Quantifying the Optical and Physical Consequences of Daily Cleaning on Conventional and Wavefront-guided Scleral
Sarah M Wilting1, Gareth D Hastings, Lan Chi Nguyen1
1University of Houston College of Optometry, Houston, Texas.
Significance:
An equivalent 12 months of cleaning did not induce significant changes in the optical aberrations or base curves of scleral lenses.
Purpose:
This study aimed to test whether an equivalent of 12 months of manual cleaning alters the optical and physical properties of conventional and wavefront-guided scleral lenses.
Methods:
Twelve scleral lenses (four repeats of three designs, termed A, B, and C) were manufactured in Boston XO material: design A, -5.00 D defocus; design B, -5.00 D defocus with -0.153-μm vertical coma; and design C, -5.00 D defocus with a full custom wavefront-guided correction (second to fifth Zernike radial orders) of an eye with severe keratoconus. One lens of each design group served as a control and was not cleaned. To simulate a year of cleaning, seven individuals cleaned nine lenses (three from each group) twice a day for 27 days using the palm technique and commercially available cleaners, resulting in 378 cleanings of each lens. Lens aberrations were optically profiled and base curve radii were measured at baseline and after every 42nd cleaning. Differences in higher-order root mean square (HORMS) wavefront error and base curve radii associated with cleaning were compared with clinical benchmarks and using sign tests.
Results:
For the experimental lenses, median change in Seidel spherical dioptric power was +0.01 D (maximum, +0.025 D). Median change in HORMS wavefront error was 0.013 μm (maximum, 0.019 μm). All lenses exhibited HORMS changes less than one-eighth equivalent diopters (P = .002). Median percentage change in HORMS wavefront error in the three wavefront-guided lenses was 0.96% (maximum, 1.25%). Median change in base curve radii was 0.00 mm, with all lenses exhibiting changes (P = .002), less than the American National Standards Institute tolerance of 0.05 mm.
Conclusions:
Cleaning over an equivalent 12-month period did not induce clinically significant changes in the optical or base curve properties of conventional or wavefront-guided scleral lenses.
