Human Iris Research Articles

Brief Research Report: Ebola Virus Differentially Infects Human Iris and Retinal Pigment Epithelial Cells

Uveitis is a common manifestation of post-Ebola syndrome, associated with persistence of Ebola virus (EBOV; Zaire ebolavirus) inside the eye. The iris and retinal pigment epithelia are key components of the blood-ocular barriers, but have the capacity to act as hosts for microorganisms. We investigated the ability of EBOV to productively infect these cell populations. Donor-matched human iris and retinal pigment epithelial isolates (n = 5) were infected with EBOV at a multiplicity of infection of 1 for up to 72 hours. Parallel cultures were infected with Reston virus (RESTV; Reston ebolavirus) or Zika virus (ZIKV), or held uninfected under the same conditions. Viral transcript expression by RT-qPCR on total cellular RNA, cytoimmunofluorescence, and assays of 50% tissue culture infected dose of culture supernatant showed that both iris and retinal pigment epithelial isolates were permissive to infection, and supported replication and release of EBOV, as well as RESTV and ZIKV. However, in comparison to cells isolated from iris, those from retina demonstrated obvious EBOV-induced cytopathic effect, had higher intracellular EBOV nucleoprotein transcript, expressed intracellular EBOV protein more widely, and released EBOV at higher titer. Comparable results were obtained for isolates infected with RESTV and ZIKV. Consistent with observations of retinal pigment epithelial scars in Ebola survivors, our results suggest that an early event in post-Ebola uveitis is infection of the retinal pigment epithelium. Relative susceptibility of retinal pigment epithelial cells to infection with RESTV and ZIKV, as well as EBOV, implies this phenomenon may relate to a cell-specific attribute, such as high phagocytic activity.

Ocular Hypotensive Properties and Biochemical Profile of QLS-101, a Novel ATP-Sensitive Potassium (KATP) Channel Opening Prodrug.

PurposeTo characterize the ocular hypotensive and pharmacological properties of QLS-101, a novel ATP-sensitive potassium (KATP) channel opening prodrug.MethodsOcular hypotensive properties of QLS-101 were evaluated by measuring IOP with a handheld rebound tonometer after daily topical ocular instillation of 0.2% (n = 5) or 0.4% QLS-101 (n = 10) in C57BL/6J mice. KATP channel specificity was characterized in HEK-293 cells stably expressing human Kir6.2/SUR2B subunits and assessed for off-target interactions using a receptor binding screen. Conversion of QLS-101 prodrug to its active moiety, levcromakalim, was evaluated in vitro using human ocular tissues and plasma samples and after incubation with human phosphatase enzymes (2.0 nM-1.0 µM).ResultsC57BL/6J mice treated once daily with 0.2% QLS-101 exhibited significant (P < 0.01) IOP reductions of 2.1 ± 0.4 mmHg after five days; however, a daily attenuation of the effect was noted by 23h post-dose. By comparison, treatment with 0.4% QLS-101 lowered IOP by 4.8 ± 0.7 mm Hg (P < 0.0001) which was sustained for 24 hours. Unlike levcromakalim, QLS-101 failed to induce KATP channel activity in HEK-Kir6.2/SUR2B cells consistent with its development as a prodrug. No off-target receptor effects were detected with either compound. In vitro ocular tissue conversion of QLS-101 prodrug was identified in human iris, ciliary body, trabecular meshwork, and sclera. Alkaline phosphatase was found to convert QLS-101 (mean Km = 630 µM, kcat = 15 min−1) to levcromakalim.ConclusionsQLS-101 is a novel KATP channel opening prodrug that when converted to levcromakalim shows 24-hour IOP lowering after once-daily topical ocular administration.

Comparison of Feature Extraction Technique for Segmentation in Human Iris Recognition Under Uncontrolled Environment Using CNN Algorithm with SVM Classifier

The main aim of this study is to compare the radical segmentation of human iris using two different machine learning algorithms in an uncontrolled environment image dataset. Materials and method: Images taken from MMU iris dataset, Convolutional Neural Network (CNN) model, and Support Vector Machine (SVM) model implemented to segment iris in uncontrolled environment image with 50 samples per group. Results: MATLAB simulation result shows that CNN has accuracy of 94% and SVM has 72% in segmenting iris. Attained significant accuracy (0.001) in SPSS statistical analysis. Conclusion: For the given images, proposed CNN shows better accuracy than SVM classifier in iris segmentation tasks.

Induction of Filopodia During Cytomegalovirus Entry Into Human Iris Stromal Cells.

Many viruses exploit thin projections of filopodia for cell entry and cell-to-cell spread. Using primary cultures of human iris stromal (HIS) cells derived from human eye donors, we report a significant increase in filopodia formation during human cytomegalovirus (HCMV) infection. Using confocal microscopy, we observed a large number of virions being frequently associated along the filopodia prior to cell infection. Depolymerization of actin filaments resulted in a significant inhibition of HCMV entry into HIS cell. Our results further revealed that the transient expression of HCMV envelope glycoprotein B (gB) triggers the induction of the filopodial system. Since gB is known to bind the diverse chains of heparan sulfate (HS), a comparative study was performed to evaluate the gB-mediated filopodial induction in cells expressing either wild-type HS and/or 3-O sulfated HS (3-OS HS). We found that cells co-expressing HCMV gB together with the 3-O sulfotranseferase-3 (3-OST-3) enzyme had a much higher and robust filopodia induction compared to cells co-expressing gB with wild-type HS. The above results were further verified by pre-treating HIS cells with anti-3-OS HS (G2) peptide and/or heparinase-I before challenging with HCMV infection, which resulted in a significant loss in the filopodial counts as well as decreased viral infectivity. Taken together, our findings highlight that HCMV entry into HIS cells actively modulates the actin cytoskeleton via coordinated actions possibly between gB and the 3-OS HS receptor to influence viral infectivity.

A Review Paper on Retina Based Cursor Movement Control

Abstract: In this paper a new system exists which uses human iris for computer interaction. With vast development in recent technologies, modern computing systems are becoming more flexible. Modern computers are capable of processing millions of instructions per second. In such situation, traditional input devices such as mouse or keyboard are relatively slow. This can overcome by human interaction with the computers. With the innovation and development in technologies, motion sensors are capable of capturing positions and natural movement of human body. Due to this a new way for interacting with computers is possible. Hence keeping all this in mind, we propose a system, which is untouched &amp; fast communication system. The system would be capable of capturing eyeball movements which is responsible for Controlling the cursor. The system processes the data from the camera feed, and calibrates the parameter interfaces in accordance to the user. The system then performs computer vision related algorithms to determine the location of the use’s pupils and eyeballs so as to implement Natural eye-computer Interaction Keywords: Human Iris, Cursor Control, Electro-oculography, CAMSHIFT algorithm, Limbus Limbus Tracking, Pupile Pupil tracking.

Dynamic Light Control Using Bionic Dielectric Elastomer Iris Actuators

AbstractApertures are used in optical systems to limit the luminous flux. In the human eye the iris serves this purpose but can be damaged requiring an implant, which to date is static, limiting the optical performance. The authors thus report the development of a prototype demonstrating the feasibility of a flexible dynamic iris implant manufactured with an automated manufacturing technique. The presented actuators are printed via aerosol jet printing allowing a high reliability in produced electrode quality. Through optimization of the actuator design for maximum contraction they demonstrate a pupil area reduction of 13.40% or 6.94% reduction of pupil diameter, respectively. Thereby the prototype demonstrates an illuminance reduction of 18.25% in the central visual axis. Furthermore, they present a first iteration of a bionic closed‐loop control mimicking the human iris reflex thus laying the foundation for a self‐controlled iris implant.

Human off Angle IRIS Liveness Detection Based on Fusion of DCT and Zernike Moments

Human off Angle IRIS Liveness Detection Based on Fusion of DCT and Zernike Moments

Region attention mechanism based dual human iris completion technology

Region attention mechanism based dual human iris completion technology

Primary angle closure glaucoma is characterized by altered extracellular matrix homeostasis in the iris.

To characterize the proteome of the iris in primary angle closure glaucoma (PACG). In this cross-sectional study, iris samples were obtained from surgical iridectomy of 48 adults with PACG and five normal controls. Peptides from iris were analysed using liquid chromatography-tandem mass spectrometry on an Orbitrap Q Exactive Plus mass spectrometer. Verification of proteins of interest was conducted using selected reaction monitoring on a triple quadrupole mass spectrometer. The main outcome was proteins with a log2 two-fold difference in expression in iris between PACG and controls. There were 3,446 non-redundant proteins identified in human iris, of which 416 proteins were upregulated and 251 proteins were downregulated in PACG compared with controls. Thirty-two upregulated proteins were either components of the extracellular matrix (ECM) (fibrillar collagens, EMILIN-2, fibrinogen, fibronectin, matrilin-2), matricellular proteins (thrombospondin-1), proteins involved in cell-matrix interactions (integrins, laminin, histidine-rich glycoprotein, paxillin), or protease inhibitors known to modulate ECM turnover (α-2 macroglobulin, tissue factor pathway inhibitor 2, papilin). Two giant proteins, titin and obscurin, were up- and down-regulated, respectively, in the iris in PACG compared with controls. This proteomic study shows that ECM composition and homeostasis are altered in the iris in PACG.

In vivo non-contact measurement of human iris elasticity by optical coherence elastography.

Quantifying the mechanical properties of the iris can offer valuable insights into the pathophysiology of primary angle closure glaucoma. However, current techniques for iris elastography remain ex vivo with limited clinical applications. This article describes a proposition for a non-contact and non-invasive air-puff optical coherence elastography (OCE) system that can evaluate iris elasticity in vivo. Ten eyes recruited from seven subjects underwent OCE imaging acquisition under three different illumination conditions. The Young's modulus of each eye was detected and shown to be inversely proportional to the iris length, indicating a relationship between mechanical properties and morphology of the iris. With its noninvasive and high-resolution features, this air-puff system shows great potential for applications in clinical ophthalmology.

SARS-CoV-2 infects human adult donor eyes and hESC-derived ocular epithelium.

The SARS-CoV-2 pandemic has caused unparalleled disruption of global behavior and significant loss of life. To minimize SARS-CoV-2 spread, understanding the mechanisms of infection from all possible routes of entry is essential. While aerosol transmission is thought to be the primary route of spread, viral particles have been detected in ocular fluid, suggesting that the eye may be a vulnerable point of viral entry. To this end, we confirmed SARS-CoV-2 entry factor and antigen expression in post-mortem COVID-19 patient ocular surface tissue and observed productive viral replication in cadaver samples and eye organoid cultures, most notably in limbal regions. Transcriptional analysis of ex vivo infected ocular surface cells and hESC-derived eye cultures revealed robust induction of NF-κB in infected cells as well as diminished type I/III interferon signaling. Together these data suggest that the eye can be directly infected by SARS-CoV-2 and implicate limbus as a portal for viral entry.

A Review of the Iris Recognition Methods Used for the Individual Authentication

The automatic iris recognition has become one of the most important techniques for authenticating the identity of individuals. The analysis of human iris is a reliable tool for the individual authentication due to the iris structure. Iris patterns constitute one of the uniqueness, permanence, and performance biometric traits. Moreover, the iris is considered as not easily tampered biometric traits. Therefore, this paper considers investigating the common automated methods of iris recognition. It surveys the development of utilizing iris images as an authentication means through the explanation of the historical improvement of the processes of the iris analysis. The contribution of this paper is to provide readers with huge information collected and discussed from more than 40 papers of iris recognition studies which have been published in a period of more than 20 years.

Large-Size Honeycomb-Shaped and Iris-Like Liquid Crystal Elastomer Actuators

Large-Size Honeycomb-Shaped and Iris-Like Liquid Crystal Elastomer Actuators

Tunable Artificial Iris Controlled by Photo/Thermal Exposure Based on Liquid Crystalline Elastomers

AbstractThe iris, part of the eye structure, is an important tissue in organisms. Here, a tunable artificial iris showing widening and closing of the pupil in response to near‐infrared (NIR) light is demonstrated. Liquid crystalline elastomers (LCEs) are synthesized via Michael addition and photopolymerization. To prepare an artificial iris, a predesigned stainless steel mold with a specific structure is created for the preparation of a single shaped LCE piece. Through the assembly of individual shaped LCE pieces, an artificial iris is fabricated. To enhance the photosensitivity, polydopamine (PDA) is coated on the surface of the fabricated iris. The PDA‐coated artificial iris shows reversible pupil widening and closing via exposure to NIR light. The dependence of pupil size on NIR intensity shows a function similar to the human iris. As far as it is known, the fabricated artificial iris with 2D radial motion is the first example prepared from a liquid crystalline elastomer showing a tunable aperture size controlled by the surrounding light intensity. The synthesized artificial iris is expected to show potential for multiple applications in biomimicry and biomedical science.

Zika Virus Infection of Human Iris Pigment Epithelial Cells.

During recent Zika epidemics, adults infected with Zika virus (ZIKV) have developed organ-specific inflammatory complications. The most serious Zika-associated inflammatory eye disease is uveitis, which is commonly anterior in type, affecting both eyes and responding to corticosteroid eye drops. Mechanisms of Zika-associated anterior uveitis are unknown, but ZIKV has been identified in the aqueous humor of affected individuals. The iris pigment epithelium is a target cell population in viral anterior uveitis, and it acts to maintain immune privilege within the anterior eye. Interactions between ZIKV and human iris pigment epithelial cells were investigated with infectivity assays and RNA-sequencing. Primary cell isolates were prepared from eyes of 20 cadaveric donors, and infected for 24 hours with PRVABC59 strain ZIKV or incubated uninfected as control. Cytoimmunofluorescence, RT-qPCR on total cellular RNA, and focus-forming assays of culture supernatant showed cell isolates were permissive to infection, and supported replication and release of infectious ZIKV. To explore molecular responses of cell isolates to ZIKV infection at the whole transcriptome level, RNA was sequenced on the Illumina NextSeq 500 platform, and results were aligned to the human GRCh38 genome. Multidimensional scaling showed clear separation between transcriptomes of infected and uninfected cell isolates. Differential expression analysis indicated a vigorous molecular response of the cell to ZIKV: 7,935 genes were differentially expressed between ZIKV-infected and uninfected cells (FDR < 0.05), and 99% of 613 genes that changed at least two-fold were up-regulated. Reactome and KEGG pathway and Gene Ontology enrichment analyses indicated strong activation of viral recognition and defense, in addition to biosynthesis processes. A CHAT network included 6275 molecular nodes and 24 contextual hubs in the cell response to ZIKV infection. Receptor-interacting serine/threonine kinase 1 (RIPK1) was the most significantly connected contextual hub. Correlation of gene expression with read counts assigned to the ZIKV genome identified a negative correlation between interferon signaling and viral load across isolates. This work represents the first investigation of mechanisms of Zika-associated anterior uveitis using an in vitro human cell model. The results suggest the iris pigment epithelium mounts a molecular response that limits intraocular pathology in most individuals.

Novel Technique for Retinal Nerve Cell Regeneration with Electrophysiological Functions Using Human Iris-Derived iPS Cells.

Regenerative medicine in ophthalmology that uses induced pluripotent stem cells (iPS) cells has been described, but those studies used iPS cells derived from fibroblasts. Here, we generated iPS cells derived from iris cells that develop from the same inner layer of the optic cup as the retina, to regenerate retinal nerves. We first identified cells positive for p75NTR, a marker of retinal tissue stem and progenitor cells, in human iris tissue. We then reprogrammed the cultured p75NTR-positive iris tissue stem/progenitor (H-iris stem/progenitor) cells to create iris-derived iPS (H-iris iPS) cells for the first time. These cells were positive for iPS cell markers and showed pluripotency to differentiate into three germ layers. When H-iris iPS cells were pre-differentiated into neural stem/progenitor cells, not all cells became positive for neural stem/progenitor and nerve cell markers. When these cells were pre-differentiated into neural stem/progenitor cells, sorted with p75NTR, and used as a medium for differentiating into retinal nerve cells, the cells differentiated into Recoverin-positive cells with electrophysiological functions. In a different medium, H-iris iPS cells differentiated into retinal ganglion cell marker-positive cells with electrophysiological functions. This is the first demonstration of H-iris iPS cells differentiating into retinal neurons that function physiologically as neurons.

A survey of iris datasets

Research on human eye image processing and iris recognition has grown steadily over the last few decades. It is important for researchers interested in this discipline to know the relevant datasets in this area to (i) be able to compare their results and (ii) speed up their research using existing datasets rather than creating custom datasets. In this paper, we provide a comprehensive overview of the existing publicly available datasets and their popularity in the research community using a bibliometric approach. We reviewed 158 different iris datasets referenced from the 689 most relevant research articles indexed by the Web of Science online library. We categorized the datasets and described the properties important for performing relevant research. We provide an overview of the databases per category to help investigators conducting research in the domain of iris recognition to identify relevant datasets.

Light microscopic iris classification using ensemble multi-class support vector machine.

Similar to other biometric systems such as fingerprint, face, DNA, iris classification could assist law enforcement agencies in identifying humans. Iris classification technology helps law-enforcement agencies to recognize humans by matching their iris with iris data sets. However, iris classification is challenging in the real environment due to its invertible and complex texture variations in the human iris. Accordingly, this article presents an improved Oriented FAST and Rotated BRIEF with Bag-of-Words model to extract distinct and robust features from the iris image, followed by ensemble multi-class-SVM to classify iris. The proposed methodology consists of four main steps; first, iris image normalization and enhancement; second, localizing iris region; third, iris feature extraction; finally, iris classification using ensemble multi-class support vector machine. For preprocessing of input images, histogram equalization, Gaussian mask and median filters are applied. The proposed technique is tested on two benchmark databases, that is, CASIA-v1 and iris image database, and achieved higher accuracy than other existing techniques reported in state of the art.

A Review of the Iris Recognition Methods Used for the Individual Authentication

The automatic iris recognition has become one of the most important techniques for authenticating the identity of individuals. The analysis of human iris is a reliable tool for the individual authentication due to the iris structure. Iris patterns constitute one of the uniqueness, permanence, and performance biometric traits. Moreover, the iris is considered as not easily tampered biometric traits. Therefore, this paper considers investigating the common automated methods of iris recognition. It surveys the development of utilizing iris images as an authentication means through the explanation of the historical improvement of the processes of the iris analysis. The contribution of this paper is to provide readers with huge information collected and discussed from more than 40 papers of iris recognition studies which have been published in a period of more than 20 years.

An Intelligent Iris Based Chronic Kidney Identification System

In recent years, the demand for alternative medical diagnostics of the human kidney or renal is growing, and some of the reasons behind this relate to its non-invasive, early, real-time, and pain-free mechanism. The chronic kidney problem is one of the major kidney problems, which require an early-stage diagnosis. Therefore, in this work, we have proposed and developed an Intelligent Iris-based Chronic Kidney Identification System (ICKIS). The ICKIS takes an image of human iris as input and on the basis of iridology a deep neural network model on a GPU-based supercomputing machine is applied. The deep neural network models are trained while using 2000 subjects that have healthy and chronic kidney problems. While testing the proposed ICKIS on 2000 separate subjects (1000 healthy and 1000 chronic kidney problems), the system achieves iris-based chronic kidney assessment with an accuracy of 96.8%. In the future, we will work to improve our AI algorithm and try data-set cleaning, so that accuracy can be increased by more efficiently learning the features.