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Soft contact lens

Eon Kim, Ravi C Bakaraju, Klaus Ehrmann
PURPOSE: To evaluate the optical power profiles of commercially available soft multifocal contact lenses and compare their optical designs. METHODS: The power profiles of 38 types of multifocal contact lenses-three lenses each-were measured in powers +6D, +3D, +1D, -1D, -3D, and -6D using NIMO TR1504 (Lambda-X, Belgium). All lenses were measured in phosphate buffered saline across 8 mm optic zone diameter. Refractive index of each lens material was measured using CLR 12-70 (Index Instruments, UK), which was used for converting measured power in the medium to in-air radial power profiles...
September 29, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Andre Childs, Hao Li, Daniella M Lewittes, Biqin Dong, Wenzhong Liu, Xiao Shu, Cheng Sun, Hao F Zhang
Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm...
October 17, 2016: Scientific Reports
Olof Sterner, Rudolf Aeschlimann, Stefan Zürcher, Kathrine Osborn Lorenz, Joseph Kakkassery, Nicholas D Spencer, Samuele G P Tosatti
Purpose: To characterize the effect of lubricant composition and in vitro ageing on the coefficient of friction (CoF) of a wide range of commercially available soft contact lenses (SCLs). Methods: The CoF of SCLs was characterized by means of microtribometry against a mucin-coated glass disk. One reusable (RU) silicone-hydrogel (SiHy) lens, senofilcon A, and two daily disposable (DD) lenses, etafilcon A (hydrogel) and nelfilcon A (hydrogel), were tested under different lubricant solutions, including a tear-like fluid (TLF) containing proteins and lipids...
October 1, 2016: Investigative Ophthalmology & Visual Science
R Ledesma-Alonso, E Raphaël, L Léger, F Restagno, C Poulard
We report on the elastic contact between a spherical lens and a patterned substrate, composed of a hexagonal lattice of cylindrical pillars. The stress field and the size of the contact area are obtained by means of numerical methods: a superposition method of discrete pressure elements and an iterative bisection-like method. For small indentations, a transition from a Hertzian to a soft-flat-punch behaviour is observed when the surface fraction of the substrate that is covered by the pillars is increased. In particular, we present a master curve defined by two dimensionless parameters, which allows one to predict the stress at the centre of the contact region in terms of the surface fraction occupied by pillars...
September 2016: Proceedings. Mathematical, Physical, and Engineering Sciences
Athira Rohit, Mark D P Willcox, Fiona Stapleton
PURPOSE: To establish the effect of lipid supplements on tear lipid biochemistry and their influence on lens wear comfort in habitual lens wearers. METHODS: Forty habitual soft contact lens wearers were recruited to a double-masked, randomized crossover trial. An emulsion drop containing phosphatidylglycerol (Systane Balance; Alcon) and a liposomal spray containing phosphatidylcholine (Tears again; BioRevive) along with saline placebos were used three times a day for 14 days with 48 hours of washout between each intervention...
October 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Deborah Jones, Craig Woods, Lyndon Jones, Nathan Efron, Philip Morgan
PURPOSE: To understand long-term contact lens prescribing habits of Canadian optometrists. METHODS: One thousand optometrists were surveyed annually from 2000 to 2015. Information was requested on the first ten patients examined after receiving the survey. RESULTS: Over the 16-year survey period, 1987 optometrists provided information on 19,143 patients. Mean age of the patients was 32.7±14.4years. Ratio of females to males was 2:1, the ratio of new fits to refits was 2:3...
September 16, 2016: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
Lia Florim Patrão, Ana Laura Caiado Canedo, João Luiz Peixoto Braga de Azevedo, Rosane Correa, Renato Ambrósio
We report two cases of suspicious asymmetric bow tie and inferior steepening on topographic evaluations with reflection (Placido) and projection (Scheimpflug). Rotating Scheimpflug corneal and anterior segment tomography (Oculus Pentacam HR, Wetzlar, Germany)® was performed in the first case, with a maximal keratometric value (Kmax) of 43.2 D and an overall deviation value from the Belin/Ambrósio Enhanced Ectasia Display (BAD-D) of 1.76, which was observed in the study eye (OD). BAD-D was 6.59 in the fellow eye, which had clinical findings that were consistent with keratoconus stage 2...
July 2016: Arquivos Brasileiros de Oftalmologia
Jun-Won Yun, Quan Hailian, Yirang Na, Byeong-Cheol Kang, Jung-Hee Yoon, Eun-Young Cho, Miri Lee, Da-Eun Kim, SeungJin Bae, Seung Hyeok Seok, Kyung-Min Lim
In an effort to explore the use of alternative methods to animal testing for the evaluation of the ocular irritancy of medical devices, we evaluated representative contact lenses with the bovine corneal opacity and permeability test (BCOP) and an in vitro eye irritation test using the three-dimensionally-reconstructed human corneal epithelium (RhCE) models, EpiOcular™ and MCTT HCE™. In addition, we compared the obtained results with the ISO standard in vivo rabbit eye irritation test (ISO10993-10). Along with the positive controls (benzalkonium chloride, BAK, 0...
December 2016: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Suphi Taneri, Saskia Oehler, Scott MacRae, H Burkhard Dick
OBJECTIVES: To examine the influence of a therapeutic soft contact lens (TSCL) after alcohol-assisted photorefractive keratectomy (PRK) on visual recovery, epithelial closure, pain perception, and haze formation. METHODS: Prospective, randomized, single-center, contralateral eye, patient-masked study. Same surgeon treated 15 patients with bilateral PRK using a Vidaurri Fluid Retention Ring (Katena) with 8.7 mm inner diameter to apply ethanol 18% for 30 sec. Each patient received a TSCL (Balafilcon A, PureVision, Bausch & Lomb) in a randomized fashion in one eye only...
August 30, 2016: Eye & Contact Lens
D E Liu, T J Dursch, N O Taylor, S Y Chan, D T Bregante, C J Radke
We measure and, for the first time, theoretically predict four prototypical aqueous-drug diffusion coefficients in five soft-contact-lens material hydrogels where solute-specific adsorption is pronounced. Two-photon fluorescence confocal microscopy and UV/Vis-absorption spectrophotometry assess transient solute concentration profiles and concentration histories, respectively. Diffusion coefficients are obtained for acetazolamide, riboflavin, sodium fluorescein, and theophylline in 2-hydroxyethyl methacrylate/methacrylic acid (HEMA/MAA) copolymer hydrogels as functions of composition, equilibrium water content (30-90%), and aqueous pH (2 and 7...
October 10, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Philip Raey Kidd Turnbull, Oliver James Munro, John Robert Phillips
PURPOSE: A number of optical methods for slowing myopia progression have been tested and are now available. However, data on real-world use in clinical use is scarce. Here, we present a review of the clinical outcomes for patients attending a specialist myopia control clinic at The University of Auckland Optometry School, NZ. CASE SERIES: We report a comparative case series of 110 patients (aged 4-33 years, mean: 12.13 ± 4.58 years, 62% female) who attended the clinic between 2010 and 2014...
September 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Manali Hazarika, Vijaya Pai H, Vinay Khanna, Harish Reddy, Kriti Tilak, Kiran Chawla
PURPOSE: To report a rare case of polymicrobial keratitis due to Balantidium coli and gram-negative bacteria, Pseudomonas aeruginosa and Klebsiella pneumoniae, in a soft contact lens (CL) wearer. METHODS: We report a case of CL-related keratitis due to B. coli, P. aeruginosa, and K. pneumoniae. RESULTS: The culture of the corneal scrapings, the CL cleaning solution, and the CL revealed the growth of a rare ciliated parasite, B. coli, along with gram-negative bacteria, namely, P...
August 24, 2016: Cornea
Meredith E Jansen, Ping Situ, Carolyn G Begley, Danielle Boree, Robin L Chalmers, Kathrine Osborn Lorenz, Tawnya Wilson
PURPOSE: To document the time course and resolution of contact lens-related corneal infiltrative events (CIEs) comparing slit-lamp images with anterior segment ocular coherence tomography (AS-OCT) images. METHODS: Six silicone hydrogel (SiHy) soft contact lens (SCL) wearers presenting with newly diagnosed symptomatic CIEs were monitored with slit-lamp images, detailed drawings, and AS-OCT until the resolution of the CIE. A final follow-up visit was completed 4 weeks after CIE resolution to determine whether scar formation was present...
August 24, 2016: Cornea
Tariq Al-Asbali
Ocular hypotony due to choroidal detachment (CD) following endocyclophotocoagulation (ECP) is transient. If hypotony lasts for more than 1 week, it could affect vision. This is a case of refractory glaucoma following cataract surgery that was managed by ECP. We drained subchoroidal fluid as CD did not resolve after 1 week. After 5 months, the intraocular pressure was restored to 16 mmHg with one topical glaucoma medication, uncorrected vision improved to 20/300, and with aphakic soft contact lens, it was 20/50...
July 2016: Middle East African Journal of Ophthalmology
Edward Lum, Blanka Golebiowski, Helen A Swarbrick
OBJECTIVES: To investigate changes in corneal sensitivity and nerve morphology in orthokeratology (OK) contact lens wear. METHODS: In a cross-sectional study, 54 subjects (aged 18-45 years) were grouped into three categories: nonlens (NL), soft lens (SCL), and OK lens wearers. Corneal sensitivity was measured at the corneal apex and 2.5 mm temporal to the apex using the Cochet-Bonnet aesthesiometer. Corneal nerve morphology was assessed by sampling a 1 mm area of the corneal sub-basal nerve plexus using the Heidelberg Retinal Tomograph with Rostock Corneal Module at the corneal apex and 2...
July 12, 2016: Eye & Contact Lens
Robin L Chalmers, Heidi Wagner, Beth Kinoshita, Luigina Sorbara, G Lynn Mitchell, Dawn Lam, Kathryn Richdale, Aaron Zimmerman
PURPOSE: To compare the habits of United States (US) soft contact lens (SCL) wearers who bought SCLs from their eye care practitioner (ECP), on the internet/telephone, or at retail (not where they were examined) to test the effect of proximity to the prescriber on SCL wear and care practices. METHODS: Adult SCL wearers completed an adapted Contact Lens Risk Survey (CLRS) online that queried items related to risk factors for SCL-related complications. Responses from subjects who purchased at the ECP, via the internet/telephone, or at a retail store were compared (Chi-Square)...
August 12, 2016: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
Pauline Kang, Colm McAlinden, Christine F Wildsoet
PURPOSE: To assess the effects of multifocal soft contact lenses (MF SCLs) used for myopia control on visual acuity (VA) and subjective quality of vision. METHODS: Twenty-four young adult myopes had baseline high and low-contrast VAs and refractions measured and quality of vision assessed by the Quality of Vision (QoV) questionnaire with single vision SCLs. Additional VA and QoV questionnaire data were collected immediately after subjects were fitted with Proclear MF SCLs and again after a 2-week adaptation period of daily lens wear...
August 6, 2016: Acta Ophthalmologica
Diana Silva, Luís F V Pinto, Dimitriya Bozukova, Luís F Santos, Ana Paula Serro, Benilde Saramago
In this study we investigated the possibility of using layer-by-layer deposition, based in natural polymers (chitosan and alginate), to control the release of different ophthalmic drugs from three types of lens materials: a silicone-based hydrogel recently proposed by our group as drug releasing soft contact lens (SCL) material and two commercially available materials: CI26Y for intraocular lens (IOLs) and Definitive 50 for SCLs. The optimised coating, consisting in one double layer of (alginate - CaCl2)/(chitosan+glyoxal) topped with a final alginate-CaCl2 layer to avoid chitosan degradation by tear fluid proteins, proved to have excellent features to control the release of the anti-inflammatory, diclofenac, while keeping or improving the physical properties of the lenses...
November 1, 2016: Colloids and Surfaces. B, Biointerfaces
Jin-Chern Chiou, Shun-Hsi Hsu, Yu-Te Liao, Yu-Chieh Huang, Guan-Ting Yeh, Cheng-Kai Kuei, Kai-Shiun Dai
This paper presents a wireless on-lens intraocular pressure monitoring system, comprising a capacitance-to-digital converter and a wirelessly powered radio-frequency identification (RFID)-compatible communication system, for sensor control and data communication. The capacitive sensor was embedded on a soft contact lens of 200 μm thickness using commercially available biocompatible lens material, to improve compliance and reduce user discomfort. The sensor chip was shown to achieve effective number of bits greater than 10 over a capacitance range up to 50 pF while consuming only 64-μW power...
September 2016: IEEE Journal of Biomedical and Health Informatics
V Compañ, M Aguilella-Arzo, L F Del Castillo, S I Hernández, J M Gonzalez-Meijome
This work is an analysis of the application of the generalized Monod kinetics model describing human corneal oxygen consumption during soft contact lens wear to models previously used by Chhabra et al. (J Biomed Mater Res B Appl Biomater, 2009a;90:202-209, Optom Vis Sci 2009b;86:454-466) and Larrea and Büchler (Invest Ophthalmol Vis Sci 2009;50:1076-1080). We use oxygen tension from in vivo estimations provided by Bonanno [Bonanno et al., Invest Ophthalmol Vis Sci 2002;43:371-376, and Bonanno et al 2009]. We consider four hydrogel and six silicone hydrogel lenses...
July 26, 2016: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
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