Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/13775

TitleWhite light interferometry to characterize the hydrogel contact lens surface
Author(s)Giraldez, Maria J.
García-Resúa, Carlos
Lira, Madalena
Oliveira, M. Elisabete
Yebra-Pimentel Vilar, Eva
KeywordsContact lenses
Hydrogels
Surface characterization
Surface roughness
Topography
White light optical profiling
Issue date1-May-2010
PublisherWiley-Blackwell
JournalOphthalmic and Physiological Optics
Abstract(s)Purpose: The aim of this study was to characterize, qualitatively and quantitatively, the surface morphology of four unworn conventional hydrogel contact lenses (Omafilcon, Hioxifilcon-based, Nefilcon A and Ocufilcon B) by White Light Optical Profiling (WLOP). WLOP is an ideal technique for sampling larger areas as well as for higher measurement speed compared with other topography techniques used in contact lens studies. Methods: Surface roughness was assessed by WLOP in the Vertical Scanning Mode, with a Wyko NT1100, which is a non-contact optical profiling system that provides high vertical resolution. Representative roughness parameters, the Average Roughness (Ra), Root-mean-square Roughness (Rms), and Maximum Roughness (Rmax), for areas of 625, 2500, 10829 and 67 646 lm2 were calculated. Results: Higher Ra, Rms and Rmax values were obtained for larger areas in all lenses. Daily disposable contact lenses (Nefilcon A and Ocufilcon B) presented the highest Ra, Rms and Rmax values, the larger changes in these parameters becoming apparent with the increase in the measured area. Differences between lenses were less obvious when data from 625 and 2500 lm2 area were compared. Conclusions: Daily disposable contact lenses showed the highest roughness surface. Analyzing larger areas might be adequate to detect differences between lenses in terms of surface characteristics, which may not be so obvious if smaller areas are studied.
TypeArticle
DescriptionUncorrected proof
URIhttp://hdl.handle.net/1822/13775
DOI10.1111/j.1475-1313.2010.00712.x
ISSN0275-5408
Publisher versionhttp://www.ingentaconnect.com/content/bsc/opo/2010/00000030/00000003/art00009?token=00461252d45c5f3b3b47462148743b3e70557b2f2a6c4f582a2f4876753375686f4961
Peer-Reviewedyes
AccessOpen access
Appears in Collections:CDF - FAMO - Artigos/Papers (with refereeing)

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