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Sapkota K, Franco S, Lira M. Reply to letter to the editor by London and Erdinest on "Contrast sensitivity function with soft contact lens wear". JOURNAL OF OPTOMETRY 2021; 14:356. [PMID: 32883646 PMCID: PMC8570954 DOI: 10.1016/j.optom.2020.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 06/11/2023]
Affiliation(s)
- Kishor Sapkota
- Center of Physics, University of Minho, Braga, Portugal.
| | - Sandra Franco
- Center of Physics, University of Minho, Braga, Portugal
| | - Madalena Lira
- Center of Physics, University of Minho, Braga, Portugal
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Efficacy of Contact Lens Care Solutions in Removing Cholesterol Deposits From Silicone Hydrogel Contact Lenses. Eye Contact Lens 2018; 45:105-111. [PMID: 30199424 DOI: 10.1097/icl.0000000000000547] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine the efficacy of multipurpose solutions (MPSs) on the removal of cholesterol deposits from silicone hydrogel (SH) contact lens materials using an in vitro model. MATERIALS AND METHODS Five SH lens materials: senofilcon A, comfilcon A, balafilcon A, lotrafilcon A, and lotrafilcon B were removed from the blister pack (n=4 for each lens type), incubated for 7 days at 37°C in an artificial tear solution containing C radiolabeled cholesterol. Thereafter, lenses were stored in a preserved saline solution control (Sensitive Eyes Saline Plus) or cleaned with 1 of the 5 MPSs incorporating different preservatives (POLYQUAD/ALDOX, polyquaternium-1/alexidine, polyquaternium-1/PHMB, and 2 based on PHMB alone) using a rub and rinse technique, according to the manufacturer's recommendations, and stored in the MPS for a minimum of 6 hr. Lenses were then extracted with 2:1 chloroform:methanol, analyzed in a beta counter, and μg/lens of cholesterol was determined. RESULTS Balafilcon A and senofilcon A lens materials showed the highest amounts of accumulated cholesterol (0.93±0.02 μg/lens; 0.95±0.01 μg/lens, respectively), whereas lotrafilcon A and lotrafilcon B deposited the lowest amounts (0.37±0.03 μg/lens; 0.47±0.12 μg/lens, respectively). For all lens materials, the MPS preserved with POLYQUAD/ALDOX removed more deposited cholesterol than any other test solution; however, the amount of removed cholesterol contamination from the individual contact lenses was only statistically significant for balafilcon A and senofilcon A (P=0.006 and P=0.042, respectively). Sensitive eyes and the other evaluated MPSs showed no significant effect on cholesterol removal (P>0.05). CONCLUSION Cholesterol-removal efficacy varies depending on the combination of lens material and solution. Only 1 MPS showed a statistically significant reduction of cholesterol deposit for only 2 of the 5 tested lens materials.
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A Review of Techniques to Measure Protein Sorption to Soft Contact Lenses. Eye Contact Lens 2017; 43:276-286. [PMID: 28198731 DOI: 10.1097/icl.0000000000000366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare and critically evaluate a variety of techniques to measure the quantity and biological activity of protein sorption to contact lenses over short time periods. METHODS A literature review was undertaken investigating the major techniques to measure protein sorption to soft contact lens materials, with specific reference to measuring protein directly on lenses using in situ, ex situ, protein structural, and biological activity techniques. RESULTS The use of in situ techniques to measure protein quantity provides excellent sensitivity, but many are not directly applicable to contact lenses. Many ex situ techniques struggle to measure all sorbed proteins, and these measurements can have significant signal interference from the lens materials themselves. Techniques measuring the secondary and tertiary structures of sorbed proteins have exhibited only limited success. CONCLUSIONS There are a wide variety of techniques to measure both the amount of protein and the biological activity of protein sorbed to soft contact lens materials. To measure the mass of protein sorbed to soft contact lenses (not just thin films) over short time periods, the method of choice should be I radiolabeling. This technique is sensitive enough to measure small amounts of deposited protein, provided steps are taken to limit and measure any interaction of the iodine tracer with the materials. To measure the protein activity over short time periods, the method of choice should be to measure the biological function of sorbed proteins. This may require new methods or adaptations of existing ones.
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Effect of lens care system on silicone hydrogel contact lens wettability. Cont Lens Anterior Eye 2015; 38:435-41. [PMID: 26189942 DOI: 10.1016/j.clae.2015.06.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/23/2015] [Accepted: 06/29/2015] [Indexed: 11/21/2022]
Abstract
PURPOSE The purpose was to compare the effect of the repeated usage of two care systems (one hydrogen peroxide cleaning and disinfecting system and one polyaminopropyl biguanide (PHMB) containing multi-purpose system) with silicone hydrogel contact lenses worn for three months on a daily wear modality. A specific aspect of interest was of the effect of the care systems on contact lens wettability. METHODS Seventy-four symptomatic contact lens wearers, habitually wearing either ACUVUE(®) OASYS(®) (n=37) or PureVision™ (n=37), constituted the study population. The study was a two-arm prospective, investigator-masked, bilateral study of three-month duration to evaluate the effects of CLEAR CARE(®) compared with renu(®) fresh™. The subjects were randomized to one of the two lens care systems. Contact lens wettability and surface cleanliness were assessed with the Tearscope and reported in terms of pre-lens non-invasive break-up time (PL-NIBUT) and visible deposits. Baseline assessments at enrollment were with the subjects' own contact lenses worn for at least 6h when using their habitual PHMB-preserved care system and at the dispensing visit with new contact lenses. At the follow-up visits, the contact lenses were worn for at least 6h, and were at least 11 days old for ACUVUE(®) OASYS(®) and 25 days old for PureVision™. RESULTS The results obtained showed that: (i) with CLEAR CARE(®), a significant improvement in contact lens wettability was recorded compared with the habitual care system at the three-month follow-up visit (mean median PL-NIBUT 5.8 vs. 4.0 s, p<0.001). Further, with this same lens care system a significant increase in wettability was observed at the three-month follow-up visit compared with dispensing (mean median PL-NIBUT 5.8 vs. 4.5s, p=0.022). (ii) Whereas no difference in contact lens wettability was observed at dispensing between the two lens care groups (mean PL-NIBUT: 4.5 vs. 4.2s, p=0.518), a significantly more stable pre-lens tear film was observed with CLEAR CARE(®) than with renu(®) fresh™ at both the two-month (mean PL-NIBUT: 4.6 vs. 3.7s, p=0.005) and three-month (mean PL-NIBUT: 5.8 vs. 4.2 s, p=0.028) visits. iii. With renu(®) fresh™, no significant differences were observed at the end of three months of use compared with either the habitual care system or the new contact lens solution (mean PL-NIBUT: 3M 4.2 vs. Disp 4.2 s (p=0.420) vs. enrolment habitual care solution 5.1s (p=0.734)). iv. With CLEAR CARE(®) significant increases in the incidence of surfaces free of both mucus (3 month 95%. vs. habitual solution 82% enrolment; p=0.005) and lipid (3 month 87% vs. habitual solution 72% enrolment; p=0.009) were observed. CONCLUSION Significantly better contact lens wettability and surface cleanliness were achieved for ACUVUE(®) OASYS(®) and PureVision™ with CLEAR CARE(®) than with renu(®) fresh™ at the end of three months of use.
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Guan A, Li Z, Phillips KS. The effects of non-ionic polymeric surfactants on the cleaning of biofouled hydrogel materials. BIOFOULING 2015; 31:689-697. [PMID: 26469384 DOI: 10.1080/08927014.2015.1094690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Block co-polymer surfactants have been used for cleaning hydrogel medical devices that contact the body (e.g., contact lenses) because of their biocompatibility. This work examined the relationship between concentration and detergency of two non-ionic polymeric surfactants (Pluronic F127 and Triton X-100) for cleaning protein soil, with anionic surfactants (sodium dodecyl sulfate and sodium laureth sulfate) as positive controls. Surface plasmon resonance was used to quantify removal of simulated tear soil from self-assembled monolayer surfaces, and a microplate format was used to study the removal of fluorescently labeled soil proteins from contact lenses. While detergency increased as a function of concentration for anionic surfactants, it decreased with concentration for the two polymeric surfactants. The fact that the protein detergency of some non-ionic polymeric surfactants did not increase with concentration above the critical micelle concentration could have implications for optimizing the tradeoff between detergency and biocompatibility.
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Affiliation(s)
- Allan Guan
- a Department of Biomedical Engineering , The George Washington University , Washington , DC , USA
| | - Zhenyu Li
- a Department of Biomedical Engineering , The George Washington University , Washington , DC , USA
| | - K Scott Phillips
- b Division of Biology, Chemistry and Materials Science , United States Food and Drug Administration, Office of Medical Products and Tobacco, Center for Devices and Radiological Health, Office of Science and Engineering Laboratories , Silver Spring , MD , USA
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Overview of factors that affect comfort with modern soft contact lenses. Cont Lens Anterior Eye 2014; 37:65-76. [DOI: 10.1016/j.clae.2013.08.154] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 07/31/2013] [Accepted: 08/13/2013] [Indexed: 11/21/2022]
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Multi-site clinical assessment of Complete Revitalens MPDS in 2981 contact lens wearers across Europe and USA. Cont Lens Anterior Eye 2013; 36:289-93. [DOI: 10.1016/j.clae.2013.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 03/30/2013] [Accepted: 05/31/2013] [Indexed: 11/22/2022]
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Chow LM, Subbaraman LN, Sheardown H, Jones L. Kinetics of in Vitro Lactoferrin Deposition on Silicone Hydrogel and FDA Group II and Group IV Hydrogel Contact Lens Materials. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 20:71-82. [PMID: 19105901 DOI: 10.1163/156856208x393509] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Lisa M. Chow
- a Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Lakshman N. Subbaraman
- b Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Heather Sheardown
- c Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L8
| | - Lyndon Jones
- d Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
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Hatou S, Fukui M, Yatsui K, Mochizuki H, Akune Y, Yamada M. Biochemical analyses of lipids deposited on silicone hydrogel lenses. JOURNAL OF OPTOMETRY 2010; 3:164-168. [PMCID: PMC3974282 DOI: 10.1016/s1888-4296(10)70023-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Accepted: 06/23/2010] [Indexed: 06/03/2023]
Abstract
Purpose This study was performed to determine the levels of lipids deposited on in vivo worn silicone hydrogel lenses. Methods Three silicone hydrogel materials, galyfilcon A, senofilcon A, and asmofilcon A, were worn for 2 weeks by 35 normal subjects. Total lipid deposition was determined by the sulfo-phospho-vanillin reaction. Cholesterol was estimated by a colorimetric probe through enzymatic oxidation. Phospholipid level was estimated by determining phosphorus with ammonium molybdate through enzymatic digestion. Results The total lipid content recovered from galyfilcon A, senofilcon A, and asmofilcon A was 32.9 ± 33.8, 42.1 ± 14.0, and 36.6 ± 31.9 μg/lens, respectively. The cholesterol content recovered from galyfilcon A, senofilcon A, and asmofilcon A was 26.2 ± 26.9, 28.6 ± 19.4, and 31.1 ± 21.1 μg/lens, respectively. There were no statistically significant differences in total lipids and cholesterol among the contact lens types. However, the quantity of phospholipid recovered from the asmofilcon A (7.0 ± 5.5 μg/lens) lenses was significantly higher than from galyfilcon A (1.1 ± 0.8 μg/lens) and senofilcon A (2.4 ± 0.8 mg/lens) lenses (p < 0.05, Mann-Whitney test). Conclusions The quantity of total lipid and cholesterol deposited on the 3 silicone hydrogel lenses tested did not differ. However, there were significant differences in the amounts of phospholipid deposited among the 3 silicone hydrogel lenses, of which clinical significance should be explored in the future study.
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Affiliation(s)
- Shin Hatou
- Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
- Department of Ophthalmology, Keio University, School of Medicine, Tokyo, Japan
| | - Masaki Fukui
- Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Keiichi Yatsui
- Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Hiroshi Mochizuki
- Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Yoko Akune
- Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Masakazu Yamada
- Division for Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
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Abstract
PURPOSE To determine the impact of the rinse step in "no rub" contact lens care systems relative to its ability to assist in removing loosely associated and bound tear film proteins from a worn silicone hydrogel lens. METHODS After informed consent, subjects were fitted with lotrafilcon B contact lenses (CIBA Vision). If the fit was acceptable, subjects were asked to wear the lenses on a daily wear basis for 5 (+2, -0) days for an outcome visit. Subjects were instructed to use AQuify Multi-Purpose Disinfecting Solution (CIBA Vision) following the manufacturer's "no rub" instructions. At the outcome visit, contact lenses were then collected by a gloved examiner, with a sterile metal forceps, who rinsed the right lens but did not rinse the left lens on removal from the eyes. Protein was extracted with a 50:50 0.2% trifluoroacetic acid-acetonitrile solution and quantified using a Bradford analyses. RESULTS Twenty contact lens wearers were enrolled in this study. For the non-rinsed lenses, the first extraction yielded 13.4 +/- 9.2 microg/lens of protein, whereas the second extraction yielded 5.8 +/- 2.8 microg/lens of protein. For the rinsed lenses, the first extraction yielded an average of 3.0 +/- 1.9 microg/lens of protein, whereas the second extraction yielded an average of 4.0 +/- 2.3 microg/lens. Repeated measures analysis of variance showed a significant interaction (F-statistic = 18.9, p < 0.0001) between the rinse of a lens and extraction number. CONCLUSIONS Rinsing a contact lens after removal from the eye removes well more than one-half of the protein associated with it. Further, to biochemically recover all protein from a silicone hydrogel lens, it may be important to perform more than one chemical extraction from it.
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In Vitro Adsorption of Tear Proteins to Hydroxyethyl Methacrylate-Based Contact Lens Materials. Eye Contact Lens 2009; 35:320-8. [DOI: 10.1097/icl.0b013e3181becd3c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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