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Contact lenses

M Á Aloy, J E Adsuara, P Cerdá-Durán, M Obergaulinger, J J Esteve-Taboada, T Ferrer-Blasco, R Montés-Micó
Measuring the eye's mechanical properties in vivo and with minimally invasive techniques can be the key for individualized solutions to a number of eye pathologies. The development of such techniques largely relies on a computational modelling of the eyeball and, it optimally requires the synergic interplay between experimentation and numerical simulation. In Astrophysics and Geophysics the remote measurement of structural properties of the systems of their realm is performed on the basis of (helio-)seismic techniques...
2017: PloS One
Prina Mehta, Ali Al-Kinani, Muhammad Sohail Arshad, Ming-Wei Chang, Raid G Alany, Zeeshan Ahmad
Despite exponential growth in research relating to sustained and controlled ocular drug delivery; anatomical and chemical barriers of the eye still pose formulation challenges. Nanotechnology integration into the pharmaceutical industry has aided efforts in potential ocular drug device development. Here, the integration and in vitro effect of four different permeation enhancers (PEs) on the release of anti-glaucoma drug timolol maleate (TM) from polymeric nanofiber formulations is explored. Electrohydrodynamic (EHD) engineering, more specifically electrospinning, was used to engineer nanofibers (NFs) which coated the exterior of contact lenses...
September 13, 2017: International Journal of Pharmaceutics
Ahmed Al-Jumaili, Kateryna Bazaka, Mohan V Jacob
Bacterial colonisation of biomedical devices demands novel antibacterial coatings. Plasma-enabled treatment is an established technique for selective modification of physicochemical characteristics of the surface and deposition of polymer thin films. We investigated the retention of inherent antibacterial activity in geranium based plasma polymer thin films. Attachment and biofilm formation by Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli was significantly reduced on the surfaces of samples fabricated at 10 W radio frequency (RF) power, compared to that of control or films fabricated at higher input power...
September 13, 2017: Nanomaterials
Tawfiq Alqurashi, Yunuen Montelongo, Pavel Penchev, Ali K Yetisen, Stefan Dimov, Haider Butt
Femtosecond laser ablation allows direct patterning of engineering materials in industrial settings without requiring multistage processes such as photolithography or electron beam lithography. However, femtosecond lasers have not been widely used to construct volumetric microphotonic devices and holograms with high reliability and cost efficiency. Here, a direct femtosecond laser writing process is developed to rapidly produce transmission 1D/2D gratings, Fresnel Zone Plate lenses, and computer-generated holograms...
September 11, 2017: Nanoscale
Jing Lin, Kun He, Guiqiu Zhao, Cui Li, Liting Hu, Guoqiang Zhu, Yawen Niu, Guipei Hao
PURPOSE: To determine whether macrophage inducible C-type lectin (Mincle) regulates neutrophils and macrophages apoptosis in A. fumigatus keratitis. MATERIALS AND METHODS: A murine model (C57BL/6) of fungal keratitis (AF) was established by gently scraping corneal central epithelium, smearing A. fumigatus on the epithelium surface and covering the eye with contact lenses. AF cell model was established by extracting neutrophils (PMN) and macrophages, and then infecting cells with A...
September 7, 2017: International Immunopharmacology
Xuemei Liu, Fan Zhang, Denise Rodeheaver, Ann Wright, Charlon Tolliver, Jamie Walker, Robert Rose
We describe a new, quantitative, cytotoxicity method using mouse lymphoma L5178Y thymidine kinase+/- (TK) suspension cells for medical device safety assessment that has equivalent sensitivity, and greater efficiency compared to the colony formation assay (CFA) using adherent V79-4 cells. Assays were carried out in 24-well plates. TK cells were seeded on concave side of six types of contact lenses and cell growth rate after 72h determined using the Vi-Cell XR. Five of six contact lenses studied demonstrated the same results between the TK and the CFA methods...
September 5, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Lin Chen, Lianhong Pi, Ning Ke, Xinke Chen, Qing Liu
BACKGROUND: Postoperative complications, lagophthalmos and exposure keratopathy sometimes occur after surgery for congenital blepharoptosis. Bandage contact lenses (BCL) can help prevent some ocular surface disorders. The study aims to evaluate the efficacy and safety of BCL for protection of the ocular surface in children aged 5 to 11 years after frontalis muscle flap suspension for congenital blepharoptosis. METHODS: We conducted a prospective randomized clinical study of 30 eyes of 30 patients with congenital blepharoptosis consecutively enrolled at the Ophthalmology Ward of the Children's Hospital of Chongqing Medical University, China from September 1, 2016, to February 30, 2017...
September 2017: Medicine (Baltimore)
Mohammad Naderan, Ali Jahanrad, Mahgol Farjadnia
BACKGROUND: The present work was conducted to investigate the prevalence of clinical biomicroscopy and retinoscopy findings of corneas with keratoconus (KC) at first presentation and their relationship with disease severity. METHOD: In a prospective cross-sectional study, 371 consecutive KC patients were examined by slitlamp biomicroscopy and retinoscopy at the time of diagnosis. This research evaluates the prevalence of clinical findings such as a corneal protrusion, Vogt's striae, Fleischer's ring, Munson's sign, Rizzuti's sign, corneal scars, as well as any additional KC signs such as prominent nerve fibres, scissoring reflex and Charleaux 'oil droplet' sign on retinoscopy...
September 6, 2017: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
Ghada Zidan, Ilva D Rupenthal, Carol Greene, Ali Seyfoddin
Corneal blindness can occur due to improper healing of the corneal tissues after induced injury or abrasion which can be accidental, pathogenic or after corneal surgery. Abnormal regulation of the healing mechanisms can lead to corneal opacity. Reducing inflammation and promoting epithelial wound healing is crucial for scar-free corneal recovery without eyesight complications. Current approaches for corneal wound healing involve amniotic membrane (AM) bandages, bandage contact lenses (BCL) and collagen shields in conjunction with frequent administration of therapeutic eye drops...
September 6, 2017: Pharmaceutical Development and Technology
Nathan Efron, Philip B Morgan
The evolution of contact lens technology and clinical practice over the past three decades has been remarkable, with dramatic improvements in material biocompatibility, better lens designs and care systems, and more flexible and convenient modalities of wear. However, our approach to the aftercare examination has remained conservative, with the general modus operandi having not fully evolved from the difficult, early years of fitting non-regular replacement rigid and low water content hydrogel lenses. In this paper, we review current aftercare practice and in particular, the preferred frequency that lens wearers should return for routine visits and the appropriateness of regulations governing contact lens prescription expiry...
September 4, 2017: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
Kelsy R Steele, Loretta Szczotka-Flynn
Corneal infiltrative events (CIEs) are well established as a risk associated with soft contact lens wear. The incidence of symptomatic CIEs during extended soft lens wear ranges from 2.5 to six per cent; when asymptomatic CIEs are included, the incidence can be as high as 20-25 per cent. In daily soft lens wear, the annual incidence of symptomatic CIEs is about three per cent. There are various accepted methods of categorising CIEs, and a scoring system based on clinical signs and symptoms is a good approach to grade severity...
September 4, 2017: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
Eric B Papas
Contact lenses have been a common means of vision correction for more than half a century. Recent developments raise the possibility that the next several years will see the range of applications in which they are used broaden considerably, with an associated expansion in both the number and type of individuals who consider them to be a valuable option. To describe this new landscape, a review of recent patent submissions covering the period 1 January 2014 to 1 February 2017 was undertaken. The results show that in the main, areas where contact lenses will be applied include drug delivery, visual augmentation and biosensing...
September 3, 2017: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
Fonthip Makkliang, Proespichaya Kanatharana, Panote Thavarungkul, Chongdee Thammakhet-Buranachai
Phthalate esters (PAEs), especially dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DEHP) are widely used as plasticizers in plastics and polymers. They are not chemically bound and can easily migrate into food and human tissue that comes into contact with these materials. The method developed in this work was applied for the preconcentration and determination of these four phthalate esters that might leach from contact lenses and baby teethers. A novel stir-bead micro-solid phase extractor of chitosan cryogel composited with polypyrrole with a steel wire core was evaluated for the extraction of DMP, DEP, DBP and DEHP before analysis by high performance liquid chromatography (HPLC)...
September 8, 2017: Analytica Chimica Acta
Maryam Mousavi, Danilo A Jesus, Izabela K Garaszczuk, Dorota H Szczesna-Iskander, D Robert Iskander
PURPOSE: To evaluate the clinical value of non-invasive keratograph tear film breakup time (NIKBUT) in the assessment of pre-corneal and pre-lens tear film quality for prescribing contact lenses (CLs). METHODS: Forty-six subjects aged 25.5±4.3 (mean±standard deviation) years were recruited. Visual acuity (VA), anterior eye health checks and NIKBUT were evaluated. On the following day, subjects were fitted with a daily Silicon Hydrogel (SiHy) CL in one eye and a Hydrogel (Hy) CL in the other...
August 29, 2017: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
Clara Llorens-Quintana, Maryam Mousavi, Dorota Szczesna-Iskander, D Robert Iskander
PURPOSE: To evaluate the effect of two types of daily contact lenses (delefilcon A and omafilcon A) on the tear film and establish whether it is dependent on pre-corneal tear film characteristics using a new method to analyse high-speed videokeratoscopy recordings, as well as to determine the sensitivity of the method in differentiating between contact lens materials on eye. METHODS: High-speed videokeratoscopy recordings were analysed using a custom made automated algorithm based on a fractal dimension approach that provides a set of parameters directly related to tear film stability...
August 29, 2017: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
Daniel Geiger, Kirsten Geiger, Tobias Neckernuss, Othmar Marti, Masoud Amirkhani
We present a method to measure contact angles of microscopic droplets with a conventional microscope that possesses a precision focus adjustment stage. The droplets are modeled as spherical caps that act as lenses. Their focal length is determined by measuring the distance from the substrate surface to the level where a sharp image of the aperture stop is observed. The lens diameter is found by edge detection of a microscope image of the microdroplets. The spherical cap model relates the focal length and diameter of such lenses to the contact angle of the used liquid with known refractive index...
August 2017: Review of Scientific Instruments
(no author information available yet)
No abstract text is available yet for this article.
September 1, 2017: MMWR. Morbidity and Mortality Weekly Report
Nevin W El-Nimri, Jeffrey J Walline
SIGNIFICANCE: Varying amounts of peripheral defocus reported in previous studies are likely due to whether peripheral defocus is measured while turning the eyes or the head. Contact lenses (CLs) lag when viewing objects in peripheral gaze, so future studies ought to measure peripheral defocus while turning the head to measure defocus through the peripheral add power. PURPOSE: Soft multifocal CL peripheral defocus studies report varying results. To determine whether soft multifocal CL lag when turning the eyes could affect the measurement of peripheral defocus, we measured how much CLs move when looking in different gazes...
August 25, 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Cecilia Chao, Fiona Stapleton, Mark D P Willcox, Blanka Golebiowski, Kathryn Richdale
SIGNIFICANCE: Established reusable contact lens (CL) wearers show higher tear inflammatory cytokine concentrations and greater conjunctival metaplasia in the region covered by standard soft CLs. The balance of proinflammatory to anti-inflammatory cytokines, but not individual tear cytokine concentrations, was associated with self-reported CL discomfort. PURPOSE: Daily disposable (DD) lenses are often used to improve CL discomfort, but the effect on ocular inflammatory responses has not been fully investigated...
August 29, 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Basal H Altoaimi, Meznah S Almutairi, Pete Kollbaum, Arthur Bradley
SIGNIFICANCE: Wearing aspheric contact lenses adds significant amounts of negative spherical aberration (SA). Also, when accommodated and converged to near targets, pupil size shrinks and SA shift from positive to more negative direction. Interestingly, in this study, pupil miosis was fully or partially able to compensate for the additional accommodation-induced negative SA. PURPOSE: The present study aims to examine the accommodative response characteristics of young eyes fit with aspheric single vision contact lenses (SVCLs) that add significant negative SA to the eye responding to a wide range of accommodation stimuli...
August 29, 2017: Optometry and Vision Science: Official Publication of the American Academy of Optometry
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