Paraperm® EW lens for extended wear

This paper reports the results of 372 patients fit with the Paraperm EW rigid gas permeable lens for extended wear. This lens material is a copolymer derived from siloxane and methylmethacrylate with an oxygen permeability (Dk) of 56 X 10^-11 at 37°C. At the end of 1 year, 270 patients had completed the study with 94.8% achieving 20/25 or better vision. Complications included a 12.3% incidence of superficial limbal keratitis with staining, a 3.1% incidence of conjunctival injection, and a 1.5% incidence of observable corneal edema. The lens appears to be a significant addition to the possibilities available for fitting extended wear patients or those who desire occasional overnight lens wear.