Dk/L and corneal hypoxia: part 1. the rising rate of exchange

Recently, the ongoing drive for still higher lens transmissibilities (Dk/L) has reached new levels of success. Emerging hybrids (e.g., “highly permeable hydrogel” materials1) showing the potential for Dk/Ls of 100 × 10⁻⁹ (cm/sec) (mL O₂/mL mm/Hg), and possibly higher, are joined by evolving generations of rigid gas permeable (RGP) lenses now challenging the “200 barrier” of transmissibility.2

But, with these higher Dk/Ls has come a clearer view of the cornea’s responses to more moderate realms of hypoxia and what transmissibility investments may be required to reduce those chronic levels still further.