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Suliński T, Nowak N, Szymański J, Pniewski J. Study of silicone hydrogel contact lenses' surface reflection characteristics using confocal microscopy. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 2023; 34:2400-2410. [PMID: 37584778 DOI: 10.1080/09205063.2023.2248816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 08/17/2023]
Abstract
The physical and chemical properties of contact lenses (CLs) differ significantly from one another. This is already covered by the FDA classification, which divides soft lenses into groups and subgroups for additional characteristics. The differences relate to both the interior and surface of the lens. Several differences in the surface characteristics of individual contact lenses have been studied and demonstrated to date. However, one of their fundamental physical properties, that is light reflection or, quantitatively, reflectance has not been compared. This paper describes the surface differences of a range of silicone-hydrogel (SiHy) lenses using reflectance confocal microscopy. It shows the relationship between the amount of light reflected from the lens surface and the material parameters. Common SiHy lens materials were used in the study, including two lenses with surface modifications. Light incident at the interface between two media (phosphate-buffered saline and lens) with different refractive indices is partially reflected. The normalized results show significant differences between the reflection signals (1 vs 0.07), and that they are not correlated with the refractive index (R2 = 0.5536). For the water content (%H2O), a general trend was observed that the higher the %H2O, the lower the reflection signal is (R2 = 0.8105). The reflection signal and surface modulus show the best correlation. (R2 = 0.9883). The proposed CLs analysis method, using reflectance confocal microscopy, provides data to differentiate between lenses with and without surface modifications.
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Affiliation(s)
- Tomasz Suliński
- Alcon Polska, Warsaw, Poland
- University of Warsaw, Warsaw, Poland
| | - Natalia Nowak
- Nencki Institute of Experimental Biology Polish Academy of Sciences, Warsaw, Poland
| | - Jędrzej Szymański
- Nencki Institute of Experimental Biology Polish Academy of Sciences, Warsaw, Poland
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Uptake and release of polyhexamethylene biguanide (PHMB) from hydrogel and silicone hydrogel contact lenses using a radiolabel methodology. Cont Lens Anterior Eye 2022; 45:101575. [DOI: 10.1016/j.clae.2022.101575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/11/2022] [Accepted: 01/26/2022] [Indexed: 11/19/2022]
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Miglio F, Ponzini E, Zeri F, Borghesi A, Tavazzi S. In vitro affinity for nicotine of soft contact lenses of different materials. Cont Lens Anterior Eye 2021; 45:101490. [PMID: 34294534 DOI: 10.1016/j.clae.2021.101490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 02/06/2023]
Abstract
Smoking is a risk factor for the development of microbial keratitis and corneal infiltrates in contact lens (CL) wearers. It is still unknown if this risk is directly associated with the presence of nicotine in the eye and if adherence of nicotine on the CL can enhance these effects. A better understanding of the interaction between nicotine and CL materials could offer insights to explain this risk associated with smoking. The aim of this work was to compare the affinity of nicotine to different soft CL materials. CLs from FDA groups I, II, IV, and V were incubated in a 2-mM nicotine solution for 24 h and then in a 0.9% saline solution for the next 24 h. The amount of absorbed and released nicotine per CL was deduced as a function of time (t) by ultraviolet (UV) spectrophotometry and normalised to the mass of the hydrated CL. The data were described by the equation y = b -a t-1, where a and b are constants, and b represents the mass reached at the plateau after ~ 10 min of exposure. Groups IV and V displayed the highest (0.80 ± 0.09 µg) and lowest (0.27 ± 0.08 µg) nicotine absorption per mg of hydrated CL, respectively. The CL affinity for nicotine could be ascribed to the interaction between the positive charge of nicotine pyrrolidine nitrogen and the negative charges of the CLs, especially for the ionic IV group.
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Affiliation(s)
- Federica Miglio
- University of Milano Bicocca, Materials Science Department, via R. Cozzi 55, I-20125 Milan, Italy; University of Milano Bicocca, COMiB Research Center, via R. Cozzi 55, I-20125 Milan, Italy
| | - Erika Ponzini
- University of Milano Bicocca, Materials Science Department, via R. Cozzi 55, I-20125 Milan, Italy; University of Milano Bicocca, COMiB Research Center, via R. Cozzi 55, I-20125 Milan, Italy.
| | - Fabrizio Zeri
- University of Milano Bicocca, Materials Science Department, via R. Cozzi 55, I-20125 Milan, Italy; University of Milano Bicocca, COMiB Research Center, via R. Cozzi 55, I-20125 Milan, Italy; School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Alessandro Borghesi
- University of Milano Bicocca, Materials Science Department, via R. Cozzi 55, I-20125 Milan, Italy; University of Milano Bicocca, COMiB Research Center, via R. Cozzi 55, I-20125 Milan, Italy
| | - Silvia Tavazzi
- University of Milano Bicocca, Materials Science Department, via R. Cozzi 55, I-20125 Milan, Italy; University of Milano Bicocca, COMiB Research Center, via R. Cozzi 55, I-20125 Milan, Italy
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Yee A, Phan CM, Chan VWY, Heynen M, Jones L. Uptake and Release of a Multipurpose Solution Biocide (MAP-D) From Hydrogel and Silicone Hydrogel Contact Lenses Using a Radiolabel Methodology. Eye Contact Lens 2021; 47:249-255. [PMID: 32604136 DOI: 10.1097/icl.0000000000000724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this study was to evaluate the uptake and release of radiolabelled myristamidopropyl dimethylamine (MAP-D) on reusable daily wear contact lenses (CLs) over 7 days. METHODS Three silicone hydrogel (SH) CL materials (lotrafilcon B, balafilcon A, senofilcon A) and two conventional hydrogel (CH) materials (etafilcon A, omafilcon A) were tested. A short-term (experiment 1, N=4) and a longer-term (experiment 2, N=3) study was conducted. In experiment 1, the CLs were incubated in 2 mL of phosphate buffered solution (PBS) containing 14C MAP-D (5 μg/mL) for 8 hrs. The release of 14C MAP-D was measured at t=0.25, 0.5, 1, 2, 4, 8, and 24 hr in PBS. In experiment 2, the CLs were incubated in the 14C MAP-D solution for 8 hrs followed by a 16-hr release in PBS. This cycle was repeated daily for 7 days. At the end of both experiments, lenses were extracted to determine the total uptake of MAP-D. The radioactivity was measured using a beta scintillation counter. RESULTS In experiment 1, all three SH lenses sorbed similar amounts of MAP-D (P=0.99), all of which were higher than the two CH materials (P<0.01). However, the CH materials released a greater amount of MAP-D than the SH materials (P<0.01). In experiment 2, the uptake of MAP-D in SH materials increased over 7 days, whereas the amount of MAP-D remained constant in the CH materials (P=0.99). Similar to experiment 1, the CH lenses released more MAP-D than SH lenses after 7 days (P<0.01). CONCLUSION The SH materials absorbed greater amounts of MAP-D compared to CH materials. However, the CH materials released the greatest amount of MAP-D. Radioactive labelling of MAP-D offers a highly sensitive method of assessing the uptake and release profiles of biocides to CL materials.
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Affiliation(s)
- Alan Yee
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada
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CLEAR - Contact lens wettability, cleaning, disinfection and interactions with tears. Cont Lens Anterior Eye 2021; 44:157-191. [DOI: 10.1016/j.clae.2021.02.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/15/2022]
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Mirzapour P, McCanna DJ, Jones L. In vitro analysis of the interaction of tear film inflammatory markers with contemporary contact lens materials. Cont Lens Anterior Eye 2021; 44:101430. [PMID: 33771440 DOI: 10.1016/j.clae.2021.02.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 02/01/2021] [Accepted: 02/12/2021] [Indexed: 11/17/2022]
Abstract
PURPOSE Several clinical studies have suggested that reusable silicone hydrogel contact lens materials exhibit a two-times increased rate of corneal infiltrative events compared to reusable hydrogels. One potential factor contributing to this complication relates to the differential uptake of tear film-based pro-inflammatory cytokines. The purpose of this study was to use an in vitro assay to investigate whether four pro-inflammatory cytokines differed in their uptake onto six contemporary contact lens materials. METHODS Conventional hydrogel (etafilcon A, omafilcon A) and silicone hydrogel (balafilcon A, comfilcon A, senofilcon A, somofilcon A) contact lens materials were soaked in solutions containing pro-inflammatory cytokines IL-1β, IL-6, IL-8 and TNF-α. Samples of the soaking solutions were collected over various time points and analyzed using the Meso Scale Discovery system, which served as a measurement of cytokine uptake onto the contact lens materials. RESULTS Both conventional hydrogels (etafilcon A, omafilcon A) and two of the four silicone hydrogels tested (balafilcon A, comfilcon A), exhibited some uptake of IL-1β, IL-8 or TNF-α (p < 0.05). Senofilcon A and somofilcon A did not exhibit uptake of any of these cytokines (p > 0.05). There was no uptake of IL-6 onto any of the contact lens materials investigated (p > 0.05). CONCLUSION The contact lens materials tested did not exhibit any uptake of IL-6 and furthermore, did not exhibit more than 10 ± 3 % to 25 ± 12 % uptake of IL-1β, IL-8 or TNF-α. Numerous factors could contribute to the reported increase in corneal infiltrative events with reusable silicone hydrogel materials, however, based on these results, it appears that uptake of these four cytokines are unlikely to contribute to this finding.
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Affiliation(s)
- Parisa Mirzapour
- Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
| | - David J McCanna
- Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Lyndon Jones
- Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada; Centre for Eye & Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong
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Reduction of Physical Strength and Enhancement of Anti-Protein and Anti-Lipid Adsorption Abilities of Contact Lenses by Adding 2-Methacryloyloxyethyl Phosphorylcholine. Macromol Res 2020. [DOI: 10.1007/s13233-020-8149-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Efron N, Brennan NA, Chalmers RL, Jones L, Lau C, Morgan PB, Nichols JJ, Szczotka-Flynn LB, Willcox MD. Thirty years of 'quiet eye' with etafilcon A contact lenses. Cont Lens Anterior Eye 2020; 43:285-297. [PMID: 32278644 DOI: 10.1016/j.clae.2020.03.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 11/17/2022]
Abstract
Frequent replacement contact lenses made from the etafilcon A hydrogel lens material were introduced onto the market over 30 years ago, and etafilcon A remains the most widely used hydrogel lens material today. Although the prescribing of silicone hydrogel lenses is increasing, millions of lens wearers globally have been wearing hydrogel lenses for many years and exhibit a physiologically-stable 'quiet eye', with a low profile of adverse events. Hydrogel lenses are demonstrated to maintain a low inflammatory response and infection risk profile during daily wear, which in the case of etafilcon A, may be related to its low modulus, and the naturally-protective, anti-microbial, non-denatured lysozyme absorbed into the lens from the tear fluid. Although improved corneal physiology from decreased hypoxia with silicone hydrogel lenses is well accepted, equivalent levels of corneal oxygenation are maintained during daily wear of low to medium powered hydrogel lenses, which do not impede the daily corneal de-swelling process, and do not induce clinically significant changes in ocular health. Therefore, hydrogel lenses remain an important alternative for daily wear in modern contact lens practice.
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Affiliation(s)
- Nathan Efron
- Institute of Health and Biomedical Innovation, School of Optometry and Vision Science, Queensland University of Technology, Australia.
| | | | | | - Lyndon Jones
- Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Charis Lau
- Johnson & Johnson Vision, Inc, Jacksonville, FL, USA
| | - Philip B Morgan
- Eurolens Research, Division of Pharmacy and Optometry, The University of Manchester, UK
| | - Jason J Nichols
- The University of Alabama at Birmingham, School of Optometry, Birmingham, AL, USA
| | - Loretta B Szczotka-Flynn
- University Hospitals Eye Institute, University Hospitals Cleveland Medical Center, Department of Ophthalmology & Visual Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Mark D Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Contact Lens Solutions and Contact Lens Discomfort: Examining the Correlations Between Solution Components, Keratitis, and Contact Lens Discomfort. Eye Contact Lens 2018; 44:355-366. [DOI: 10.1097/icl.0000000000000458] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hui A. Contact lenses for ophthalmic drug delivery. Clin Exp Optom 2018; 100:494-512. [PMID: 28940532 DOI: 10.1111/cxo.12592] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 07/03/2017] [Accepted: 07/03/2017] [Indexed: 01/28/2023] Open
Abstract
Contact lenses as a means to deliver pharmaceuticals to the eye have seen a significant increase in research interest in the past few years. This review will detail the in vitro experiments which have investigated use of these contact lenses in the context of the desired pharmacological treatment goals in the management of infectious, inflammatory, allergic and glaucomatous diseases of the eye. The techniques researchers have employed to modify and tailor drug release rates from these materials, including the use of vitamin E diffusion barriers, modified ionicity, molecular imprinting and incorporation of drug reservoirs, will be discussed, as well as their impact on drug release kinetics. Finally, the demonstration of the feasibility of these materials when applied in vivo in animal models as well as in humans with and without disease will be presented and their results discussed relating to their implications for the future of the field.
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Affiliation(s)
- Alex Hui
- School of Optometry and Vision Science, The University of New South Wales, Sydney, New South Wales, Australia
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Hampton D, Green JA, Robboy M, Eydelman M. Food and Drug Administration Efforts to Mitigate Contact Lens Discomfort. Eye Contact Lens 2017; 43:2-4. [PMID: 27941360 DOI: 10.1097/icl.0000000000000324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The premarket review of contact lenses and accessories by the FDA involves the assessment of nonclinical and clinical information in support of clearance or approval of marketing applications. The review process for these medical devices, including attributes, which may contribute to comfort for lens wearers, is summarized, as are mechanisms by which FDA continues to assess and improve recommendations through the review process and through collaboration with external entities.
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Affiliation(s)
- Denise Hampton
- Division of Ear, Nose and Throat Devices, Office of Device Evaluation, Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD
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Raman imaging of layered soft contact lenses. J Appl Biomater Funct Mater 2017; 15:e149-e152. [PMID: 27791229 DOI: 10.5301/jabfm.5000329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2016] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Daily disposable contact lenses are gaining in popularity among practitioners and wearers for the improved ocular health and subjective outcomes they offer. Recently a novel daily disposable contact lens material with water gradient technology was introduced. Delefilcon A lenses consist of a 33% water content silicone hydrogel core and an outer hydrogel layer which is totally free of silicone and contains 80% water. METHODS The aim of the present study was to confirm the layered structure of delefilcon A contact lenses. Thickness of hydrogel coating on the silicone hydrogel core was assessed using Raman spectroscopy. To investigate the layered structure of the material, depth spectra of the lenses were recorded. RESULTS The results obtained suggest that at about 6 μm a boundary between the hydrogel layer and silicone hydrogel core exists, which is in good agreement with the manufacturer's data. CONCLUSIONS Data collected in this experiment confirm a water gradient at the delefilcon A lens surface.
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Wygladacz KA, Hook DJ. Visualization of a hyaluronan network on the surface of silicone-hydrogel materials. Clin Ophthalmol 2016; 10:1423-33. [PMID: 27555749 PMCID: PMC4968858 DOI: 10.2147/opth.s105902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Biotrue multipurpose solution (MPS) is a bioinspired disinfecting and conditioning solution that includes hyaluronic acid (HA) as a natural wetting agent. Previous studies demonstrated that HA sorbed from Biotrue MPS on both conventional and silicone hydrogel (SiHy) contact lens materials; an in vitro simulated-wear test validated the presence of HA on the lens surfaces for as long as 20 hours. In this study, the morphology and distribution of HA sorbed from both Biotrue and pure HA solution on SiHy contact lens surfaces was examined. Atomic force microscopy imaging was used to illustrate the topography of fresh SiHy contact lens materials before and after incubation with 0.1% (w/v) HA solution. The distribution, as well as fine details of the HA network, were resolved by first staining HA with Gram's safranin, then imaging with confocal laser-scanning microscopy and differential interference-contrast microscopy. In this approach, SiHy materials take up the dye (safranin) nonspecifically, such that the resultant safranin-HA complex appears dim against the fluorescent lens background. Balafilcon A was chosen as the representative of glassy SiHy lenses that require postpolymerization plasma treatment to increase wettability. Senofilcon A and samfilcon A were chosen as representatives of SiHy materials fabricated with an internal wetting agent. A confluent and dim HA-safranin network was observed adhered to balafilcon A, senofilcon A, and samfilcon A lens surfaces incubated with either 0.1% (w/v) HA solution or Biotrue MPS. Therefore, the conditioning function provided by Biotrue MPS may be in part explained by the presence of the HA humectant layer that readily sorbs on the various types of SiHy contact lens materials.
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Affiliation(s)
| | - Daniel J Hook
- Vision Care, Bausch & Lomb Incorporated, Rochester, NY, USA
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Material properties that predict preservative uptake for silicone hydrogel contact lenses. Eye Contact Lens 2013; 38:350-7. [PMID: 23085619 DOI: 10.1097/icl.0b013e318272c470] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To assess material properties that affect preservative uptake by silicone hydrogel lenses. METHODS We evaluated the water content (using differential scanning calorimetry), effective pore size (using probe penetration), and preservative uptake (using high-performance liquid chromatography with spectrophotometric detection) of silicone and conventional hydrogel soft contact lenses. RESULTS Lenses grouped similarly based on freezable water content as they did based on total water content. Evaluation of the effective pore size highlighted potential differences between the surface-treated and non-surface-treated materials. The water content of the lens materials and ionic charge are associated with the degree of preservative uptake. CONCLUSIONS The current grouping system for testing contact lens-solution interactions separates all silicone hydrogels from conventional hydrogel contact lenses. However, not all silicone hydrogel lenses interact similarly with the same contact lens solution. Based upon the results of our research, we propose that the same material characteristics used to group conventional hydrogel lenses, water content and ionic charge, can also be used to predict uptake of hydrophilic preservatives for silicone hydrogel lenses. In addition, the hydrophobicity of silicone hydrogel contact lenses, although not investigated here, is a unique contact lens material property that should be evaluated for the uptake of relatively hydrophobic preservatives and tear components.
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Preclinical Research to Aid in the Development of Test Methods for Contact Lenses and Their Care Products. Eye Contact Lens 2012; 38:385-7. [DOI: 10.1097/icl.0b013e318260c93f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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