Changes in Mini-scleral Lens Parameters after Repetitive Ethylene Oxide Sterilization

ABSTRACT

Purpose@#We analyzed changes in mini-scleral lens parameters after repetitive ethylene oxide (EO) sterilization. @*Methods@#We measured the base curve radius (BCR), the optical power, the central lens thickness (CLT), and the overall lens diameter (OLD) of 67 basic, oblate-type mini-scleral lenses (Onefit A; BIUMTEC, Seoul, Korea) before and after three repeats of EO sterilization at 2-week intervals. The sterilization process (15 hours in duration) included a core step featuring exposure to gaseous EO for 180 minutes at 1.5 bar and 56°C. @*Results@#The BCR changes in the basic type of mini-scleral lens after EO sterilization were -0.011 ± 0.004 mm, -0.024 ± 0.005 mm, and -0.021 ± 0.005 mm for the first, second, and third sterilizations, respectively; all changes were significant. None of optical power, CLT, or OLD were affected by EO sterilization. We found no significant correlation between any baseline value and the change thereof after sterilization. @*Conclusions@#Repeated EO sterilization of mini-scleral lenses did not change the optical power, CLT, or OLD, but significantly reduced the BCR. EO should not be used to sterilize mini-scleral lenses.