In Vivo Confocal Microscopy Evaluation of Ocular Surface with Graft-Versus-Host Disease-Related Dry Eye Disease

Imaging assessment of conjunctival goblet cells in dry eye disease

Dry eye disease (DED) is a widespread, multifactorial, and chronic disorder of the ocular surface with disruption of tear film homeostasis as its core trait. Conjunctival goblet cells (CGCs) are specialised secretory cells found in the conjunctival epithelium that participate in tear film formation by secreting mucin. Changes in both the structure and function of CGCs are hallmarks of DED, and imaging assessment of CGCs is important for the diagnosis, classification, and severity evaluation of DED. Existing imaging methods include conjunctival biopsy, conjunctival impression cytology and in vivo confocal microscopy, which can be used to assess the morphology, distribution, and density of the CGCs. Recently, moxifloxacin-based fluorescence microscopy has emerged as a novel technique that enables efficient, non-invasive and in vivo imaging of CGCs. This article presents a comprehensive overview of both the structure and function of CGCs and their alterations in the context of DED, as well as current methods of CGCs imaging assessment. Additionally, potential directions for the visual evaluation of CGCs are discussed.

Assessment of Corneal Epithelial Changes and Related Factors in Ocular Chronic Graft-Versus-Host Disease (GVHD) by in Vivo Confocal Microscopy

PURPOSE

To evaluate corneal epithelial changes and related factors in chronic ocular graft-versus-host disease (oGVHD) patients.

METHODS

21 patients (35 eyes) with chronic oGVHD and 8 patients (12 eyes) without oGVHD after bone marrow transplantation were recruited for assessment involving in vivo confocal microscopy (IVCM) analysis, ocular surface parameter determination and tear cytokine level analysis. The IVCM corneal epithelial scoring system was used to evaluate corneal epithelial changes.

RESULTS

There was a significant difference in the corneal epithelial score (p = .001) between the two groups. The corneal epithelial scores were significantly correlated with the corneal fluorescein staining scores (CFS, r = 0.463, p < .001), Schirmer's test (r = -0.389, p = .009) and tear cytokine levels of EGF (r = -0.491, p < .001) and APRIL (r = -0.318, p = .030).

CONCLUSIONS

The depth of corneal epithelial defects can be estimated by the CFS. Corneal epithelial changes of chronic oGVHD are considered to be associated with lacrimal deficiency and a lack of EGF.

Lessons Learned From Ocular Graft versus Host Disease: An Ocular Surface Inflammatory Disease of Known Time of Onset

ABSTRACT

The ocular surface inflammatory disorders (OSIDs) comprise a group of conditions characterized by persistent inflammation of the ocular surface and adnexal tissues. Systemic autoimmune diseases and hypersensitivity reactions cause them, and, if left untreated, can result in severe inflammatory dry eye, corneal damage, and vision loss. Ocular graft-versus-host disease (oGVHD) forms part of the ocular surface inflammatory disease umbrella. It is a condition occurring after allogeneic hematopoietic stem cell or bone marrow transplantation, usually in chronic graft-versus-host disease. oGVHD can virtually affect any ocular adnexal tissue, especially the meibomian glands, and cause persistent inflammation, tissue fibrosis, and subsequent chronic, severe dry eye disease. Among the OSIDs, oGVHD has the particularity that it has a "time zero," meaning we know when the disease started. As such, preclinical models have leveraged this to investigate the molecular mechanisms involved in the damage oGVHD causes to the ocular surface. In oGVHD, establishing a "time zero" allows for predicting the clinical course and establishing adequate treatment. This is also possible because the inflammatory infiltration occurs in ocular surface tissues, which are readily accessible. Using oGVHD, we might be able to understand the immune response mechanisms in other OSIDs better (i.e., Sjögren syndrome, Stevens-Johnson syndrome, among others). This review presents an up-to-date overview of the pathogenesis, clinical presentation, and treatment of oGVHD. In addition, we will discuss the value of the "time zero" concept in the study of oGVHD.

Ophthalmic Manifestations in Patients with Blood Malignancies

Ocular complications can occur in up to 90% of patients with blood malignancies. Such complications range from direct infiltration to local hemostatic imbalance and treatment-related toxicity. This narrative review is based on a systematic computerized search of the literature conducted until January 2024 and examines the common ocular complications associated with blood cancers. Ocular complications from primary disease include mass effects from ocular adnexal lymphomas and intraocular lymphomas, with B-cell lymphomas accounting for 95% of primary ocular presentations. Secondary disease involvement from systemic hematological malignancies can lead to a wide range of ocular manifestations, such as leukemic retinopathy. Furthermore, toxicity from antineoplastic therapies and ocular graft versus host disease (oGVHD) after hematopoietic stem cell transplantation present additional risks to ocular health. In conclusion, ocular complications in blood cancer patients are an integral part of patient management, requiring regular ophthalmic evaluations and close collaboration between oncologists and ophthalmologists. Advances in therapy and an increased focus on early symptom recognition are essential for preserving vision and enhancing patient quality of life.

Advances in the ocular complications after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) has benefited an increasing number of patients with hematological disease in the clinic. It is a curative therapy for malignant and nonmalignant hematological diseases. With the advancement and further clinical application of HSCT in recent years, the life expectancy of patients has increased, but complications have become more common. The occurrence of ocular complications is receiving increasing attention because they can seriously affect the quality of life of patients. Ocular complications require increased attention from clinicians because of their negative impact on patients and increasing incidence. Most of recent reports on posttransplant ocular complications involve ocular manifestations of graft-versus-host disease (GVHD), and a few ocular complications that do not originate from GVHD have also been reported. This review summarizes the diagnosis, scoring criteria, pathophysiology, and clinical manifestations of and common therapies for ocular graft-versus-host disease(oGVHD) after HSCT, and includes a description of some rare cases and novel therapies.

Development and validation of a diagnostic model for the identification of chronic ocular graft-versus-host disease (oGVHD)

Purpose

To verify the International Chronic Ocular Graft-Versus-Host Disease (ICCGVHD) Group diagnostic criteria and establish an easy-to-use and reliable diagnosis model for quick identification of chronic oGVHD.

Methods

This study included 180 patients (355 eyes) who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) and visited the Peking University Third Hospital Cornea and Ocular Surface Disease Specialist Clinic from July 2020 to February 2021. The proportion of chronic oGVHD was 76.06% (279/355).

Results

Five complaints, including eye dryness, photophobia, foreign body sensation, eye redness, and burning sensation; six ophthalmic examinations, including Ocular Surface Disease Index (OSDI) score, corneal fluorescein staining (CFS), tear break-up time (TBUT), Schirmer's test score without anesthesia, conjunctival score, tear meniscus height, and non-ocular GVHD-involved organs were significantly different between patients with chronic oGVHD and control group (p < 0.05). Binary logistic regression (backward LR algorithm) selection demonstrated that three variables retained diagnostic significance for chronic oGVHD: CFS (OR = 2.71 (1.92-3.81), p < 0.001), Schirmer's test score without anesthesia (OR = 0.83 (0.76-0.91), p < 0.001), and conjunctival score (OR = 1.96 (1.13-3.42), p = 0.031). A nomogram for the identification of chronic oGVHD was developed, and its performance was examined using an internal validation cohort (118 eyes). The areas under the curve (AUCs) for the three-variable-based nomogram were 0.976 (95% CI (0.959-0.992), p < 0.01) and 0.945 (95% CI (0.904-0.986), p < 0.01) in the development and internal validation cohorts, respectively.

Conclusion

This concise three-variable-based nomogram based on ICCGVHD criteria could serve as an easy-to-use and reliable tool for rapid screening of chronic oGVHD.

Challenges and concepts in the diagnosis and management of ocular graft-versus-host disease

Graft-versus-host disease (GVHD) is characterized by tissue inflammation in the host following an allogeneic hematopoietic cell transplantation (HCT). The pathophysiology is complex and only incompletely understood yet. Donor lymphocyte interaction with the histocompatibility antigens of the host plays a crucial role in the pathogenesis of the disease. Inflammation may affect multiple organs and tissues, e.g., the gastrointestinal tract, liver, lung, fasciae, vaginal mucosa, and the eye. Subsequently, alloreactive donor-derived T and B lymphocytes may lead to severe inflammation of the ocular surface (i.e., cornea and conjunctiva) and the eyelids. Furthermore, fibrosis of the lacrimal gland may lead to severe dry eye. This review focuses on ocular GVHD (oGVHD) and provides an overview of current challenges and concepts in the diagnosis and management of oGVHD. Ophthalmic manifestations, diagnostic procedures, grading of severity and recommendations for ophthalmic examination intervals are provided. Management of ocular surface disease with lubricants, autologous serum eye drops, topical anti-inflammatory agents and systemic treatment options are described based on the current evidence. Ocular surface scarring and corneal perforation are severe complications of oGVHD. Therefore, ophthalmic screening and interdisciplinary treatment approaches are highly relevant to improve the quality of life of patients and to prevent potentially irreversible visual loss.

A novel combination of corneal confocal microscopy, clinical features and artificial intelligence for evaluation of ocular surface pain

OBJECTIVES

To analyse various corneal nerve parameters using confocal microscopy along with systemic and orthoptic parameters in patients presenting with ocular surface pain using a random forest artificial intelligence (AI) model.

DESIGN

Observational, cross-sectional.

METHODS

Two hundred forty eyes of 120 patients with primary symptom of ocular surface pain or discomfort and control group of 60 eyes of 31 patients with no symptoms of ocular pain were analysed. A detailed ocular examination included visual acuity, refraction, slit-lamp and fundus. All eyes underwent laser scanning confocal microscopy (Heidelberg Engineering, Germany) and their nerve parameters were evaluated. The presence or absence of orthoptic issues and connective tissue disorders were included in the AI. The eyes were grouped as those (Group 1) with symptom grade higher than signs, (Group 2) with similar grades of symptoms and signs, (Group3) without symptoms but with signs, (Group 4) without symptoms and signs. The area under curve (AUC), accuracy, recall, precision and F1-score were evaluated.

RESULTS

Over all, the AI achieved an AUC of 0.736, accuracy of 86%, F1-score of 85.9%, precision of 85.6% and recall of 86.3%. The accuracy was the highest for Group 2 and least for Group 3 eyes. The top 6 parameters used for classification by the AI were microneuromas, immature and mature dendritic cells, presence of orthoptic issues and nerve fractal dimension parameter.

CONCLUSIONS

This study demonstrated that various corneal nerve parameters, presence or absence of systemic and orthoptic issues coupled with AI can be a useful technique to understand and correlate the various clinical and imaging parameters of ocular surface pain.

Corneal Cellular and Neuroinflammatory Changes After SARS-CoV-2 Infection

PURPOSE

The purpose of this study was to evaluate corneal cellular and ultrastructural changes and to quantify the neuroinflammatory process in patients after mild severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

METHODS

Thirty patients after SARS-CoV-2 infection and 41 age-matched controls were examined. All subjects underwent in vivo confocal microscopy of the corneal cell layers and subbasal nerve fibers with the Heidelberg Retina Tomograph II. Semiautomated analysis of basal epithelial, anterior and posterior stromal keratocyte, and endothelial cell density was performed. Dendritic cell (DC) density and area were also calculated, and subbasal nerve plexus morphology was analyzed.

RESULTS

The posterior stromal keratocyte density was significantly lower in patients after SARS-CoV-2 infection ( P = 0.0006). DC density in the central cornea was significantly higher in patients after SARS-CoV-2 infection ( P = 0.0004). There was a significant difference in the DC area between the 2 groups ( P < 0.0001). Significantly altered subbasal nerve fiber morphology was detected in patients after SARS-CoV-2 infection compared with healthy volunteers ( P < 0.05).

CONCLUSIONS

Corneal cellular and ultrastructural changes demonstrated in this study suggest neuroinflammatory consequences of COVID-19 in the cornea in the absence of ophthalmoscopic alterations.

Corneal Confocal Microscopy Features and Tear Molecular Profile in Study Participants with Discordance between Ocular Surface Disease Clinical Signs and Discomfort

Various ocular surface conditions such as dry eye disease can present with severe discomfort and pain. However, it is clinically challenging to establish etiology and prescribe correct treatment in patients who have a lot of discordance between symptoms and signs. To understand the basis of such discordance, we stratified subjects with ocular surface pain based on concordance between the severity of signs and symptoms and evaluated corneal structural features and tear molecular factors. All subjects underwent slit lamp examination, dry eye evaluation, and ocular surface disease index (OSDI) scoring. Subjects were stratified into group 1—without symptoms or clinical signs; group 2—without symptoms but with signs; group 3—with similar severity of symptoms and signs; and group 4—with symptom severity greater than that of the signs. Laser scanning in vivo confocal microscopy (IVCM) and tear fluid analysis for soluble factors by multiplex ELISA was performed for all subjects. Patients with a higher grade of symptoms and signs showed increased corneal dendritic cell (cDC) density (p < 0.05) which was more pronounced in subjects with discordance between the symptoms and signs (group 4). A significantly higher proportion of microneuroma-like structures and cDC were observed in group 4. IL-17A levels were significantly elevated in the tears of subjects with more discomfort. Our results demonstrate that corneal IVCM and the measurement of tear film factors can help clinicians improve diagnosis and treatment choice. Stratifying patients with ocular surface discomfort on the basis of discordance between symptoms and clinical signs may help identify patients who need additional adjunctive targeted therapy to resolve their condition.

Keeping an 'eye' on ocular GVHD

Ocular graft versus host disease (GVHD) is a common manifestation in patients undergoing allogeneic haematopoietic stem cell transplantation (allo-HSCT). Ocular GVHD affects approximately 10% of patients with acute GVHD and more than 50% of patients with chronic GVHD. Symptoms of dry eye disease are one of the clinical hallmarks of ocular GVHD, and inflammatory changes to the ocular surface, cornea, conjunctiva, eyelids and lacrimal glands have been observed. Less commonly, the posterior segment of the eye is involved in the form of microvascular retinopathy, scleritis or intraretinal and vitreous haemorrhage. Although ocular GVHD does not usually result in permanent visual loss, it often impairs the patient's quality of life and activities of daily living. Regular and more consistent ocular assessment of allo-HSCT patients, including screening prior to transplantation will allow for the earlier detection and treatment of ocular complications associated with GVHD and potentially prevent more severe outcomes. The implementation of additional screening including corneal endothelial cell density assessment and non-invasive analysis of tear biomarkers may be valuable additions to current clinical testing and assist in better detection and clinical intervention in patients with GVHD. This review describes the clinical features, diagnostic criteria and clinical scoring of ocular GVHD, as well as current treatment strategies and potential ophthalmic screening tools for common ocular complications. Further, we describe the clinical and histopathological features of ocular GVHD in preclinical mouse models.

Observation of Chronic Graft-Versus-Host Disease Mouse Model Cornea with In Vivo Confocal Microscopy

Graft-versus-host disease (GVHD) is a major complication after hematopoietic stem cell transplantation (HSCT), and ocular GVHD can cause severe dry eye disease that can lead to visual impairment. Epithelial damage, vascular invasion, corneal fibrosis, and corneal perforation may occur in severe cases. It is generally accepted that inflammatory cells such as dendritic cells and T cells contribute to this pathological condition. However, it is still unknown what pathological condition occurs on the ocular surface after HSCT, and when. We therefore observed the dynamics of inflammatory cells in the cornea of chronic GVHD (cGVHD) model mice from 1 to 4 weeks after bone marrow transplantation (BMT) by in vivo confocal microscopy (IVCM) and considered the relationship with the pathophysiology of ocular GVHD (tear volume, corneal epithelial damage). In the allogeneic group, neovascularization occurred in all eyes at 1 week after BMT, although almost all vessels disappeared at 2 weeks after BMT. In addition, we revealed that infiltration of globular cells, and tortuosity and branching of nerves in the cornea occurred in both cGVHD mice and human cGVHD patients. Thus, we consider that cGVHD mouse model study by IVCM reproduces the state of ocular GVHD and may contribute to elucidating the pathological mechanism for ocular GVHD.

Alterations in corneal nerves in different subtypes of dry eye disease: An in vivo confocal microscopy study

PURPOSE

To evaluate corneal subbasal nerve alterations in evaporative and aqueous-deficient dry eye disease (DED) as compared to controls.

METHODS

In this retrospective, cross-sectional, controlled study, eyes with a tear break-up time of less than 10 s were classified as DED. Those with an anesthetized Schirmer's strip of less than 5 mm were classified as aqueous-deficient DED. Three representative in vivo confocal microscopy images were graded for each subject for total, main, and branch nerve density and numbers.

RESULTS

Compared to 42 healthy subjects (42 eyes), the 70 patients with DED (139 eyes) showed lower total (18,579.0 ± 687.7 μm/mm² vs. 21,014.7 ± 706.5, p = 0.026) and main (7,718.9 ± 273.9 vs. 9,561.4 ± 369.8, p < 0.001) nerve density, as well as lower total (15.5 ± 0.7/frame vs. 20.5 ± 1.3, p = 0.001), main (3.0 ± 0.1 vs. 3.8 ± 0.2, p = 0.001) and branch (12.5 ± 0.7 vs. 16.5 ± 1.2, p = 0.004) nerve numbers. Compared to the evaporative DED group, the aqueous-deficient DED group showed reduced total nerve density (19,969.9 ± 830.7 vs. 15,942.2 ± 1,135.7, p = 0.006), branch nerve density (11,964.9 ± 749.8 vs. 8,765.9 ± 798.5, p = 0.006), total nerves number (16.9 ± 0.8/frame vs. 13.0 ± 1.2, p = 0.002), and branch nerve number (13.8 ± 0.8 vs. 10.2 ± 1.1, p = 0.002).

CONCLUSIONS

Patients with DED demonstrate compromised corneal subbasal nerves, which is more pronounced in aqueous-deficient DED. This suggests a role for neurosensory abnormalities in the pathophysiology of DED.

Cascade of Inflammatory, Fibrotic Processes, and Stress-Induced Senescence in Chronic GVHD-Related Dry Eye Disease

Ocular graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation. Ocular GVHD affects recipients' visual function and quality of life. Recent advanced research in this area has gradually attracted attention from a wide range of physicians and ophthalmologists. This review highlights the mechanism of immune processes and the molecular mechanism, including several inflammation cascades, pathogenic fibrosis, and stress-induced senescence related to ocular GVHD, in basic spectrum topics in this area. How the disease develops and what kinds of cells participate in ocular GVHD are discussed. Although the classical immune process is a main pathological pathway in this disease, senescence-associated changes in immune cells and stem cells may also drive this disease. The DNA damage response, p16/p21, and the expression of markers associated with the senescence-associated secretory phenotype (SASP) are seen in ocular tissue in GVHD. Macrophages, T cells, and mesenchymal cells from donors or recipients that increasingly infiltrate the ocular surface serve as the source of increased secretion of IL-6, which is a major SASP driver. Agents capable of reversing the changes, including senolytic reagents or those that can suppress the SASP seen in GVHD, provide new potential targets for the treatment of GVHD. Creating innovative therapies for ocular GVHD is necessary to treat this intractable ocular disease.

Update on ocular graft-versus-host disease

Ocular graft-versus-host disease (oGVHD) occurs as a complication following hematopoietic stem cell transplantation and is associated with significant ocular morbidity resulting in a marked reduction in the quality of life. With no current consensus on treatment protocols, management becomes challenging as recurrent oGVHD often refractory to conventional treatment. Most authors now diagnose and grade the disease based on criteria provided by the National Institutes of Health Consensus Conference (NIH CC) or the International Chronic oGVHD (ICCGVHD) consensus group. This article will provide an insight into the diagnostic criteria of oGVHD, its classification, and clinical severity grading scales. The inflammatory process in oGVHD can involve the entire ocular surface including the eyelids, meibomian gland, corneal, conjunctiva, and lacrimal system. The varied clinical presentations and treatment strategies employed to manage them have been discussed in the present study. The recent advances in ocular surface imaging in oGVHD patients such as the use of meibography and in vivo confocal microscopy may help in early diagnosis and prognostication of the disease. Researching tear proteomics and identification of novel potential tear biomarkers in oGVHD patients is an exciting field as they may help in objectively diagnosing the disease and monitoring the response to treatment.

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: IIa. The 2020 Clinical Implementation and Early Diagnosis Working Group Report

Recognition of the earliest signs and symptoms of chronic graft-versus-host disease (GVHD) that lead to severe manifestations remains a challenge. The standardization provided by the National Institutes of Health (NIH) 2005 and 2014 consensus projects has helped improve diagnostic accuracy and severity scoring for clinical trials, but utilization of these tools in routine clinical practice is variable. Additionally, when patients meet the NIH diagnostic criteria, many already have significant morbidity and possibly irreversible organ damage. The goals of this early diagnosis project are 2-fold. First, we provide consensus recommendations regarding implementation of the current NIH diagnostic guidelines into routine transplant care, outside of clinical trials, aiming to enhance early clinical recognition of chronic GVHD. Second, we propose directions for future research efforts to enable discovery of new, early laboratory as well as clinical indicators of chronic GVHD, both globally and for highly morbid organ-specific manifestations. Identification of early features of chronic GVHD that have high positive predictive value for progression to more severe manifestations of the disease could potentially allow for future pre-emptive clinical trials.

Two case reports of continued progression of chronic ocular graft-versus-host disease without concurrent systemic comorbidities treated by amniotic membrane transplantation

Background

Chronic ocular graft-versus-host disease (oGVHD) is an ocular comorbidity of graft-versus-host disease (GVHD) that usually occurs concurrently with systemic manifestations. Failure to detect and treat oGVHD in its early stages may lead to progression of ocular signs and symptoms leading to oGVHD that is refractory to conventional treatment.

Case presentation

We report the clinical course of a 19-year-old male and a 59-year-old female with severe and progressive chronic oGVHD without concurrent systemic signs of chronic graft-versus-host disease (cGVHD). Although their systemic conditions had been stable, both suffered from severe oGVHD and were referred to our clinic. Both cases exhibited marked improvement in conjunctival inflammation and fibrotic changes after amniotic membrane transplantation (AMT). Both cases underwent keratoplasty eventually to stabilize ocular surface conditions and to improve visual function.

Conclusions

We reported the clinical outcomes of 2 cases of chronic oGVHD without concurrent systemic comorbidities that were treated with AMT. The clinician should be aware that cGVHD may persist in target organs even in the absence of concurrent systemic comorbidities following seemingly successful systemic treatment. A multidisciplinary team approach is essential in the early detection and therapeutic intervention for chronic oGVHD.

Can in vivo confocal microscopy differentiate between sub-types of dry eye disease? A review

Many studies utilised in vivo confocal microscopy (IVCM) to associate variations in corneal structures with dry eye disease (DED). However, DED is an umbrella term that covers various aetiologies and presentations. This review analyses populations by DED aetiology to determine the relationships between IVCM parameters and specific DED sub-types. It focuses on the most commonly examined structures, sub-basal nerves and dendritic cells. Across the literature, most studies found individuals with immune-mediated DED had lower sub-basal nerve fibre number and density than controls, with smaller differences between non-immune DED and controls. However, wide ranges of values reported across studies demonstrate considerable overlap between DED sub-types and controls, rendering these metrics less helpful when diagnosing an individual patient. Dendritic cell density was considerably higher in individuals with immune-mediated DED than in non-immune DED or controls. As such, dendritic cell density may be a better indicator of DED associated with a systemic immune-mediated process.

Altered Corneal Epithelial Dendritic Cell Morphology and Phenotype Following Acute Exposure to Hyperosmolar Saline

Purpose

The purpose of this study was to assess the morphological and phenotypic responses of corneal epithelial dendritic cells (DCs) to acute topical hyperosmolar stress, given a pathogenic role for tear hyperosmolarity in dry eye disease (DED).

Methods

C57BL/6J mice were anesthetized and received 350 mOsm/L (physiological; n = 5 mice), 450 mOsm/L (n = 6), or 600 mOsm/L (n = 6) saline on a randomly assigned eye. Corneas were harvested 2 hours later. Immunofluorescent staining was performed using CD45, CD86, and CD68 antibodies to investigate DC morphology (density, viability, field area, circularity, and dendritic complexity) and immunological phenotype. Flow cytometry was used to confirm CD86 and CD68 expression in CD11c⁺ DCs, using C57BL/6J mice that received topical applications of 350 mOsm/L, 450 mOsm/L, or 600 mOsm/L (n = 5 per group) bilaterally for 2 hours.

Results

Following exposure to 450 mOsm/L topical saline for 2 hours, DCs in the central and peripheral cornea were larger (field area: P_central = 0.005, P_peripheral = 0.037; circularity: P_central = 0.026, and P_peripheral = 0.013) and had higher expression of CD86 compared with 350 mOsm/L controls (immunofluorescence: P < 0.0001; flow cytometry: P = 0.0058). After application of 600 mOsm/L saline, DC morphology was unchanged, although the percentage of fragmented DCs, and phenotypic expression of CD86 (immunofluorescence: P < 0.0001; and flow cytometry: P = 0.003) and CD68 (immunofluorescence: P = 0.024) were higher compared to 350 mOsm/L controls.

Conclusions

Short-term exposure to mild hyperosmolar saline (450 mOsm/L) induced morphological and phenotypic maturation in corneal epithelial DCs. More severe hyperosmolar insult (600 mOsm/L) for 2 hours appeared toxic to these cells. These data suggest that hyperosmolar conditions activate corneal DCs, which may have implications for understanding DC activation in DED.

A Review of Imaging Biomarkers of the Ocular Surface

A biomarker is a "characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions." Recently, calls for biomarkers for ocular surface diseases have increased, and advancements in imaging technologies have aided in allowing imaging biomarkers to serve as a potential solution for this need. This review focuses on the state of imaging biomarkers for ocular surface diseases, specifically non-invasive tear break-up time (NIBUT), tear meniscus measurement and corneal epithelial thickness with anterior segment optical coherence tomography (OCT), meibomian gland morphology with infrared meibography and in vivo confocal microscopy (IVCM), ocular redness with grading scales, and cellular corneal immune cells and nerve assessment by IVCM. Extensive literature review was performed for analytical and clinical validation that currently exists for potential imaging biomarkers. Our summary suggests that the reported analytical and clinical validation state for potential imaging biomarkers is broad, with some having good to excellent intra- and intergrader agreement to date. Examples of these include NIBUT for dry eye disease, ocular redness grading scales, and detection of corneal immune cells by IVCM for grading and monitoring inflammation. Further examples are nerve assessment by IVCM for monitoring severity of diabetes mellitus and neurotrophic keratitis, and corneal epithelial thickness assessment with anterior segment OCT for the diagnosis of early keratoconus. However, additional analytical validation for these biomarkers is required before clinical application as a biomarker.

The Association between Meibomian Gland Atrophy and Corneal Subbasal Nerve Loss in Patients with Chronic Ocular Graft-versus-host Disease

Purpose: To investigate the association between meibomian gland (MG) loss and corneal subbasal nerve plexus density in patients with chronic graft-versus-host disease (GVHD) related dry eye disease (DED).Materials and Methods: This cross-sectional study included 22 adult patients with severe DED secondary to chronic GVHD. Control group comprised age- and sex-matched 28 healthy subjects with no evidence of ocular disease. All subjects underwent tear breakup time (TBUT), corneal staining, Schirmer I test without anesthesia, quantitative MG drop-out assessment using infrared meibography and corneal subbasal nerve density measurements with in vivo confocal microscopy (IVCM) (ConfoScan4, Nidek, Japan). One eye per patient was included for statistical purposes. Mann-Whitney U test and one-way multivariate ANOVA test were used for comparative analyses.Results: Compared to healthy subjects (mean age = 26.9 ± 13.5 years (range = 20-44 years)), patients with chronic GVHD (mean age = 29.6 ± 12.6 years (range = 19-45 years)) had worse meibography scores (p < .001), reduced corneal subbasal nerve plexus densities (p < .001), lower TBUT scores (p = .012), lower Schirmer I values (p = .001) and higher corneal staining scores (p = 003). Meiboscores in the GVHD and control groups were 2.9 ± 1.1 (range = 1-4) vs. 0.7 ± 0.4 (range = 0-2) for the superior (p < .001), and 3.2 ± 1.2 (range = 2-4) vs. 0.5 ± 0.3 (range = 0-2) for inferior (p < .001) eyelids, respectively. Corneal subbasal nerve densities of patients with GVHD did not reveal a correlation with meiboscores (r = 0.030; p = .709 for the inferior and r = 0.268; p = .075 for the superior eyelids) but showed a weak correlation with Schirmer I test values (r = 0.268; p = .014).Conclusions: Patients with chronic GVHD are at high risk for developing DED and MG dysfunction. In the setting of chronic GVHD-related DED, MG loss does not appear to be a significant factor for corneal subbasal nerve damage.

Corneal Nerve Abnormalities in Ocular and Systemic Diseases

The trigeminal nerve gives rise to the corneal subbasal nerve system, which plays a crucial role in sensations of touch, pain, and temperature and in ocular healing processes. Technological advancements in instruments, in particular in vivo confocal microscopy and aethesiometry, have allowed for the structural and functional evaluation of corneal nerves in health and disease. Through application of these technologies in humans and animal models, structural and functional abnormalities have been detected in several ocular and systemic disorders, including dry eye disease (DED), glaucoma, migraine, and fibromyalgia. However, studies across a number of conditions have found that structural abnormalities do not always relate to functional abnormalities. This review will discuss instruments used to evaluate corneal nerves and summarize data on nerve abnormalities in a number of ocular and systemic conditions. Furthermore, it will discuss potential treatments that can alleviate the main manifestations of nerve dysfunction, namely ocular surface pain and persistent epithelial defects.

Correlation of corneal immune cell changes with clinical severity in dry eye disease: An in vivo confocal microscopy study

PURPOSE

To evaluate corneal immune dendritiform cell (DC) changes in dry eye disease (DED) using in vivo confocal microscopy (IVCM) and to correlate IVCM parameters with clinical severity.

METHODS

This was a retrospective, cross-sectional study including 300 eyes of 150 DED patients and 49 eyes of 49 age-matched controls. Severity of DED was based on the Dry Eye Workshop (DEWS) classification. IVCM images of subbasal layer of the central cornea were analyzed for DC density and morphology (including number of dendrites per DC, DC size and DC field).

RESULTS

DC density was significantly higher in DED compared to controls (93.4 ± 6.3 vs. 25.9 ± 3.9 cells/mm²; P < 0.001). Morphologically, number of dendrites, DC size and field were significantly larger in DED (3.3 ± 0.1, 106.9 ± 4.7 μm², 403.8 ± 20.1 μm² than controls (2.3 ± 0.1, 62.5 ± 5.7 μm², 241.4 ± 24.4 μm², P < 0.001). Significantly higher DC density compared to controls was observed as early as Level 1 DED severity (87 ± 10 cells/mm², p < 0.001. Significant morphological changes in DC were detected for Levels 2 to 4 (p=<0.001, and p =< 0.05) for dendrites and DC field, respectively. Similarly, DC size showed significant increase at DED level 3-4. (p < 0.05). Linear regression analysis showed that both conjunctival and corneal staining were independently associated with DC density, while corneal staining was independently associated with DC morphology.

CONCLUSION

DC density and morphology correlated with clinical severity of DED. While, DC density is increased in mild DED, morphological changes are seen only in severe cases. IVCM may be a powerful tool to detect early immune changes and may complement clinical examination in DED.

Limbal and Conjunctival Epithelial Thickness in Ocular Graft-Versus-Host Disease

PURPOSE

To compare the thickness of the limbal epithelium (LE) and the bulbar conjunctival epithelium (BCE) between patients with dry eye disease (DED) with and without ocular graft-versus-host disease (GVHD).

METHODS

This cross-sectional study enrolled 40 patients with moderate to severe DED including 20 with and 20 without chronic ocular GVHD. All patients had a comprehensive clinical ophthalmic assessment. Moreover, the thickness of the LE and BCE in both nasal and temporal regions of both eyes was measured using spectral domain optical coherence tomography.

RESULTS

The average LE thickness in all patients with dry eye (GVHD and non-GVHD) was 65.8 ± 11.9 μm temporally and 69.7 ± 11.1 μm nasally (P = 0.02). The average BCE thickness was 55.8 ± 11.4 μm temporally and 60.1 ± 11.0 μm nasally (P = 0.03). There were no statistically significant differences between GVHD and non-GVHD groups in LE thickness (69.6 ± 11.7 vs. 66.1 ± 6.2 μm, respectively, P = 0.31) or BCE thickness (58.9 ± 9.6 vs. 57.3 ± 9.8 μm, respectively, P = 0.82). There was a significant correlation between LE thickness and BCE thickness (P = 0.01, Rs = 0.41). A statistically significant negative correlation was also observed between LE thickness and age (P = 0.002, Rs = -0.35). There were no significant correlations between the thickness of the LE or BCE and other clinical parameters.

CONCLUSIONS

No difference exists in the thickness of the ocular surface epithelia between dry eyes with and without ocular GVHD, which would suggest that these epithelial changes may be independent of the underlying etiology and possibly only reflect the disease severity. Furthermore, there are regional variations in the thickness of the ocular surface epithelia in patients with DED.

The Innate Immune Cell Profile of the Cornea Predicts the Onset of Ocular Surface Inflammatory Disorders

Ocular surface inflammatory disorder (OSID) is a spectrum of disorders that have features of several etiologies whilst displaying similar phenotypic signs of ocular inflammation. They are complicated disorders with underlying mechanisms related to several autoimmune disorders, such as rheumatoid arthritis (RA), Sjögren’s syndrome, and systemic lupus erythematosus (SLE). Current literature shows the involvement of both innate and adaptive arms of the immune system in ocular surface inflammation. The ocular surface contains distinct components of the immune system in the conjunctiva and the cornea. The normal conjunctiva epithelium and sub-epithelial stroma contains resident immune cells, such as T cells, B cells (adaptive), dendritic cells, and macrophages (innate). The relative sterile environment of the cornea is achieved by the tolerogenic properties of dendritic cells in the conjunctiva, the presence of regulatory lymphocytes, and the existence of soluble immunosuppressive factors, such as the transforming growth factor (TGF)-β and macrophage migration inhibitory factors. With the presence of both innate and adaptive immune system components, it is intriguing to investigate the most important leukocyte population in the ocular surface, which is involved in immune surveillance. Our meta-analysis investigates into this with a focus on both infectious (contact lens wear, corneal graft rejection, Cytomegalovirus, keratitis, scleritis, ocular surgery) and non-infectious (dry eye disease, glaucoma, graft-vs-host disease, Sjögren’s syndrome) situations. We have found the predominance of dendritic cells in ocular surface diseases, along with the Th-related cytokines. Our goal is to improve the knowledge of immune cells in OSID and to open new dimensions in the field. The purpose of this study is not to limit ourselves in the ocular system, but to investigate the importance of dendritic cells in the disorders of other mucosal organs (e.g., lungs, gut, uterus). Holistically, we want to investigate if this is a common trend in the initiation of any disease related to the mucosal organs and find a unified therapeutic approach. In addition, we want to show the power of computational approaches to foster a collaboration between computational and biological science.

Complement and CD4+ T cells drive context-specific corneal sensory neuropathy

Whether complement dysregulation directly contributes to the pathogenesis of peripheral nervous system diseases, including sensory neuropathies, is unclear. We addressed this important question in a mouse model of ocular HSV-1 infection, where sensory nerve damage is a common clinical problem. Through genetic and pharmacologic targeting, we uncovered a central role for C3 in sensory nerve damage at the morphological and functional levels. Interestingly, CD4 T cells were central in facilitating this complement-mediated damage. This same C3/CD4 T cell axis triggered corneal sensory nerve damage in a mouse model of ocular graft-versus-host disease (GVHD). However, this was not the case in a T-dependent allergic eye disease (AED) model, suggesting that this inflammatory neuroimmune pathology is specific to certain disease etiologies. Collectively, these findings uncover a central role for complement in CD4 T cell-dependent corneal nerve damage in multiple disease settings and indicate the possibility for complement-targeted therapeutics to mitigate sensory neuropathies.

Inflammatory Response in Dry Eye

Purpose

Dry eye is a major ocular pathology worldwide. Although dry eye is a multifactorial disease, recent studies have shown that chronic immunologic processes have a pivotal role in its pathogenesis, characterized by the infiltration of immune cells in the lacrimal glands, elevated levels of tear inflammatory cytokines, and increased density of immune cells in the cornea and conjunctiva. This review describes the recent advances in understanding the relationship between dry eye and inflammation.

Methods

This narrative review is based on searches of recent international literature using terms related to the immune response in dry eye, and includes clinical trials, animal experiments, and expert reviews.

Results

Although dry eye presents clinically as tear film instability associated with corneal/conjunctival epithelial disorders, Meibomian gland dysfunction, and decreased visual function, recent laboratory and clinical studies have indicated inflammation in the lacrimal glands, Meibomian glands, conjunctiva, cornea, and aqueous tears. Furthermore, inflammation at these locations leads to conjunctival goblet cell apoptosis, corneal epithelial barrier disruption, and corneal nerve damage. These inflammatory outcomes can be exacerbated by intrinsic and extrinsic factors, such as aging, sex steroid hormone, autoimmune diseases, contact lens use, visual display terminals, and dry environment.

Conclusions

Recent advances in dry eye research have revealed the inflammatory process and its pathogenesis, which has been proposed as an "inflammatory vicious cycle" of dry eye. Comprehensive assessment of dry eye based on inflammation will improve the selection of treatments and help break the inflammatory cycle in clinical settings.

Sjögren's Syndrome, Non-Sjögren's Syndrome, and Graft-Versus-Host Disease Related Dry Eye

I have reviewed available literature on dry eye related to Sjögren's syndrome (SS), non-Sjögren's syndrome (non-SS), and graft-versus-host disease (GVHD) to examine aqueous tear deficient dry eye as a subtype of dry eye. This section will focus on clinical studies regarding those subtypes of dry eye. I searched the PubMed database from 1990-2017 for discussion of clinical features, diagnostic criteria, and risk factors of SS, non-SS, and GVHD-related dry eye. In addition, therapeutic options for each subtype of dry eye are described. Although the clinical presentations of SS and chronic graft-versus-host disease (cGVHD) are similar, ocular surface fibrotic changes are characteristic of ocular GVHD but not SS- or non-SS-related dry eye. Recently, diagnostic criteria for each disease have been proposed and include the American College of Rheumatology/European League Against Rheumatism (ACR-EULAR) for SS and the International Chronic Ocular GVHD consensus criteria. Although there has been gradual progress, there are currently no specific therapies and few approved treatment options for these intractable diseases, including SS and GVHD. As judged by the findings, these subtypes of dry eye are different clinical entities from simple dry eye. Therefore, novel therapies, specific to these subtypes of dry eye, may be required in the future.

Application of In Vivo Confocal Microscopy in Dry Eye Disease

Confocal microscopy is a new, emerging, noninvasive technology that can aid in the in vivo assessment of structural changes in several ocular surface diseases at the cellular level. In the dry eye field, in vivo confocal microscopy has been applied to the examination of the cornea, bulbar and palpebral conjunctiva, Meibomian gland, and lacrimal gland. The device can assess the morphology, including superficial/wing/basal epithelial cell density, stromal keratocyte density, endothelial cell density, nerve fiber density, the number of beadings, nerve tortuosity, nerve reflectivity, and inflammatory cell density in the cornea. Furthermore, the device can not only assess epithelial cell density and area, goblet cell, microcyst, and inflammatory cell density but also the cellular architecture, including nucleocytoplasmic ratio in conjunctiva. The device also can disclose acinar unit density, acinar unit longest diameter, acinar unit shortest diameter, and inflammatory cell density in the Meibomian gland and lacrimal gland by other potential applications. Relevant research in Europe and the United States focused on the morphologic changes in the cornea in the dry eye field, while Japanese research focused on the conjunctival, Meibomian gland, and lacrimal gland alterations. The application of in vivo confocal microscopy in dry eye disease will be a powerful method to evaluate the morphologic change of the ocular surface around the world in the future.

Ocular surface system alterations in ocular graft-versus-host disease: all the pieces of the complex puzzle

PURPOSE

Graft-versus-host disease (GVHD) is a major complication of allogeneic hematopoietic stem cells transplantation, occurring in about half of transplanted patients. This condition seems to be the result of a progressive immune-mediated damage that can involve various tissues, including the eyes. The ocular surface system is the ocular structure most frequently impaired, and dry eye disease is considered the hallmark of ocular GVHD. Given the increasing prevalence and the frequent severe involvement of the ocular surface with vision-threatening complications, ocular GVHD represents a current diagnostic and therapeutic challenge. The purpose of this literature review is to describe all the clinical manifestations occurring in the setting of ocular GVHD, and to further report the outcomes of conventional and novel therapies.

METHODS

A literature search about ocular GVHD was performed in PubMed, Scopus, Medline databases, and ClinicalTrials.gov as well as through the reference lists of identified publications until January 2019. We have included RCTs, prospective observational studies, prospective and retrospective cohort studies, pilot studies, and review articles.

RESULTS

Overall, 107 articles, 3 book chapters, and 6 ongoing registered clinical trials were collected and analyzed. Ocular GVHD can affect all the structures of the entire ocular surface system, including lacrimal and meibomian glands, cornea, conjunctiva, eyelids, nasolacrimal duct, and tears. Current medical treatment is mainly focused on lubrication and control of drainage, tear evaporation, and ocular surface inflammation. Surgical treatment may be necessary in severe, recalcitrant, or complicated cases. Amniotic membrane and tectonic keratoplasty can be valid options to restore the integrity of the cornea. Recently, conjunctival and limbal transplantation from the same living-related bone marrow donor has been proposed to manage both dry eye and limbal stem cell deficiency, without any risk of immunologic rejection.

CONCLUSION

This review provides an up-to-date analysis on clinical findings and current and future management of ocular GVHD. A correct and prompt diagnosis along with an appropriate and aggressive treatment are fundamental for avoiding the occurrence of vision-threatening complications.

Ocular graft-versus-host disease after hematopoietic cell transplantation: Expert review from the Late Effects and Quality of Life Working Committee of the CIBMTR and Transplant Complications Working Party of the EBMT

Ocular graft-versus-host disease (GVHD) occurs in more than half of patients who develop chronic GVHD after allogeneic hematopoietic cell transplantation (HCT), causing prolonged morbidity, which affects activities of daily living and quality of life. Here we provide an expert review of ocular GVHD in a collaboration between transplant physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Recent updates in ocular GVHD, regarding pathophysiology, preclinical models, risk factors, prevention, screening, diagnosis, response criteria, evaluation measures, and treatment are discussed in this review. Ocular GVHD has at least three biological processes: lacrimal gland dysfunction, meibomian gland dysfunction, and corneoconjunctival inflammation. Preclinical models have found several novel pathogenic mechanisms, including renin angiotensin system and endoplasmic reticulum stress signaling that can be targeted by therapeutic agents. Many studies have identified reliable tests for establishing diagnosis and response assessment of ocular GVHD. Efficacy of systemic and topical treatment for ocular GVHD is summarized. It is important for all health professionals taking care of HCT recipients to have adequate knowledge of ocular GVHD for optimal care.

Ocular Graft-versus-Host Disease after Hematopoietic Cell Transplantation: Expert Review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation

Ocular graft-versus-host disease (GVHD) occurs in more than one-half of patients who develop chronic GVHD after allogeneic hematopoietic cell transplantation (HCT), causing prolonged morbidity that affects activities of daily living and quality of life. Here we provide an expert review of ocular GVHD in a collaboration between transplantation physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Recent updates in ocular GVHD regarding pathophysiology, preclinical models, risk factors, prevention, screening, diagnosis, response criteria, evaluation measures, and treatment are discussed. Ocular GVHD involves at least 3 biological processes: lacrimal gland dysfunction, meibomian gland dysfunction, and corneoconjunctival inflammation. Preclinical models have identified several novel pathogenic mechanisms, including the renin angiotensin system and endoplasmic reticulum stress signaling, which can be targeted by therapeutic agents. Numerous studies have identified reliable tests for establishing diagnosis and response assessment of ocular GVHD. The efficacy of systemic and topical treatment for ocular GVHD is summarized. It is important that all health professionals caring for HCT recipients have adequate knowledge of ocular GVHD to provide optimal care.