Possible mechanisms for the loss of goblet cells in mucin-deficient disorders

Clinical ocular surface characteristics and expression of MUC5AC in diabetics: a population-based study

OBJECTIVES

To investigate the clinical characteristics and the expression of mucin 5AC (MUC5AC) in in diabetic and non-diabetic subjects with or without dry eye disease.

METHODS

A total of 399 participants (796 eyes) aged 50-80 years were enrolled in this study. Participants were divided into 4 groups: non-diabetic without dry eye group (normal group), non-diabetic with dry eye group, diabetic without dry eye group and diabetic with dry eye group. Demographic information, fasting plasma glucose (FBG), and glycated haemoglobin A1C (HbA1C) data were collected. Additionally, ocular surface disease index (OSDI) questionnaire, signs of dry eye, tear osmolarity, and meibomian glands were evaluated. Tear MUC5AC expression and conjunctival goblet cells density (GCD) were tested.

RESULTS

Compared with non-diabetic with dry eye group, diabetic with dry eye group showed significantly lower tear film osmolarity (TFO), but higher corneal fluorescein and conjunctival lissamine green staining scores. In comparison with diabetic without dry eye group, diabetic with dry eye group showed significantly higher TFO, corneal fluorescein and conjunctival lissamine green staining scorers. The MUC5AC concentration and GCD of diabetic with dry eye group was significantly lower than those of the non-diabetic with dry eye group. Diabetic subjects with higher HbA1c levels (≥7.8%) showed higher TFO and shorter fluorescein tear break time.

CONCLUSION

Diabetics with dry eye exhibited notably higher corneal fluorescein and conjunctival lissamine green staining scores. Conjunctival goblet cells and MUC5AC were significantly reduced in diabetics. Higher TFO was associated with the duration of diabetes and HbA1c levels.

Single-cell landscape reveals the epithelial cell-centric pro-inflammatory immune microenvironment in dry eye development

Dry eye disease (DED) is a prevalent chronic eye disease characterized by an aberrant inflammatory response in ocular surface mucosa. The immunological alterations underlying DED remain largely unknown. In this study, we employed single-cell transcriptome sequencing of conjunctival tissue from environment-induced DED mice to investigate multicellular ecosystem and functional changes at different DED stages. Our results revealed an epithelial subtype with fibroblastic characteristics and pro-inflammatory effects emerging in the acute phase of DED. We also found that T helper (Th)1, Th17, and regulatory T cells (Treg) were the dominant clusters of differentiation (CD)4+ T-cell types involved in regulating immune responses and identified three distinct macrophage subtypes, with the CD72+CD11c+ subtype enhancing chronic inflammation. Furthermore, bulk transcriptome analysis of video display terminal-induced DED consistently suggested the presence of the pro-inflammatory epithelial subtype in human conjunctiva. Our findings have uncovered a DED-associated pro-inflammatory microenvironment in the conjunctiva, centered around epithelial cells, involving interactions with macrophages and CD4+ T cells, which deepens our understanding of ocular surface mucosal immune responses during DED progression.

The impact of prolonged face mask use on ocular surface health during COVID-19 pandemic: a clinical, and conjunctiva impression cytology study

PURPOSE

To investigate the relationship between prolonged face mask use and ocular surface health utilizing conjunctival impression cytology, the Schirmer test, the tear break-up time (TBUT) test, and the ocular surface disease index (OSDI) questionnaire.

METHODS

In this cross-sectional prospective study, individuals who used face masks for at least eight hours per day for at least six months were compared to healthy volunteers who used face masks for no more than one hour per day. Each participant completed an OSDI questionnaire. The Schirmer test (under anesthesia), the TBUT test, and conjunctiva impression cytology analysis according to the Nelson classification method were performed on each participant.

RESULTS

This study included 102 (49 male, 53 female) face mask users with an average age of 33.29 ± 7.71 years and 110 (60 male, 50 female) healthy controls with an average age of 32.96 ± 7.10 years (p = 0.746). The total OSDI score was significantly higher in face mask users than the control group (25.18 ± 3.54 vs 9.46 ± 2.13, p < 0.001). The mean Schirmer test value and TBUT were significantly lower in the study group than the control group (p < 0.001, p < 0.001). There was a statistically significant difference between the two groups in total score and stage of the Nelson classification system (p < 0.001, and p = 0.024, respectively). All conjunctiva impression cytology assessments, including cellularity, cell-cell contact, nucleus/cytoplasma ratio, goblet cell amount, and metaplasia, revealed statistically significant deterioration in the study group compared to the control group (p < 0.001, p = 0.025, p < 0.001, p < 0.001, and p < 0.001, respectively).

CONCLUSION

The prolonged use of face masks leads to dry eyes. The findings of conjunctiva impression cytology indicate the role of inflammation in the pathogenesis of mask associated dry eye.

Ocular Surface in Patients With Obstructive Sleep Apnea Syndrome: Evaluation of Clinical Parameters and Impression Cytology

PURPOSE

To evaluate the effect of obstructive sleep apnea syndrome (OSAS) on the ocular surface and conjunctival cytology and the relationship between the findings and disease severity.

METHODS

One hundred six eyes of 106 patients (77 patients with OSAS and 29 control subjects) were included in the study. Twenty-three patients with an apnea-hypopnea index (AHI) of 5 to 15 were classified as mild OSAS (group 1), 27 patients with an AHI of 15 to 30 were classified as moderate OSAS (group 2), and 27 patients with an AHI≥30 were classified as severe OSAS (group 3). The following tests were used to evaluate the ocular surface: tear break-up time (TBUT), Schirmer I test, ocular surface disease index (OSDI), and conjunctival impression cytology (CIC). The results obtained from the tests were analyzed and compared between the groups.

RESULTS

The mean value of the Schirmer I test was 15.03±10.16 (1-35) mm in the control group, whereas it was found as 13.39±8.80 (3-35) mm, 9.85±7.81 (1-30) mm, and 9.41±7.53 (2-35) mm in the mild, moderate, and severe OSAS groups, respectively, and the difference between the groups was significant ( P =0.002). Although the mean TBUT score was 9.83±5.03 (3-23) seconds in the control group, it was 11.04±6.22 (3-20), 6.26±3.48 (1-16), and 5.44±3.09 (1-10) in the mild, moderate, and severe OSAS groups, respectively, and the difference between the groups was significant ( P <0.001). Although the mean OSDI score was 12.76±14.84 (range, 0-41.65) in the control group, it was 11.52±12.95 (range, 0-44.40), 25.06±19.45 (range, 0-75), and 20.31±19.87 (range, 0-77.70) in the mild, moderate, and severe OSAS groups, respectively, and the difference between the groups was significant ( P =0.015). Although the mean CIC stage was 0.47±0.60 (0-2) in the control group, it was 0.89±0.74 (0-2), 1.52±0.75 (0-3), and 1.83±0.69 (1-3) in the mild, moderate, and severe OSAS groups, respectively, and the difference between groups was significant ( P <0.001).

CONCLUSION

In addition to decreased tear production and TBUT, cytological changes including squamous metaplasia were detected between patients with OSAS and the control group.

Analytical Study of Ocular Surface Changes in Patients of Chronic Kidney Disease undergoing Hemodialysis and Peritoneal Dialysis

Objectives The idiopathic group is a significant cause of chronic kidney disease (CKD) in developing countries. Literature available on ocular surface changes has predominantly been reported in patients undergoing hemodialysis. Little is known about the changes in patients undergoing peritoneal dialysis. The present study aimed to identify ocular surface changes in an idiopathic group of CKD undergoing dialysis.

Aim To compare tear film disorders and the severity of ocular surface changes (goblet cell density, squamous metaplasia, and corneoconjunctival calcification) in patients of idiopathic etiology with CKD undergoing hemodialysis and peritoneal dialysis. This is an analytical study.

Materials and Methods Asymptomatic adult patients of idiopathic CKD, on treatment with dialysis underwent comprehensive ophthalmic examination, including best-corrected visual acuity, slit-lamp examination, and a dilated fundus examination. Dry eye assessment was done by ocular surface staining score, Schirmer test, and tear breakup time (TBUT). Conjunctival impression cytology was studied to assess changes on ocular surface. Chest X-rays for aortic calcification were reviewed and data analyzed.

Results Both eyes of 76 patients of hemodialysis and 32 patients of peritoneal dialysis were studied. Ocular surface staining (OSS) scores were low. Impression cytology showed a drop in goblet cell density, presence of squamous metaplasia, and conjunctival keratinization significantly more in the hemodialysis group. No correlation was seen between the presence of conjunctival calcification and aortic calcification.

Conclusion The hemodialysis group had mild subclinical dry eye but keratinization of conjunctiva was seen. Similarly, advanced squamous metaplasia was seen in the peritoneal dialysis group. These changes were positively correlated to decrease in goblet cell density.

Mesenchymal Stromal Cell-Based Therapy for Dry Eye: Current Status and Future Perspectives

Dry eye is one of the most common chronic diseases in ophthalmology. It affects quality of life and has become a public health problem that cannot be ignored. The current treatment methods mainly include artificial tear replacement therapy, anti-inflammatory therapy, and local immunosuppressive therapy. These treatments are mainly limited to improvement of ocular surface discomfort and other symptoms. In recent years, regenerative medicine has developed rapidly, and ophthalmologists are working on new methods to treat dry eye. Mesenchymal stromal cells (MSCs) have anti-inflammatory, tissue repair, and immune regulatory effects, and have become a promising tool for the treatment of dry eye. These effects can also be produced by MSC-derived exosomes (MSC-Exos). As a cell-free therapy, MSC-Exos are hypoimmunogenic, serve more stable entities, and compared with MSCs, reduce the safety risks associated with the injection of live cells. This article reviews current knowledge about MSCs and MSC-Exos, and highlights the latest progress and future prospects of MSC-based therapy in dry eye treatment.

Changes in Tear Meniscus Analysis of Children Who Have Type 1 Diabetes Mellitus, With and Without Vitamin D Deficiency

PURPOSE

The aim of this study was to quantitatively evaluate dry eye test parameters of pediatric patients with and without vitamin D deficiency (VDD) in type 1 diabetes mellitus.

METHODS

In this prospective cross-sectional study, the Ocular Surface Disease Index, Schirmer test, tear film breakup time, corneal staining score, and anterior segment optical coherence tomography were used to determine the dry eye test parameters of pediatric patients with type 1 diabetes mellitus (T1-DMPs) (group 1) and a healthy pediatric control group (group 2). Group 1 was divided into 2 subgroups based on their vitamin D status: group 1a, who had a VDD, and group 1b, who had vitamin D levels that were within the normal range.

RESULTS

This study compared 90 eyes of 90 pediatric T1-DMPs with 80 eyes of 80 healthy controls. The demographic characteristics of the groups were similar ( P > 0.05). The tear film breakup time, Schirmer test, corneal staining score, and values of the tear meniscus height and area were observed to have been lower in the patients in group 1a than the healthy pediatric control group, at P < 0.001. The same parameters were statistically significantly lower in the patients in group 1a when compared with group 1b ( P < 0.05 for both).

CONCLUSIONS

The tear measurements of the pediatric T1-DMPs were lower than those in the healthy pediatric control group. The accompanying VDD made this situation more pronounced.

Dietary mannan oligosaccharides strengthens intestinal immune barrier function via multipath cooperation during Aeromonas Hydrophila infection in grass carp (Ctenopharyngodon Idella)

In recent years, mannose oligosaccharide (MOS) as a functional additive is widely used in aquaculture, to enhance fish immunity. An evaluation of the effect of dietary MOS supplementation on the immune barrier function and related signaling molecules mechanism of grass carp (Ctenopharyngodon idella) was undertaken in the present study. Six diets with graded amounts of MOS supplementation (0, 200, 400, 600, 800, and 1000 mg/kg) were fed to 540 grass carp over 60 days. To examine the immune response and potential mechanisms of MOS supplementation on the intestine, a challenge test was conducted using injections of Aeromonas hydrophila for 14 days. Results of the study on the optimal supplementation with MOS were found as follows (1) MOS enhances immunity partly related to increasing antibacterial substances content and antimicrobial peptides expression; (2) MOS attenuates inflammatory response partly related to regulating the dynamic balance of intestinal inflammatory cytokines; (3) MOS regulates immune barrier function may partly be related to modulating TLRs/MyD88/NFκB and TOR/S6K1/4EBP signalling pathways. Finally, the current study concluded that MOS supplementation could improve fish intestinal immune barrier function under Aeromonas hydrophila infected conditions.

Dry eye disease in patients with type II diabetes mellitus: A retrospective, population-based cohort study in Taiwan

Purpose

To investigate the risk and protective factors of dry eye disease (DED) in patients with type II diabetes mellitus (DM).

Design

A retrospective cohort study using Chang- Gung research database collecting data from 2005 to 2020.

Methods

Patients with type II DM were included, and those with previous ocular diseases were excluded. Ten thousand twenty nine developed DED (DED group), and 142,491 didn't (non-DED group). The possible risk and protective factors were compared and analyzed using the logistic regression model.

Results

A majority of the DED group were female with significantly higher initial and average glycated hemoglobin levels, and higher incidence of diabetic neuropathy and retinopathy. In conditional logistic regression model, advanced age was a risk factor. After adjusting for sex, age, and DM duration; average glycated hemoglobin level, diabetic neuropathy, retinopathy, and nephropathy with eGFR 30 ~ 59 and intravitreal injection, vitrectomy, pan-retinal photocoagulation, and cataract surgery were contributing factors of DED. Considering antihyperglycemic agents, DPP4 inhibitor, SGLT2 inhibitor, GLP-1 agonist, and insulin monotherapy and dual medications combining any two of the aforementioned agents were protective factors against DED compared with metformin alone. In the monotherapy group, SLGT2 inhibitor had the lowest odds ratio, followed by GLP1 agonist, DPP4 inhibitor, and insulin.

Conclusions

DED in patients with DM is associated with female sex, advanced age, poor diabetic control, microvascular complications and receiving ocular procedures. GLP-1 agonist, SGLT-2 inhibitor, DPP4 inhibitor, and insulin are superior to metformin alone in preventing DM-related DED. A prospective randomized control trial is warranted to clarify our results.

Moxifloxacin-Based Extended Depth-of-Field Fluorescence Microscopy for Real-Time Conjunctival Goblet Cell Examination

Conjunctival goblet cells (CGCs) are mucin-secreting cells in the eye and play essential roles for ocular surface homeostasis. Since various ocular surface pathologies are related to CGC dysfunction, CGC examination is important for the evaluation of ocular surface conditions. Recently we introduced moxifloxacin-based fluorescence microscopy (MBFM) for non-invasive CGC imaging. However, the imaging speed was up to 1 frame per second (fps) and needed to be improved for clinical applications. In this study, we developed a high-speed moxifloxacin-based, extended depth-of-field (EDOF) microscopy system that operates at a maximum imaging speed of 15 fps. The system used a deformable mirror for the high-speed axial sweeping of focal plane during single-frame acquisitions. The acquired images contained both in-focus and out-of-focus information, and deconvolution was used to filter the in-focus information. The system had a DOF of 800 [Formula: see text], field-of-view of 1.2 mm ×1.2 mm, and resolution of [Formula: see text]. Its performance was demonstrated by real-time, breathing-motion-insensitive CGC imaging of mouse and rabbit models, in vivo. High-speed EDOF microscopy has potentials for non-invasive, real-time CGC examinations of human subjects.

Cytokeratin profile and keratinocyte gene expression in keratinized lid margins of patients with chronic Stevens-Johnson syndrome

PURPOSE

To study the cytokeratin profile and keratinization-related gene expression in keratinized lid margins of chronic Stevens-Johnson syndrome (SJS) patients.

METHODS

Posterior eyelid margins from 24 chronic SJS patients undergoing mucous membrane grafting and six healthy margins (orbital exenteration, fresh body donors) were studied using immunofluorescence staining (CK10, CK1, filaggrin, transglutaminase 1 (TGM1), (CK19, MUC5AC)) and quantitative PCR (keratinization-related genes-HBEGF, KGF, EGF, TGFα, TGFβ, and TNFα). The staining and gene expression were studied separately in the lid margin epidermis (LME) and lid margin conjunctiva (LMC).

RESULTS

The expression of CK 1/10, filaggrin, and TGM1 in the LMC was similar to the LME in SJS patients. CK19 was expressed only in the basal epithelial layer of the LMC with loss of MUC5AC expression. Increased expression of KGF (p ≤ 0.056), TNFα (p ≤ 0.02), and TGFα (p ≤ 0.01) was observed in the LME of SJS patients compared to normal LME. LMC of SJS patients showed an increased expression of HBEGF (p ≤ 0.002), EGF (p ≤ 0.0002), KGF (p ≤ 0.02), TNFα (p ≤ 0.04), TGFα (p ≤ 0.003), and TGFβ (p ≤ 0.001) compared to normal LMC. Significant differences were observed in the expression of these genes between LME and LMC of SJS patients. These genes were validated using String analysis, which revealed the positive regulation of keratinization.

CONCLUSION

In lid margins of SJS, there is an increased expression of keratinization-related genes compared to the normal lid margin. Keratinized LMC shares similar cytokeratin profile and keratinization gene expression as seen in cutaneous epithelium of SJS patients, indicating the possibility of the cutaneous epithelium as a source for keratinized LMC.

Assessment of Tear Film Anomalies in Childhood Obesity

PURPOSE

To determine if childhood obesity has an effect on the ocular surface and tear film of children who are afflicted.

METHODS

Patients who had childhood obesity, 85 eyes, and patients who were healthy, 75 eyes, were enrolled in this prospective and comparative study. The tear film breakup time (TF-BUT), tear meniscus area and height (TMA and TMH) values, Schirmer test scores, and ocular surface disease index (OSDI) scores were obtained for all participants.

RESULTS

The TMH, TMA, TF-BUT, and Schirmer test results were statistically significantly lower in the obesity group (p < 0.001 for all). The children with obesity and insulin resistance had lower TMH, TMA, TF-BUT, and Schirmer test results when compared to the children without insulin resistance (p < 0.05 for all). The body mass index was found to be correlated with the TMH, TMA, TF-BUT, and Schirmer test results (p < 0.001 for all).

CONCLUSION

Children with obesity had lower TMA, TMH, TF-BUT, and Schirmer test results than healthy subjects. When insulin resistance was added to obesity, these values were even lower.

Tear Function Alterations and Conjunctival Impression Cytology Findings in Patients With Gout

OBJECTIVES

The aim of this study was to evaluate the tear functions and conjunctival impression cytology (CIC) findings of patients with gout and compare them with healthy controls.

METHODS

Thirty-four patients with gout (group 1) and 32 age-matched and gender-matched healthy individuals (group 2) were included in this cross-sectional study. Schirmer 1 test, tear breakup time (TBUT), Ocular Surface Disease Index (OSDI) score, and CIC grade were evaluated and compared between the groups.

RESULTS

There was no significant difference between the groups in gender and age (P=0.923 and P=0.078, respectively). The mean of Schirmer 1 test result was significantly lower in group 1 (9.74±6.03 mm) than that in group 2 (17.16±9.33 mm) (P<0.001). The TBUT was also significantly lower in group 1 (7.00±2.09 seconds) than that in group 2 (12.75±5.25 seconds) (P<0.001). The OSDI score (20.04±12.92) was significantly higher in group 1 than that in group 2 (6.19±10.07) (P<0.001). Although 10 patients (29.4%) in group 1 had the CIC grade of 2 to 3, none of the controls had CIC grade 2 to 3. The mean CIC grade in group 1 (1.15±0.89) was significantly higher than that in group 2 (0.47±0.51) (P<0.001).

CONCLUSIONS

The results of this study suggest that ocular surface alterations assessed by CIC and tear function abnormalities are more common in patients with gout.

Conjunctival impression cytology and tear film parameters in patients with multiple sclerosis

PURPOSE

To evaluate conjunctival impression cytology (CIC) findings and tear film parameters in patients with multiple sclerosis (MS) compared with controls.

METHODS

Thirty-three patients with MS (MS group) and 33 age- and sex-matched healthy subjects (control group) were included in this cross-sectional comparative study. CIC grades, tear break-up time (TBUT), Schirmer 1 test results, and Ocular Surface Disease Index (OSDI) scores were compared between the two groups, and correlations between CIC grade, TBUT, Schirmer 1 test result, OSDI score, Expanded Disability Status Scale score, and disease duration were analyzed.

RESULTS

Mean CIC grade was higher in the MS group than in the control group (1.48 ± 0.71 and 0.39 ± 0.56, respectively; p < 0.001). In the MS group, CIC of the 14 participants (42.4%) was grade 2-3. In the control group, CIC of the only one participant (3.3%) was grade 2, and none of them was grade 3. TBUT (8.12 ± 3.16, 13.06 ± 4.23 s in MS and control groups, respectively; p < 0.001) and Schirmer 1 test results (8.45 ± 5.75, 17.36 ± 10.89 mm in MS and control groups, respectively; p < 0.001) were lower, and OSDI score (36.36 ± 19.19, 13.70 ± 15.36 in MS and control groups, respectively; p < 0.001) was higher in the MS group compared to the control group.

CONCLUSION

In patients with MS, objective findings of dry eye, subjective symptoms related to dry eye, and CIC abnormalities, including high grades of conjunctival squamous metaplasia and goblet cell loss, are more common. Patients with MS should be monitored for ocular surface alterations and dry eye disease.

Ocular Surface Microbiota in Diabetic Patients With Dry Eye Disease

Purpose

To investigate the ocular surface (OS) commensal bacteria profiles of patients with diabetes mellitus (DM) and dry eye disease (DED).

Methods

In the present study, subjects were assigned to four groups: 37 to the diabetic mellitus with dry eye disease (DM with DED) group, 22 to the diabetes mellitus (DM)-only group, 34 to the dry eye disease (DED)-only group, and 22 to the control group. Tear fluid was collected using Schirmer's tear secretion test paper. 16S ribosomal ribonucleic acid (rRNA) gene sequencing was used to analyze the bacterial microbiota.

Results

The DM with DED group showed the highest operational taxonomic unit (OTU) numbers and alpha diversity and the most different beta diversity. The groups shared the four most abundant phyla, accounting for over 96% of the total abundance. At the genus level, there were 10 types of overlap in the core microbiota in the groups. They showed significant differences between the groups. Additionally, the DM with DED group and the control group showed four unique core genera, respectively. Unclassified Clostridiales and Lactobacillus were the core microbiota members of the DM with DED group, the DM-only group, and the DED-only group, but not the control group.

Conclusions

In the present study, our results showed that the patients in the DM with DED group had a more complex and comprehensive ocular surface microbial composition. To the best of our knowledge, this is the first study to reveal the microbial profile of dry eye disease in patients with diabetes mellitus.

The ocular surface findings in alopecia areata patients: clinical parameters and impression cytology

PURPOSE

The objective of this study was to examine the effects of alopecia areata (AA) on the ocular surface and conjunctival cytology.

METHODS

A total of 48 subjects were included in the present study. Twenty-three subjects were assigned to group 1 as the patient group, and 25 healthy individuals were included in group 2 as the control group. The ocular surface examination was performed, and the right eyes of all participants were included in the analysis. Both groups underwent the following tests for evaluation of ocular surface: tear break-up time (TBUT), Schirmer I test, Ocular Surface Disease Index (OSDI), and conjunctival impression cytology (CIC). Results obtained from the tests were then analyzed and compared between the groups.

RESULTS

The mean TBUT value was significantly lower in Group 1 compared to Group 2 (4.96 ± 3.4 vs 10.52 ± 4.8 s) (p < 0.001). There was no significant difference between Group 1 and Group 2 in terms of the mean Schirmer I test score (p = 0.129). The mean OSDI score was higher in Group 1 compared to Group 2 (15.48 ± 10.4 vs 9.61 ± 13.4), but the difference between both groups was not statistically significant (p = 0.1). The mean CIC score was statistically significantly higher in Group 1 than in Group 2 (1.65 ± 0.7 vs 0.52 ± 0.5) (p < 0.001).

CONCLUSION

The results of this study showed that AA was correlated with significant disturbances in conjunctival cytology and the tear function.

The effect of active smoking, passive smoking, and e-cigarettes on the tear film: An updated comprehensive review

Active tobacco smoking, passive smoking, and e-cigarette smoking have been associated with different systemic and ocular diseases. The precorneal tear film plays an important role in eye health and its analysis can provide useful information on ocular status. This review investigates the effects of different types of smoking on the precorneal tear film, by analyzing the peer-reviewed literature on this topic. Specifically, tear evaporation rate, stability, volume, ferning, osmolarity, and physical composition (lipids and proteins) of tear film are detailed. Most of the reported works show that cigarette smoking reduces tear film stability and quality by affecting its components. This review highlights that smoking severely affects the tear film, but a single test is not sufficient to determine these effects because smoking can impact different parts of the eye.

Defining Dry Eye from a Clinical Perspective

Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: “Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities.” The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint.

Moxifloxacin based axially swept wide-field fluorescence microscopy for high-speed imaging of conjunctival goblet cells

Goblet cells (GCs) in the conjunctiva are specialized epithelial cells producing mucins on the ocular surface. GCs play important roles in maintaining homeostasis of the ocular surface, and GC dysfunction is associated with various complications including dry eye diseases. Current GC examination methods, which are conjunctival impression cytology and confocal reflection microscopy, have limitations for routine examination. Fluorescence microscopy using moxifloxacin was recently introduced as a non-invasive and high-contrast imaging method, but further development is needed to be used for GC examination. Here we developed a non-invasive high-speed high-contrast GC imaging method, called moxifloxacin based axially swept wide-field fluorescence microscopy (MBAS-WFFM). This method acquired multiple fluorescence images with the axial sweeping of the focal plane to capture moxifloxacin labeled GCs on the tilted conjunctival surface in focus and generated all-in-focus images by combining the acquired images. The imaging field of view and imaging speed were increased to 1.6 mm × 1.6 mm and 30 fps. An image processing method was developed for the analysis of GC density. MBAS-WFFM was applied to alkali burn mouse models and detected GC damage and recovery via longitudinal imaging. MBAS-WFFM could assess the status of GCs rapidly and non-invasively. We anticipate MBAS-WFFM to be a starting point for non-invasive GC examination and the diagnosis of GC associated diseases. For example, MBAS-WFFM could be used to classify dry eye diseases into detail categories for effective treatment.

Altered mucins and aquaporins indicate dry eye outcome in patients undergoing Vitreo-retinal surgery

Vitreo-retinal (VR) surgeries induce conjunctival changes. However, there are no study reports regarding prevalence and severity of dry eye after these surgeries. This study evaluated dry eye outcome after VR surgery. Patients undergoing VR surgery classified as scleral buckle and microincision vitrectomy surgery (n = 44, mean age: 56.09±10.2 years) were recruited. Dry eye evaluation was done before and 8 weeks after surgery (2 weeks after omitting topical eye drops). Conjunctival imprint cytology for goblet cell count and tear Mucin 5AC (MUC5AC) protein estimation was done. Gene expressions of MUC5AC, MUC4, MUC16, Aquaporin 4 (AQP4) and AQP5 were analyzed in the conjunctival imprint cells by qPCR. None of the patients exhibited clinical signs of dry eye after VR surgery. But the conjunctival goblet cell density (GCD) was significantly lowered post-VR surgery (63% cases, **p = 0.012) with no alterations in the tear MUC5AC protein. Post-VR surgery, the conjunctival cell gene expression of MUC4, MUC16 and AQP4 were significantly increased (*p = 0.025, *p = 0.05 and *p = 0.02 respectively) and AQP5 was significantly lowered (*p = 0.037), with no change in MUC5AC expression. Tear cytokines were significantly increased post-VR surgery (anti-inflammatory: IL1RA, IL4, IL5, IL9, FGF; PDGFbb and pro-inflammatory: IL2, IL6, IL15, GMCSF and IFNg). Though clinical signs of dry eye were not observed after VR surgery, ocular surface changes in the form of reduced GCD, altered MUC5AC, MUC4, MUC16, AQP4, AQP5 and cytokines are suggestive of dry eye outcome at the molecular level especially inpatients aged above 51 years, especially female gender and those who are diabetic.

Alterations of Tear Film and Ocular Surface in Children with Type 1 Diabetes Mellitus

Purpose: To investigate whether diabetes mellitus (DM) affects ocular surface of children with well-controlled type 1 DM.Methods: Sixty-five diabetic patients and 55 age-matched controls enrolled to study. Detailed ocular surface assessment including, ocular surface disease index (OSDI) questionnaire, tear film break-up time (TBUT) analysis, Schirmer test, and conjunctival impression cytologic analysis were performed.Results: Schirmer test and TBUT results were significantly lower in DM group than controls (p = 0.001, for all). OSDI scores of all participants were within normal range. Impression cytology analysis showed grade 0 changes in all participants and there was no difference between groups for goblet cell density (p > 0.05). The TBUT results were significantly associated with duration of DM (r = -0.309, p = 0.036).Conclusion: Diabetic children without symptoms, signs, and definite diagnosis of dry eye still had lower TBUT and Schirmer test results than controls; however, impression cytology analysis was similar in both groups.

Evaluation of the ocular surface by impression cytology in patients with endometriosis

OBJECTIVE

The aim of this study was to investigate the effect of endometriosis on the ocular surface.

METHODS

A total of 50 patients were included in the study and divided into two groups. Group 1 consisted of 25 patients with endometriosis. Group 2 had 25 control patients. All patients underwent complete ophthalmic examination, and the right eyes were included in the study. To evaluate the ocular surface, both groups were tested with the following: the Schirmer I test, tear breakup time (TBUT), the conjunctival impression cytology (CIC), and the Ocular Surface Disease Index (OSDI). The results were subsequently compared.

RESULTS

The average Schirmer I test results were 8.40 ± 2.74 mm in group 1 and were significantly lower in patients with endometriosis (P < 0.001). The average TBUT test results were 9.04 ± 3.61 s in group 1 and were significantly lower in patients with endometriosis (P < 0.001). The average OSDI results were 24.04 ± 9.29 in group 1 and were significantly higher in patients with endometriosis (P < 0.001). The average CIC results were 1.76 ± 0.88 in group 1 and were significantly higher in patients with endometriosis (P < 0.001).

CONCLUSIONS

Ocular surface changes, including squamous metaplasia, may be observed in the conjunctiva of patients with endometriosis.

In vivo fluorescence imaging of conjunctival goblet cells

Conjunctival goblet cells (GCs) are specialized epithelial cells that secrete mucins onto the ocular surface to maintain the wet environment. Assessment of GCs is important because various ocular surface diseases are associated with their loss. Although there are GC assessment methods available, the current methods are either invasive or difficult to use. In this report, we developed a simple and non-invasive GC assessment method based on fluorescence imaging. Moxifloxacin ophthalmic solution was used to label GCs via topical administration, and then various fluorescence microscopies could image GCs in high contrasts. Fluorescence imaging of GCs in the mouse conjunctiva was confirmed by both confocal reflection microscopy and histology with Periodic acid-Schiff (PAS) labeling. Real-time in-vivo conjunctival GC imaging was demonstrated in a rat model by using both confocal fluorescence microscopy and simple wide-field fluorescence microscopy. Different GC densities were observed in the forniceal and bulbar conjunctivas of the rat eye. Moxifloxacin based fluorescence imaging provides high-contrast images of conjunctival GCs non-invasively and could be useful for the study or diagnosis of GC related ocular surface diseases.

The Efficacy of 2% Topical Rebamipide on Conjunctival Squamous Metaplasia and Goblet Cell Density in Dry Eye Disease

Purpose: To clarify the pharmacological effects of 2% rebamipide eye drops on mucosal membrane functions of the ocular surface epithelium, we investigated keratoconjunctival alterations at the cellular level in this study. Methods: Fifteen patients with definite dry eye disease were recruited from outpatient clinics of the Department of Ophthalmology, Ichikawa General Hospital. The patients received treatment with 2% rebamipide eye drops q.i.d for 12 weeks. Symptom score assessment, tear film breakup time, fluorescein and lissamine green ocular surface vital staining, grading of lid wiper epitheliopathy, Cochet-Bonnet corneal sensitivity, assessment of squamous metaplasia grades, and goblet cell density calculations from conjunctival impression cytology samples, as well as evaluation of nucleocytoplasmic ratios and corneal epithelial cells from in vivo confocal microscopy images before and 3 months after treatment were performed. Results: The mean symptom scores, tear film breakup time values, ocular surface fluorescein and lissamine green vital staining scores, and lid wiper scores showed a significant improvement after treatment (P < 0.01). The mean squamous metaplasia grade also showed a significant improvement (1.2 ± 0.1 → 0.3 ± 0.1) 3 months after treatment (P = 0.004). There were similar significant improvements in the mean corneal epithelial cell density (660.1 ± 62.6 → 1015.5 ± 43.5 cells/mm2) (P = 0.002) and nucleocytoplasmic ratios (0.1 ± 0.0 → 0.2 ± 0.0) (P = 0.0042) after treatment. Conclusions: Topical use of 2% rebamipide for 3 months was associated with improvements in ocular surface differentiation due to changes of mucosal functions at the cellular level. These alterations may explain objective and subjective improvements in dry eye disease.

Reconsidering the central role of mucins in dry eye and ocular surface diseases

Mucins are key actors in tear film quality and tear film stability. Alteration of membrane-bound mucin expression on corneal and conjunctival epithelial cells and/or gel-forming mucin secretion by goblet cells (GCs) promotes in ocular surface diseases and dry eye disease (DED). Changes in the mucin layer may lead to enhanced tear evaporation eventually contributing to tear hyperosmolarity which has been associated with ocular surface inflammation. Inflammatory mediators in turn may have a negative impact on GCs differentiation, proliferation, and mucin secretion. This sheds new light on the position of GCs in the vicious circle of DED. As contributor to ocular surface immune homeostasis, GC loss may contribute to impaired ocular surface immune tolerance observed in DED. In spite of this, there are no tools in routine clinical practice for exploring ocular surface mucin deficiency/dysregulation. Therefore, when selecting the most appropriate treatment options, there is a clear unmet need for a better understanding of the importance of mucins and options for their replacement. Here, we comprehensively revisited the current knowledge on ocular surface mucin biology, including functions, synthesis, and secretion as well as the available diagnostic tools and treatment options to improve mucin-associated homeostasis. In particular, we detailed the potential link between mucin dysfunction and inflammation as part of the uncontrolled chronic inflammation which perpetuates the vicious circle in DED.

Goblet cells: multifaceted players in immunity at mucosal surfaces

Goblet cells (GCs) are specialized epithelial cells that line multiple mucosal surfaces and have a well-appreciated role in barrier maintenance through the secretion of mucus. Moreover, GCs secrete anti-microbial proteins, chemokines, and cytokines demonstrating functions in innate immunity beyond barrier maintenance. Recently it was appreciated that GCs can form goblet cell-associated antigen passages (GAPs) and deliver luminal substances to underlying lamina propria (LP) antigen-presenting cells (APCs) in a manner capable of inducing adaptive immune responses. GCs at other mucosal surfaces share characteristics with the GAP forming intestinal GCs, suggesting that GAP formation may not be restricted to the gut, and that GCs may perform this gatekeeper function at other mucosal surfaces. Here we review observations of how GCs contribute to immunity at mucosal surfaces through barrier maintenance, the delivery of luminal substances to APCs, interactions with APCs, and secretion of factors modulating immune responses.

Successful single treatment with ziv-aflibercept for existing corneal neovascularization following ocular chemical insult in the rabbit model

PURPOSE

To evaluate the efficacy of ziv-aflibercept as a treatment for established corneal neovascularization (NV) and to compare its efficacy to that of bevacizumab following ocular chemical insult of sulfur mustard (SM) in the rabbit model.

METHODS

Chemical SM burn was induced in the right eye of NZW rabbits by vapor exposure. Ziv-aflibercept (2 mg) was applied once to neovascularized eyes by subconjunctival injection while subconjunctival bevacizumab (5 mg) was administered twice a week, for 3 weeks. Non-treated exposed eyes served as a control. A clinical follow-up employed by slit-lamp microscope, was performed up to 12 weeks following exposure and digital photographs of the cornea were taken for measurement of blood vessels length using the image analysis software. Eyes were taken for histological evaluation 2, 4 and 8 weeks following treatment for general morphology and for visualization of NV, using H&E and Masson Trichrome stainings, while conjunctival goblet cell density was determined by PAS staining.

RESULTS

Corneal NV developed, starting as early as two weeks after exposure. A single subconjunctival treatment of ziv-aflibercept at 4 weeks post exposure, significantly reduced the extent of existing NV already one week following injection, an effect which lasted for at least 8 weeks following treatment, while NV in the non-treated exposed eyes continued to advance. The extensive reduction in corneal NV in the ziv-aflibercept treated group was confirmed by histological evaluation. Bevacizumab multiple treatment showed a benefit in NV reduction, but to a lesser extent compared to the ziv-aflibercept treatment. Finally, ziv-aflibercept increased the density of conjunctival goblet cells as compared to the exposed non-treated group.

CONCLUSIONS

Subconjunctival ziv-aflibercept single treatment presented a highly efficient long-term therapeutic benefit in reducing existing corneal NV, following ocular sulfur mustard exposure. These findings show the robust anti-angiogenic efficacy of ziv-aflibercept and demonstrate the advantage of this treatment over the other anti-angiogenic therapies in ameliorating corneal NV and protecting the ocular surface.

The Pathophysiology of Dry Eye Disease: What We Know and Future Directions for Research

Clinical and laboratory studies performed over the past few decades have discovered that dry eye is a chronic inflammatory disease that can be initiated by numerous extrinsic or intrinsic factors that promote an unstable and hyperosmolar tear film. These changes in tear composition, in some cases combined with systemic factors, lead to an inflammatory cycle that causes ocular surface epithelial disease and neural stimulation. Acute desiccation activates stress signaling pathways in the ocular surface epithelium and resident immune cells. This triggers production of innate inflammatory mediators that stimulate the production of matrix metalloprotease, inflammatory cell recruitment, and dendritic cell maturation. These mediators, combined with exposure of autoantigens, can lead to an adaptive T cell-mediated response. Cornea barrier disruption develops by protease-mediated lysis of epithelial tight junctions, leading to accelerated cell death; desquamation; an irregular, poorly lubricated cornea surface; and exposure and sensitization of epithelial nociceptors. Conjunctival goblet cell dysfunction and death are promoted by the T helper 1 cytokine interferon gamma. These epithelial changes further destabilize the tear film, amplify inflammation, and create a vicious cycle. Cyclosporine and lifitegrast, the 2 US Food and Drug Administration-approved therapies, inhibit T-cell activation and cytokine production. Although these therapies represent a major advance in dry eye therapy, they are not effective in improving discomfort and corneal epithelial disease in all patients. Preclinical studies have identified other potential therapeutic targets, biomarkers, and strategies to bolster endogenous immunoregulatory pathways. These discoveries will, it is hoped, lead to further advances in diagnostic classification and treatment.

Can the optimum artificial tear treatment for dry eye disease be predicted from presenting signs and symptoms?

PURPOSE

To assess dry eye treatment with four preservative-free dry eye artificial tear treatments to facilitate evidence-based prescribing.

METHODS

A randomised, single masked crossover trial of Clinitas Soothe, Hyabak, Tears Again and TheraTears artificial tears was conducted on 50 symptomatic dry eye patients, aged 60.8±14.2years. At baseline and after trialling each treatment for 4 weeks, signs and symptoms were assessed using the Ocular Surface Disease Index (OSDI), non-invasive tear break-up time, fluorescein tear break-up time, tear meniscus height (TMH), Phenol Red test, lid-parallel conjunctival folds (LIPCOF), ocular surface staining, and lipid layer grading and osmolarity (baseline visit only).

RESULTS

OSDI (p=0.002), LIPCOF (p=0.014) and conjunctival staining (p<0.001) significantly improved from baseline, however, the impact of each dry eye treatment on ocular symptoms and signs was similar. Clinitas Soothe and Hyabak were preferred by 34%/30% of participants, but only subjective comparison with the other drops influenced this choice. TheraTears was preferred (by 24%) by those with a lower baseline tear volume (p=0.01) and Tears Again (by 12%) by those with a thinner baseline lipid layer (p=0.04). The treatment that afforded the greatest improvement in clinical signs did not consistently match each individual's preferred treatment.

CONCLUSIONS

If prescribed to a general dry eye population, the artificial tears performed similarly, improving symptoms and conjunctival signs. However, osmolarity balanced artificial tears were the preferred treatment in individuals with low baseline tear volume and lipisomal spray for individuals with a baseline lipid layer deficiency.

Conjunctival Cytological Alterations in Ocular Behçet Disease

PURPOSE

To evaluate the ocular surface alterations and tear film functions in patients with ocular Behçet disease (BD).

METHODS

This study included 48 eyes of 48 patients with inactive BD and a control group of 33 age- and sex-matched subjects. Schirmer I and tear break-up time (TBUT) tests were used to evaluate the tear film of the subjects. Impression cytology was used to evaluate morphological changes of the conjunctival surface epithelial cells.

RESULTS

The mean Schirmer I test result was 11.6 ± 5.9 mm/5 minutes and 16.1 ± 4.6 mm/5 minutes in the Behçet and control groups, respectively. The mean TBUT test result was 9.8 ± 5.6 seconds and 13.2 ± 5.7 seconds in the study and control groups, respectively. The Schirmer and TBUT test results were significantly lower in the study group than in the controls (P = 0.001 and P = 0.011, respectively). The mean impression cytology score was 1.3 ± 0.9 in the study group and significantly higher than the control group value of 0.4 ± 0.6 (P = 0.001).

CONCLUSIONS

Tear film functions and conjunctival surface epithelial morphology were significantly altered in patients with ocular BD.

Local ocular surface parameters in patients with systemic celiac disease

PurposeThis was a collaborative study from the Ophthalmology and Gastroenterology departments of a tertiary care hospital, designed to investigate the local ocular surface parameters in patients with celiac disease (CD).MethodsFifty-six eyes of 28 patients with CD and 58 eyes of 29 healthy adult subjects serving as controls were evaluated. The Schirmer test, tear-film break-up time, and conjunctival impression cytology were performed in addition to a complete ophthalmological examination. Impression cytology specimens of each group were graded and scored in the range 0-3.ResultsThe 28 patients with CD consisted of 24 females (86%) and 4 males (14%). The mean age was 34.4±11.3 years (22-55 years). Tear-film break-up time and Schirmer test results were significantly lower in the study group than in the controls (P<0.05). Also, there was a significant difference between the groups for impression cytology grading scores (P=0.001).ConclusionsThe CD group showed a marked preponderance of females with an F/M ratio of six females per male, as reported in the literature. Tear-film functions and conjunctival surface epithelial morphology were significantly altered in patients with CD.

Impact of Cigarette Smoking on Tear Function and Correlation between Conjunctival Goblet Cells and Tear MUC5AC Concentration in Office Workers

The first aim of this study was to clarify whether cigarette smoking affects tear secretion, goblet cell density, and tear MUC5AC concentration. The second purpose was to evaluate the correlations of conjunctival goblet cell density with tear MUC5AC concentration and other ocular surface evaluation factors. This cross-sectional study included 88 office workers. All subjects were required to fill in dry eye and smoking questionnaires, in addition to ocular surface evaluation. Tear wash fluid was collected from inferior fornix, and conjunctival epithelium was obtained by impression cytology. Tear MUC5AC concentration was quantified using enzyme-linked immunoassay, and conjunctival goblet cell density was counted after Periodic-acid Schiff staining. Tear MUC5AC concentration had significant positive correlation with conjunctival goblet cell density (r = 0.181, P = 0.03). In current smokers, Schirmer I test value, goblet cell density and tear MUC5AC concentration were significantly lower than non-smokers. Pack-years of smoking have significant negative correlation with goblet cell density (r = −0.174, P = 0.036) and tear MUC5AC concentration (r = −0.183, P = 0.028). We concluded that smoking might decrease tear secretion, goblet cell density and tear MUC5AC concentration. In addition, MUC5AC concentration in tears depends on goblet cell density in the conjunctiva among office workers.

Dry Eye Syndrome in Patients with Diabetes Mellitus: Prevalence, Etiology, and Clinical Characteristics

There has been substantial progress in our understanding of the ocular surface system/lacrimal function unit in the past 15 years. Keratoconjunctivitis sicca, more commonly referred to as dry eye syndrome (DES), is the most frequently encountered condition and diabetes mellitus (DM) has been identified as one of the leading causes of DES. Poor glycemic control affects both the anterior and the posterior segments of the eye and increasing prevalence of diabetes-associated DES (DMDES) has been reported in recent years. The pathogenesis and specific features of DMDES remain uncertain and interventions are limited to those used in DES. This review outlines the pathogenesis, clinical manifestations, and the current preventive and treatment strategies for diabetes-related DES.

Immunomodulatory cross-talk between conjunctival goblet cells and dendritic cells

Goblet cells are secretory epithelial cells of mucosal tissues that confer protection from environmental agents or pathogens via expression and secretion of soluble mucins. Loss of these cells is associated with several chronic inflammatory disorders of the mucosa. Although demonstrated to transfer antigens from the luminal surface to stromal cells in the intestinal mucosa, it is not known if goblet cells contribute to the regulation of an immune response. In this study we report that similar to intestinal and respiratory mucosal epithelia, mouse ocular surface epithelia predominantly express the TGF-ß2 isoform. Specifically, we demonstrate the ability of goblet cells to express TGF-ß2 and increase it in response to Toll-Like Receptor 4 mediated stimulus in cultures. Goblet cells not only express TGF-ß2, but are also able to activate it in a thrombospondin-1 (TSP-1) dependent manner via their cell surface receptor CD36. Furthermore, goblet cell derived soluble factors that possibly include TGF-ß2, alter dendritic cell (DC) phenotype to a tolerogenic type by downregulating DC expression of MHC class II and co-stimulatory molecules CD80, CD86 and CD40. Thus our study demonstrates goblet cells as a cellular source of active TGF-ß2 in ocular mucosa and implicates their immunomodulatory function in maintaining mucosal immune homeostasis.

Assessment of size and nucleo-cytoplasmic characteristics of the squamous cells of the corneal epithelium

PURPOSE

The aim was to objectively assess size, nucleus and nucleo-cytoplasmic ratio features of squamous cells from the corneal epithelium

METHODS

The corneas of recent post-mortem sheep eyes were either glutaraldehyde-fixed for transmission electron microscopy or impression cytology samples taken, glutaraldehyde-fixed and stained with Giemsa. From the specimens for impression cytology, a representative region was photographed from 12 different samples taken from the central region and 16 different samples taken from mid-peripheral regions of the corneal epithelium. Images were subjected to morphometry after overlays were generated.

RESULTS

Electron microscopy revealed a very distinctive stratified corneal epithelium with several superficial layers, confirming the squamous phenotype. Impression cytology from such superficial layers revealed a cell size of 60.1 ± 4.8 μm, nucleus dimension of 12.3 ± 1.5 μm, cell area of 2,419 ± 416 μm(2) and nucleus area of 131 ± 31 μm(2) . A nucleo-cytoplasmic ratio based on nucleus-to-cell length had a mean of 0.207 ± 0.022, while a cytoplasm-to-nucleus length ratio was 3.975 ± 0.474. Estimates of the nucleo-cytoplasmic ratio based on areas had a mean value of 0.059 ± 0.011. Very similar results were found for mid-peripheral corneal epithelium.

CONCLUSIONS

The results strongly indicate that the squamous phenotype of the superficial corneal epithelial cells is characterised by a large size, large nucleus and low nucleo-cytoplasmic ratio. These morphological characteristics show a notable resemblance to data obtained from impression cytological studies on human conjunctival epithelial cells showing severe squamous metaplasia.

Ocular surface reconstruction with a tissue-engineered nasal mucosal epithelial cell sheet for the treatment of severe ocular surface diseases

Severe ocular surface diseases (OSDs) with severe dry eye can be devastating and are currently some of the most challenging eye disorders to treat. To investigate the feasibility of using an autologous tissue-engineered cultivated nasal mucosal epithelial cell sheet (CNMES) for ocular surface reconstruction, we developed a novel technique for the culture of nasal mucosal epithelial cells expanded ex vivo from biopsy-derived human nasal mucosal tissues. After the protocol, the CNMESs had 4-5 layers of stratified, well-differentiated cells, and we successfully generated cultured epithelial sheets, including numerous goblet cells. Immunohistochemistry confirmed the presence of keratins 3, 4, and 13; mucins 1, 16, and 5AC; cell junction and basement membrane assembly proteins; and stem/progenitor cell marker p75 in the CNMESs. We then transplanted the CNMESs onto the ocular surfaces of rabbits and confirmed the survival of this tissue, including the goblet cells, up to 2 weeks. The present report describes an attempt to overcome the problems of treating severe OSDs with the most severe dry eye by treating them using tissue-engineered CNMESs to supply functional goblet cells and to stabilize and reconstruct the ocular surface. The present study is a first step toward assessing the use of tissue-engineered goblet-cell transplantation of nonocular surface origin for ocular surface reconstruction.

Meibomian gland loss due to trabeculectomy

PURPOSE

To evaluate meibomian gland loss after trabeculectomy with mitomycin C (MMC).

METHODS

This cross-sectional observational case study involved 55 eyes in 39 patients who had undergone trabeculectomy with MMC administered to the upper area of the eye. We used a mobile pen-shaped noncontact meibography system to access the morphology and determine loss of the meibomian glands. Meibomian gland loss was scored (meiboscore) from grade 0 (no loss of the meibomian glands) through grade 3 (loss of more than two-thirds of the total area) in the bleb-contacting and bleb-noncontacting upper eyelid areas in the primary position and in the lower eyelid. The tear film breakup time (BUT) was also measured.

RESULTS

The median duration from trabeculectomy to examination was 7.4 years (interquartile range 3.1-14.2). The meiboscores of the bleb-contacting upper eyelid areas were significantly higher than those for the bleb-noncontacting upper eyelid areas (P < 0.001). The meiboscores for both the bleb-contacting and the bleb-noncontacting upper eyelid areas were significantly higher when the bleb was avascular (P = 0.011 and P = 0.008, respectively). The meiboscores of the bleb-contacting and bleb-noncontacting upper eyelid areas showed a significant negative correlation with the BUT (r = -0.330, P = 0.014 and r = -0.296, P = 0.028, respectively).

CONCLUSION

Blebs that occur after trabeculectomy with MMC may be the cause of meibomian gland loss, particularly when the bleb is avascular. The presence of an avascular bleb warrants extra vigilance for decreased meibomian gland secretions because this decrease can lead to tear dysfunction and ocular surface damage, including bleb-wall damage.

Peripheral neuropathy and tear film dysfunction in type 1 diabetes mellitus

PURPOSE

To compare tear film metrics in patients with type 1 diabetes mellitus (DM) and healthy controls and investigate the association between peripheral neuropathy and ocular surface quality.

METHODS

Dry eye symptoms were quantified in 53 patients with type 1 DM and 40 age-matched controls. Ocular examination included tear film lipid layer thickness grading, tear film stability and quantity measurement, and retinal photography. DM individuals additionally underwent a detailed neuropathy assessment.

RESULTS

Neither mean age nor dry eye symptom scores differed significantly between the DM and control groups (P = 0.12 and P = 0.33, resp.). Tear lipid thickness (P = 0.02), stability (P < 0.0001), and quantity (P = 0.01) were significantly lower in the DM group. Corneal sensitivity was also reduced in the DM group (P < 0.001) and tear film stability was inversely associated with total neuropathy score (r = -0.29, P = 0.03).

CONCLUSION

The DM group exhibited significantly reduced tear film stability, secretion, and lipid layer quality relative to the age-matched control group. The negative correlation between tear film parameters and total neuropathy score suggests that ocular surface abnormalities occur in parallel with diabetic peripheral neuropathy.

Modulation of conjunctival goblet cell function by inflammatory cytokines

Ocular surface inflammation associated with Sjögren's syndrome is characterized by a loss of secretory function and alteration in numbers of mucin secreting goblet cells. Such changes are a prominent feature of ocular surface inflammatory diseases and are attributed to inflammation; however, the exact effect of the inflammatory cytokines on conjunctival goblet cell function remains largely unknown. In this study, we developed a primary culture of mouse goblet cells from conjunctival tissue and evaluated the effects on their function by inflammatory cytokines detected in the conjunctiva of mouse model of Sjögren's syndrome (Thrombospondin-1 deficient mice). We found that apoptosis of goblet cells was primarily induced by TNF-α and IFN-γ. These two cytokines also inhibited mucin secretion by goblet cells in response to cholinergic stimulation, whereas IL-6 enhanced such secretion. No changes in secretory response were detected in the presence of IL-13 or IL-17. Goblet cells proliferated to varying degrees in response to all the tested cytokines with the greatest response to IL-13 followed by IL-6. Our results therefore reveal that inflammatory cytokines expressed in the conjunctiva during an ocular surface disease directly disrupt conjunctival goblet cell functions, compromising the protective function of tears, thereby contributing to ocular surface damage.

Effects of diquafosol tetrasodium administration on visual function in short break-up time dry eye

PURPOSE

To investigate the effect of diquafosol tetrasodium on tear and visual function in short break-up time (sBUT) dry eye (DE).

METHODS

This interventional nonrandomized comparative study involved 11 eyes in 11 patients with sBUT DE (symptom-positive sBUT group) and 13 eyes in 13 volunteers with BUT values ≤5 s without DE symptoms (symptom-negative sBUT group). Tear function was assessed by measuring BUT and Schirmer values. Serial measurements were made of visual acuities (using a functional visual acuity measurement system) and higher-order aberrations (using a wavefront sensor). The parameters were compared before and 1 month after diquafosol tetrasodium instillation. Any changes in symptomatology after administration were also recorded.

RESULTS

After diquafosol tetrasodium administration, BUT values tended to increase in the symptom-positive sBUT group (P=0.07) and significantly increased in the symptom-negative sBUT group (P<0.05). LogMAR functional, minimal, and maximal visual acuities and higher-order aberrations significantly decreased after diquafosol tetrasodium administration in the symptom-positive sBUT group (P<0.05), while there were no significant changes in these values in the symptom-negative sBUT group (P>0.05). Diquafosol tetrasodium administration provided relief of DE symptoms in 75% of patients in the symptom-positive sBUT group.

CONCLUSIONS

Diquafosol tetrasodium appeared to improve tear film stability and visual function in sBUT DE.

Limbal epithelial cell therapy: past, present, and future

The cornea, the clear window at the front of the eye, transmits light to the retina to enable vision. The corneal surface is renewed by stem cells located at the peripheral limbal region. These cells can be destroyed by a number of factors, including chemical burns, infections, and autoimmune diseases, which result in limbal stem cell deficiency (LSCD), a condition that can lead to blindness. Established therapy for LSCD based on ex vivo expanded limbal epithelial cells is currently at a stage of refinement. Therapy for LSCD is also rapidly evolving to include alternative cell types and clinical approaches as treatment modalities. In the present perspectives chapter, strategies to treat LSCD are discussed and advances in this important field of regenerative medicine are highlighted.