On paper, it is easy to list the many advantages that rigid gas-permeable (RGP) lenses have to offer over hydrogel contact lenses. One of their most important advantages is their good optical quality, since they mask all irregularities of the corneal surface, correcting higher-order aberrations (Dorronsoro et al. 2003). Another benefit of RGP lenses is the potential for high oxygen transmissibility, making them suitable for both daily-wear (DW) and extendedwear (EW) modalities. Hence even tear film exchange is superior to that of hydrogel lenses, which is beneficial for oxygen delivery to the cornea (Burger 1974) and for removal of tear debris and metabolic waste (Key 1990).