Soft DW & EW lens materials are basically the same, & so too are their permeability. In EW, low oxygen & insufficient soft lens hydration & cleanliness during sleep increases significantly the probability of infections & inflammatory tissue reactions in relation to the continuous duration of wear Microbial Keratitis is 10-15 times more common with EW as with DW. The vast majority of contact lens clinical researchers advise most patients against soft lens EW, except for occasional periods of short duration.