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Effective elastic modulus of an intact cornea related to indentation behavior: A comparison between the Hertz model and Johnson-Kendall-Roberts model.

Exp Eye Res 2021 Jun 12;209:108670. Epub 2021 Jun 12.

College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China; State Key Lab. of Traction Power, Southwest Jiaotong University, Chengdu, China. Electronic address:

In this study, a macro-indentation test on the submillimeter scale was performed to analyze the indentation behavior of an intact cornea under physiological pressures. The Hertz and Johnson-Kendall-Roberts (JKR) models were employed to solve the elastic modulus (E) of the intact cornea. The relevant detailed analysis showed that the JKR model, which accounted for the contribution from the adhesion energy, could be used to obtain the E values that were more than two-folds of those obtained from the Hertz model, which only considered the external force. Read More

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Association among pterygium, cataracts, and cumulative ocular ultraviolet exposure: A cross-sectional study in Han people in China and Taiwan.

PLoS One 2021 15;16(6):e0253093. Epub 2021 Jun 15.

Department of Ophthalmology, Kanazawa Medical University, Uchinada, Ishikawa, Japan.

Purpose: Pterygium is an ocular surface disorder mainly caused by ultraviolet (UV) light exposure. This study explored the relationships between six cataract types with pterygium and UV exposure.

Methods: We have previously studied cataracts in residents of three regions in China and Taiwan with different UV intensities. Read More

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Neuropathic Corneal Pain Following LASIK Surgery: A Retrospective Case Series.

Ophthalmol Ther 2021 Jun 15. Epub 2021 Jun 15.

HDR Research Center, Hoopes Vision, University of Utah Health Sciences Center, 11820 S. State Street Suite #200, Draper, UT, 84020, USA.

Introduction: Transient dry eye symptoms have been reported following laser in situ keratomileusis (LASIK). Very rarely, patients may present with debilitating symptoms of dry eye syndrome (DES) with limited or no evidence of ocular surface disease. These patients are diagnosed with a form of DES known as neuropathic corneal pain (NCP). Read More

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A Novel Multi-Ingredient Supplement Reduces Inflammation of the Eye and Improves Production and Quality of Tears in Humans.

Ophthalmol Ther 2021 Jun 15. Epub 2021 Jun 15.

G7 Synergon Private Limited, 537, 5th Main, 9th Cross, Sahakarnagar Post, Tatanagar, Bangalore, Karnataka, 560092, India.

Introduction: Dry eye is a multifactorial condition of the eye caused by insufficient tear production and imbalance in tear composition leading to faster evaporation of tear fluid. It is also associated with inflammation that often leads to ocular surface damage. Symptoms of dry eyes include itchiness, soreness, red eyes, a burning sensation, eye fatigue and blurred vision. Read More

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Complications and visual outcomes of cataract surgery in patients with pseudoexfoliation.

Int Ophthalmol 2021 Jun 15. Epub 2021 Jun 15.

Cataract & Refractive Surgery Services, L V Prasad Eye Institute, Hyderabad, India.

Purpose: To compare outcomes of cataract surgery performed by ophthalmic trainees and consultants in patients associated with pseudoexfoliation (PXF) METHODS: Retrospective review of medical records of all patients with PXF who had undergone cataract surgery from January 2016 to December 2018 at L V Prasad Eye Institute, Hyderabad, India, were analysed RESULTS: A total of 914 eyes were included in the study; surgeries on 501 (54.8%) eyes with PXF were performed by trainees, while 413 (45.2%) were performed by consultants. Read More

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Differential Effect of Proinflammatory Cytokines on Corneal and Conjunctival Epithelial Cell Mucins and Glycocalyx.

Transl Vis Sci Technol 2021 Jun;10(7):17

Chapman University School of Pharmacy, Chapman University, Irvine, CA, USA.

Purpose: Ocular surface mucins and glycocalyx are critical for providing ocular hydration as well lubrication and repelling pathogens or allergens. Elevated levels of tear proinflammatory cytokines in dry eye may have detrimental effect on mucins and glycocalyx. The present study tested the effect of proinflammatory cytokines IL-6, TNF-α, and IFN-γ on membrane-tethered mucins expression, glycocalyx, and viability of ocular surface epithelial cells. Read More

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Studying human nociceptors: from fundamentals to clinic.

Brain 2021 Jun 15. Epub 2021 Jun 15.

Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.

Chronic pain affects one in five of the general population and is the third most important cause of disability-adjusted life-years globally. Unfortunately, treatment remains inadequate due to poor efficacy and tolerability. There has been a failure in translating promising preclinical drug targets into clinic use. Read More

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Spherical Aberration for Expanding the Depth of Focus: A Review for the Anterior Segment Surgeon.

J Cataract Refract Surg 2021 Jun 12. Epub 2021 Jun 12.

Department of Ophthalmology (Qvision), VITHAS Hospital, 04120, Almería, Spain Department of Ophthalmology, Hospital Virgen de las Nieves, Av. de las Fuerzas Armadas, 2, 18014 Granada, Spain Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain Department of Ophthalmology (IMQO-Oftalmar), Vithas Medimar International Hospital, Alicante, Spain.

Abstract: The increase of the depth of focus (DOF) for the treatment of presbyopia or cataracts is a topic of great interest for anterior segment surgeons that have seen how new surgical possibilities to achieve DOF enlargement have emerged. Nowadays, several technologies to extend the DOF are available, from corneal laser refractive surgery (LRS) procedures in presbyopia to intraocular lens (IOL) implantation in cataract or refractive lens exchange. Some of these procedures are based on aspherical profiles, either in the cornea or in the IOL, which modulate the spherical aberration (SA) and therefore extend the light energy on different focal planes. Read More

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Human Induced pluripotent stem cells-derived corneal endothelial-like cells promote corneal transparency in a rabbit model of bullous keratopathy.

Stem Cells Dev 2021 Jun 15. Epub 2021 Jun 15.

First Affiliated Hospital of Harbin Medical University, 74559, Harbin, Heilongjiang, China;

The corneal endothelium(CE) is vital for the cornea to maintain its transparency. However, CE dysfunction occurs due to aging, intraocular surgery, trauma, dystrophy, etc. Corneal transplantation is the only method to clinically treat CE dysfunction; however, this treatment strategy faces the disadvantages of a global cornea shortage, graft failure, and severe side effects. Read More

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Experimental-based validation of corneal lenticule banking in a health authority-licensed facility.

Tissue Eng Part A 2021 Jun 15. Epub 2021 Jun 15.

Singapore National Eye Centre, Cornea External Disease and Refractive, 11 Third Hospital Avenue, Level 8, Singapore, Singapore, 168751.

With the expected rise in patients undergoing refractive lenticule extraction worldwide, the amount of discarded corneal stromal lenticules will increase. Therefore, establishing a lenticule bank to collect, catalog, process, cryopreserve and distribute the lenticules (for future therapeutic needs) could be advantageous. Here, we validated the safety of lenticule banking, which involved the collection of human lenticules from our eye clinic, transportation of the lenticules to a Singapore Ministry of Health-licensed lenticule bank, processing and cryopreservation of the lenticules, which after 3 months or, a longer-term, 12 months, were retrieved and transported to our laboratory for implantation in rabbit corneas. Read More

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Spectral-domain optical coherence tomography for evaluating palisades of Vogt in ocular surface disorders with limbal involvement.

Sci Rep 2021 Jun 14;11(1):12502. Epub 2021 Jun 14.

Department of Ophthalmology, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei, Taiwan.

Spectral-domain optical coherence tomography (SD-OCT) has been used to observe the morphology of the palisades of Vogt (POV) with satisfactory resolutions. In this study, we used SD-OCT to examine the microstructure of the POV in ocular surface disorders with limbal involvement. We detect subclinical limbal pathologies based on five parameters, including (1) decreased epithelial thickness, (2) loss of the sharp stromal tip, (3) loss of the smooth epithelial-stromal interface, (4) dilated stromal vessels, and (5) decreased POV density. Read More

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Changes in the geometry of modern daily disposable soft contact lenses during wear.

Sci Rep 2021 Jun 14;11(1):12460. Epub 2021 Jun 14.

Division of Ophthalmology and Optometry, Department of Ophthalmology, Collegium Medicum, Nicolaus Copernicus University, ul. Ujejskiego 75, 85-168, Bydgoszcz, Poland.

The geometry of contact lenses can be altered by wear but determining the changes that occur in soft contact lenses (SCLs) is challenging. This study aimed to investigate the shape alterations of daily disposable SCLs after wear using swept-source optical coherence tomography (SS-OCT). Forty-five eyes with myopia of - 3. Read More

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Comparison of Corneal Wave Speed and Ocular Rigidity in Normal and Glaucomatous Eyes.

J Glaucoma 2021 Jun 15. Epub 2021 Jun 15.

Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA Department of Radiology, Mayo Clinic, Rochester, MN, USA.

Precis: Ocular biomechanics were compared between treated glaucoma patients and healthy subjects matched for age, IOP, and axial length. There was no difference in corneal wave propagation speed, but ocular rigidity was lower in glaucomatous eyes.

Purpose: Ocular biomechanical properties are important in understanding glaucoma pathogenesis but the affected tissues are unclear. Read More

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Herpes simplex virus PCR in 2230 explanted corneal buttons.

Acta Ophthalmol 2021 Jun 14. Epub 2021 Jun 14.

Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg/Saar, Germany.

Purpose: To determine herpes simplex virus (HSV) DNA prevalence and mean cycle threshold of polymerase chain reaction (PCR) in corneal tissue of patients with penetrating keratoplasty (PKP), with (HSK+) and without (HSK-) previous clinical herpetic keratitis history.

Methods: Retrospective review of recipient corneal buttons which were explanted through PKP between March 2010 and September 2018 at the Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar, Germany. Corneal tissue samples were analysed by real-time PCR for the presence of HSV DNA. Read More

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Non-invasive recognition of eye torsion through optical imaging of the iris pattern in ocular proton therapy.

Phys Med Biol 2021 Jun 14. Epub 2021 Jun 14.

Paul Scherrer Institute Center for Proton Therapy, Villigen, SWITZERLAND.

The introduction of noninvasive imaging techniques such as MRI imaging for treatment planning and optical eye tracking for in-room eye localization would obviate the requirement of clips implantation for many patients undergoing ocular proton therapy. This study specifically addresses the issue of torsional eye movement detection during patient positioning. Noninvasive detection of eye torsion is performed by measuring the iris pattern rotations using a BEV (Beams Eye View) optical camera. Read More

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Awareness and attitudes toward corneal donation among Canadians: informational and motivational videos can increase willingness toward corneal donation.

Can J Ophthalmol 2021 Jun 11. Epub 2021 Jun 11.

Department of Ophthalmology, Faculty of Medicine, University of Montreal, Montreal, Que.

Objective: To assess the knowledge of corneal transplantation, willingness toward corneal donation, and the efficacy of a short informational and motivational video in increasing the willingness toward corneal donation among Canadian adults.

Methods: Cross-sectional interventional study. A survey targeted Canadian adults, assessing their knowledge and attitude toward corneal donation and the efficacy of a 1-minute-long informative and motivational video on increasing willingness toward corneal donation. Read More

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Frequency and impact of individual symptoms on quality of life in dry eye disease in patients presenting to a tertiary care hospital.

J Pak Med Assoc 2021 Apr;71(4):1063-1068

Department of Ophthalmology, Pakistan Institute of Medical Sciences, Islamabad, Pakistan.

Objective: To assess the frequency of symptoms and impact on quality of life in individuals with dry eye disease.

Methods: The cross-sectional, study was conducted from December 2018 to June 2019 at the outpatient clinic of the Department of Ophthalmology, Pakistan Institute of Medical Sciences, Islamabad, Pakistan, and comprised dry eye disease patients aged at least 13 years with ocular burning sensation, lacrimation, grittiness, photophobia, redness or itching. Tear Film Breakup time <10 sec and / or positive ocular surface staining >5 corneal spots, >9 conjunctival spots, lid margin staining ≥ 2mm in length were used to diagnose the disease. Read More

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Deepening of lipidome annotation by associating cross-metathesis reaction with mass spectrometry: application to an in vitro model of corneal toxicity.

Anal Bioanal Chem 2021 Jun 14. Epub 2021 Jun 14.

C-TAC, CiTCoM, UMR 8038, CNRS Université de Paris, Faculté de Pharmacie, 75006, Paris, France.

The in-depth knowledge of lipid biological functions needs a comprehensive structural annotation including a method to locate fatty acid unsaturations, which remains a thorny problem. For this purpose, we have associated Grubbs' cross-metathesis reaction and liquid chromatography hyphenated to tandem mass spectrometry to locate double bond positions in lipid species. The pretreatment of lipid-containing samples by Grubbs' catalyst and an appropriate alkene generates substituted lipids through cross-metathesis reaction under mild, chemoselective, and reproducible conditions. Read More

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COVID-19 Associated Bilateral Acute Iris Transillumination.

Ocul Immunol Inflamm 2021 Jun 14:1-3. Epub 2021 Jun 14.

Department of Ophthalmology, Dokuz Eylul University School of Medicine, Izmir, Turkey.

: To report a case of bilateral acute iris transillumination (BAIT) in association with coronavirus disease 2019 (COVID-19).: A 44-year-old woman patient presented with decreased visual acuity, pain, photophobia, and redness in both eyes. The patient reported that she had recent close contact with severe acute respiratory syndrome - coronavirus-2 (SARS-CoV-2) case; also, she mentioned that she was hospitalized for bilateral pneumonia for 14 days. Read More

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"Post Coronavirus Disease (COVID-19) Reactivation of a Quiescent Unilateral Anterior Uveitis".

SN Compr Clin Med 2021 Jun 7:1-5. Epub 2021 Jun 7.

Department of Neuro-ophthalmology, Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India.

Coronavirus disease (COVID-19) can be associated with ophthalmic manifestations like conjunctivitis, retinal haemorrhages, retinal vascular occlusions, papillophlebitis, and Adie's syndrome. We herein report for a case of a unilateral acute anterior uveitis which was quiescent for 13 years and was reactivated post COVID-19 infection in a 43-year-old Asian Indian male. He had a past history of recurrent unilateral granulomatous anterior and intermediate uveitis in the right eye (RE), and all the investigations done 14 years ago were negative and had been on treatment with topical and oral steroids. Read More

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Mini-Review: Regenerating the Corneal Epithelium With Simple Limbal Epithelial Transplantation.

Front Med (Lausanne) 2021 28;8:673330. Epub 2021 May 28.

Department of Cornea, Anterior Segment and Uveitis, Dr. Shroff's Charity Eye Hospital, New Delhi, India.

Simple limbal epithelial transplantation (SLET) is an ingenious, low cost and effective technique of limbal stem cell transplantation (LSCT) that is increasingly being undertaken in practice across the world. Since it was first described a decade ago, the technique has been performed in a variety of cases of limbal stem cell deficiency (LSCD) and has underwent several innovative modifications. Published literature on SLET has progressively increased over time and successful outcomes in various clinical scenarios have been reported. Read More

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Infectious crystalline keratitis induced by Citrobacter.

GMS Ophthalmol Cases 2021 17;11:Doc09. Epub 2021 May 17.

Department of Microbiology, J. N. Medical College, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Microbial keratitis is an important cause of ocular morbidity, with emerging organisms and drug resistance posing a real threat to vision of patients. A 30-year-old female presented with infective keratitis in the left eye. She had been using rose nectar as home remedy for her ailment. Read More

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A Cross-Sectional Study of Time Since Death From Image Analysis of Corneal Opacity.

Cureus 2021 May 11;13(5):e14975. Epub 2021 May 11.

Department of Forensic Medicine, North Eastern Indira Gandhi Regional Institute of Health & Medical Sciences (NEIGRIHMS), Shillong, IND.

Estimation of time since death (TSD) is an important aspect of forensic medicine. Methods used so far are subjective and have human errors. Corneal opacity images using software to analyze the red, green, and blue (RGB) components of corneal color against the TSD may prove to be an objective method. Read More

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The Analysis of Dynamic Changes and Prognosis of Posner-Schlossman Syndrome with Cytomegalovirus Infection and Antiviral Therapy.

J Ophthalmol 2021 2;2021:6687929. Epub 2021 Jun 2.

Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai 200031, China.

Purpose: To analyze how keratic precipitate (KP) morphology changes during Posner-Schlossman syndrome (PSS) prognosis and raise medication suggestions on 2% ganciclovir eye drops.

Materials And Methods: Clinical retrospective cohort study in the Eye & ENT Hospital of Fudan University, Shanghai, China. The attacked eyes of 98 eligible subjects diagnosed unilateral PSS were enrolled between 2016 and 2019. Read More

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Pulsed Radiofrequency of the Trigeminal Ganglion for Treating Postherpetic Neuralgia of the Ophthalmic Branch.

Pain Res Manag 2021 30;2021:6638392. Epub 2021 May 30.

Department of Pain Management, The State Key Clinical Specialty for Pain Medicine, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong 510260, China.

Postherpetic neuralgia (PHN) is a painful, long-lasting condition as a consequence of nerve damage resulting from a herpes zoster infection. Although there are many different treatments available to reduce pain duration and severity, PHN is often refractory to them and no single therapy shows an effective cure for all cases of PHN, especially for those involving the ophthalmic branch of the trigeminal nerve. Pulsed radiofrequency (PRF) is a minimally invasive procedure for pain treatment that has been practiced over the past decade. Read More

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Association of Extracellular Signal-Regulated Kinase Genes With Myopia: A Longitudinal Study of Chinese Children.

Front Genet 2021 27;12:654869. Epub 2021 May 27.

The Eye Hospital, Wenzhou Medical University, Wenzhou, China.

Objective: The present study was designed to investigate whether the extracellular signal-regulated kinase (ERK) signaling pathway, a downstream component of dopamine signaling, is involved in myopia among Chinese children.

Methods: During a 3.5-year follow-up, 488 primary school students were enrolled in this study. Read More

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Cell-Free Biological Approach for Corneal Stromal Wound Healing.

Front Pharmacol 2021 28;12:671405. Epub 2021 May 28.

Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, United States.

Corneal opacification is the fourth most common cause of blindness globally behind cataracts, glaucoma, and age-related macular degeneration. The standard treatment of serious corneal scarring is corneal transplantation. Though it is effective for restoring vision, the treatment outcome is not optimal, due to limitations such as long-term graft survival, lifelong use of immunosuppressants, and a loss of corneal strength. Read More

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Nano-in-Nano Dendrimer Gel Particles for Efficient Topical Delivery of Antiglaucoma Drugs into the Eye.

Chem Eng J 2021 Dec 28;425. Epub 2021 May 28.

Linda and Bipin Doshi Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409, United States.

Low bioavailability of topically applied drugs remains a significant challenge for long-term glaucoma therapy. To enhance drug delivery efficiency, we developed dendrimer gel particles that collectively exhibit structural benefits of dendrimer, hydrogel, and particles, using the inverse emulsion method coupled with the highly efficient aza-Michael addition reaction (IEaMA). This hierarchical approach would maximize the utility of the structural features of existing ocular drug delivery systems. Read More

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December 2021

Topical Delivery of Levocarnitine to the Cornea and Anterior Eye by Thermosensitive in-situ Gel for Dry Eye Disease.

Drug Des Devel Ther 2021 2;15:2357-2373. Epub 2021 Jun 2.

School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, People's Republic of China.

Purpose: To prepare the levocarnitine thermosensitive in situ gel (LCTG) and evaluate its effect on dry eye disease (DED).

Methods: Draize eye irritation test and other examinations were used to evaluate the eye irritation after multiple administration of LCTG. The Schirmer test, fluorescein sodium staining, HE staining and TUNEL staining were used to detect the tear secretion, corneal injury, histopathological changes of the cornea and lacrimal gland, and the apoptosis rate of cornea epithelial cells after 3 days of the administration. Read More

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Cataract Surgical Services in Palestine.

Ophthalmic Epidemiol 2021 Jun 13:1-9. Epub 2021 Jun 13.

London School of Hygiene and tropical medicine, London, UK.

: Cataract surgery, quantity and quality, is an indicator of ophthalmic care. A comprehensive assessment of cataract surgical services has never been carried out in Palestine, including West Bank, Gaza Strip and East Jerusalem. The objective of this study was to estimate the cataract surgical rate in 2015 to and to explore the modes of payment and referral systems. Read More

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