Dynamic wettability properties of a soft contact lens hydrogel

Ketelson, Howard A.; Meadows, David; Stone, Ralph

doi:10.1016/j.colsurfb.2004.07.010

Cited by 108 publications

(79 citation statements)

References 36 publications

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“…소프트 콘택트렌즈(soft 또는 hydrogel contact lens) 선 택에서 주요한 파라미터(parameter) [1,2]는 산소 공급 능 력(oxygen performance) [3], 함수율(water content) [4], 습 윤성(wettability) [5], 렌즈 두께(lens thickness) [6] 등을 들 수 있다. 콘택트렌즈는 각막에 직접 닿는 경우로 눈에서 생리적 반응을 고려할 때 가장 중요한 성질은 산소 공급 능력이다 [7].…”

Section: 서론unclassified

Evaluation of Oxygen Permeability of Soft Contact Lenses Based on Thickness

유동식¹,

문병연²

2009

Journal of the Korea Academia-Industrial cooperation Society

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The oxygen permeability of a soft contact lens is an important parameter for determining corneal health when considering the physiological response of the eye. The aim of this study is to evaluate the oxygen permeability of soft contact lenses based on thickness, using the polarographic method. The thickness of lens was measured using contact and non-contact method. To assess accuracy and reliability, the Bland-Altman plot was used. The reliability was high for the oxygen permeability based on center thickness measured by contact method, whereas the accuracy was high for the oxygen permeability based on center thickness measured by non-contact method. These results indicate that the permeability characteristics were variable according to the measurement and criteria of thickness of soft contact lenses and the measurement of soft contact lenses by non-contact method was more reasonable. Thus, contact lens practitioners should consider some basic differences between methodologies when interpreting or quoting oxygen performance data.

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Section: 서론unclassified

Evaluation of Oxygen Permeability of Soft Contact Lenses Based on Thickness

유동식¹,

문병연²

2009

Journal of the Korea Academia-Industrial cooperation Society

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“…For example, contact angle measurements have been reported in several studies and have shown that the advancing angles of hydrogel lenses depend on their exposure environment and the measurement methodology [11][12][13]. In general, these studies have shown that contact lens hydrogels have surfaces that are not usually at thermodynamic equilibrium when used in the ocular environment and, as a result, there can be significant changes in the surface chemistry over time due to the migration of hydrophobic groups to the air/lens interface.…”

Section: Introductionmentioning

confidence: 99%

“…In general, these studies have shown that contact lens hydrogels have surfaces that are not usually at thermodynamic equilibrium when used in the ocular environment and, as a result, there can be significant changes in the surface chemistry over time due to the migration of hydrophobic groups to the air/lens interface. To overcome these dynamic changes, the surfaces have been modified through plasma treatment, the inclusion of free polymers into the lenses' matrix, and/or the soaking of lenses in saline solutions containing block copolymers to physically modify the surfaces [1,6,7,9,10,13].…”

Section: Introductionmentioning

confidence: 99%

Impact of Ethylene Oxide Butylene Oxide Copolymers on the Composition and Friction of Silicone Hydrogel Surfaces

et al. 2012

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The surface chemical compositions of three types of silicone hydrogel contact lenses, PureVision Ò (balafilcon A), ACUVUE Ò OASYS Ò (senofilcon A), and O 2 OPTIX Ò (lotrafilcon B), were analyzed using X-ray photoelectron spectroscopy prior to and following treatment in a test solution of diblock copolymer of poly (ethylene oxide) and poly(butylene oxide) (EO-BO). Prior to treatment, differences in surface elemental compositions of the lenses were found to reflect known bulk compositions and/or respective surface treatments. Following solution treatment, surface chemical modifications were apparent in balafilcon A and lotrafilcon B, especially in the distribution of chemical functionalities present at the surface. Only modest changes in surface composition were observed for the senofilcon A material. Atomic force microscopy (AFM) was employed to evaluate the surface topography and frictional properties of the lenses prior to and following similar solution treatments. AFM measurements in saline revealed large disparities between the coefficients of friction of the three lenses, with balafilcon A and lotrafilcon B exhibiting coefficients of friction approximately five times greater than that of senofilcon A. Lens surface treatment with the diblock copolymer test solution produced a significant reduction in the coefficients of friction of the two lenses exhibiting higher friction, yet only a small reduction in friction was observed for senofilcon A lens. Together, these results depict a strong correlation between the surface chemistry and frictional response of the lens systems as they relate to solution treatment with this specific diblock copolymer.

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“…Contact angle is one of the most widely used techniques in the surface characterization and wettability of pharmaceuticals formulations. The sessile drop technique is commonly used for estimating contact angle of pharmaceutical powders (Buckton, 1993), drug-carrier adhesion (Podczeck et al, 1996), compaction and granulation (Puri et al, 2010), emulsion stability (Hansen and Fagerheim, 1998), human biological fluids (Noordman et al, 1999) and dynamic wettability properties of contact lens hydrogels (Ketelson et al, 2005).…”

Section: Sessile Drop Methodsmentioning

confidence: 99%