Purchase this article with an account.
D. Fonn, A. Moezzi, J. Varikooty; Distribution of Overnight Corneal Swelling Across Subjects With Four Different Silicone Hydrogel Lenses. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5658.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To compare central and peripheral corneal swelling after 8 hours of sleep in eyes wearing silicone hydrogel lenses with various oxygen transmissibility (Dk/t) values and to eyes without lenses.
Twenty nine neophyte subjects wore lotrafilcon A (Dk/t, 175 x 10-9), balafilcon A (Dk/t, 101 x 10-9), galyfilcon A (Dk/t, 86 x 10-9) and senofilcon A (Dk/t, 147 x 10-9) lenses using powers -3.0, -10.0 and +6.0 D in each material on separate nights, in random order, and in one eye only. The contra-lateral eye (no lens) served as the control. Corneal thickness was measured using a digital optical pachometer before lens insertion, immediately after lens removal on waking, then 20, 40 minutes, 1, 2 and 3 hours later.
The range of central corneal swelling (CCS) across subjects was 3.3 to 11.3%. The average difference between the mean (7%) and the median (6.8%) CCS of all lenses was only 0.2% resulting in a distribution across the study participants that was not significantly different than the expected normal distribution (p>0.20). There was no correlation between the mean and the range of the CCS (r=0.058, p=0.766), and the intra-subject range of CCS was the same across all participants irrespective of the magnitude of their swelling. The same trend of normal distribution was also found for CCS with each lens as well as the control eyes (p>0.20 for all). There was a significant correlation between CCS in lens wearing and control eyes (r=0.895, p<0.001).
The small difference between the mean and the median CCS with the silicone hydrogel lenses in this study indicates an insignificant skewness of the distribution of the mean CCS across the study participants. This suggests that approximately 50% of the participants swell more than the mean, irrespective of lens type.
This PDF is available to Subscribers Only