Vivo Confocal Microscopy Research Articles

Segmentation and Evaluation of Corneal Nerves and Dendritic Cells From In Vivo Confocal Microscopy Images Using Deep Learning

Segmentation and Evaluation of Corneal Nerves and Dendritic Cells From In Vivo Confocal Microscopy Images Using Deep Learning

Amantadine therapy for Parkinson’s Disease: In Vivo Confocal Microscopy corneal findings, case report and revision of literature

BackgroundTo report a case of a patient showing bilateral corneal opacities after amantadine chronic treatment for Parkinson’s Disease (PD) and corneal edema associated with intra-epithelial and -endothelial depositions. After amantadine discontinuation a complete clinical remission with only a partial ultrastructural corneal recovery was reported.Case presentationWe describe a 78-year-old man with non-medical-responding bilateral corneal edema in treatment with systemic Amantadine for PD. In vivo confocal Microscopy (IVCM) analysis revealed hyperreflective particles at the epithelial level and expanded hyperreflective keratocyte and a disarrangement of stromal lamellae; endothelial cells showed hyperreflective intracellular inclusions in central and in peripheral areas with central polymegatism and pleomorphism. After 1 and 6 months the amantadine discontinuation, the absence of bilateral corneal edema and opacities were noted at the slit lamp examination, associated with the disappearance of epithelial and stromal abnormalities, but the persistence of endothelial hyperreflective deposits with a pleomorphism and polymegatism worsening at the IVCM exam.ConclusionThe evaluation of a patient’s cornea 6 months after the discontinuation of systemic amantadine therapy showed a clinical complete remission, with a complete resolution of the bilateral corneal oedema. On the other hand, ultrastructurally, amantadine toxicity is a completely reversible phenomenon at the epithelial level; conversely IVCM showed persistent endothelial degradation.

Impression Cytology and In Vivo Confocal Microscopy of Lip Mucosa Compared With Labial Gland Biopsy and Classification Criteria In Patients With Clinically Suspected Primary Sjögren's Syndrome.

PurposeThe study assessed the validity of impression cytology (IC) and in vivo confocal microscopy (IVCM) of lip mucosa compared with labial gland biopsy, anti-Sjögren’s syndrome A (SSA)/Ro antibody status, and classification criteria in suspected primary Sjögren’s syndrome (pSS) patients.MethodsClinically suspected pSS patients (n = 201) were enrolled consecutively and were divided into pSS (n = 56) and control (n = 145, only with dryness) groups according to the American College of Rheumatology-European League Against Rheumatism (ACR-EULAR) criteria. All patients underwent lip mucosa IC (inflammatory cell density) and IVCM (epithelium/intrinsic layer thickness and labial gland density/diameter) analyses. The associations between IC/IVCM parameters and clinical/laboratory results were analyzed.ResultsThe absolute agreement between positive lip mucosal IC (≥50 cells/4 mm2) and the ACR-EULAR criteria (94.5%)/labial gland biopsy (95.5%) was good, with sensitivities of 82.1 and 85.2%, respectively, and a specificity of 99.3%. Compared with controls, IVCM revealed significant lip mucosal atrophy and glandular decreases in the pSS group (all P = 0.000). The sensitivities for diagnosing pSS corresponding to a lamina propria thickness ≤128 μm and a gland diameter ≤114 μm were 85.7 and 89.3%; the specificities were 90.3 and 95.9%, respectively. A combination of positive IC/IVCM and anti-SSA/Ro antibody results showed a high predictive value for diagnosing pSS.ConclusionsIC and IVCM could detect distinctive cellular and morphological changes in the lip mucosa of patients with pSS. These noninvasive and easy-to-perform examinations may be an alternative to labial gland biopsy for diagnosing pSS.

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.

The effects of the systemic isotretinoin treatment on ocular surface and meibomian glands: a prospective longitudinal study

Purpose To assess the effects of systemic isotretinoin therapy (SIT) on the ocular surface, meibomian glands (MG) and cornea microstructure in acne vulgaris (AV) patients. Methods Patients with AV (n = 20) and healthy controls (n = 20) were enrolled in the study. All participants underwent ocular surface tests in the order of ocular surface disease index (OSDI) questionnaire, corneal sensitivity, tear break-up time (BUT), fluorescein and lissamine green (LG) staining and Schirmer II test with anaesthesia. MG alterations were evaluated with meibography for upper (UE) and lower eyelids (LE) separately. Corneal basal epithelium and subbasal nerve plexus (SNP) were evaluated using In Vivo Confocal Microscopy (IVCM). Results Schirmer II test with anaesthesia, BUT, corneal sensitivity, fluorescein and LG staining grades and OSDI score results showed no difference between the control group and the baseline of the patient group. Whereas the meibomian gland dysfunction (MGD) grades, UE and LE meiboscores were higher in the patient group at the baseline (p = 0.013, p = 0.004, p = 0.008 respectively). The Control group possessed higher numbers of total and long nerve fibres compared with patients at the baseline (p ≤ 0.001 for both two values). Compared to the baseline and the third month, BUT decreased and fluorescein staining grades increased (p = 0.017 and p = 0.043, respectively). MGD grades, UE and LE meiboscores increased in the third month compared to the baseline (p < 0.001, p < 0.001, p = 0.008 respectively). Basal epithelial cell density (BECD) decreased in the third month of SIT (p = 0.043). Conclusions This prospective study showed that systemic Isotretinoin treatment effects not only ocular surface parameters but also corneal and Meibomian glands structure. Considering early alterations in the course of treatment, ophthalmological assessment and follow-up during SIT are mandatory.

Corneal Densitometry and In Vivo Confocal Microscopy in Patients with Monoclonal Gammopathy—Analysis of 130 Eyes of 65 Subjects

Background: Corneal imaging may support an early diagnosis of monoclonal gammopathy. The goal of our study was to analyze corneal stromal properties using Pentacam and in vivo confocal cornea microscopy (IVCM) in subjects with monoclonal gammopathy. Patients and methods: In our cross-sectional study, patients with monoclonal gammopathy (130 eyes of 65 patients (40.0% males; age 67.65 ± 9.74 years)) and randomly selected individuals of the same age group, without hematological disease (100 eyes of 50 control subjects (40.0% males; age 60.67 ± 15.06 years)) were included. Using Pentacam (Pentacam HR; Oculus GmbH, Wetzlar, Germany), corneal stromal light scattering values were obtained (1) centrally 0–2 mm zone; (2) 2–6 mm zone; (3) 6–10 mm zone; (4) 10–12 mm zone. Using IVCM with Heidelberg Retina Tomograph with Rostock Cornea Module (Heidelberg Engineering, Heidelberg, Germany), the density of hyperreflective keratocytes and the number of hyperreflective spikes per image were manually analyzed, in the stroma. Results: In the first, second and third annular zone, light scattering was significantly higher in subjects with monoclonal gammopathy, than in controls (p ≤ 0.04). The number of hyperreflective keratocytes and hyperreflective spikes per image was significantly higher in stroma of subjects with monoclonal gammopathy (p ≤ 0.012). Conclusions: Our study confirms that increased corneal light scattering in the central 10 mm annular zone and increased keratocyte hyperreflectivity may give rise to suspicion of monoclonal gammopathy. As corneal light scattering is not increased at the limbal 10–12 mm annular zone in monoclonal gammopathy subjects, our spatial analysis provides evidence against the limbal origin of corneal paraprotein deposition. Using IVCM, stromal hyperreflective spikes may represent specific signs of monoclonal gammopathy.

Temporal and Spatial Assessment of the Corneal Response to UV Cross-Linking Using 3-Dimensional In Vivo Confocal Microscopy.

The goal of this study was to evaluate the temporal and spatial pattern of wound healing following UV corneal cross-linking (CXL) using 3-dimensional (3-D) confocal imaging in vivo. Using a modified Heidelberg Retinal Tomograph with Rostock Corneal Module confocal microscope, we performed 3-D scans on two patients at multiple time points after CXL. Patient 1 showed a normal post-CXL wound healing response, with initial subbasal nerve loss and keratocyte apoptosis in the anterior stroma, followed by partial restoration of both the nerve plexus and stromal keratocytes by 6 months. In patient 2, in addition to anterior corneal damage, pyknotic nuclei were observed in the posterior stroma 7 days after CXL. Acellular areas were present in the posterior stroma at 3 months, with only partial keratocyte repopulation at 6 months. Regeneration of the subbasal nerve plexus was also delayed. Three-dimensional confocal imaging allowed these unusual wound healing responses to be identified in the absence of any corresponding clinical observations.

In Vivo Confocal Microscopy Evaluation in Patients with Keratoconus.

Keratoconus is the most common primary corneal ectasia characterized by progressive focal thinning. Patients experience increased irregular astigmatism, decreased visual acuity and corneal sensitivity. Corneal collagen crosslinking (CXL), a minimally invasive procedure, is effective in halting disease progression. Historically, keratoconus research was confined to ex vivo settings. In vivo confocal microscopy (IVCM) has been used to examine the corneal microstructure clinically. In this review, we discuss keratoconus cellular changes evaluated by IVCM before and after CXL. Cellular changes before CXL include decreased keratocyte and nerve densities, disorganized subbasal nerves with thickening, increased nerve tortuosity and shortened nerve fibre length. Repopulation of keratocytes occurs up to 1 year post procedure. IVCM also correlates corneal nerve status to functional corneal sensitivity. Immediately after CXL, there is reduced nerve density and keratocyte absence due to mechanical removal of the epithelium and CXL effect. Nerve regeneration begins after 1 month, with nerve fibre densities recovering to pre-operative levels between 6 months to 1 year and remains stable up to 5 years. Nerves remain tortuous and nerve densities are reduced. Corneal sensitivity is reduced immediately postoperatively but recovers with nerve regeneration. Our article provides comprehensive review on the use of IVCM imaging in keratoconus patients.

In Vivo Confocal Microscopy of the Corneal Sub-Basal Nerve plexus in Medically Controlled Glaucoma.

The present study investigated the corneal sub-basal nerve plexus (SNP) modifications in glaucoma. Ninety-five glaucomatous patients were enrolled and divided into Group 1 and 2, preserved and preservative-free mono-therapy (30 and 28 patients), and Group 3, multi-therapy (37). Thirty patients with dry eye disease (DED) and 32 healthy subjects (HC) served as controls. In vivo confocal microscopy evaluated the nerve fibers density (CNFD), length (CNFL), thickness (CNFT), branching density (CNBD), and dendritic cell density (DCD). CNFD, CNFL, and CNBD were reduced in Group 3 and DED compared to HC (p < 0.05). CNFL was reduced in Group 3 compared to Group 2 (p < 0.05), and in Group 1 compared to HC (p < 0.001). CNFD, CNBD, and CNFT did not differ between glaucomatous groups. DCD was higher in Group 3 and DED compared to HC and Group 2 (p < 0.01). Group 3 showed worse ocular surface disease index (OSDI) scores compared to Group 1, 2, and HC (p < 0.05). CNFL and DCD correlated with OSDI score in Group 3 (r = −0.658, p < 0.001; r = 0.699, p = 0.002). Medical therapy for glaucoma harms the corneal nerves, especially in multi-therapy regimens. Given the relations with the OSDI score, SNP changes seem features of glaucoma therapy-related OSD and negatively affects the patient's quality of life.

Interobserver and Intraobserver Agreements of the Detection of Demodex Infestation by in Vivo Confocal Microscopy.

Objectives:The purpose of the study was to determine interobserver and intraobserver agreement, repeatability, and intrasubject variation of the detection of Demodex infestation in eyelids of blepharitis patients using in vivo confocal microscopy (IVCM).Methods:Eighty-three eyes of 42 blepharitis patients were included in the study. All eyelids were evaluated from temporal to nasal with IVCM using section mode and 10 lashes with their follicles were imagined, and every image with suspicion of Demodex infestation was recorded. Two experienced and two inexperienced ophthalmologists were masked for the diagnosis and interpreted the IVCM images regarding the presence of Demodex infestation with a 3-week interval. Interobserver and intraobserver agreements were calculated with Cohen’s kappa and its variant statistics between and within experienced observers and between inexperienced observers.Results:While average sensitivity for the diagnosis of demodicosis in IVCM images was 83.35% for experienced and 51.35% for inexperienced observers, the average positive predictive value was 88.6% for experienced observers and 91.05% for inexperienced ones. Interobserver agreement between experienced observers was moderate (κ = 0.529) and intraobserver agreements within experienced observers were perfect (κ = 0.918 for observer-1; κ = 0.958 for observer-2). Interobserver agreement between inexperienced observers was poor (κ = 0.162) and intraobserver agreements within inexperienced observers were fair (κ = 0.427 for observer-3; κ = 0.475 for observer-4).Conclusion:The sensitivity, interobserver and intraobserver agreements in IVCM image analysis for the detection of Demodex infestation were highly associated with the clinical experience on IVCM imaging. In the hands of an experienced clinician, IVCM could be reliable for the diagnosis of ocular demodicosis.

Clinical Observation of Corneal Endothelial Plaques With Fungal and Bacterial Keratitis by Anterior Segment Optical Coherence Tomography and In Vivo Confocal Microscopy.

Endothelial plaque is an important sign of fungal keratitis and is related to diagnosis, surgical indications, and prognosis. However, bacterial keratitis sometimes involves fibrin formation on the back corneal surface, similar to endothelial plaques. Because corneal infiltration interferes with precise observation of the posterior corneal plaque, distinguishing pathogens with a slitlamp is difficult. We hope to assist clinicians in early diagnosis and timely treatment by observing the connection state of endothelial plaques and the corneal endothelium through anterior segment optical coherence tomography (AS-OCT) and the different forms of endothelial plaques in infectious keratopathy through in vivo confocal microscopy (IVCM). We analyzed 52 patients in the Eye Hospital of the First Affiliated Hospital of Harbin Medical University who were clearly diagnosed with fungal or bacterial keratitis with endothelial plaques. All patients underwent AS-OCT and IVCM on admission. According to the smear, IVCM, or fungal and bacterial culture results, the patients were diagnosed with fungal (28 patients) or bacterial keratitis (24 patients). AS-OCT in 25 patients diagnosed with fungal keratitis revealed that the corneal endothelium-endothelial plaque boundary was unclear and wavy, and 24 patients had unclear cell boundaries and a large number of compactly distributed inflammatory cells in the endothelial layer according to IVCM. AS-OCT in 23 patients diagnosed with bacterial keratitis revealed clear corneal endothelium-endothelial plaque boundaries, and insufficient endothelial cell boundaries with a large number of visible and scattered inflammatory cell structures were observed through IVCM in 22 patients. Corneal endothelial plaque detection by AS-OCT and IVCM can be used for early diagnosis of infectious keratitis.

Observation of Conjunctiva-Associated Lymphoid Tissue With In Vivo Confocal Microscopy in Healthy Patients and Patients With Meibomian Gland Dysfunction.

Purpose:The purpose of this study was to assess the distribution and morphological variation of conjunctiva-associated lymphoid tissue (CALT) in healthy human subjects and patients with meibomian gland dysfunction (MGD) using laserscanningin vivo confocal microscopy.Methods:A total of 34 healthy subjects and 32 patients with MGD were enrolled. All subjects underwent a conventional examination consisting of slitlamp biomicroscopy, tear film break-up time, and the Schirmer test. In vivo microscopy was applied to analyze the morphological changes in the diffuse lymphoid layer and lymphoid follicles in CALT. Conjunctival impression cytology (CIC) of samples of patients' palpebral conjunctiva and immunofluorescence staining of CD4 and CD8 antibodies were also performed to indicate the immune response status of CALT.Results:In the MGD group, the density of diffuse lymphocytes (P < 0.001), follicles (P < 0.001), and perifollicular lymphocytes was higher (P < 0.001) and the central reflection of the follicles was stronger (P < 0.001) than in the control group, while there was no difference in the follicle area (P = 0.758). Besides, diffuse lymphocyte density was correlated with telangiectasia, and follicular center reflection intensity was correlated with plugging. CIC immunofluorescence staining showed a higher percentage of CD4+ (P < 0.001) and CD8+ (P < 0.001) cells in the MGD group than in the control group.Conclusions:Using laser scanning in vivo confocal microscopy and CIC immunofluorescence staining, we observed the activation of CALT in patients with MGD, and some CALT-related parameters correlated with the lid margin findings of patients with MGD.

Activation of Conjunctiva-Associated Lymphoid Tissue in Patients With Infectious Keratitis Using In Vivo Confocal Microscopy.

PurposeWe aimed to evaluate activation of conjunctiva-associated lymphoid tissue (CALT) in patients with keratitis using in vivo confocal microscopy (IVCM) and conjunctival impression cytology (CIC).MethodsIn addition to anterior segment photography and corneal fluorescein staining, IVCM revealed the palpebral conjunctiva in all subjects, and CIC and immunofluorescence staining were performed.ResultsDiffuse lymphoid tissue cell density in the eyes of patients with keratitis was significantly greater compared with healthy volunteers (P < 0.001). Similar trends were found in perifollicular lymphocyte density (P < 0.001), follicular density (P = 0.029), follicular center reflection intensity (P = 0.011), and follicular area (P < 0.001). Immunofluorescence staining showed that the proportions of CD4+ (61.7% ± 8.0% vs. 17.3% ± 10.2%, respectively, P < 0.001) and CD8+ (46.9% ± 10.0% vs. 19.6% ± 11.5%, respectively, P < 0.001) cells in patients with keratitis was greater compared with healthy volunteers. Interestingly, we also observed changes in the contralateral eye in subjects with keratitis.ConclusionsOur research suggests that CALT, as an ocular immune structure, is activated and plays an important role in the pathogenesis of keratitis. This has been overlooked previously. CALT is also active in the contralateral eye of subjects with keratitis.

In Vivo confocal microscopy findings after COVID-19 infection

ABSTRACT Purpose: To evaluate clinical and in vivo confocal microscopy (IVCM) findings of a patient who developed multiple unilateral subepithelial stromal opacities following conjunctivitis that developed during a COVID-19 infection. Methods: A 22-year-old female presented to our clinic with blurred right vision. The history revealed that she had experienced a COVID-19 infection one month ago. Redness and stinging of the right eye had started at the same time and she had been prescribed topical antibiotic drops and ointments. The redness in the right eye had decreased but blurred vision had then developed. Results: Slit lamp examination revealed a normal left eye. Several tiny subepithelial infiltrates without fluorescein staining of the cornea were present in the right eye. The anterior chamber, lens and fundus were bilaterally normal. IVCM revealed irregular corneal epithelial cells with bright borders in addition to scattered inflammatory cells and cell debris in the right eye. There were activated dendritic cells in the subbasal epithelial area with a significant decrease in the subbasal corneal nerve plexus. Clusters of highly reflective cells with an irregular shape were seen in the anterior corneal stroma together with foci of activated keratocytes. The corneal endothelial cell layer was normal. The left eye IVCM findings were all within normal limits. The right eye also showed decreased corneal sensitivity compared to the left. Conclusions: The possible role of corneal infiltrates as a trigger for COVID-19 could be explained with an immune-mediated mechanism. SARS-CoV-2 can result in decreased corneal sensitivity through corneal nerve involvement. The clinical results of this effect need to be evaluated in larger series.

Corneal Subbasal Nerve Plexus Evaluation by in Vivo Confocal Microscopy in Multiple Sclerosis: A Potential New Biomarker

ABSTRACT Purpose/Aim: Our study aims to evaluate corneal subbasal nerve plexus morphology by in vivo corneal confocal microscopy (CCM) in Multiple Sclerosis (MS) patients and to explore its potential ability to distinguish between MS patients and healthy subjects. Materials and methods: Cross-sectional study, including 60 MS patients and 22 healthy subjects. Expanded Disability Status Scale (EDSS) was used to assess neurological disability. All participants underwent full ophthalmology evaluation, CCM and optical coherence tomography (OCT). Corneal nerve fibre density (CNFD), branch density (CNBD), fibre length (CNFL) and fibre tortuosity (CNFT) were analysed. Generalized additive regression models were used to analyse the data. Results: Compared to controls, MS patients had lower CNFD, CNBD and CNFL (p < .001) and higher CNFT (p = .002). The area under the ROC curve to distinguish MS patients from healthy controls with CNFD and CNBD was 0.84 (95%CI: 0.75 to 0.93; 95%CI: 0.75 to 0.92, respectively). A nonlinear association between EDSS and CNFD was found, with an initial density increase followed by a significant decrease until more severe disability status. EDSS was associated with CNFL and CNBD, with values being significantly lower for patients with an EDSS > 2.5 (−2.06 mm/mm2; 95%CI: −3.84 to −0.28; p = .027 and −8.70 branches/mm2; 95%CI: −14.69 to −2.71; p = .006, respectively). An optic neuritis (ON) history did not influence CCM parameters. Conclusions: Our results confirm CCM parameters’ potential to differentiate MS patients from healthy subjects, not being influenced by a previous ON history. A significant relationship between patient’s disability and corneal nerve morphology was also found.

Face Mask-Related Ocular Surface Modifications During COVID-19 Pandemic: A Clinical, In Vivo Confocal Microscopy, and Immune-Cytology Study.

PurposeThe purpose of this study was to describe the face mask (FM)-related ocular surface changes using clinical tests, in vivo confocal microscopy (IVCM) and impression cytology (IC), and to investigate the Dry Eye-related Quality of life Score (DEQS).MethodsSixty-six patients with dry eye disease (DED) and 62 healthy subjects (group 2) using FM were enrolled. Groups were divided into: groups 1A and 2A: < 3 hours of FM wear; groups 1B and 2B: 3 to 6 hours; and groups 1C and 2C: > 6 hours. Patients underwent DEQS questionnaire, break-up time (BUT), Schirmer test I (STI), fluorescein and lissamine staining (FS and LS), IVCM to determine corneal dendritic cell density (DCD) and goblet cell density (GCD), and IC to measure HLA-DR, at baseline and after 3 months.ResultsFM use duration before enrollment was 27 ± 2.3 and 30 ± 4.1 (days ± SD) for groups 1 and 2 (P > 0.05). After 3 months, DEQS worsened in groups 1B and 1C, STI in groups 1A to 1C, FS and LS in group 1C (P < 0.05); in controls, BUT and FS worsened only in group 2C (P < 0.05). DCD significantly increased in groups 1A to 1C and HLA-DR in groups 1B and 1C (P < 0.05), whereas GCD did not significantly change. DCD and HLA-DR increased only in group 2C (P < 0.05). DEQS significantly correlated with DCD (P = 0.05, r = 0.698; P < 0.001, r = 0.832) and HLA-DR (P = 0.043, r = −0.687; P < 0.001, r = 0.861) at baseline and 3 months.ConclusionsUse of FM increases ocular surface inflammation and negatively impacts the quality of life in patients with DED.Translational RelevanceThe study of the prolonged use of FM effects may be relevant to managing DED.

In Vivo Confocal Microscopy of the Corneal-Conjunctival Transition in the Evaluation of Epithelial Renewal after SLET.

Examination of the corneal surface by in vivo confocal microscopy (IVCM) allows for objective identification of corneal and conjunctival cell phenotypes to evaluate different epithelialization patterns. Detection of a corneal-conjunctival epithelial transition could be considered as a sign of restored epithelial function following simple limbal epithelial transplantation (SLET). This is a prospective, interventional case series. We assessed patients with limbal stem cell deficiency (LSCD) by IVCM, preoperatively and at monthly intervals following SLET. Sectors in the central and peripheral cornea were scanned. Immediately upon detection of multi-layered cells with the epithelial phenotype in the central cornea and confirmation of epithelial transition in all corneal sectors, the decision for keratoplasty was taken. Ten patients were enrolled. After SLET, epithelial phenotype in the central cornea and an epithelial transition were identified within six and nine months in seven and one patients, respectively. One patient was a partial success and one failed. Five patients underwent keratoplasty, with stable results up to 12 months. Identification of the epithelial transition zone by IVCM permits assessment of the efficacy of SLET, enabling subsequent planning of keratoplasty for visual rehabilitation. The stability of the corneal surface following keratoplasty confirms that the renewal of the corneal epithelium was effectively retained.

Development and Assessment of a Simulator for in Vivo Confocal Microscopy in Fungal and Acanthamoeba Keratitis

ABSTRACT Background and Purpose In vivo confocal microscopy (IVCM) is a non-invasive imaging technique that allows morphological analysis as a diagnostic approach of the cornea in real time, thus providing a suspected diagnosis of fungal or amoebic keratitis immediately, whereas culture or PCR require several days or even weeks. Since these infections are rare, it is difficult for ophthalmologists to gain the experience necessary to differentiate infection from normal findings or artefacts. The purpose of this project was to establish a simulator, on which physicians could practice as well as acquiring a database of IVCM images of fungal or amoebic keratitis and respective analyses. Patients and methods An IVCM simulator was set up with cadaver human corneas, infected with either acanthamoeba, candida or aspergillus. Twenty-one ophthalmologists were trained in IVC microscopy first in a Dry Lab, then practically on the simulator. For evaluation, the participants were asked to fill out a standardized questionnaire, with a pre- and post-course self-assessment. Results The self-assessed theoretical and practical skills in differentiating infectious from non-infectious keratitis in IVCM significantly increased (p = 0.0001, p = 0.0002, respectively). The barrier to use this technique decreased (p = 0.0474). Conclusion A very simple protocol based on a model of ex vivo corneal mycotic and amoebic infections can be used to train novices in the structured approach and diagnostic use of IVCM for corneal infections.

A Deep Learning Model for Automated Sub-Basal Corneal Nerve Segmentation and Evaluation Using In Vivo Confocal Microscopy.

PurposeThe purpose of this study was to establish a deep learning model for automated sub-basal corneal nerve fiber (CNF) segmentation and evaluation with in vivo confocal microscopy (IVCM).MethodsA corneal nerve segmentation network (CNS-Net) was established with convolutional neural networks based on a deep learning algorithm for sub-basal corneal nerve segmentation and evaluation. CNS-Net was trained with 552 and tested on 139 labeled IVCM images as supervision information collected from July 2017 to December 2018 in Peking University Third Hospital. These images were labeled by three senior ophthalmologists with ImageJ software and then considered ground truth. The areas under the receiver operating characteristic curves (AUCs), mean average precision (mAP), sensitivity, and specificity were applied to evaluate the efficiency of corneal nerve segmentation. The relative deviation ratio (RDR) was leveraged to evaluate the accuracy of the corneal nerve fiber length (CNFL) evaluation task.ResultsThe model achieved an AUC of 0.96 (95% confidence interval [CI] = 0.935–0.983) and an mAP of 94% with minimum dice coefficient loss at 0.12. For our dataset, the sensitivity was 96% and specificity was 75% in the CNF segmentation task, and an RDR of 16% was reported in the CNFL evaluation task. Moreover, the model was able to segment and evaluate as many as 32 images per second, much faster than skilled ophthalmologists.ConclusionsWe established a deep learning model, CNS-Net, which demonstrated a high accuracy and fast speed in sub-basal corneal nerve segmentation with IVCM. The results highlight the potential of the system in assisting clinical practice for corneal nerves segmentation and evaluation.Translational RelevanceThe deep learning model for IVCM images may enable rapid segmentation and evaluation of the corneal nerve and may provide the basis for the diagnosis and treatment of ocular surface diseases associated with corneal nerves.

Development of Feasible Methods to Image the Eyelid Margin Using In Vivo Confocal Microscopy.

To develop a feasible method to image eyelid margin structures using in vivo confocal microscopy (IVCM) for use in clinical research. Second, to assess the association between IVCM and meibography images. IVCM was performed on the central upper eyelid margin of 13 healthy participants (31 ± 5 years). Overall morphology montages (1600 × 1600 μm) were created of 3 participants. Single frames (400 × 400 μm) of 10 participants were imaged to determine the feasibility of measuring eyelid features. Meibography was performed with EASYTEARview+ in the same 10 participants. ImageJ software was used to quantify image structures. In the montages, structures of rete ridges, meibomian gland openings, and the lid wiper region were observed. The maximum possible montage size, using multiple single frames, was approximately 5200 × 1500 × 150 μm in the X, Y, and Z directions, respectively. The mean number, density, area, perimeter, and shortest and longest diameters of rete ridges of the 9 nonoverlapped frames were 12 ± 2/frame, 73 ± 5/mm, 2504 ± 403 μm, 250 ± 33 μm, 40 ± 6 μm, and 84 ± 13 μm, respectively. Sampling analysis determined at least 5 nonoverlapped frames were necessary to accurately represent the parameters of the ridges. The mean areas of 3 meibomian openings were 785 ± 784 μm, 1036 ± 963 μm, 950 ± 1071 μm, 848 ± 954 μm, 737 ± 831 μm, 735 ± 743 μm, and from 30 μm to 130 μm at 20-μm depth intervals, respectively. No significant association between IVCM and meibography parameters (P = 0.53) was found. Imaging rete ridges with IVCM should include at least 5 nonoverlapping single frames in the upper eyelid margin. At least 3 openings imaged between 30 and 130 μm at 20-μm depth intervals are recommended to determine the opening area.