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Cherie B Nau, Muriel Schornack; Scleral Lens Settling in 20 minute Intervals Over 2 Hours with Three Lens Designs. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3083.
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© ARVO (1962-2015); The Authors (2016-present)
Small-diameter scleral lenses were previously found to settle by almost 50% after two hours of wear. The rate of lens settling over time in 3 different diameter lenses is evaluated in this study. We examined the clearance between the lens and cornea at 20 minute intervals during the first two hours of scleral lens wear.
Thirty-five participants, fourteen men and twenty-one women age 20-44 years (29 ± 7 years, mean ± SD) with healthy eyes (no history of eye disease or surgery and no previous scleral lens wear), were fitted on one eye with a15.0-mm and 18.2-mm diameter Jupiter scleral lens (Visionary Optics, Front Royal, VA), and a 18.0-mm Digiform lens (TruForm Optics, Bedford, Tx). Lenses were selected from a diagnostic fitting set to provide 200-300 μm clearance between the lens and central cornea immediately after application. Each lens was evaluated at a separate visit. Within 5 minutes after placement, and every 20 minutes for 2 hours, slit images of the lens and cornea were recorded by Scheimpflug photography (Pentacam, Oculus, Inc.). The clearance between the posterior surface of the lens and the anterior surface of the cornea was measured twice, over the central cornea, in each of two vertical Scheimpflug images, using the caliper tool in the Pentacam analysis software. For each lens, the corneal clearance for each measurement was compared to the initial clearance by using a paired t-test.
Scleral lens clearance after initial application was 201 ± 90 μm in the 15.0 mm lens, 244 ± 91 μm in the 18.0 mm lens, and 200 ± 82 μm in the 18.2 mm lens. After 40 minutes of lens wear, clearance decreased 38% (179 ± 95 μm, p =0.003) in the 15.0 mm lens, 30% (170 ± 79 μm, p<0.001) in the 18.0 mm lens, and 20% (161± 72 μm, p<0.001) in the 18.2 mm lens. At 2 hours lens clearance was reduced 40% (121 ± 70 μm, p<0.001) in the 15.0mm lens, 39%(149 ± 78 μm, p<0.001) in the 18.0 mm lens, and 29% (143 ± 89 μm, P<0.001) in the 18.2 mm lens.
The majority of lens settling over 2 hours occurred within the first 40 minutes for larger diameter lenses. The different diameter lenses and lens designs settled at different rates. The potential for lens settling needs to be considered when fitting these lenses.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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