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L. Sorbara, F. Lu, R. Kort, D. Fonn, T. Simpson, Centre for Contact Lens Research (CCLR); Topographic Keratometric Effects of Corneal Refractive Therapy After One Month of Lens Wear . Invest. Ophthalmol. Vis. Sci. 2004;45(13):1580.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To examine the topographical corneal shape change over a horizontal chord after one month of wearing CRTTM corneal reshaping contact lenses. Methods: Twenty three participants wore CRTTM HDS 100 contact lenses in both eyes while sleeping. Topography was measured using the Humphrey AtlasTM corneal topographer the night prior to lens insertion, immediately after lens removal on the following morning and 1, 3, 7 and 14 hours afterwards at days 1, 4, 10 and 28 and after a 72 hour washout period of no lens wear. Topographic changes were measured over a 6–8mm chord in 1mm steps. Results: There were significant differences in corneal curvature over time (p=0.000), day (p=0.000) and at various corneal locations (p=0.000). The central positions flattened and the mid peripheral positions steepened throughout the month of the study The mean (±sd) change in curvature centrally and at 3mm temporal from the centre was –1.54±1.59D and 2.31±2.26D respectively, immediately after lens removal, at Day 1 and –2.76±1.52D and 4.08±2.41D at Day 28 respectively. On Day 28, after 14 hours, there was little regression noted compared to the morning, 18% centrally and 29% mid–peripherally. At the 72 hour (post–discontinuation) visit, the cornea did not recover to baseline, the central cornea was still flatter (approx. 0.75D, 69% recovery) and the mid–periphery was still steeper by the same amount, representing a 77% recovery. Conclusions: After one month of lens wear, the CRTTM lens wearing eyes showed a significant topographic shift. The shape of the cornea did not recover to baseline at 14 hours after one month or after a 72 hour recovery period, indicating that the change in shape can be maintained.
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