Corneal nerve changes by anti-glaucoma medications examined by in vivo confocal microscopy

AIM:To evaluate the effects of antiglaucoma eye drops on corneal nerves by in vivo confocal microscopy(IVCM).METHODS:This study comprised 79 patients diagnosed with glaucoma and 16 healthy control individuals.Among the glaucoma patients,54 were treated with medication,while 25 remained untreated.Central corneal images were evaluated by IVCM,and then ACCMetrics was used to calculate the following parameters:corneal nerve fiber density(CNFD),branch density(CNBD),fiber length(CNFL),total branch density(CTBD),fiber area(CNFA),fiber width(CNFW),and fractal dimension(CNFrD).The correlation between IVCM parameters and drugs was evaluated using non-parametric measurements of Spearman’s rank correlation coefficient.RESULTS:The CNFD was reduced in glaucoma groups compared to healthy subjects(P<0.01).Patients using anti-glaucoma medications exhibited poorer confocal parameters compared to untreated patients.As the number of medications and usage count increased,CNFD,CNBD,CNFL,CTBD,CNFA,and CNFrD experienced a decline,while CNFW increased(all P<0.01).For the brinzolamide-therapy group,there was a significant decrease in CNFD and CNFL compared to the other monotherapy groups(P<0.001).In the absence of medication,CNFD in males was lower than that in females(P<0.05).Among patients under medication therapy,CNFD remained consistent between males and females.CONCLUSION:Antiglaucoma eye drops affect the microstructure of corneal nerves.IVCM and ACCMetrics are useful tools that could be used to evaluate the corneal nerve changes.

Effects of contact lens wearing on keratoconus:a confocal microscopy observation

AIM： To evaluate the corneal cell morphology of new keratoconus patients wearing two different types of rigid gas-permeable（RGP） contact lenses for 1y.METHODS： Thirty nine eyes of 39 new keratoconus patients were selected and randomly fitted with two types of RGP contact lenses.Group 1 had 21 eyes with regular rigid gas-permeable（RRGP） contact lens and rest 18 eyes were in group 2 with specially designed rigid gas-permeable（SRGP） contact lens.Corneal cell morphology was evaluated using a slit scanning confocal microscope at no-lens wear and after 1y of contact lens wearing.RESULTS： After 1y of contact lens wearing in group 1,the mean anterior and posterior stromal keratocyte density were significantly less（P=0.006 and P=0.001,respectively） compared to no-lens wear.The mean cell area of anterior and posterior stromal keratocyte were also significantly different（P=0.005 and P=0.001） from no-lens wear.The anterior and posterior stromal haze increased by 18.74% and 23.81%,respectively after 1y of contact lens wearing.Whereas in group 2,statistically significant changes were observed only in cell density ＆ area of anterior stroma（P=0.001 and P=0.001,respectively） after 1y.While,level of anterior and posterior stromal haze increased by 16.67% and 11.11% after 1y of contact lens wearing.Polymegathism and pleomorphism also increased after 1y of contact lens wearing in both the contact lens groups.CONCLUSION： Confocal microscopy observation shows the significant alterations in corneal cell morphology of keratoconic corneas wearing contact lenses especially in group 1.The type of contact lens must be carefully selected to minimize changes in corneal cell morphology.

Clinical features and in vivo confocal microscopy assessment in 12 patients with ocular cicatricial pemphigoid

AIM： To describe the clinical features and microstructural characteristics assessed by in vivo confocal microscopy（IVCM） in patients with ocular cicatricial pemphigoid（OCP）.· METHODS： A descriptive, uncontrolled case series study. Patients diagnosed with OCP were examined by clinical history, slit-lamp biomicroscopy features and IVCM images. The results of direct immunofluorescence（DIF） biopsies and indirect immunofluorescence（IIF） were also recorded. Local and systemic immunosuppressive therapy were administered and adjusted according to response.·RESULTS： A total of 12 consecutive OCP patients（7male, 5 female; mean age 60.42 ±10.39y） were recruited.All patients exhibited bilateral progressive conjunctival scarring and recurrent chronic conjunctivitis was the most frequent clinical pattern. The mean duration of symptoms prior to diagnosis of OCP was 2.95 ±2.85y（range： 5mo to 10y）. The Foster classification varied from stage I to IV and 20 eyes（83%） were within or greater than Foster stage Ⅲ on presentation. Two of the 12patients（17%） demonstrated positive DIF; 3 of the 12（25%） patients reported positive IIF. The mean duration of the follow-up period was 20.17 ±11.88mo（range： 6 to48mo）. IVCM showed variable degrees of abnormality in the conjuctiva-cornea and conjuctival scarring was detected in all the involved eyes. Corneal stromal cell activation and dendritic cell infiltration presented asocular surface inflammation, ocular surface keratinization along with the destroyed Vogt palisades was noted in eyes with potential limbal stem cell deficiency. After treatment, remission of ocular surface inflammation was achieved in all the patients, 18 eyes（75%） remained stable, 6 eyes（25%） had recurrent conjunctivitis and cicatrization in 2 eyes（8%） was progressing.· CONCLUSION： As an autoimmune disease, OCP manifests as variable degrees of clinical and laboratory abnormalities with both local and systemic immunosuppressive treatment playing important roles in disease therapy. IVCM can be as a valuable non-invasive technique to assess ocular surface changes in a cellular level with a potential value for providing diagnostic evidence and monitoring therapeutic effects during follow-up.

Investigation of confocal microscopy for differentiation of renal cell carcinoma versus benign tissue.Can an optical biopsy be performed?

Objective:Novel optical imaging modalities are under development with the goal of obtaining an“optical biopsy”to efficiently provide pathologic details.One such modality is confocal microscopy which allows in situ visualization of cells within a layer of tissue and imaging of cellular-level structures.The goal of this study is to validate the ability of confocal microscopy to quickly and accurately differentiate between normal renal tissue and cancer.Methods:Specimens were obtained from patients who underwent robotic partial nephrectomy for renal mass.Samples of suspected normal and tumor tissue were extracted from the excised portion of the kidney and stained with acridine orange.The stained samples were imaged on a Nikon E600 C1 Confocal Microscope.The samples were then submitted for hematoxylin and eosin processing and read by an expert pathologist to provide a gold-standard diagnosis that can later be compared to the confocal images.Results:This study included 11 patients,17 tissue samples,and 118 confocal images.Of the 17 tissue samples,10 had a gold-standard diagnosis of cancer and seven were benign.Of 118 confocal images,66 had a gold-standard diagnosis of cancer and 52 were benign.Six confocal images were used as a training set to train eight observers.The observers were asked to rate the test images on a six point scale and the results were analyzed using a web based receiver operating characteristic curve calculator.The average accuracy,sensitivity,specificity,and area under the empirical receiver operating characteristic curve for this study were 91%,98%,81%,and 0.94 respectively.Conclusion:This preliminary study suggest that confocal microscopy can be used to distinguish cancer from normal tissue with high sensitivity and specificity.The observers in this study were trained quickly and on only six images.We expect even higher performance as observers become more familiar with the confocal images.

EFFECT OF THE TOTAL SAPONIN OF DIPSACUS ASPER ON INTRACELLULAR FREE CALCIUM CONCENTRATION IN THE CELLULAR MODEL OF ALZHEIMER'S DISEASE-SCANNING CONFOCAL MICROSCOPY

Objective To study the effect of ginsenoside Rb1 and total saponin of dipsacus asper on intracellular free calcium concentration mediated by β amyloid protein.So as to lay a foundation for developing effective Chinese traditional medicine to treat Alzheimer’s disease.Methods The technique of laser scanning confocal microscopy combining primary cultured neurons was adopted to quantitatively analyze the change of [Ca 2+ ] i.Results The [Ca 2+ ] i of primary cultured hippocampal neurons was nmol·L -1 on basal levels.Control group showed obvious change of calcium vibration,[Ca 2+ ] i was elevated to nmol·L -1 .The peak of [Ca 2+ ] i of Rb1 group reached nmol·L -1 and was lower than that of control group .The tSDA group displayed distinct change of calcium vibration too,and [Ca 2+ ] i reached nmol·L -1 .There was a significant difference in [Ca 2+ ] i between control and tSDA group .Conclusion The research indicated that one of mechanisms by which Rb1 and tSDA protected the neurons was to maintain the balance of [Ca 2+ ] i.

Aplication of <i>in Vivo</i>Confocal Microscopy in Ophtalmology—Overview

Confocal microscopy is a method which has been increasingly used over the last decade in the study of the anterior ocular surface. The method allows testing and in vivo high resolution imaging of the structures of the anterior eye segment, at a cellular level, which is close to the histological examination of tissues. The data provided by this method allow for a better understanding of both the functional and pathological processes occurring in the anterior ocular surface not only for scientific purposes but also in clinical practice. The aim of the present work is to summarize the current knowledge and applications of confocal microscopy of the anterior ocular surface.

Studies of Microstructure of Kernels of Macadamia integrifolia and Its Hybrids through MRI, X-Ray Tomography and Confocal Microscopy

The aim of this study was to apply the existing techniques that enable examination ofmacadamia kernels to provide a better understanding of physico-chemical properties of kernels during postharvest processing. These techniques, such as X-ray tomography, could be applied for quality monitoring in the macadamia industry. The objectives of this study were to investigate the browning centre symptoms that usually occur in macadamia nuts-in-shell. The applied techniques included confocal microscopy, X-ray tomography and magnetic resonance imaging （MRI）. Five different varieties of macadamia nuts （A38, 246, 816, 842 and Daddow） were selected to include distinct characteristics, such as drop pattern and growing location. Analysis of the microstructure of kernels by confocal microscopy showed the distribution of possible brown pigment compounds as well as the distribution of lipids, carbohydrates and proteins inside macadamia cells. Physical properties data, including shell density and seed to volume ratio, were obtained by X-ray tomography. Magnetic resonance diffusion tensor imaging used in this study showed marked differences in microstructure which indicate that different varieties exhibit different microstructures expressed as fraction ofanisotropy and apparent diffusion coefficient that appear to be related to the occurrence of the brown centre. Hence, the findings of this study have potential to improve the existing postharvest techniques used in the macadamia processing industry. They will be of benefit to the industry in terms of improved quality control and cost reduction.

SSL Depth: self-supervised learning enables 16× speedup in confocal microscopy-based 3D surface imaging [Invited]

In scientific and industrial research, three-dimensional (3D) imaging, or depth measurement, is a critical tool that provides detailed insight into surface properties. Confocal microscopy, known for its precision in surface measurements, plays a key role in this field. However, 3D imaging based on confocal microscopy is often challenged by significant data requirements and slow measurement speeds. In this paper, we present a novel self-supervised learning algorithm called SSL Depth that overcomes these challenges. Specifically, our method exploits the feature learning capabilities of neural networks while avoiding the need for labeled data sets typically associated with supervised learning approaches. Through practical demonstrations on a commercially available confocal microscope, we find that our method not only maintains higher quality, but also significantly reduces the frequency of the z-axis sampling required for 3D imaging. This reduction results in a remarkable 16×measurement speed, with the potential for further acceleration in the future. Our methodological advance enables highly efficient and accurate 3D surface reconstructions, thereby expanding the potential applications of confocal microscopy in various scientific and industrial fields.

Comparison of Ex‑PRESS implantation versus trabeculectomy combined with phacoemulsification in primary open‑angle glaucoma:a retrospective in vivo confocal microscopy study

Background:To compare the efficacy of Ex-PRESS implantation versus trabeculectomy combined with phacoemulsification.Methods:A retrospective 12-month study on patients with coincident primary open-angle glaucoma(POAG)and cataract.The patients underwent combined phacoemulsification and Ex-PRESS implant(Phaco-ExPRESS,n=35)or phacotrabeculectomy(Phaco-Trab,n=35).The morphological structures of the filtering bleb were examined by slitlamp,anterior segment optical coherence tomography(AS-OCT)and in vivo confocal microscopy(IVCM).Complete success was defined as postoperative intraocular pressure(IOP)<18 mmHg without the use of anti-glaucoma medication.Qualified success was defined as postoperative IOP<18 mmHg with or without anti-glaucoma medications.The data were collected preoperatively and postoperatively at 2 weeks,1 month,3 months,6 months,and 12 months.Results:No significant difference in the variables such as age,IOP and perimetry was found between the groups of Phaco-ExPRESS and Phaco-Trab.At the one-year postoperative visit for filtering blebs,Phaco-ExPRESS increased the mean area of epithelial microcysts significantly from 0.10±0.05 to 0.20±0.09μm^(2)perμm^(2),while Phaco-Trab decreased the mean area significantly from 0.08±0.04 to 0.04±0.06μm^(2)perμm^(2).Notably,the hyperreflective dots detected by IVCM decreased by 84.9%in Phaco-ExPRESS but increased by 36.3%in Phaco-Trab.The hyperreflective dots were further identified as neutrophil-and monocyte-like cells.The number of these cells were negatively correlated with the microcysts area(r=−0.7,P<0.01)but positively associated with the grade of connective tissue(r=0.5,P<0.01).By creating different microstructural changes in the filtering blebs,Phaco-ExPRESS produced a higher complete success rate(84.9%vs.41.2%,P<0.01)and significant decrease in the number of anti-glaucoma medications(P<0.01)when compared with those in Phaco-Trab.However,the qualified success showed no significant difference between the two groups(100.0%vs.91.2%,P=0.24).Conclusions:At the one-year follow-up,Phaco-ExPRESS generated better filtering bleb with larger area of microcysts,looser connective tissues,and less inflammation than that of Phaco-Trab,providing adequate IOP control and less IOP-lowering medications.These findings indicate that Phaco-ExPRESS could be more preferred than Phaco-Trab for the treatment of patients with coincident POAG and cataract.

Large-field objective lens for multi-wavelength microscopy at mesoscale and submicron resolution

Conventional microscopes designed for submicron resolution in biological research are hindered by a limited field of view,typically around 1 mm.This restriction poses a challenge when attempting to simultaneously analyze various parts of a sample,such as different brain areas.In addition,conventional objective lenses struggle to perform consistently across the required range of wavelengths for brain imaging in vivo.Here we present a novel mesoscopic objective lens with an impressive field of view of 8 mm,a numerical aperture of 0.5,and a working wavelength range from 400 to 1000 nm.We achieved a resolution of 0.74μm in fluorescent beads imaging.The versatility of this lens was further demonstrated through high-quality images of mouse brain and kidney sections in a wide-field imaging system,a confocal laser scanning system,and a two-photon imaging system.This mesoscopic objective lens holds immense promise for advancing multi-wavelength imaging of large fields of view at high resolution.

Confocal laser endomicroscopy in the “in vivo” histological diagnosis of the gastrointestinal tract

Recent technological advances in miniaturization have allowed for a confocal scanning microscope to be integrated into a conventional flexible endoscope,or into trans-endoscopic probes,a technique now known as confocal endomicroscopy or confocal laser endomicroscopy.This newly-developed technology has enabled endoscopists to collect real-time in vivo histological images or "virtual biopsies" of the gastrointestinal mucosa during endoscopy,and has stimulated significant interest in the application of this technique in clinical gastroenterology.This review aims to evaluate the current data on the technical aspects and the utility of this new technology in clinical gastroenterology and its potential impact in the future,particularly in the screening or surveillance of gastrointestinal neoplasia.

Revealing the F_actin Networks in Interphase Nuclei of Garlic Clove Cells by Confocal Fluorescence Microscopy

The interphase nuclei of parenchyma cells and epidermal cells of garlic ( Allium sativum L.) clove were labelled with rabbit anti_actin antibody and FITC_conjugated goat anti_rabbit IgG antibody. The authors observed results with fluorescence microscopy and confocal laser scanning microscopy. The nuclei showed prominent green_yellow fluorescence, indicating the presence of actin in the nuclei. Fluorescence examination with TRITC_phalloidin showed distinctive red fluorescence in the nuclei, indicating that F_actin is present in the nuclei. Confocal laser scanning microscopy indicated the presence of F_actin containing network structures in the nuclei, but the network structures were absent and the nuclei still showed red fluorescence when the cells were treated with cytochalasin D before fixation; the red fluorescence in the nuclei was hard to be observed when the cells were treated with unlabelled phalloidin before the cells were stained with TRITC_phalloidin. These results indicate that F_actin is in the nuclei and forms network structures in the nuclei of garlic cells.

In vivo Confocal Microscopy Evaluation of Meibomian Gland Dysfunction in Dry Eye Patients with Different Symptoms

Background：Dry eye patients suffer from all kinds of symptoms.Sometimes,the clinical signs evaluation does not disclose any obvious difference in routine examination;in vivo confocal microscopy （IVCM） is a powerful tool for ocular surface disease.This study aimed to clarify meibomian gland （MG） alterations in dry eye patients with different symptoms and to compare the findings using IVCM.Methods：A total of sixty patients were recruited,all subjected to Ocular Surface Disease Index （OSDI） and Salisbury Eye Evaluation Questionnaire （SEEQ）,and questionnaires for the assessment of dry eye symptoms before clinical sign examinations were given to the patients.Finally,IVCM was applied to observe MG＇s structure.Statistical analysis was performed using the t-test,Mann-Whitney U-test and Spearman correlation analysis.The differences were statistically significant when P 〈 0.05.Results：In the severe symptom group,OSDI and SEEQ scores were significantly higher （P 〈 0.05） compared with the mild symptoms group.All other clinical sign examinations had no statistical difference in the two groups （P 〉 0.05）.However,all the IVCM-observed data showed that patients with severe symptoms had more significant fibrosis in MG （acinar unit area 691.87 ± 182.01 μm^2 for the severe,992.17 ± 170.84 μm^2 for the mild;P 〈 0.05） and severer decrease in the size of MG acinar units than those observed in patients with mild symptoms （MG acinar unit density [MGAUD] 70.08 ± 18.78 glands/mm2,MG acinar unit longest diameter [MGALD] 51.50 ± 15.51 μm,MG acinar unit shortest diameter [MGASD] 20.30 ± 11.85 μm for the severe,MGAUD 89.53 ± 39.88 glands/mm2,MGALD 81.57 ± 21.14 μm,MGASD 42.37 ± 14.55 μm for the mild;P 〈 0.05）.Dry eye symptoms were negatively correlated with MG confocal microscopic parameters and positively correlated with conjunctival inflammatory cells and Langerhans cells （P 〈 0.05）.Conclusions：IVCM application provides a strong support to differentiate dry eye patients with different symptoms：meibomian gland dysfunction （MGD） plays a pivotal role in dry eye aggravation,and using IVCM to observe MG fibrosis,changes in size and density of MG as well as status of inflammation cells can help not only correctly diagnose the type and severity of dry eye,but also possibly prognosticate in routine eye examination in the occurrence of MGD.

Effect of melatonin on the spatial and temporal changes of [Ca^(2+) ]i in single living cells of cortical neurons by laser scanning confocal microscopy

Objective To examine the effects of melatonin on the dynamic changes in the concentration of intracellular free Ca 2+ ([Ca 2+ ]i) in single intact cultured cortical neurons isolated from fetal rats, in order to explore the possible antiaging mechanisms of melatonin (MT) Methods Using the highly fluorescent Ca 2+ sensitive indicator Fluo 3/AM, cortical neurons cultured in a 35?mm Tissue Culture Dish were in incubated for 45?min at room temperature with 5?μmol/L Fluo 3/AM, resulting in proper intracellular dye concentration to provide adequate signal strength for detection and excellent Laser Scanning Confocal Microscopy (LSCM) imaging of [Ca 2+ ]i while not disturbing normal intracellular physiology The changes in fluorescent intensity were monitored by LSCM Results Bay K8644 (10 6 ?mol/L), KCl (20 ?mmol/L), sodium L glutamate (Glu, 50?μmol/L) caused a rapid increase of [Ca 2+ ]i in cortical neurons, and this increase could be significantly attenuated by 10 6 and 10 7 mol/L MT Conclusions MT could antagonize the extracellular Ca 2+ influx, reduce Ca 2+ overload, and have a protective effect on neurons This may be one of the important antiaging mechanisms of MT

In vivo subsurface morphological and functional cellular and subcellular imaging of the gastrointestinal tract with confocal mini-microscopy

AIM： To evaluate a newly developed hand-held confocal probe for in vivo microscopic imaging of the complete gastrointestinal tract in rodents. METHODS： A novel rigid confocal probe （diameter 7 mm） was designed with optical features similar to the flexible endomicroscopy system for use in humans using a 488 nm single line laser for fluorophore excitation, Light emission was detected at 505 to 750 nm. The field of view was 475 μm × 475 μm. Optical slice thickness was 7 μm with a lateral resolution of 0.7 μm. Subsurface serial images at different depths （surface to 250 μm） were generated in real time at 1024 × 1024 pixels （0.8 frames/s） by placing the probe onto the tissue in gentle, stable contact. Tissue specimens were sampled for histopathological correlation.RESULTS： The esophagus, stomach, small and large intestine and meso, liver, pancreas and gall bladder were visualised in vivo at high resolution in n = 48 mice. Real time microscopic imaging with the confocal minimicroscopy probe was easy to achieve. The different staining protocols （fluorescein, acriflavine, FITC-labelled dextran and L. esculentum lectin） each highlighted specific aspects of the tissue, and in vivo imaging correlated excellently with conventional histology. In vivo blood flow monitoring added a functional quality to morphologic imaging.CONCLUSION： Confocal microscopy is feasible in vivo allowing the visualisation of the complete GI tract at high resolution even of subsurface tissue structures. The new confocal probe design evaluated in this study is compatible with laparoscopy and significantly expands the field of possible applications to intra-abdominal organs. It allows immediate testing of new in vivo staining and application options and therefore permits rapid transfer from animal studies to clinical use in patients.

Potential use of corneal confocal microscopy in the diagnosis of Parkinson's disease associated neuropathy

Parkinson's disease(PD)is a chronic,progressive neurodegenerative disease affecting about 2%-3% of population above the age of 65.In recent years,Parkinson's research has mainly focused on motor and non-motor symptoms while there are limited studies on neurodegeneration which is associated with balance problems and increased incidence of falls.Corneal confocal microscopy(CCM)is a real-time,non-invasive,in vivo ophthalmic imaging technique for quantifying nerve damage in peripheral neuropathies and central neurodegenerative disorders.CCM has shown significantly lower corneal nerve fiber density(CNFD)in patients with PD compared to healthy controls.Reduced CNFD is associated with decreased intraepidermal nerve fiber density in PD.This review provides an overview of the ability of CCM to detect nerve damage associated with PD.

Endoscopic ultrasound-guided through-the-needle microforceps biopsy and needle-based confocal laser-endomicroscopy increase detection of potentially malignant pancreatic cystic lesions:A single-center study

BACKGROUND Currently,there is insufficient data about the accuracy in the diagnosing of pancreatic cystic lesions(PCLs),especially with novel endoscopic techniques such as with direct intracystic micro-forceps biopsy(mFB)and needle-based confocal laser-endomicroscopy(nCLE).AIM To compare the accuracy of endoscopic ultrasound(EUS)and associated techniques for the detection of potentially malignant PCLs:EUS-guided fine needle aspiration(EUS-FNA),contrast-enhanced EUS(CE-EUS),EUS-guided fiberoptic probe cystoscopy(cystoscopy),mFB,and nCLE.METHODS This was a single-center,retrospective study.We identified patients who had undergone EUS,with or without additional diagnostic techniques,and had been diagnosed with PCLs.We determined agreement among malignancy after 24-mo follow-up findings with detection of potentially malignant PCLs via the EUSguided techniques and/or EUS-guided biopsy when available(EUS malignancy detection).RESULTS A total of 129 patients were included, with EUS performed alone in 47/129. In 82/129 patients,EUS procedures were performed with additional EUS-FNA (21/82), CE-EUS (20/82), cystoscopy(27/82), mFB (36/82), nCLE (44/82). Agreement between EUS malignancy detection and the 24-mo follow-up findings was higher when associated with additional diagnostic techniques thanEUS alone [62/82 (75.6%) vs 8/47 (17%);OR 4.35, 95%CI: 2.70-7.37;P < 0.001]. The highestmalignancy detection accuracy was reached when nCLE and direct intracystic mFB were bothperformed, with a sensitivity, specificity, positive predictive value, negative predictive value andobserved agreement of 100%, 89.4%, 77.8%, 100% and 92.3%, respectively (P < 0.001 comparedwith EUS-alone).CONCLUSIONThe combined use of EUS-guided mFB and nCLE improves detection of potentially malignantPCLs compared with EUS-alone, EUS-FNA, CE-EUS or cystoscopy.

In vivo confocal microscopy: qualitative investigation of the conjunctival and corneal surface in open angle glaucomatous patients undergoing the XEN-Gel implant, trabeculectomy or medical therapy

Purpose:Assessing the quality of the ocular surface by in vivo scanning laser confocal microscopy(IVCM)in primary open angle glaucoma(POAG)patients treated by Xen 45 Gel Stent,medical therapy and trabeculectomy.Methods:Retrospective,single-center,single-masked,comparative study including 60 eyes of 30 patients(mean age 61.16±10 years)affected by POAG.Eyes were divided into 3 groups:Group 1 eyes underwent the Xen 45 Gel Stent procedure,Group 2 eyes were under medical therapy,Group 3 eyes were surgically treated by trabeculectomy.All patients underwent HRT II IVCM analysis of cornea,limbus,conjunctiva,sub-tenionian space and sclera.Results:The Xen 45 Gel stent,if properly positioned in the sub-conjunctival space preserves goblet cells and limits ocular surface inflammation.Regular corneal epithelial cells with micro-cysts,and normo-reflective sub-epithelial nerve plexus are documented by IVCM.In sub Tenon’s implants an alternative lamellar intra-scleral filtration is detectable.Combined surgical procedures show a noticeable number of inflammatory cells with rare micro-cysts.Post-trabeculectomy inflammatory reaction is more evident than Xen 45 Gel Stent associated surgical procedures,but less than medical therapy where a conspicuous presence of Langerhans cells,peri-neural infiltrates,marked loss of goblet cells and fibrosis is visible.Conclusion:Ocular surface inflammation was more notable in topical therapy than after trabeculectomy,which itself causes more inflammation than XEN Gel stents.

Deep learning-based analysis of macaque corneal sub-basal nerve fibers in confocal microscopy images

Background:To develop and validate a deep learning-based approach to the fully-automated analysis of macaque corneal sub-basal nerves using in vivo confocal microscopy(IVCM).Methods:IVCM was used to collect 108 images from 35 macaques.58 of the images from 22 macaques were used to evaluate different deep convolutional neural network(CNN)architectures for the automatic analysis of sub-basal nerves relative to manual tracings.The remaining images were used to independently assess correlations and interobserver performance relative to three readers.Results:Correlation scores using the coefficient of determination between readers and the best CNN averaged 0.80.For inter-observer comparison,inter-correlation coefficients(ICCs)between the three expert readers and the automated approach were 0.75,0.85 and 0.92.The ICC between all four observers was 0.84,the same as the average between the CNN and individual readers.Conclusions:Deep learning-based segmentation of sub-basal nerves in IVCM images shows high to very high correlation to manual segmentations in macaque data and is indistinguishable across readers.As quantitative measurements of corneal sub-basal nerves are important biomarkers for disease screening and management,the reported work offers utility to a variety of research and clinical studies using IVCM.

Nonlinear optical characterization of single β-barium-borate nanocrystals using second-harmonic confocal microscopy

The confocal microscopy technique was applied for nonlinear optical characterization of single β-barium-borate（β-BBO） nanocrystals. The experimental setup allows measurements of the laser polarization-selective secondharmonic（SH） generation, and the results can be used to determine the nanocrystals＇ c-axis orientation, as well as to obtain information about their second-order susceptibility χ^（2）. The dependence of the SH signal on the laser polarization allowed the discrimination of individual particles from aggregates. The data were fitted using a model that takes into account the BBO properties and the experimental setup characteristics considering（i） the electrostatic approximation,（ii） the effects of the microscope objective used to focus the light on the sample in an epi-geometry configuration, and（iii） the symmetry of χ^（2） for the β-BBO nanocrystals. A signal at the third-harmonic frequency was also detected, but it was too weak to be studied in detail.