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Nancy J. Keir, Craig Woods, Desmond Fonn; The Impact Of Lens Wear On In Vivo Wettability Of Silicone Hydrogel Contact Lenses. Invest. Ophthalmol. Vis. Sci. 2011;52(14):6505.
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© ARVO (1962-2015); The Authors (2016-present)
To assess the impact of lens wear on in vivo wettability of silicone hydrogel contact lenses.
Two silicone hydrogel materials (lotrafilcon B (LB), balafilcon A (BA)) were worn by 19 subjects in a contralateral eye, dispensing study. Measurements were completed at baseline (BLN) and 4wks. In vivo wettability measures included graded wettability (0-4, 0=perfect) and pre-lens non-invasive tear break-up time (NITBUT, seconds). Differences between materials and individual changes were assessed.
Mean±SD (range) graded wettability at BLN and 4wks was: 1.08±0.85 (0-2.75) and 1.33±1.01 (0-3.75) for LB and 1.86±1.14 (0-3.75) and 2.11±1.16 (0.25-3.75) for BA. Graded wettability was better for LB compared to BA (p<0.05) but did not change over time (p=0.06). NITBUT at BLN and 4wks was: 6.5±3.0 (3.7-16.1) and 5.6±2.2 (2.9-10.9) for LB and 6.2±2.9 (3.4-13.3) and 5.0±2.6(1.3-12.8) for BA. There was no difference in NITBUT between materials, however there was a decrease over time (p<0.05). Individually, graded wettability decreased (>0.5 change in grade) with lens wear in 47% and 53% and improved in 26% and 37% of subjects for LB and BA, respectively. Pre-lens NITBUT decreased (>1 second change) with lens wear in 47% and 53% and improved in 16% and 11% of subjects for LB and BA, respectively.
In vivo wettability varied between subjects and differed between materials. While lens wear reduced in vivo wettability for most subjects, in some cases there was an improvement with wear. This would suggest that the tear film may act to enhance wettability in some subjects fitted with silicone hydrogels, and that initial wettability may not predict that seen over time.
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