Rigid lenses: the pump is still alive and well

Abstract

With the continuing advancement of rigid gas permeable lenses, not much is heard about the traditional tear pump anymore (the bulk flow movment of tears and gases driven by lid action on the lens). The decline of edema with increasing Dk's has markedly reduced the fitters dependance on this mechanism as the sole source of corneal oxygen, yet, have the pumps benefits entirely disappeared What portion of the corneas oxygen may still be derived by this mechanical (pump) means, and what other benefits do rigid lens sytems accrue through such bulk-flow exchange.