Corneal confocal scanning laser microscopy in patients with dry eye disease treated with topical cyclosporine

Geometrical Features of Subbasal Corneal Whorl-like Nerve Patterns in Dry Eye Disease: An In Vivo Confocal Microscopy Study

Purpose

To investigate the geometrical feature of the whorl-like corneal nerve in dry eye disease (DED) across different severity levels and subtypes and preliminarily explore its diagnostic ability.

Design

Cross-sectional study.

Participants

The study included 29 healthy subjects (51 eyes) and 62 DED patients (95 eyes).

Methods

All subjects underwent comprehensive ophthalmic examinations, dry eye tests, and in vivo confocal microscopy to visualize the whorl-like corneal nerve at the inferior whorl (IW) region and the straight nerve at the central cornea. The structure of the corneal nerve was extracted and characterized using the fractal dimension (CNDf), multifractal dimension (CND0), tortuosity (CNTor), fiber length (CNFL), and numbers of branching points.

Main Outcome Measures

The characteristics of quantified whorl-like corneal nerve metrics in different groups of severity and subtype defined by symptoms and signs of DED.

Results

Compared with the healthy controls, the CNDf, CND0, and CNFL of the IW decreased significantly as early as grade 1 DED (P < 0.05), whereas CNTor increased (P < 0.05). These parameters did not change significantly in the straight nerve. As the DED severity increased, CNDf and CNFL in the whorl-like nerve further decreased in grade 3 DED compared with grade 1. Significant nerve fiber loss was observed in aqueous-deficient DED compared with evaporative DED (P < 0.05). Whorl-like nerve metrics correlated with ocular discomfort, tear film break-up time, tear secretion, and corneal fluorescein staining, respectively (P < 0.05). Furthermore, merging parameters of whorl-like and linear nerve showed an area under the curve value of 0.910 in diagnosing DED.

Conclusions

Geometrical parameters of IW could potentially allow optimization of the staging of DED. Reliable and objective measurements for the whorl-like cornea nerve might facilitate patient stratification and diagnosis of DED.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Segmentation and multiparametric evaluation of corneal whorl-like nerves for in vivo confocal microscopy images in dry eye disease

OBJECTIVE

To establish an automated corneal nerve analysis system for corneal in vivo confocal microscopy (IVCM) images from both the whorl-like corneal nerves in the inferior whorl (IW) region and the straight ones in the central cornea and to characterise the geometric features of cornea nerves in dry eye disease (DED).

METHODS AND ANALYSIS

An encoder-decoder-based semi-supervised method was proposed for corneal nerve segmentation. This model's performance was compared with the ground truth provided by experienced clinicians, using Dice similarity coefficient (DSC), mean intersection over union (mIoU), accuracy (Acc), sensitivity (Sen) and specificity (Spe). The corneal nerve total length (CNFL), tortuosity (CNTor), fractal dimension (CNDf) and number of branching points (CNBP) were used for further analysis in an independent DED dataset including 50 patients with DED and 30 healthy controls.

RESULTS

The model achieved 95.72% Acc, 97.88% Spe, 80.61% Sen, 75.26% DSC, 77.57% mIoU and an area under the curve value of 0.98. For clinical evaluation, the CNFL, CNBP and CNDf for whorl-like and straight nerves showed a significant decrease in DED patients compared with healthy controls (p<0.05). Additionally, significantly elevated CNTor was detected in the IW in DED patients (p<0.05). The CNTor for straight corneal nerves, however, showed no significant alteration in DED patients (p>0.05).

CONCLUSION

The proposed method segments both whorl-like and straight corneal nerves in IVCM images with high accuracy and offered parameters to objectively quantify DED-induced corneal nerve injury. The IW is an effective region to detect alterations of multiple geometric indices in DED patients.

Confocal Microscopy of the Cornea in Aqueous-Deficient Dry Eye Disease-A Literature Review

BACKGROUND

In vivo confocal microscopy (IVCM) is a vital tool in studying dry eye disease (DED), providing insights into morphological changes at ocular surface unit levels. This review presents the main differences in corneal structure between aqueous-deficient dry eye disease (AD-DED) and normal eyes.

METHODS

A comprehensive search of PubMed, Web of Science, Embase, and MEDLINE databases from January 2000 to December 2023 was conducted. The study selection process, as well as data selection and examination, were independently performed by two members of the review team.

RESULTS

The review reveals a consistent decrease in corneal surface epithelial cell density in AD-DED cases compared to a control group, but conflicting data on basal epithelial cell density. Notably, the abnormal hyperreflectivity of keratocytes in patients with Sjogren's syndrome was recorded, and there was a significant keratocyte density in AD-DED subjects compared to evaporative DED and control groups. Studies also found a decrease in sub-basal nerve density, increased tortuosity, and the fragmentation of nerve fibers. Dendritic cell density and dendritic cell dendrites increase in AD-DED patients compared to healthy subjects.

CONCLUSIONS

IVCM is a powerful tool for enhancing our understanding of the pathophysiological mechanisms underlying DED. However, the review underscores the urgent need to standardize the terminology, analysis, and units used for accurate interpretation, a crucial step in advancing our knowledge of DED.

Effects of Topical 0.05% Cyclosporine A on Dry Eye Symptoms and Parameters Following Small Incision Lenticule Extraction

PURPOSE

To evaluate the effects of topical 0.05% cyclosporine A on Ocular Surface Disease Index (OSDI) score and ocular surface parameters after small incision lenticule extraction (SMILE) for myopia.

METHODS

In this study, 151 patients who underwent SMILE were randomized into the control group (71 eyes) and the 0.05% cyclosporine A group (80 eyes). Both groups received standard treatment during the 1 month after SMILE. Over the next 3 months, The control group continued standard therapy (0.3% sodium hyaluronate) and the 0.05% cyclosporine A group received additional 0.05% cyclosporine A. OSDI total and subscale scores, non-invasive tear break-up time (NIBUT), tear lipid layer thickness (LLT), and tear meniscus height (TMH) were assessed preoperatively and postoperatively.

RESULTS

Compared to baseline, the OSDI scores significantly increased in both groups (P < .001). The 0.05% cyclosporine A group exhibited lower OSDI total scores after administering 0.05% cyclosporine A versus the control group (P = .026). At 1 month of follow-up, NIBUT, LLT, and TMH values significantly decreased in both groups compared to baseline (P < .05). The 0.05% cyclosporine A group exhibited higher NIBUT, LLT, and TMH versus the control group, returning to preoperative values after 2 months. Overall, the OSDI total score and NIBUT values during follow-up were not significantly different between the two groups; however, the LLT and TMH values were significantly different between the two groups (P < .001 and .041, respectively) by repeated measures analysis of variance.

CONCLUSIONS

Topical 0.05% cyclosporine A was effective in relieving subjective dry eye symptoms and maintaining ocular surface stability in the early postoperative period of SMILE. [J Refract Surg. 2024;40(4):e229-e238.].

New advances in medical management of dry eye: optimizing treatment strategies for enhanced relief

PURPOSE

Dry eye disease (DED) is a prevalent ocular surface disease that is conventionally characterized by tear film hyperosmolarity and instability. This review presents a summarized classification of DED, followed by a comprehensive discussion of the most recent topical and systemic medications and clinical recommendations for selecting the most appropriate option for each patient.

METHODS

An extensive literature search was conducted on electronic databases, such as PubMed, Scopus, and Web of Science, using keywords including "dry eye syndrome," "ocular surface disease," "medical management," "artificial tears," "topical immunomodulators," and "meibomian gland dysfunction."

RESULTS

The underlying reasons for DED can range from insufficient aqueous tear production to increased tear evaporation. Recent literature has provided a more in-depth understanding of the pathophysiology of DED by examining the tear film's lipid, aqueous, and mucin layers. However, despite these advancements, medical management of patients with symptomatic DED has not fully reflected this modernized knowledge of its pathophysiology.

CONCLUSION

To develop a rationalized strategy for treating DED, it is crucial to have updated knowledge of therapeutic options, their mechanisms of actions, and indications based on the DED type and underlying causes.

Biomarkers of ocular allergy and dry eye disease

The most common disorders of the ocular surface are dry eye disease (DED) and ocular allergy (OA). These conditions are frequently coexisting with or without a clinical overlap and can cause a severe impact on the patient's quality of life. Therefore, it can sometimes be hard to distinguish between DED and OA because similar changes and manifestations may be present. Atopic patients can also develop DED, which can aggravate their manifestations. Moreover, patients with DED can develop ocular allergies, so these two pathological entities of the ocular surface can be considered as mutual conditions that share the same background. Nowadays, by using different techniques to collect tissue from ocular surfaces, the changes in molecular homeostasis can be detected and this can lead to a precise diagnosis. The article provides an up-to-date review of the various ocular surface biomarkers that have been identified in DED, OA, or both conditions. Abbreviations: DED = dry eye disease, OA = ocular allergy, SS = Sjogren syndrome, TBUT = tear break up time, TFO = tear film osmolarity, AKC = Atopic keratoconjunctivitis, ANXA1 = Annexin 1, ANXA11 = Annexin 11, CALT = Conjunctival associated lymphoid tissue, CCL2/MIP-1 = Chemokine (C-C motif) ligand2/Monocyte chemoattractant protein 1, CCL3/MIP-1α = Chemokine (C-C motif) ligand 3/Macrophage inflammatory protein 1 alpha, CCL4/MIP-1β = Chemokine (C-C motif) ligand 4/Macrophage inflammatory protein 1 beta, CCL5/RANTES = Chemokine (C-C motif) ligand 5 /Regulated on Activation, Normal T cell Expressed and Secreted, CCR2 = Chemokine (C-C motif) receptor 2, CCR5 = Chemokine (C-C motif) receptor 5, CD3+ = Cluster of differentiation 3 positive, CD4+ = Cluster of differentiation 4 positive, CD8+ = Cluster of differentiation 8 positive, CGRP = Calcitonin-gene-related peptide, CX3CL1 C-X3 = C motif -chemokine ligand 1 /Fractalkine, CXCL8 = Chemokine (C-X-C motif) ligand 8, CXCL9 = Chemokine (C-X-C motif) ligand 9, CXCL10 = Chemokine (C-X-C motif) ligand 10, CXCL11 = Chemokine (C-X-C motif) ligand 11, CXCL12 = Chemokine (C-X-C motif) ligand 12, CXCR4 = Chemokine (C-X-C motif) receptor 4, EGF = Epidermal growth factor, HLA-DR = Human leukocyte antigen-D-related, ICAM-1 = Intercellular adhesion molecule 1, IFN-γ = Interferon-gamma, IgG = Immunoglobulin G, IgE = Immunoglobulin E, IL-1 = Interleukin-1, IL-1α = Interleukin-1 alpha, IL-1β = Interleukin-1 beta, CGRP = Calcitonin-Gene-Related Peptide, IL-3 = Interleukin-3, IL-4 = Interleukin-4, IL-6 = Interleukin-6, IL-8 = Interleukin-8, IL-10 = Interleukin-10, IL-17 = Interleukin-17, IL-17A = Interleukin-17A, LPRR3 = Lacrimal proline-rich protein 3, LPRR4 = Lacrimal proline-rich protein 4, MUC5AC = Mucin 5 subtype AC, oligomeric mucus/gel-forming, MUC16 = Mucin 16, OCT = Optical coherence tomography, OGVHD = Ocular graft versus host disease, PAX6 = Paired-box protein 6, VKC = Vernal keratoconjunctivitis, TGF-β = Transforming growth factor β, S100 = proteins Calcium activated signaling proteins, Th1 = T helper 1 cell, Th17 = T helper 17 cell, MGD = Meibomian gland dysfunction, TFOS = Tear film and ocular surface society, SS-KCS = Keratoconjunctivitis Sicca, MMP-9 = Matrix metalloproteinase 9, MMP-1 = Matrix metalloproteinase 1, ZAG = Zinc alpha glycoprotein, CBA = Cytometric bead array, MALDI TOF-MS = matrix assisted laser desorption ionization-time of flight, SELDI TOF-MS = surface-enhanced laser desorption ionization-time of flight, IVCM = in vivo confocal microscopy, AS-OCT = anterior segment optical coherence tomography, iTRAQ = Isobaric tags for relative and absolute quantitation, LC-MS = Liquid chromatography-mass spectrometry, LCN-1 = lipocalin 1, PIP = prolactin induced protein, NGF = Nerve growth factor, PRR4 = proline rich protein 4, VIP = Vasoactive intestinal peptide, ELISA = enzyme linked immunoassay, TNF-α = tumor necrosis factor alpha, PAC = perennial allergic conjunctivitis, SAC = seasonal allergic conjunctivitis, IC = impression cytology, RT-PCR = reverse transcription polymerase chain reaction, PCR = polymerase chain reaction, APCs = antigen-presenting cells, NK cells = natural killer cells, HEL = hexanoyl-lysine, 4-HNE = 4-hydroxy-2-nonenal, MDA = malondialdehyde.

Novel Treatments for Chronic Ocular Surface Pain

ABSTRACT

Several etiologies can contribute to ocular surface pain including nociceptive, peripheral neuropathic, and central neuropathic mechanisms. Clinical clues can help identify contributors to ocular surface pain in a patient. In individuals whose pain persists despite targeting nociceptive contributors, neuropathic mechanisms should be considered and addressed using oral, topical, and/or adjuvant agents.

Evaluation of Corneal Parameters and Meibomian Gland Alterations After Corneal Cross-Linking in Patients With Progressive Keratoconus

OBJECTIVES

The aim of the study was to evaluate the changes in corneal parameters and meibomian gland alterations after corneal cross-linking (CXL) for progressive keratoconus.

METHODS

Thirty nine eyes of 39 keratoconus patients were treated with CXL. Corneal topography, specular microscopy, the Ocular Surface Disease Index© (OSDI), noninvasive tear break-up time (NITBUT), and meibography indices were evaluated preoperatively and at the first, third, and sixth months after CXL.

RESULTS

The flattest keratometry (K1) ( P =0.003), steepest keratometry (K2) ( P <0.001), apex, central, and thinnest corneal thicknesses ( P <0.001) showed significant differences after cross-linking, whereas the changes in the maximum keratometry (Kmax) were not significant ( P =0.140). The endothelial cell density, coefficient of variation, and hexagonality were unchanged. The NITBUT values decreased after cross-linking; however, there was no significant change in OSDI index ( P =0.313), meiboscore ( P =0.392), and meibomian gland loss degrees ( P =0.300). No change was detected in the morphology of the meibomian glands after CXL.

CONCLUSION

In eyes with keratoconus, a flattening in keratometry readings and thinning in corneal thickness were observed after CXL. The corneal endothelium is protected by dextran-free riboflavin. Cross-linking procedure causes dry eye by changing the corneal structure without affecting the morphology of the meibomian glands.

Recovery of Corneal Innervation after Treatment in Dry Eye Disease: A Confocal Microscopy Study

PURPOSE

To analyze the changes in corneal innervation by means of in vivo corneal confocal microscopy (IVCM) in patients diagnosed with Evaporative (EDE) and Aqueous Deficient Dry Eye (ADDE) and treated with a standard treatment for Dry Eye Disease (DED) in combination with Plasma Rich in Growth Factors (PRGF).

METHODS

Eighty-three patients diagnosed with DED were enrolled in this study and included in the EDE or ADDE subtype. The primary variables analyzed were the length, density and number of nerve branches, and the secondary variables were those related to the quantity and stability of the tear film and the subjective response of the patients measured with psychometric questionnaires.

RESULTS

The combined treatment therapy with PRGF outperforms the standard treatment therapy in terms of subbasal nerve plexus regeneration, significantly increasing length, number of branches and nerve density, as well as significantly improving the stability of the tear film (p < 0.05 for all of them), and the most significant changes were located in the ADDE subtype.

CONCLUSIONS

the corneal reinnervation process responds in a different way depending on the treatment prescribed and the subtype of dry eye disease. In vivo confocal microscopy is presented as a powerful technique in the diagnosis and management of neurosensory abnormalities in DED.

Evaluation of warm compresses and topical cyclosporine treatment in meibomian gland dysfunction by confocal scanning laser microscopy

PURPOSE

The aim of our study is to confirm the utility of warm compresses (WC) and artificial tears (AT) in meibomian gland dysfunction (MGD) management and to understand if its association with topical cyclosporine A (CsA) improves outcomes.

METHODS

Patients with diagnosis of MGD-related dry eye were evaluated. In this prospective, randomized, double-masked study, patients were randomized in two treatments: AT plus WC (group A), and AT plus WC plus CsA 0.05% ophthalmic emulsion (group B). At baseline and at 1, 3, and 6 months, Ocular Surface Disease Index (OSDI) questionnaire was completed, and tear evaluation (BUT, Schirmer and osmolarity test), ocular surface evaluation (fluorescein and lissamine green staining), clinical (Shimazaki grading) and in vivo confocal microscopy (IVCM) evaluation of rete ridges (RRs) were performed.

RESULTS

A total of 40 eyes, 20 in each group, completed the study. Analysis of OSDI, tear test, ocular surface evaluation and clinical grading of MG showed significant improvement at 6 months, whereas no difference was found between the two groups at 6 months. The analysis of IVCM showed significant improvement in both groups, but significantly better results in group B were found compared to group A at 6 months.

CONCLUSION

WC performed 3 times daily during the 1st month and once daily afterwards, in addition to AT, were useful to manage the obstruction of MG and related signs and symptoms. Additional effects of CsA were visible in IVCM only at 6 months. IVCM is an effective tool to monitor treatments in MGD.

The Effect of Anti-Inflammatory Topical Ophthalmic Treatments on In Vitro Corneal Epithelial Cells

Purpose

To compare the effect of three commonly prescribed anti-inflammatory eye drops on corneal epithelial cells in vitro.

Methods

Three different lines of human corneal epithelial cells were tested: primary cells cultured from donor tissue, commercially available primary cells, and immortalized cells. Cells were seeded on 96-well plates and treated with the following eye drops: cyclosporine 0.05%, lifitegrast 5%, and tacrolimus 0.03% or 0.1%. Exposure times tested were 30 seconds, 1 minute, 2 minutes, 1 hour, 2 hours, 4 hours, and 24 hours. Brightfield images and viability assays were analyzed 48 to 72 hours after the initiation of treatments. At least five replicates were tested per drug and time exposure.

Results

Commercially obtained primary cells showed reduced viability following 1 hour with tacrolimus 0.1% (8%; P = 0.043%) and 4 hours with tacrolimus 0.03% (17%; P = 0.042%). Lifitegrast exposure reduced primary cell viability after 4 hours (10%; P = 0.042). Cell viability in primary cells was not deleteriously affected following exposure to cyclosporine for up to 4 hours. A similar trend was observed in both primary cells cultured from donor tissue and immortalized human corneal epithelial cells, demonstrating greater decreases in cell viability in tacrolimus compared to lifitegrast and cyclosporine. Light microscopy imaging for analysis of cell morphology and confluence supported the results.

Conclusions

Tacrolimus showed the highest impact on corneal epithelium survival in vitro, and cyclosporine proved the most protective.

Translational Relevance

Comparing anti-inflammatory eye drops on corneal epithelial cells in vitro may inform eye drop selection and development for clinical purposes.

In Vivo Confocal Microscopy in Different Types of Dry Eye and Meibomian Gland Dysfunction

In vivo confocal microscopy (IVCM) imaging is increasingly popular in ocular surface disease diagnosis and management. We conducted a systematic review to update the use of IVCM in the diagnosis and treatment of dry eye and meibomian gland dysfunction (MGD). A literature review was conducted on IVCM studies in MGD, dry eye disease, systemic disease causing dry eye, dry eye in glaucoma patients, contact lens-associated ocular conditions, graft-versus-host disease, and Sjogren’s syndrome-related dry eye. The articles were identified through PubMed and a total number of 63 eligible publications were analyzed in detail. All primary research studies on confocal microscopy on dry eye and related conditions from 2017 onwards were included. The reports were reviewed for their contribution to the existing literature as well as potential biases and drawbacks. Despite limitations such as small field of view, lack of population-based norms, and lack of standardization of image acquisition, interpretation, and quantification, IVCM is useful as a complementary technique for clinical diagnosis in various ocular surface disorders related to dry eye. With advances in hardware and software in the near future, it has the potential for further practical impact.

Dry eye and inflammation of the ocular surface after cataract surgery: effectiveness of a tear film substitute based on trehalose/hyaluronic acid vs hyaluronic acid to resolve signs and symptoms

PURPOSE

To compare the effect of trehalose 3%/hyaluronic acid 0.15% vs hyaluronic acid 0.15% eyedrops in reducing ocular surface inflammation after cataract surgery.

SETTING

Perugia, Italy.

DESIGN

Randomized, prospective study.

METHODS

Patients with healthy ocular surface were enrolled. Tear break-up time (TBUT), Schirmer test, corneal fluorescein staining (CFS), ocular surface disease index (OSDI) and in vivo confocal microscopy (IVCM) were performed preoperatively and at 1 months, 4 months, and 8 months postoperatively. Patients were randomly assigned to receive trehalose 3%/hyaluronic acid 0.15% eyedrops (Group A), hyaluronic acid 0.15% eyedrops (Group B), or no treatment (Group C).

RESULTS

98 patients were randomized as follows: 33 in Group A, 33 in Group B, and 32 in Group C. Schirmer test increased at 1-month follow-up in Group A and unchanged in Groups B and C. TBUT and CFS increased at 1-month follow-up in Group A and after 8 months in Groups B and C. OSDI score decreased at 1-month follow-up in Group A and at in Groups B and C. IVCM showed a reduction in the number of nerve fibers of the subbasal nerve plexus at 1 month in all groups and progressively increased to preoperative levels at 4 months in Group A, and at 8 months in Groups B and C. Tortuosity and reflectivity of subbasal plexus progressively decreased to became significant at 4-month follow-up in Group A whereas increased at 1-month follow-up and become normal at 8-month follow-up in Groups B and C. Langerhans cells and activated stromal keratocytes were higher in Groups B and C throughout the follow-up with a significantly lower density of hyperreflective stromal cells in Group A.

CONCLUSIONS

Trehalose 3%/hyaluronic acid 0.15% eyedrops were effective in reducing inflammation and dry-eye symptoms.

Femtosecond laser-assisted cataract surgery in eyes with shallow anterior chamber depth: comparison with conventional phacoemulsification

PURPOSE

To compare the postoperative outcomes between femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification in eyes with shallow anterior chamber depth (ACD).

SETTING

Eye Clinic, NEUROFARBA Department, University of Florence, Italy.

DESIGN

Prospective case series.

METHODS

Forty eyes of 40 patients with senile cataract and true ACD less than 2.00 mm underwent FLACS (femto group, n = 20) or manual phacoemulsification (phacoemulsification group, n = 20). Preoperatively and 1 week and 1 month and 6 months postoperatively, central corneal thickness (CCT) and endothelial cell density were evaluated; basal epithelial cell (BEC) and Langerhans dendritic cell (LDC) densities and keratocyte activation were assessed using in vivo corneal confocal microscopy. Intraoperative parameters such as cumulative dissipated energy (CDE) and ultrasound (US) power were recorded.

RESULTS

Endothelial cell loss (ECL) was significantly lower in the femto group at all timepoints (P ≤ .001). In the phacoemulsification group, the CCT was significantly higher 1 week (P < .001) and 1 month (P < .001) postoperatively than preoperatively; conversely, in the femto group, it was higher only after 1 week (P < .001). BECs and LDCs significantly increased at 1 postoperative week (P < .001), returning to preoperative values after 1 month in both groups. Keratocyte activation remained significantly higher at 1 postoperative month only in the phacoemulsification group (P = .005). CDE and US power were lower in the femto group (P = .017 and P = .001, respectively); they were correlated with ECL (r = 0.662, P = .000; r = 0.389, P = .013).

CONCLUSIONS

In eyes with shallow ACD, FLACS was a safe and an effective technique, significantly reducing the postoperative ECL and corneal inflammation compared with conventional phacoemulsification.

Neuronal-epithelial cell alignment: A determinant of health and disease status of the cornea

PURPOSE

How sensory neurons and epithelial cells interact with one another, and whether this association can be considered an indicator of health or disease is yet to be elucidated.

METHODS

Herein, we used the cornea, Confetti mice, a novel image segmentation algorithm for intraepithelial corneal nerves which was compared to and validated against several other analytical platforms, and three mouse models to delineate this paradigm. For aging, eyes were collected from 2 to 52 week-old normal C57BL/6 mice (n ≥ 4/time-point). For wound-healing and limbal stem cell deficiency, 7 week-old mice received a limbal-sparing or limbal-to-limbal epithelial debridement to their right cornea, respectively. Eyes were collected 2-16 weeks post-injury (n=4/group/time-point), corneas procured, immunolabelled with βIII-tubulin, flat-mounted, imaged by scanning confocal microscopy and analyzed for nerve and epithelial-specific parameters.

RESULTS

Our data indicate that nerve features are dynamic during aging and their curvilinear arrangement align with corneal epithelial migratory tracks. Moderate corneal injury prompted axonal regeneration and recovery of nerve fiber features. Limbal stem cell deficient corneas displayed abnormal nerve morphology, and fibers no longer aligned with corneal epithelial migratory tracks. Mechanistically, we discovered that nerve pattern restoration relies on the number and distribution of stromal-epithelial nerve penetration sites.

CONCLUSIONS

Microstructural changes to innervation may explain corneal complications related to aging and/or disease and facilitate development of new assays for diagnosis and/or classification of ocular and systemic diseases.

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.

Real-world experience of using ciclosporin-A 0.1% (Ikervis) in the management of ocular surface inflammatory diseases

PURPOSE

To report the real-world experience of using topical ciclosporin, Ikervis, in the management of ocular surface inflammatory diseases (OSIDs).

METHODS

This was a retrospective study of patients treated with Ikervis for OSIDs at the Queen's Medical Centre, Nottingham, between 2016 and 2019. Relevant data, including demographics, indications, clinical parameters, outcomes and adverse events, were collected and analysed for patients who had completed at least 6 months follow-up. For analytic purpose, clinical outcome was categorised as 'successful' (resolved or stable disease), 'active disease' and 'drug intolerance'.

RESULTS

463 patients were included; mean age was 51.1±21.6 years, with a 59.0% female predominance. Mean follow-up was 14.6±9.2 months. The most common diagnosis was dry eye disease (DED; 322, 69.5%), followed by allergic eye disease (AED; 53, 11.4%) and ocular mucous membrane pemphigoid/Steven-Johnson syndrome (OMMP/SJS; 38, 8.2%). Successful treatment was achieved in 343 (74.1%) patients, with 44 (9.5%) requiring additional treatment and 76 (16.4%) reporting drug intolerance. The efficacy of Ikervis was highest in DED (264, 82.0%), followed by OMMP/SJS (25, 65.8%) and post-keratoplasty (7, 50.0%; p<0.001). Logistic regression analysis demonstrated age <70 years (p=0.007), AED (p=0.002) and OMMP/SJS (p=0.001) as significant predictive factors for Ikervis intolerance. AED and post-keratoplasty were 8.16 times (95% CI, 2.78 to 23.99) and 13.98 times (95% CI, 4.22 to 46.28), respectively, more likely to require additional treatment compared with DED.

CONCLUSIONS

Ikervis is a useful steroid-sparing topical treatment for managing OSIDs in the real-world setting. Preparations with improved tolerability are needed to benefit a larger number of patients.

Allergy and Dry Eye Disease

Ocular allergy (OA) and dry eye disease (DED) are the most common ocular surface disorders with a potential severe impact on the patient's quality of life. OA and DED may coexist and have a significant clinical overlap. Therefore, clinical features commonly believed to be distinctive of OA or DED may be sometimes insufficient for a differential diagnosis. Alterations of the tear film, epithelial barrier, and corneal innervation are described in OA and can pave the way to DED. Conversely, DED may facilitate or worsen allergic reactions in predisposed (atopic) patients. For these reasons, OA and DED should be considered as reciprocal predisposing conditions that share ocular surface inflammation as a common background.

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.

A Review of the Mechanism of Action of Cyclosporine A: The Role of Cyclosporine A in Dry Eye Disease and Recent Formulation Developments

Dry eye disease (DED) is a multifactorial disease of the ocular surface and tear film that has gained awareness as a public health problem. Characteristics of DED include tear film instability, hyperosmolarity, and ocular surface inflammation, which can occur independently or may be a sequela of numerous ocular diseases, ocular surgery or contact lens wear. Much has been learned about the impact of the disease to help affected individuals who report symptoms of poor vision, pain, and tearing. Recently, new research highlights the importance of the role of ocular surface inflammation and damage in DED-leading to a vicious cycle of inflammation as well as loss of tear film homeostasis. DED immunopathophysiology is characterized by four stages: initiation, amplification, recruitment, and re-initiation. Cyclosporine is proven to be a valuable ophthalmic therapeutic for DED through its immunomodulatory actions and regulation of the adaptive immune response. Cyclosporine mechanism of action is well described in the published literature and the myriad of benefits in all four stages lend a broad-based immunomodulatory function particularly suitable for addressing DED. Furthermore, cyclosporine has unique goblet cell density improvement capabilities as well as anti-apoptotic properties. Topical formulations of cyclosporine are centered around addressing the highly lipophilic nature of the molecule. The poor aqueous solubility of cyclosporine traditionally presented technical challenges in drug delivery to the ocular surface. Newer formulations such as cationic emulsions and nanomicellar aqueous solutions address formulation, tissue concentration, and drug delivery challenges.

Changes in Corneal Subbasal Nerves after Punctal Occlusion in Dry Eye Disease

PURPOSE

To evaluate corneal subbasal nerve plexus by in vivo confocal microscopy (IVCM) following punctal occlusion in patients with moderate to severe dry eye disease (DED).

MATERIALS AND METHODS

Patients with grade 3 or 4 severity of DED based on Delphi Panel dry eye severity grading scheme were enrolled in the study. Permanent inferior punctal occlusion was performed. A comprehensive ophthalmic evaluation, including Ocular Surface Disease Index (OSDI) questionnaire, tear break-up time (TBUT), corneal fluorescein staining, conjunctival Rose bengal staining, Schirmer's test, and corneal sensation by Cochet-Bonnet esthesiometry, were performed at baseline, and 1 and 3 months after punctal occlusion. Furthermore, density and number of corneal subbasal nerves were evaluated by IVCM.

RESULTS

Forty-one eyes of 23 patients with a mean age of 46.3 ± 9.0 years were enrolled. Corneal fluorescein staining, Rose bengal staining, and TBUT significantly improved at 3 months following punctal occlusion (p < .015). Corneal esthesiometry significantly increased at both postoperative visits (p < .03), and OSDI scores improved only at 3-month follow-up (p < .005). Nerve density and total number significantly increased 3 months after punctal occlusion (p < .045). Baseline nerve density had significant correlations with TBUT, fluorescein staining, Rose bengal staining (p < .012), but not with esthesiometry, Schirmer scores, or OSDI scores (p > .329).

CONCLUSIONS

Corneal subbasal nerve density and total number increased following punctal occlusion in patients with moderate to severe DED. These findings were associated with improvements in corneal sensation, and signs and symptoms of DED. This emphasizes the effect of punctal occlusion in regeneration of corneal subbasal nerve plexus.

Novel Approaches for Imaging-Based Diagnosis of Ocular Surface Disease

Imaging has become indispensable in the diagnosis and management of diseases in the posterior part of the eye. In recent years, imaging techniques for the anterior segment are also gaining importance and are nowadays routinely used in clinical practice. Ocular surface disease is often synonymous with dry eye disease, but also refers to other conditions of the ocular surface, such as Meibomian gland dysfunction or keratitis and conjunctivitis with different underlying causes, i.e., allergies or infections. Therefore, correct differential diagnosis and treatment of ocular surface diseases is crucial, for which imaging can be a helpful tool. A variety of imaging techniques have been introduced to study the ocular surface, such as anterior segment optical coherence tomography, in vivo confocal microscopy, or non-contact meibography. The present review provides an overview on how these techniques can be used in the diagnosis and management of ocular surface disease and compares them to clinical standard methods such as slit lamp examination or staining of the cornea or conjunctiva. Although being more cost-intensive in the short term, in the long term, the use of ocular imaging can lead to more individualized diagnoses and treatment decisions, which in turn are beneficial for affected patients as well as for the healthcare system. In addition, imaging is more objective and provides good documentation, leading to an improvement in patient follow-up and education.

Objective Imaging Diagnostics for Dry Eye Disease

Traditional diagnostic tests for dry eye disease (DED), such as fluorescein tear film break-up time and the Schirmer test, are often associated with poor reproducibility and reliability, which make the diagnosis, follow-up, and management of the disease challenging. Advances in ocular imaging technology enables objective and reproducible measurement of changes in the ocular surface, tear film, and optical quality associated with DED. In this review, the authors will discuss the application of various imaging techniques, such as, noninvasive tear break-up time, anterior segment optical coherence tomography, in vivo confocal microscopy, meibography, interferometry, aberrometry, thermometry, and tear film imager in DED. Many studies have shown these devices to correlate with clinical symptoms and signs of DED, suggesting the potential of these imaging modalities as alternative tests for diagnosis and monitoring of the condition.

Corneal In Vivo Laser-Scanning Confocal Microscopy Findings in Dry Eye Patients with Sjögren's Syndrome

PURPOSE

To evaluate the changes in cornea in Sjögren's syndrome (SS) with a novel confocal microscopy device.

METHODS

Twenty-three right eyes of patients with SS (23 women; mean age, 65.4 ± 11.4 years) and 13 right eyes of 13 age- and sex-matched control subjects (13 women; mean age, 68.8 ± 9.8 years) were studied. Furthermore, eight right eyes of patients with SS (8 women; mean age, 66.9 ± 9.6 years) were studied to evaluate the corneal microscopic alterations after the treatment with topical 3% diquafosol sodium eye drops. All cases had tear quantity, tear breakup time (BUT), ocular surface staining measurements, and corneal in vivo laser-scanning confocal microscopy examinations. The density and area of corneal epithelial cells (superficial, wing, and basal), density of corneal stromal cells (anterior, intermediate, and posterior), density and area of corneal endothelial cells, density and morphology of corneal sub-basal nerve plexus, density of corneal sub-basal inflammatory cells were also assessed.

RESULTS

The tear quantity, stability, and vital staining scores were significantly worse in patients with SS than in control subjects (p < 0.0001). Corneal superficial epithelial cell density was significantly lower in SS compared with control subjects (p < 0.0001). Corneal superficial epithelial cell area was significantly larger in SS compared with control subjects (p = 0.007). Corneal sub-basal nerve fiber density was lower in SS compared with control subjects (p < 0.0001). Morphological abnormality of nerve fibers was observed in SS patients. Corneal sub-basal inflammatory cell density was significantly higher in SS patients compared with control subjects (p < 0.0001). Furthermore, the mean corneal superficial epithelial cell density and area, inflammatory cell density, corneal sub-basal nerve fiber density, and morphological abnormality of nerve fibers, were improved with topical 3% diquafosol sodium treatment in the dry eye patients with SS (p < 0.05).

CONCLUSIONS

The diagnostic modality using in vivo laser-scanning confocal microscopy was a useful method for the evaluation of the corneal cell density and area, nerve fiber density and morphology, and inflammatory cell density in patients with SS and also a useful tool in the assessment of treatment effect with topical 3% diquafosol sodium in the SS patients.

C-Fiber Assays in the Cornea vs. Skin

C-fibers are unmyelinated nerve fibers that transmit high threshold mechanical, thermal, and chemical signals that are associated with pain sensations. This review examines current literature on measuring altered peripheral nerve morphology and discusses the most relevant aspects of corneal microscopy, especially whether corneal imaging presents significant method advantages over skin biopsy. Given its relative merits, corneal confocal microscopy would seem to be a more practical and patient-centric approach than utilizing skin biopsies.

Whole-Eye Perfusion Model for Screening of the Ocular Formulations via Confocal Laser Scanning Microscopy

Various physiological, anatomical barriers make ocular drug delivery very challenging. Hence, better in vitro screening models are needed for rapid screening of the formulations. In this study, a simple whole-eye perfusion model was designed and its application was explored for screening targeted formulation across the full-thickness cornea using confocal laser scanning microscopy. PEG-cholecalciferol-based integrin targeted coumarin-6 micelles (TC6M) and non-targeted coumarin-6 micelles (NTC6M) were developed by solvent diffusion evaporation technique. The formulations NTC6M and TC6M had particles size 23.5 ± 5 nm and 28.5 ± 6 nm respectively and osmolality of 294-300 mOsml/Kg. The whole-eye perfusion model was developed using porcine eye. TC6M and NTC6M were instilled on the excised porcine eyes as well as in the eyes of NZW rabbits. Corneas were excised from the experimental eyes; coumarin-6 penetration across the corneas was analyzed using confocal microscope. Coumarin-6-loaded micelles had particle size below 50 nm. NTC6M formulations showed penetration to the deeper layers up to 500 μm porcine eyes and up to 50 μm in rabbit corneas. However, TC6M formulations exhibited superior retention, as higher fluorescent intensities were observed in upper layers up to 50 μm depth in the porcine eye and 20 μm depth in rabbit eye. Hence, applicability of whole-eye perfusion model in preliminary screening of the formulations was successfully demonstrated. Whole-eye perfusion model when combined with confocal microscopy has potential to be used as an efficient tool for rapid screening and optimization of various ophthalmic formulations.

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.

En Face and Cross-sectional Corneal Tomograms Using Sub-micron spatial resolution Optical Coherence Tomography

Accurate diagnosis of corneal pathology and morphological identification of different corneal layers require clear delineation of corneal three-dimensional structures and en face or cross-sectional imaging of palisade of Vogt (POV), neovascularization (NV) or corneal nerves. Here we report a prototype of full-field optical coherence tomography (FF-OCT) system with isotropic sub-micron spatial resolution in the en face and cross-sectional views. It can also provide three-dimensional reconstructed images and a large field of view (FOV) by stitching tomograms side by side. We validated the imaging power of this prototype in in vivo rat and rabbit eyes, and quantified anatomical characteristics such as corneal layer thickness, endothelial cell density and the intensity profile of different layers. This FF-OCT delineated the ridge-like structure of POV, corneal nerve bundles, and conjunctival vessels in rat eyes. It also clearly identified the vessel walls and red blood cells in rabbit model of corneal NV. The findings provided by this FF-OCT are expected to facilitate corneal disease diagnosis and treatment.

Epi-Off versus Epi-On Corneal Collagen Cross-Linking in Keratoconus Patients: A Comparative Study through 2-Year Follow-Up

Aim

To evaluate two different techniques of cross-linking: standard epithelium-off (CXL epi-off) versus transepithelial (CXL epi-on) cross-linking in patient with progressive keratoconus.

Methods

Forty eyes from 32 patients with progressive keratoconus were prospectively enrolled from June 2014 to June 2015 in this nonblinded, randomized comparative study. Twenty eyes were treated by CXL epi-off and 20 by CLX epi-on, randomly assigned, and followed for 2 years. All patients underwent a complete ophthalmologic testing that included uncorrected and best corrected visual acuity, central and peripheral corneal thickness, corneal astigmatism, simulated maximum, minimum, and average keratometry, corneal confocal microscopy, Schirmer I and break-up time (BUT) tests, and the Ocular Surface Disease Index. Intra- and postoperative complications were recorded. The solution used for CXL epi-off comprised riboflavin 0.1% and dextran 20.0% (Ricrolin), whereas the solution for CXL epi-on (Ricrolin TE) comprised riboflavin 0.1%, dextran 15.0%, trometamol (Tris), and ethylenediaminetetraacetic acid. Ultraviolet-A treatment was performed with a UV-X system at 3 mW/cm².

Results

In both groups, a significant improvement in visual function (Group 1: baseline 0.36 ± 0.16 logMAR, two-year follow-up 0.22 ± 0.17 logMAR, p=0.01; Group 2: baseline 0.32 ± 0.18 logMAR, 2-year follow-up 0.27 ± 0.19 logMAR, p=0.01) was recorded. Keratometry remained unchanged in both groups. The mean corneal thickness showed a significant reduction (mean difference of corneal thickness: −55 micron and −71 micron, resp.). One-month after treatment, OSDI^© reached 13.56 ± 2.15 in Group 1 (p=0.03) and 11.26 ± 2.12 in Group 2 (p=0.04). At confocal microscopy, abnormal corneal nerve alterations were found in both groups. Fibrotic reaction (43.75%) and activated keratocyte (62.6%) were more commonly recorded in Group 1 than in Group 2 (25.0% and 18.75%), with p=0.668 and 0.356, respectively.

Conclusion

Our findings demonstrate that both procedures are able to slow keratoconus progression. Both treatment modalities are equivalent in terms of results and related complications. CXL epi-on technique is preferable to CXL epi-off since it preserves the corneal thickness and improves visual acuity, also reducing the postoperative ocular discomfort during the study period.

Confocal scanning laser microscopy in patients with postoperative endophthalmitis

PURPOSE

To investigate alterations of corneal layers in eyes treated for acute postoperative endophthalmitis.

METHODS

In this retrospective, nonrandomized comparative study, eyes treated with 25 gauge pars plana vitrectomy (PPV) for acute post-cataract endophthalmitis (group A) were compared to eyes receiving uneventful cataract surgery (group B) and uneventful 25 gauge PPV for epiretinal membrane (group C). After a minimum follow-up of 8 months from last surgical procedure, laser scanning in vivo confocal microscopy (IVCM) was performed.

RESULTS

Twelve eyes for each group were recruited. Comparing study eyes with control eyes of group B and C, no statistical difference was found in corneal epithelial cell density (p = n.s.), in density of nerve fibers (p = n.s.), mean grade of nerve reflectivity (p = n.s.), mean grade of nerve tortuosity (p = n.s.), mean grade of anterior keratocyte activation (p = n.s.), and corneal endothelium cell density (p = n.s.), whereas a statistically higher mean grade of posterior keratocyte activation was found in group A (p < 0.01). Epithelial and endothelial corneal morphologies were graded as regular in all groups. Langerhans cells and corneal dendritic-shaped hyper-reflective endothelial deposits were found in group A. Both findings were absent in group B and C, and the difference was statistically significant (p < 0.01).

CONCLUSIONS

IVCM was a useful tool in the detection of microscopic chronic corneal abnormalities caused by postoperative endophthalmitis. These findings confirmed the presence of a subclinical chronic corneal inflammation localized to the posterior stroma that should be related to the infectious process. Future studies might clarify pathological processes in the acute phase of postoperative endophthalmitis.

Patient and physician perspectives on the use of cyclosporine ophthalmic emulsion 0.05% for the management of chronic dry eye

Dry eye disease (DED) is a multifactorial disease of the ocular surface and is one of the most common reasons for patients to visit an eye care provider. Cyclosporine A (CsA) is an immune modulating drug that was approved in the US for topical use in the treatment of DED in 2003, which led to a paradigm change in our understanding and treatment of DED, turning attention to control of inflammation for treatment. This review summarizes the literature to date regarding the impact of CsA on the treatment of DED. A special focus is given to the patient and physician perspectives of CsA, including dry eye symptom improvement, medication side effects, and overall patient satisfaction. Studies evaluating CsA in DED have considerable heterogeneity making generalized conclusions about the effect of CsA difficult. However, most studies have demonstrated improvement in at least some symptoms of dry eye in CsA-treated patients. Side effects, most commonly ocular burning on administration of CsA, are common. The literature is sparse regarding long-term follow-up of patients treated with CsA, optimal duration of treatment, and identifying which patients may receive the most benefit from CsA.

Automatic analysis of corneal nerves imaged using in vivo confocal microscopy

Interest has grown over the past decade in using in vivo confocal microscopy to analyse the morphology of corneal nerves and their changes over time. Advances in computational modelling techniques have been applied to automate the estimation of sub-basal nerve structure. These objective methods have the potential to quantify nerve density (and length), tortuosity, variations in nerve thickness, as well as temporal changes in nerve fibres such as migration patterns. Different approaches to automated nerve analysis, methods proposed and how they were validated in previous literature are reviewed. Improved understanding of these approaches and their limitations will help improve the diagnostic leverage of emerging developments for monitoring the onset and progression of a broad class of systemic diseases, including diabetes.