Clinicians prescribing scleral lenses can reassure patients that cleaning their lenses won’t damage them, even long-term, according to new research. A research team from the University of Houston and the University of California, Berkeley found that manually cleaning conventional and wavefront-guided scleral lenses for a year didn’t cause any significant changes in optical aberrations or base curves.

Their study assessed how 12 months of manual cleaning affected 12 scleral lenses with various designs, including a -5.00D defocus lens, a -5.00D defocus lens with -0.153μm vertical coma and a -5.00D defocus lens with a full custom wavefront-guided correction 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, which resulted in 378 cleanings of each lens. Researchers optically profiled lens aberrations and measured base curve at baseline and after every 42nd cleaning. Additionally, the study compared the differences in wavefront error and base curve radii associated with cleaning.

For the experimental lenses, the median change in spherical dioptric power was +0.01D and the median change in wavefront error was 0.013μm.

All lenses exhibited changes of less than one-eighth equivalent diopters. In the three wavefront-guided lenses, the median percentage change in wavefront error was 0.96%. Although all lenses exhibiting a change in their base curve radius, the researchers noted it was less than the American National Standards Institute tolerance of 0.05mm and the median change was 0.00mm.

Based on these negligible changes, conventional and wavefront-guided lenses should not have to be replaced because of changes to the optics or base curve of the lens induced by the manual cleaning process after having undergone a recommended cleaning schedule of one year, the study noted.