Dehydration at the lens surface: surface energy and surfactant persistence

Sarah Carnell, Darren Campbell, Gareth Ross, Brian Tighe

Research output: Contribution to conferencePoster

Abstract

Purpose: Most published surface wettability data are based on hydrated materials and are dominated by the air-water interface. Water soluble species with hydrophobic domains (such as surfactants) interact directly with the hydrophobic domains in the lens polymer. Characterisation of relative polar and non-polar fractions of the dehydrated material provides an additional approach to surface analysis.
Method: Probe liquids (water and diiodomethane) were used to characterise polar and dispersive components of surface energies of dehydrated lenses using the method of Owens and Wendt. A range of conventional and silicone hydrogel soft lenses was studied. The polar fraction (i.e. polar/total) of surface energy was used as a basis for the study of the structural effects that influence surfactant persistence on the lens surface.
Results: When plotted against water content of the hydrated lens, polar fraction of surface energy (PFSE) values of the dehydrated lenses fell into two rectilinear bands. One of these bands covered PFSE values ranging from 0.4 to 0.8 and contained only conventional hydrogels, with two notable additions: the plasma coated silicone hydrogels lotrafilcon A and B. The second band covered PFSE values ranging from 0.04 to 0.28 and contained only silicone hydrogels. Significantly, the silicone hydrogel lenses with lowest PFSE values (p<0.15) are found to be prone to lipid deposition duringwear. Additionally, more hydrophobic surfactants were found to be more persistent on lenses with lower PFSE values.
Conclusions: Measurement of polar fraction of surface energy provides an importantmechanistic insight into surface interactions of silicone hydrogels.
Original languageEnglish
Publication statusPublished - 2011
EventBritish Contact Lens Association - Birmingham, United Kingdom
Duration: 27 May 201030 May 2010

Conference

ConferenceBritish Contact Lens Association
CountryUnited Kingdom
CityBirmingham
Period27/05/1030/05/10

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surface energy
dehydration
surfactant
persistence
wettability
water
polymer
lipid
water content
probe
plasma
liquid
air

Bibliographical note

Abstract published on Abstracts of the 2011 BCLA Annual Clinical Conference / Contact Lens & Anterior Eye 34, Supplement 1 (2011) S32 DOI http://dx.doi.org/10.1016/S1367-0484(11)60145-8

Cite this

Carnell, S., Campbell, D., Ross, G., & Tighe, B. (2011). Dehydration at the lens surface: surface energy and surfactant persistence. Poster session presented at British Contact Lens Association, Birmingham, United Kingdom.
Carnell, Sarah ; Campbell, Darren ; Ross, Gareth ; Tighe, Brian. / Dehydration at the lens surface : surface energy and surfactant persistence. Poster session presented at British Contact Lens Association, Birmingham, United Kingdom.
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abstract = "Purpose: Most published surface wettability data are based on hydrated materials and are dominated by the air-water interface. Water soluble species with hydrophobic domains (such as surfactants) interact directly with the hydrophobic domains in the lens polymer. Characterisation of relative polar and non-polar fractions of the dehydrated material provides an additional approach to surface analysis.Method: Probe liquids (water and diiodomethane) were used to characterise polar and dispersive components of surface energies of dehydrated lenses using the method of Owens and Wendt. A range of conventional and silicone hydrogel soft lenses was studied. The polar fraction (i.e. polar/total) of surface energy was used as a basis for the study of the structural effects that influence surfactant persistence on the lens surface.Results: When plotted against water content of the hydrated lens, polar fraction of surface energy (PFSE) values of the dehydrated lenses fell into two rectilinear bands. One of these bands covered PFSE values ranging from 0.4 to 0.8 and contained only conventional hydrogels, with two notable additions: the plasma coated silicone hydrogels lotrafilcon A and B. The second band covered PFSE values ranging from 0.04 to 0.28 and contained only silicone hydrogels. Significantly, the silicone hydrogel lenses with lowest PFSE values (p<0.15) are found to be prone to lipid deposition duringwear. Additionally, more hydrophobic surfactants were found to be more persistent on lenses with lower PFSE values.Conclusions: Measurement of polar fraction of surface energy provides an importantmechanistic insight into surface interactions of silicone hydrogels.",
author = "Sarah Carnell and Darren Campbell and Gareth Ross and Brian Tighe",
note = "Abstract published on Abstracts of the 2011 BCLA Annual Clinical Conference / Contact Lens & Anterior Eye 34, Supplement 1 (2011) S32 DOI http://dx.doi.org/10.1016/S1367-0484(11)60145-8; British Contact Lens Association ; Conference date: 27-05-2010 Through 30-05-2010",
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Carnell, S, Campbell, D, Ross, G & Tighe, B 2011, 'Dehydration at the lens surface: surface energy and surfactant persistence' British Contact Lens Association, Birmingham, United Kingdom, 27/05/10 - 30/05/10, .

Dehydration at the lens surface : surface energy and surfactant persistence. / Carnell, Sarah; Campbell, Darren; Ross, Gareth; Tighe, Brian.

2011. Poster session presented at British Contact Lens Association, Birmingham, United Kingdom.

Research output: Contribution to conferencePoster

TY - CONF

T1 - Dehydration at the lens surface

T2 - surface energy and surfactant persistence

AU - Carnell, Sarah

AU - Campbell, Darren

AU - Ross, Gareth

AU - Tighe, Brian

N1 - Abstract published on Abstracts of the 2011 BCLA Annual Clinical Conference / Contact Lens & Anterior Eye 34, Supplement 1 (2011) S32 DOI http://dx.doi.org/10.1016/S1367-0484(11)60145-8

PY - 2011

Y1 - 2011

N2 - Purpose: Most published surface wettability data are based on hydrated materials and are dominated by the air-water interface. Water soluble species with hydrophobic domains (such as surfactants) interact directly with the hydrophobic domains in the lens polymer. Characterisation of relative polar and non-polar fractions of the dehydrated material provides an additional approach to surface analysis.Method: Probe liquids (water and diiodomethane) were used to characterise polar and dispersive components of surface energies of dehydrated lenses using the method of Owens and Wendt. A range of conventional and silicone hydrogel soft lenses was studied. The polar fraction (i.e. polar/total) of surface energy was used as a basis for the study of the structural effects that influence surfactant persistence on the lens surface.Results: When plotted against water content of the hydrated lens, polar fraction of surface energy (PFSE) values of the dehydrated lenses fell into two rectilinear bands. One of these bands covered PFSE values ranging from 0.4 to 0.8 and contained only conventional hydrogels, with two notable additions: the plasma coated silicone hydrogels lotrafilcon A and B. The second band covered PFSE values ranging from 0.04 to 0.28 and contained only silicone hydrogels. Significantly, the silicone hydrogel lenses with lowest PFSE values (p<0.15) are found to be prone to lipid deposition duringwear. Additionally, more hydrophobic surfactants were found to be more persistent on lenses with lower PFSE values.Conclusions: Measurement of polar fraction of surface energy provides an importantmechanistic insight into surface interactions of silicone hydrogels.

AB - Purpose: Most published surface wettability data are based on hydrated materials and are dominated by the air-water interface. Water soluble species with hydrophobic domains (such as surfactants) interact directly with the hydrophobic domains in the lens polymer. Characterisation of relative polar and non-polar fractions of the dehydrated material provides an additional approach to surface analysis.Method: Probe liquids (water and diiodomethane) were used to characterise polar and dispersive components of surface energies of dehydrated lenses using the method of Owens and Wendt. A range of conventional and silicone hydrogel soft lenses was studied. The polar fraction (i.e. polar/total) of surface energy was used as a basis for the study of the structural effects that influence surfactant persistence on the lens surface.Results: When plotted against water content of the hydrated lens, polar fraction of surface energy (PFSE) values of the dehydrated lenses fell into two rectilinear bands. One of these bands covered PFSE values ranging from 0.4 to 0.8 and contained only conventional hydrogels, with two notable additions: the plasma coated silicone hydrogels lotrafilcon A and B. The second band covered PFSE values ranging from 0.04 to 0.28 and contained only silicone hydrogels. Significantly, the silicone hydrogel lenses with lowest PFSE values (p<0.15) are found to be prone to lipid deposition duringwear. Additionally, more hydrophobic surfactants were found to be more persistent on lenses with lower PFSE values.Conclusions: Measurement of polar fraction of surface energy provides an importantmechanistic insight into surface interactions of silicone hydrogels.

M3 - Poster

ER -

Carnell S, Campbell D, Ross G, Tighe B. Dehydration at the lens surface: surface energy and surfactant persistence. 2011. Poster session presented at British Contact Lens Association, Birmingham, United Kingdom.