Quantifying the Optical, Physical, and Predicted Visual Consequences of Daily Cleaning on Conventional and Wavefront-Guided Scleral Lenses

Date

2021-05

Journal Title

Journal ISSN

Volume Title

Publisher

Abstract

Purpose: To test whether an equivalent of 12 months of manual cleaning alters optical aberrations, base curve or predicted visual performance of conventional and wavefront-guided scleral contact lenses. Methods: Twelve scleral lenses (4 repeats of 3 designs, A-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; Design C: –5.00 D defocus with a full custom wavefront-guided (WFG) correction (2nd - 5th 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, 7 individuals cleaned 9 lenses (3 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 (WFE) and base curve radii associated with cleaning were compared to clinical benchmarks using sign tests. Given that aberrations interact with one another, the change over time in the visual Strehl ratio was used to estimate the predicted change in visual acuity associated with manual cleaning. Results: For the experimental lenses, median change in Seidel spherical dioptric power was +0.01D (range: +0.001D to +0.023D). Median change in HORMS WFE was 0.013 µm (range:0.008 to 0.019 µm). Median percent change in HORMS in the three wavefront-guided lenses was 0.96% (max = 1.25%). Median change in base curve radii was 0.00 mm, with all lenses exhibiting changes (P = .002), less than the ANSI tolerance of 0.05 mm. The predicted change in visual acuity derived from the visual Strehl ratio for all coma and wavefront-guided lenses was less than 2.5 letters. Conclusion: Cleaning scleral contact lenses in a manner consistent with the method and number of cleanings that would occur over a 12-month period did not induce clinically significant changes in the optical properties, base curve radii of curvature or predicted changes in visual acuity of conventional or wavefront-guided scleral lenses.

Description

Keywords

Scleral lenses, Wavefront-guided optics

Citation

Portions of this document appear in: Wilting, Sarah M., Gareth D. Hastings, Lan Chi Nguyen, Matthew J. Kauffman, Elizabeth S. Bell, Chuan Hu, Sujata Rijal, and Jason D. Marsack. "Quantifying the Optical and Physical Consequences of Daily Cleaning on Conventional and Wavefront-guided Scleral Lenses." Optometry and Vision Science 97, no. 9 (2020): 754-760.