Clinical investigation of the Paraperm EW rigid gas-permeable contact lens. 
Paraperm EW is a high oxygen flux silicone/acrylate rigid lens material currently under clinical investigation for extended wear.  The purpose of this paper is to report the clinical findings after 12 months of a 2-year investigation of 18 patients fitted with this material.  Fifteen were successfully wearing Paraperm EW lenses at 1 year.  The only significant clinical finding was keratometric flattening at the 1-month visit.  It was concluded that the Paraperm EW lens was durable, comfortable, and provided excellent visual acuity during the course of this investigation without inducing any of the ocular complications sometimes associated with extended wear of hydrogel lenses.