma and non-glaucoma surgeries, locations of LSCD, and severity of LSCD were compared. Fifty-one eyes of 41 patients with LSCD associated with glaucoma surgery were included in this study. LSCD in these patients uniquely featured sectoral replacement of corneal epithelium by conjunctival epithelium, without corneal neovascularization or pannus. The sites of glaucoma surgery strongly correlated with the locations of LSCD (P = 0.002). There was a trend toward increased severity of LSCD in eyes with 2 or more glaucoma surgeries as compared to eyes with 1 glaucoma surgery, although the difference did not reach statistical significance (P = 0.3). Use of topical glaucoma medications correlated with LSCD severity, while the impact of antimetabolites did not reach statistical significance. The location of glaucoma drainage surgery is correlated with the location of LSCD. LSCD associated with glaucoma surgery has clinical features distinct from LSCD resulting from other etiologies. Further study is required to delineate the full impact of glaucoma surgery on limbal stem cell function and survival.

Angiogenesis modulatory factors in subjects with chronic ocular complications of Sulfur Mustard exposure: A case-control study

BackgroundChronic ocular complications of Sulfur Mustard (SM) exposure leads to severe ocular morbidity during time. The aim of this study was to compare serum levels of Interleukin 17 (IL-17), IL-12, vascular endothelial growth factor (VEGF)-C, VEGF-D and nitric oxide (NO) in SM-exposed patients versus the control group and to measure tear concentration of VEGF-C only in the SM-exposed group. MethodsIn this prospective case control, 128 SM-exposed patients and 31 healthy control subjects were included. In the case group ocular manifestations were classified to three subgroups of mild (19 cases), moderate (31 cases) and severe (78 cases) forms of disease. Serum levels of IL-17, IL-12, NO, VEGF-C and VEGF-D, in all subjects and tear concentration of VEGF-C in SM-exposed group was evaluated. ResultsAll subjects were male and mean ± standard deviation (SD) of age in the case and control groups were 44.9 ± 8.8 and 40.9 ± 10.1 years, respectively. Except for significantly lower serum level of IL-17 (p < 0.001) and NO (p = 0.003), other values were not significantly different. The tear concentration of VEGF-C and serum level of IL-12 were not different between subgroups in the SM-exposed group, yet were significantly lower among those with abnormally dilated and tortuous conjunctival vessels and corneal pannus, respectively (p = 0.01, p = 0.015). ConclusionsExposure to SM significantly reduced serum level of IL-17 and NO in the delayed phase, yet did not influence VEGF-C; VEGF-D or IL-12.

Management of corneal pannus caused by late stage complication of honey bee sting

Management of corneal pannus caused by late stage complication of honey bee sting

Ectodysplasin A regulates epithelial barrier function through sonic hedgehog signalling pathway

Ectodysplasin A (Eda), a member of the tumour necrosis factor superfamily, plays an important role in ectodermal organ development. An EDA mutation underlies the most common of ectodermal dysplasias, that is X‐linked hypohidrotic ectodermal dysplasia (XLHED) in humans. Even though it lacks a developmental function, the role of Eda during the postnatal stage remains elusive. In this study, we found tight junctional proteins ZO‐1 and claudin‐1 expression is largely reduced in epidermal, corneal and lung epithelia in Eda mutant Tabby mice at different postnatal ages. These declines are associated with tail ulceration, corneal pannus formation and lung infection. Furthermore, topical application of recombinant Eda protein markedly mitigated corneal barrier dysfunction. Using cultures of a human corneal epithelial cell line and Tabby mouse skin tissue explants, Eda up‐regulated expression of ZO‐1 and claudin‐1 through activation of the sonic hedgehog signalling pathway. We conclude that EDA gene expression contributes to the maintenance of epithelial barrier function. Such insight may help efforts to identify novel strategies for improving management of XLHED disease manifestations in a clinical setting.

Pilot Study of a “Large-Eye,” Surgically Induced Dry Eye Rabbit Model by Selective Removal of the Harderian, Lacrimal, and Meibomian Glands

Background/Aims: Establish a reliable rabbit dry eye (DE) model. Methods: An interventional cohort study surgically removing glands contributing to the tear film. Eight rabbits were studied after removal of left lacrimal, Harderian, or both glands. Additional rabbits had Meibomian glands in the left eye thermally obstructed. All were followed for 10 weeks with phenol red thread (PRT) and slit-lamp examination with 2% fluorescein. We assessed corneal sensitivity using a Cochet-Bonnet esthesiometer. Outcome measures were severity/duration of reduced PRT, punctate epithelial erosions (PEE), and histologic evidence of corneal pannus. Results: Fluorescein staining demonstrated signs of dryness including PEE in all of the interventional eyes. The subjective measurement of epithelial erosions correlated with decreased tear production. PRT measurements in the control eyes averaged 31.54 mm (±1.83) and 22.71 mm (±1.60) in the eight left eyes, without loss of corneal sensitivity. Conclusions: Surgical removal of either the Harderian or lacrimal gland results in statistically significant decreases in tear volume and the development of severe DE. Removal of both glands results in the occurrence of a DE of comparable severity/duration to removal of either the lacrimal or Harderian gland alone. Meibomian gland obstruction contributes less to the DE model.