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Majdoub F, Belin M, Perret-Liaudet J. Ultra-low friction in soft contact lenses: Analysis of dynamic free responses measured by the dynamic oscillating tribometer. J Mech Behav Biomed Mater 2024; 149:106236. [PMID: 37984287 DOI: 10.1016/j.jmbbm.2023.106236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 11/06/2023] [Accepted: 11/08/2023] [Indexed: 11/22/2023]
Abstract
Friction coefficient is considered as a measurement for clinical comfort of soft contact lenses. One of the main challenges in the tribology field is to evaluate the friction in soft materials such as soft contact lenses. In this work, we aim to evaluate the friction at the eyelid-lens contact using a new technique. This technique is based on a single-degree-of-freedom (SDOF) mass-spring system having a sliding contact. The experimental technique measures the free responses of the mechanical system. The friction is then evaluated from the damped free responses with a high accuracy. A variety of soft contact lenses are tested with some lubricants under many physiological conditions. The results are discussed and compared with those in the literature.
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Affiliation(s)
- Fida Majdoub
- LabECAM, ECAM La Salle, Université de Lyon, 69005, Lyon, France.
| | - Michel Belin
- Laboratory of Tribology and System Dynamics, École Centrale de Lyon, UMR CNRS 5513, Université de Lyon, 69134, Écully, France
| | - Joël Perret-Liaudet
- Laboratory of Tribology and System Dynamics, École Centrale de Lyon, UMR CNRS 5513, Université de Lyon, 69134, Écully, France
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Costa D, De Matteis V, Treso F, Montani G, Martino M, Rinaldi R, Corrado M, Cascione M. Impact of the physical properties of contact lens materials on the discomfort: role of the coefficient of friction. Colloids Surf B Biointerfaces 2024; 233:113630. [PMID: 37956592 DOI: 10.1016/j.colsurfb.2023.113630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023]
Abstract
Contact Lens Discomfort (CLD) is the main cause in contact lens (CLs) discontinuation, referred in literature as drop-out phenomenon. Despite such evidence was reported in several clinical studies, a relationship between physico-chemical properties of CLs and CLD is not still totally understood. In this regard, the friction of CLs surfaces seems to be related to discomfort feeling events, probably due to an alteration of the lubricate function of the tear film after the CL placement inside the ocular environment. In the last years, many studies have been finalized to the friction measurements of CLs surface, finding conflicting data due to a lack in standardized protocol. The aim of this review is primarily to show evident relationships between CLs surface properties (i.e. wettability, tear evaporation, tear film quality, etc.) and the coefficient of friction (CoF), resulting therefore the most relevant physical quantity in the CLs characterization. In addition, we reported the most recent studies in CLs tribology, which highlight that the introduction of a standard protocol in CoF measurements is necessary to obtain reproducible results, considering the aim to evaluate in a more precise way the relationship between this material surface property and comfort in CLs users.
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Affiliation(s)
- D Costa
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy
| | - V De Matteis
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy; Institute for Microelectronics and Microsystems (IMM), CNR, Via Monteroni, Lecce 73100, Italy.
| | - F Treso
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy; Centro di Ricerca in Contattologia Avanzata, Via Arnesano, Lecce 73100, Italy
| | - G Montani
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy; Centro di Ricerca in Contattologia Avanzata, Via Arnesano, Lecce 73100, Italy
| | - M Martino
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy; Centro di Ricerca in Contattologia Avanzata, Via Arnesano, Lecce 73100, Italy
| | - R Rinaldi
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy; Institute for Microelectronics and Microsystems (IMM), CNR, Via Monteroni, Lecce 73100, Italy
| | - M Corrado
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy
| | - M Cascione
- Department of Mathematics and Physics "Ennio De Giorgi", University of Salento, Via Arnesano, Lecce 73100, Italy; Institute for Microelectronics and Microsystems (IMM), CNR, Via Monteroni, Lecce 73100, Italy; Centro di Ricerca in Contattologia Avanzata, Via Arnesano, Lecce 73100, Italy.
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Iwashita H, Mabuchi K, Itokawa T, Okajima Y, Suzuki T, Hori Y. Evaluation of the Lubricating Effect of Hyaluronic Acid on Contact Lenses Using a Pendulum-Type Friction Tester Under Mimicking Physiological Conditions. Eye Contact Lens 2022; 48:83-87. [PMID: 35058419 PMCID: PMC8759543 DOI: 10.1097/icl.0000000000000853] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2021] [Indexed: 12/02/2022]
Abstract
OBJECTIVE To evaluate the lubricating effect of hyaluronic acid (HA) on soft contact lenses (SCLs) measured using a pendulum-type friction tester. METHODS We measured the coefficient of friction (CoF) of narafilcon A, delefilcon A, and etafilcon A with polyvinylpyrrolidone (PVP), daily disposable SCL material, using a modified pendulum-type friction tester. Sample SCLs were set on an acrylic plastic half-ball and placed into the polyethylene terephthalate hemisphere cup filled with 0.4 mL of test lubricants that included saline and 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% (wt/vol) HA (molecular weight, 850 kDa). The viscosities of saline and HA were measured using an Ubbelohde viscometer. RESULTS The CoF of the SCL under a low concentration (0.05%) of HA was the lowest and significantly lower than saline in narafilcon A and delefilcon A (P<0.05, Steel multiple comparison test). Under higher HA concentrations (0.3%, 0.4%, and 0.5%), the CoF was significantly higher than that of saline (P<0.01, Steel' multiple comparison test) in all three SCLs. There were no significant differences of CoF among three SCLs in saline and all concentrations of HA. The HA viscosities increased exponentially with the concentration (Y=1.2829e9.286X). CONCLUSION The viscosity of a high concentration of HA may increase the friction of SCLs, which may have a deleterious effect on the ocular surface.
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Affiliation(s)
- Hiroko Iwashita
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Kiyoshi Mabuchi
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Takashi Itokawa
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Yukinobu Okajima
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Takashi Suzuki
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | - Yuichi Hori
- Department of Ophthalmology (H.I., K.M., T.I., Y.O., T.S., Y.H.), Faculty of Medicine, Toho University, Tokyo, Japan; and Department of Biomedical Engineering (K.M.), School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
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